git subrepo clone --branch=sono6good https://github.com/essej/JUCE.git deps/juce

subrepo:
  subdir:   "deps/juce"
  merged:   "b13f9084e"
upstream:
  origin:   "https://github.com/essej/JUCE.git"
  branch:   "sono6good"
  commit:   "b13f9084e"
git-subrepo:
  version:  "0.4.3"
  origin:   "https://github.com/ingydotnet/git-subrepo.git"
  commit:   "2f68596"
This commit is contained in:
essej
2022-04-18 17:51:22 -04:00
parent 63e175fee6
commit 25bd5d8adb
3210 changed files with 1045392 additions and 0 deletions

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/*
* Copyright (c) 2006-2010 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2ChainAndCircleContact.h"
#include "../../Common/b2BlockAllocator.h"
#include "../b2Fixture.h"
#include "../../Collision/Shapes/b2ChainShape.h"
#include "../../Collision/Shapes/b2EdgeShape.h"
#include <new>
using namespace std;
b2Contact* b2ChainAndCircleContact::Create(b2Fixture* fixtureA, int32 indexA, b2Fixture* fixtureB, int32 indexB, b2BlockAllocator* allocator)
{
void* mem = allocator->Allocate(sizeof(b2ChainAndCircleContact));
return new (mem) b2ChainAndCircleContact(fixtureA, indexA, fixtureB, indexB);
}
void b2ChainAndCircleContact::Destroy(b2Contact* contact, b2BlockAllocator* allocator)
{
((b2ChainAndCircleContact*)contact)->~b2ChainAndCircleContact();
allocator->Free(contact, sizeof(b2ChainAndCircleContact));
}
b2ChainAndCircleContact::b2ChainAndCircleContact(b2Fixture* fixtureA, int32 indexA, b2Fixture* fixtureB, int32 indexB)
: b2Contact(fixtureA, indexA, fixtureB, indexB)
{
b2Assert(m_fixtureA->GetType() == b2Shape::e_chain);
b2Assert(m_fixtureB->GetType() == b2Shape::e_circle);
}
void b2ChainAndCircleContact::Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB)
{
b2ChainShape* chain = (b2ChainShape*)m_fixtureA->GetShape();
b2EdgeShape edge;
chain->GetChildEdge(&edge, m_indexA);
b2CollideEdgeAndCircle( manifold, &edge, xfA,
(b2CircleShape*)m_fixtureB->GetShape(), xfB);
}

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_CHAIN_AND_CIRCLE_CONTACT_H
#define B2_CHAIN_AND_CIRCLE_CONTACT_H
#include "b2Contact.h"
class b2BlockAllocator;
class b2ChainAndCircleContact : public b2Contact
{
public:
static b2Contact* Create( b2Fixture* fixtureA, int32 indexA,
b2Fixture* fixtureB, int32 indexB, b2BlockAllocator* allocator);
static void Destroy(b2Contact* contact, b2BlockAllocator* allocator);
b2ChainAndCircleContact(b2Fixture* fixtureA, int32 indexA, b2Fixture* fixtureB, int32 indexB);
~b2ChainAndCircleContact() {}
void Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB);
};
#endif

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/*
* Copyright (c) 2006-2010 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2ChainAndPolygonContact.h"
#include "../../Common/b2BlockAllocator.h"
#include "../b2Fixture.h"
#include "../../Collision/Shapes/b2ChainShape.h"
#include "../../Collision/Shapes/b2EdgeShape.h"
#include <new>
using namespace std;
b2Contact* b2ChainAndPolygonContact::Create(b2Fixture* fixtureA, int32 indexA, b2Fixture* fixtureB, int32 indexB, b2BlockAllocator* allocator)
{
void* mem = allocator->Allocate(sizeof(b2ChainAndPolygonContact));
return new (mem) b2ChainAndPolygonContact(fixtureA, indexA, fixtureB, indexB);
}
void b2ChainAndPolygonContact::Destroy(b2Contact* contact, b2BlockAllocator* allocator)
{
((b2ChainAndPolygonContact*)contact)->~b2ChainAndPolygonContact();
allocator->Free(contact, sizeof(b2ChainAndPolygonContact));
}
b2ChainAndPolygonContact::b2ChainAndPolygonContact(b2Fixture* fixtureA, int32 indexA, b2Fixture* fixtureB, int32 indexB)
: b2Contact(fixtureA, indexA, fixtureB, indexB)
{
b2Assert(m_fixtureA->GetType() == b2Shape::e_chain);
b2Assert(m_fixtureB->GetType() == b2Shape::e_polygon);
}
void b2ChainAndPolygonContact::Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB)
{
b2ChainShape* chain = (b2ChainShape*)m_fixtureA->GetShape();
b2EdgeShape edge;
chain->GetChildEdge(&edge, m_indexA);
b2CollideEdgeAndPolygon( manifold, &edge, xfA,
(b2PolygonShape*)m_fixtureB->GetShape(), xfB);
}

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_CHAIN_AND_POLYGON_CONTACT_H
#define B2_CHAIN_AND_POLYGON_CONTACT_H
#include "b2Contact.h"
class b2BlockAllocator;
class b2ChainAndPolygonContact : public b2Contact
{
public:
static b2Contact* Create( b2Fixture* fixtureA, int32 indexA,
b2Fixture* fixtureB, int32 indexB, b2BlockAllocator* allocator);
static void Destroy(b2Contact* contact, b2BlockAllocator* allocator);
b2ChainAndPolygonContact(b2Fixture* fixtureA, int32 indexA, b2Fixture* fixtureB, int32 indexB);
~b2ChainAndPolygonContact() {}
void Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB);
};
#endif

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2CircleContact.h"
#include "../b2Body.h"
#include "../b2Fixture.h"
#include "../b2WorldCallbacks.h"
#include "../../Common/b2BlockAllocator.h"
#include "../../Collision/b2TimeOfImpact.h"
#include <new>
using namespace std;
b2Contact* b2CircleContact::Create(b2Fixture* fixtureA, int32, b2Fixture* fixtureB, int32, b2BlockAllocator* allocator)
{
void* mem = allocator->Allocate(sizeof(b2CircleContact));
return new (mem) b2CircleContact(fixtureA, fixtureB);
}
void b2CircleContact::Destroy(b2Contact* contact, b2BlockAllocator* allocator)
{
((b2CircleContact*)contact)->~b2CircleContact();
allocator->Free(contact, sizeof(b2CircleContact));
}
b2CircleContact::b2CircleContact(b2Fixture* fixtureA, b2Fixture* fixtureB)
: b2Contact(fixtureA, 0, fixtureB, 0)
{
b2Assert(m_fixtureA->GetType() == b2Shape::e_circle);
b2Assert(m_fixtureB->GetType() == b2Shape::e_circle);
}
void b2CircleContact::Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB)
{
b2CollideCircles(manifold,
(b2CircleShape*)m_fixtureA->GetShape(), xfA,
(b2CircleShape*)m_fixtureB->GetShape(), xfB);
}

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_CIRCLE_CONTACT_H
#define B2_CIRCLE_CONTACT_H
#include "b2Contact.h"
class b2BlockAllocator;
class b2CircleContact : public b2Contact
{
public:
static b2Contact* Create( b2Fixture* fixtureA, int32 indexA,
b2Fixture* fixtureB, int32 indexB, b2BlockAllocator* allocator);
static void Destroy(b2Contact* contact, b2BlockAllocator* allocator);
b2CircleContact(b2Fixture* fixtureA, b2Fixture* fixtureB);
~b2CircleContact() {}
void Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB);
};
#endif

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2Contact.h"
#include "b2CircleContact.h"
#include "b2PolygonAndCircleContact.h"
#include "b2PolygonContact.h"
#include "b2EdgeAndCircleContact.h"
#include "b2EdgeAndPolygonContact.h"
#include "b2ChainAndCircleContact.h"
#include "b2ChainAndPolygonContact.h"
#include "b2ContactSolver.h"
#include "../../Collision/b2Collision.h"
#include "../../Collision/b2TimeOfImpact.h"
#include "../../Collision/Shapes/b2Shape.h"
#include "../../Common/b2BlockAllocator.h"
#include "../b2Body.h"
#include "../b2Fixture.h"
#include "../b2World.h"
b2ContactRegister b2Contact::s_registers[b2Shape::e_typeCount][b2Shape::e_typeCount];
bool b2Contact::s_initialized = false;
void b2Contact::InitializeRegisters()
{
AddType(b2CircleContact::Create, b2CircleContact::Destroy, b2Shape::e_circle, b2Shape::e_circle);
AddType(b2PolygonAndCircleContact::Create, b2PolygonAndCircleContact::Destroy, b2Shape::e_polygon, b2Shape::e_circle);
AddType(b2PolygonContact::Create, b2PolygonContact::Destroy, b2Shape::e_polygon, b2Shape::e_polygon);
AddType(b2EdgeAndCircleContact::Create, b2EdgeAndCircleContact::Destroy, b2Shape::e_edge, b2Shape::e_circle);
AddType(b2EdgeAndPolygonContact::Create, b2EdgeAndPolygonContact::Destroy, b2Shape::e_edge, b2Shape::e_polygon);
AddType(b2ChainAndCircleContact::Create, b2ChainAndCircleContact::Destroy, b2Shape::e_chain, b2Shape::e_circle);
AddType(b2ChainAndPolygonContact::Create, b2ChainAndPolygonContact::Destroy, b2Shape::e_chain, b2Shape::e_polygon);
}
void b2Contact::AddType(b2ContactCreateFcn* createFcn, b2ContactDestroyFcn* destoryFcn,
b2Shape::Type type1, b2Shape::Type type2)
{
b2Assert(0 <= type1 && type1 < b2Shape::e_typeCount);
b2Assert(0 <= type2 && type2 < b2Shape::e_typeCount);
s_registers[type1][type2].createFcn = createFcn;
s_registers[type1][type2].destroyFcn = destoryFcn;
s_registers[type1][type2].primary = true;
if (type1 != type2)
{
s_registers[type2][type1].createFcn = createFcn;
s_registers[type2][type1].destroyFcn = destoryFcn;
s_registers[type2][type1].primary = false;
}
}
b2Contact* b2Contact::Create(b2Fixture* fixtureA, int32 indexA, b2Fixture* fixtureB, int32 indexB, b2BlockAllocator* allocator)
{
if (s_initialized == false)
{
InitializeRegisters();
s_initialized = true;
}
b2Shape::Type type1 = fixtureA->GetType();
b2Shape::Type type2 = fixtureB->GetType();
b2Assert(0 <= type1 && type1 < b2Shape::e_typeCount);
b2Assert(0 <= type2 && type2 < b2Shape::e_typeCount);
b2ContactCreateFcn* createFcn = s_registers[type1][type2].createFcn;
if (createFcn)
{
if (s_registers[type1][type2].primary)
{
return createFcn(fixtureA, indexA, fixtureB, indexB, allocator);
}
else
{
return createFcn(fixtureB, indexB, fixtureA, indexA, allocator);
}
}
else
{
return NULL;
}
}
void b2Contact::Destroy(b2Contact* contact, b2BlockAllocator* allocator)
{
b2Assert(s_initialized == true);
if (contact->m_manifold.pointCount > 0)
{
contact->GetFixtureA()->GetBody()->SetAwake(true);
contact->GetFixtureB()->GetBody()->SetAwake(true);
}
b2Shape::Type typeA = contact->GetFixtureA()->GetType();
b2Shape::Type typeB = contact->GetFixtureB()->GetType();
b2Assert(0 <= typeA && typeB < b2Shape::e_typeCount);
b2Assert(0 <= typeA && typeB < b2Shape::e_typeCount);
b2ContactDestroyFcn* destroyFcn = s_registers[typeA][typeB].destroyFcn;
destroyFcn(contact, allocator);
}
b2Contact::b2Contact(b2Fixture* fA, int32 indexA, b2Fixture* fB, int32 indexB)
{
m_flags = e_enabledFlag;
m_fixtureA = fA;
m_fixtureB = fB;
m_indexA = indexA;
m_indexB = indexB;
m_manifold.pointCount = 0;
m_prev = NULL;
m_next = NULL;
m_nodeA.contact = NULL;
m_nodeA.prev = NULL;
m_nodeA.next = NULL;
m_nodeA.other = NULL;
m_nodeB.contact = NULL;
m_nodeB.prev = NULL;
m_nodeB.next = NULL;
m_nodeB.other = NULL;
m_toiCount = 0;
m_friction = b2MixFriction(m_fixtureA->m_friction, m_fixtureB->m_friction);
m_restitution = b2MixRestitution(m_fixtureA->m_restitution, m_fixtureB->m_restitution);
}
// Update the contact manifold and touching status.
// Note: do not assume the fixture AABBs are overlapping or are valid.
void b2Contact::Update(b2ContactListener* listener)
{
b2Manifold oldManifold = m_manifold;
// Re-enable this contact.
m_flags |= e_enabledFlag;
bool touching = false;
bool wasTouching = (m_flags & e_touchingFlag) == e_touchingFlag;
bool sensorA = m_fixtureA->IsSensor();
bool sensorB = m_fixtureB->IsSensor();
bool sensor = sensorA || sensorB;
b2Body* bodyA = m_fixtureA->GetBody();
b2Body* bodyB = m_fixtureB->GetBody();
const b2Transform& xfA = bodyA->GetTransform();
const b2Transform& xfB = bodyB->GetTransform();
// Is this contact a sensor?
if (sensor)
{
const b2Shape* shapeA = m_fixtureA->GetShape();
const b2Shape* shapeB = m_fixtureB->GetShape();
touching = b2TestOverlap(shapeA, m_indexA, shapeB, m_indexB, xfA, xfB);
// Sensors don't generate manifolds.
m_manifold.pointCount = 0;
}
else
{
Evaluate(&m_manifold, xfA, xfB);
touching = m_manifold.pointCount > 0;
// Match old contact ids to new contact ids and copy the
// stored impulses to warm start the solver.
for (int32 i = 0; i < m_manifold.pointCount; ++i)
{
b2ManifoldPoint* mp2 = m_manifold.points + i;
mp2->normalImpulse = 0.0f;
mp2->tangentImpulse = 0.0f;
b2ContactID id2 = mp2->id;
for (int32 j = 0; j < oldManifold.pointCount; ++j)
{
b2ManifoldPoint* mp1 = oldManifold.points + j;
if (mp1->id.key == id2.key)
{
mp2->normalImpulse = mp1->normalImpulse;
mp2->tangentImpulse = mp1->tangentImpulse;
break;
}
}
}
if (touching != wasTouching)
{
bodyA->SetAwake(true);
bodyB->SetAwake(true);
}
}
if (touching)
{
m_flags |= e_touchingFlag;
}
else
{
m_flags &= ~e_touchingFlag;
}
if (wasTouching == false && touching == true && listener)
{
listener->BeginContact(this);
}
if (wasTouching == true && touching == false && listener)
{
listener->EndContact(this);
}
if (sensor == false && touching && listener)
{
listener->PreSolve(this, &oldManifold);
}
}

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_CONTACT_H
#define B2_CONTACT_H
#include "../../Common/b2Math.h"
#include "../../Collision/b2Collision.h"
#include "../../Collision/Shapes/b2Shape.h"
#include "../b2Fixture.h"
class b2Body;
class b2Contact;
class b2Fixture;
class b2World;
class b2BlockAllocator;
class b2StackAllocator;
class b2ContactListener;
/// Friction mixing law. The idea is to allow either fixture to drive the restitution to zero.
/// For example, anything slides on ice.
inline float32 b2MixFriction(float32 friction1, float32 friction2)
{
return std::sqrt(friction1 * friction2);
}
/// Restitution mixing law. The idea is allow for anything to bounce off an inelastic surface.
/// For example, a superball bounces on anything.
inline float32 b2MixRestitution(float32 restitution1, float32 restitution2)
{
return restitution1 > restitution2 ? restitution1 : restitution2;
}
typedef b2Contact* b2ContactCreateFcn( b2Fixture* fixtureA, juce::int32 indexA,
b2Fixture* fixtureB, juce::int32 indexB,
b2BlockAllocator* allocator);
typedef void b2ContactDestroyFcn(b2Contact* contact, b2BlockAllocator* allocator);
struct b2ContactRegister
{
b2ContactCreateFcn* createFcn;
b2ContactDestroyFcn* destroyFcn;
bool primary;
};
/// A contact edge is used to connect bodies and contacts together
/// in a contact graph where each body is a node and each contact
/// is an edge. A contact edge belongs to a doubly linked list
/// maintained in each attached body. Each contact has two contact
/// nodes, one for each attached body.
struct b2ContactEdge
{
b2Body* other; ///< provides quick access to the other body attached.
b2Contact* contact; ///< the contact
b2ContactEdge* prev; ///< the previous contact edge in the body's contact list
b2ContactEdge* next; ///< the next contact edge in the body's contact list
};
/// The class manages contact between two shapes. A contact exists for each overlapping
/// AABB in the broad-phase (except if filtered). Therefore a contact object may exist
/// that has no contact points.
class b2Contact
{
public:
/// Get the contact manifold. Do not modify the manifold unless you understand the
/// internals of Box2D.
b2Manifold* GetManifold();
const b2Manifold* GetManifold() const;
/// Get the world manifold.
void GetWorldManifold(b2WorldManifold* worldManifold) const;
/// Is this contact touching?
bool IsTouching() const;
/// Enable/disable this contact. This can be used inside the pre-solve
/// contact listener. The contact is only disabled for the current
/// time step (or sub-step in continuous collisions).
void SetEnabled(bool flag);
/// Has this contact been disabled?
bool IsEnabled() const;
/// Get the next contact in the world's contact list.
b2Contact* GetNext();
const b2Contact* GetNext() const;
/// Get fixture A in this contact.
b2Fixture* GetFixtureA();
const b2Fixture* GetFixtureA() const;
/// Get the child primitive index for fixture A.
juce::int32 GetChildIndexA() const;
/// Get fixture B in this contact.
b2Fixture* GetFixtureB();
const b2Fixture* GetFixtureB() const;
/// Get the child primitive index for fixture B.
juce::int32 GetChildIndexB() const;
/// Override the default friction mixture. You can call this in b2ContactListener::PreSolve.
/// This value persists until set or reset.
void SetFriction(float32 friction);
/// Get the friction.
float32 GetFriction() const;
/// Reset the friction mixture to the default value.
void ResetFriction();
/// Override the default restitution mixture. You can call this in b2ContactListener::PreSolve.
/// The value persists until you set or reset.
void SetRestitution(float32 restitution);
/// Get the restitution.
float32 GetRestitution() const;
/// Reset the restitution to the default value.
void ResetRestitution();
/// Evaluate this contact with your own manifold and transforms.
virtual void Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB) = 0;
protected:
friend class b2ContactManager;
friend class b2World;
friend class b2ContactSolver;
friend class b2Body;
friend class b2Fixture;
// Flags stored in m_flags
enum
{
// Used when crawling contact graph when forming islands.
e_islandFlag = 0x0001,
// Set when the shapes are touching.
e_touchingFlag = 0x0002,
// This contact can be disabled (by user)
e_enabledFlag = 0x0004,
// This contact needs filtering because a fixture filter was changed.
e_filterFlag = 0x0008,
// This bullet contact had a TOI event
e_bulletHitFlag = 0x0010,
// This contact has a valid TOI in m_toi
e_toiFlag = 0x0020
};
/// Flag this contact for filtering. Filtering will occur the next time step.
void FlagForFiltering();
static void AddType(b2ContactCreateFcn* createFcn, b2ContactDestroyFcn* destroyFcn,
b2Shape::Type typeA, b2Shape::Type typeB);
static void InitializeRegisters();
static b2Contact* Create(b2Fixture* fixtureA, juce::int32 indexA, b2Fixture* fixtureB, juce::int32 indexB, b2BlockAllocator* allocator);
static void Destroy(b2Contact* contact, b2Shape::Type typeA, b2Shape::Type typeB, b2BlockAllocator* allocator);
static void Destroy(b2Contact* contact, b2BlockAllocator* allocator);
b2Contact() : m_fixtureA(NULL), m_fixtureB(NULL) {}
b2Contact(b2Fixture* fixtureA, juce::int32 indexA, b2Fixture* fixtureB, juce::int32 indexB);
virtual ~b2Contact() {}
void Update(b2ContactListener* listener);
static b2ContactRegister s_registers[b2Shape::e_typeCount][b2Shape::e_typeCount];
static bool s_initialized;
juce::uint32 m_flags;
// World pool and list pointers.
b2Contact* m_prev;
b2Contact* m_next;
// Nodes for connecting bodies.
b2ContactEdge m_nodeA;
b2ContactEdge m_nodeB;
b2Fixture* m_fixtureA;
b2Fixture* m_fixtureB;
juce::int32 m_indexA;
juce::int32 m_indexB;
b2Manifold m_manifold;
juce::int32 m_toiCount;
float32 m_toi;
float32 m_friction;
float32 m_restitution;
};
inline b2Manifold* b2Contact::GetManifold()
{
return &m_manifold;
}
inline const b2Manifold* b2Contact::GetManifold() const
{
return &m_manifold;
}
inline void b2Contact::GetWorldManifold(b2WorldManifold* worldManifold) const
{
const b2Body* bodyA = m_fixtureA->GetBody();
const b2Body* bodyB = m_fixtureB->GetBody();
const b2Shape* shapeA = m_fixtureA->GetShape();
const b2Shape* shapeB = m_fixtureB->GetShape();
worldManifold->Initialize(&m_manifold, bodyA->GetTransform(), shapeA->m_radius, bodyB->GetTransform(), shapeB->m_radius);
}
inline void b2Contact::SetEnabled(bool flag)
{
if (flag)
{
m_flags |= e_enabledFlag;
}
else
{
m_flags &= ~((unsigned int) e_enabledFlag);
}
}
inline bool b2Contact::IsEnabled() const
{
return (m_flags & e_enabledFlag) == e_enabledFlag;
}
inline bool b2Contact::IsTouching() const
{
return (m_flags & e_touchingFlag) == e_touchingFlag;
}
inline b2Contact* b2Contact::GetNext()
{
return m_next;
}
inline const b2Contact* b2Contact::GetNext() const
{
return m_next;
}
inline b2Fixture* b2Contact::GetFixtureA()
{
return m_fixtureA;
}
inline const b2Fixture* b2Contact::GetFixtureA() const
{
return m_fixtureA;
}
inline b2Fixture* b2Contact::GetFixtureB()
{
return m_fixtureB;
}
inline juce::int32 b2Contact::GetChildIndexA() const
{
return m_indexA;
}
inline const b2Fixture* b2Contact::GetFixtureB() const
{
return m_fixtureB;
}
inline juce::int32 b2Contact::GetChildIndexB() const
{
return m_indexB;
}
inline void b2Contact::FlagForFiltering()
{
m_flags |= e_filterFlag;
}
inline void b2Contact::SetFriction(float32 friction)
{
m_friction = friction;
}
inline float32 b2Contact::GetFriction() const
{
return m_friction;
}
inline void b2Contact::ResetFriction()
{
m_friction = b2MixFriction(m_fixtureA->m_friction, m_fixtureB->m_friction);
}
inline void b2Contact::SetRestitution(float32 restitution)
{
m_restitution = restitution;
}
inline float32 b2Contact::GetRestitution() const
{
return m_restitution;
}
inline void b2Contact::ResetRestitution()
{
m_restitution = b2MixRestitution(m_fixtureA->m_restitution, m_fixtureB->m_restitution);
}
#endif

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@ -0,0 +1,832 @@
/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2ContactSolver.h"
#include "b2Contact.h"
#include "../b2Body.h"
#include "../b2Fixture.h"
#include "../b2World.h"
#include "../../Common/b2StackAllocator.h"
#define B2_DEBUG_SOLVER 0
struct b2ContactPositionConstraint
{
b2Vec2 localPoints[b2_maxManifoldPoints];
b2Vec2 localNormal;
b2Vec2 localPoint;
int32 indexA;
int32 indexB;
float32 invMassA, invMassB;
b2Vec2 localCenterA, localCenterB;
float32 invIA, invIB;
b2Manifold::Type type;
float32 radiusA, radiusB;
int32 pointCount;
};
b2ContactSolver::b2ContactSolver(b2ContactSolverDef* def)
{
m_step = def->step;
m_allocator = def->allocator;
m_count = def->count;
m_positionConstraints = (b2ContactPositionConstraint*)m_allocator->Allocate(m_count * sizeof(b2ContactPositionConstraint));
m_velocityConstraints = (b2ContactVelocityConstraint*)m_allocator->Allocate(m_count * sizeof(b2ContactVelocityConstraint));
m_positions = def->positions;
m_velocities = def->velocities;
m_contacts = def->contacts;
// Initialize position independent portions of the constraints.
for (int32 i = 0; i < m_count; ++i)
{
b2Contact* contact = m_contacts[i];
b2Fixture* fixtureA = contact->m_fixtureA;
b2Fixture* fixtureB = contact->m_fixtureB;
b2Shape* shapeA = fixtureA->GetShape();
b2Shape* shapeB = fixtureB->GetShape();
float32 radiusA = shapeA->m_radius;
float32 radiusB = shapeB->m_radius;
b2Body* bodyA = fixtureA->GetBody();
b2Body* bodyB = fixtureB->GetBody();
b2Manifold* manifold = contact->GetManifold();
int32 pointCount = manifold->pointCount;
b2Assert(pointCount > 0);
b2ContactVelocityConstraint* vc = m_velocityConstraints + i;
vc->friction = contact->m_friction;
vc->restitution = contact->m_restitution;
vc->indexA = bodyA->m_islandIndex;
vc->indexB = bodyB->m_islandIndex;
vc->invMassA = bodyA->m_invMass;
vc->invMassB = bodyB->m_invMass;
vc->invIA = bodyA->m_invI;
vc->invIB = bodyB->m_invI;
vc->contactIndex = i;
vc->pointCount = pointCount;
vc->K.SetZero();
vc->normalMass.SetZero();
b2ContactPositionConstraint* pc = m_positionConstraints + i;
pc->indexA = bodyA->m_islandIndex;
pc->indexB = bodyB->m_islandIndex;
pc->invMassA = bodyA->m_invMass;
pc->invMassB = bodyB->m_invMass;
pc->localCenterA = bodyA->m_sweep.localCenter;
pc->localCenterB = bodyB->m_sweep.localCenter;
pc->invIA = bodyA->m_invI;
pc->invIB = bodyB->m_invI;
pc->localNormal = manifold->localNormal;
pc->localPoint = manifold->localPoint;
pc->pointCount = pointCount;
pc->radiusA = radiusA;
pc->radiusB = radiusB;
pc->type = manifold->type;
for (int32 j = 0; j < pointCount; ++j)
{
b2ManifoldPoint* cp = manifold->points + j;
b2VelocityConstraintPoint* vcp = vc->points + j;
if (m_step.warmStarting)
{
vcp->normalImpulse = m_step.dtRatio * cp->normalImpulse;
vcp->tangentImpulse = m_step.dtRatio * cp->tangentImpulse;
}
else
{
vcp->normalImpulse = 0.0f;
vcp->tangentImpulse = 0.0f;
}
vcp->rA.SetZero();
vcp->rB.SetZero();
vcp->normalMass = 0.0f;
vcp->tangentMass = 0.0f;
vcp->velocityBias = 0.0f;
pc->localPoints[j] = cp->localPoint;
}
}
}
b2ContactSolver::~b2ContactSolver()
{
m_allocator->Free(m_velocityConstraints);
m_allocator->Free(m_positionConstraints);
}
// Initialize position dependent portions of the velocity constraints.
void b2ContactSolver::InitializeVelocityConstraints()
{
for (int32 i = 0; i < m_count; ++i)
{
b2ContactVelocityConstraint* vc = m_velocityConstraints + i;
b2ContactPositionConstraint* pc = m_positionConstraints + i;
float32 radiusA = pc->radiusA;
float32 radiusB = pc->radiusB;
b2Manifold* manifold = m_contacts[vc->contactIndex]->GetManifold();
int32 indexA = vc->indexA;
int32 indexB = vc->indexB;
float32 mA = vc->invMassA;
float32 mB = vc->invMassB;
float32 iA = vc->invIA;
float32 iB = vc->invIB;
b2Vec2 localCenterA = pc->localCenterA;
b2Vec2 localCenterB = pc->localCenterB;
b2Vec2 cA = m_positions[indexA].c;
float32 aA = m_positions[indexA].a;
b2Vec2 vA = m_velocities[indexA].v;
float32 wA = m_velocities[indexA].w;
b2Vec2 cB = m_positions[indexB].c;
float32 aB = m_positions[indexB].a;
b2Vec2 vB = m_velocities[indexB].v;
float32 wB = m_velocities[indexB].w;
b2Assert(manifold->pointCount > 0);
b2Transform xfA, xfB;
xfA.q.Set(aA);
xfB.q.Set(aB);
xfA.p = cA - b2Mul(xfA.q, localCenterA);
xfB.p = cB - b2Mul(xfB.q, localCenterB);
b2WorldManifold worldManifold;
worldManifold.Initialize(manifold, xfA, radiusA, xfB, radiusB);
vc->normal = worldManifold.normal;
int32 pointCount = vc->pointCount;
for (int32 j = 0; j < pointCount; ++j)
{
b2VelocityConstraintPoint* vcp = vc->points + j;
vcp->rA = worldManifold.points[j] - cA;
vcp->rB = worldManifold.points[j] - cB;
float32 rnA = b2Cross(vcp->rA, vc->normal);
float32 rnB = b2Cross(vcp->rB, vc->normal);
float32 kNormal = mA + mB + iA * rnA * rnA + iB * rnB * rnB;
vcp->normalMass = kNormal > 0.0f ? 1.0f / kNormal : 0.0f;
b2Vec2 tangent = b2Cross(vc->normal, 1.0f);
float32 rtA = b2Cross(vcp->rA, tangent);
float32 rtB = b2Cross(vcp->rB, tangent);
float32 kTangent = mA + mB + iA * rtA * rtA + iB * rtB * rtB;
vcp->tangentMass = kTangent > 0.0f ? 1.0f / kTangent : 0.0f;
// Setup a velocity bias for restitution.
vcp->velocityBias = 0.0f;
float32 vRel = b2Dot(vc->normal, vB + b2Cross(wB, vcp->rB) - vA - b2Cross(wA, vcp->rA));
if (vRel < -b2_velocityThreshold)
{
vcp->velocityBias = -vc->restitution * vRel;
}
}
// If we have two points, then prepare the block solver.
if (vc->pointCount == 2)
{
b2VelocityConstraintPoint* vcp1 = vc->points + 0;
b2VelocityConstraintPoint* vcp2 = vc->points + 1;
float32 rn1A = b2Cross(vcp1->rA, vc->normal);
float32 rn1B = b2Cross(vcp1->rB, vc->normal);
float32 rn2A = b2Cross(vcp2->rA, vc->normal);
float32 rn2B = b2Cross(vcp2->rB, vc->normal);
float32 k11 = mA + mB + iA * rn1A * rn1A + iB * rn1B * rn1B;
float32 k22 = mA + mB + iA * rn2A * rn2A + iB * rn2B * rn2B;
float32 k12 = mA + mB + iA * rn1A * rn2A + iB * rn1B * rn2B;
// Ensure a reasonable condition number.
const float32 k_maxConditionNumber = 1000.0f;
if (k11 * k11 < k_maxConditionNumber * (k11 * k22 - k12 * k12))
{
// K is safe to invert.
vc->K.ex.Set(k11, k12);
vc->K.ey.Set(k12, k22);
vc->normalMass = vc->K.GetInverse();
}
else
{
// The constraints are redundant, just use one.
// TODO_ERIN use deepest?
vc->pointCount = 1;
}
}
}
}
void b2ContactSolver::WarmStart()
{
// Warm start.
for (int32 i = 0; i < m_count; ++i)
{
b2ContactVelocityConstraint* vc = m_velocityConstraints + i;
int32 indexA = vc->indexA;
int32 indexB = vc->indexB;
float32 mA = vc->invMassA;
float32 iA = vc->invIA;
float32 mB = vc->invMassB;
float32 iB = vc->invIB;
int32 pointCount = vc->pointCount;
b2Vec2 vA = m_velocities[indexA].v;
float32 wA = m_velocities[indexA].w;
b2Vec2 vB = m_velocities[indexB].v;
float32 wB = m_velocities[indexB].w;
b2Vec2 normal = vc->normal;
b2Vec2 tangent = b2Cross(normal, 1.0f);
for (int32 j = 0; j < pointCount; ++j)
{
b2VelocityConstraintPoint* vcp = vc->points + j;
b2Vec2 P = vcp->normalImpulse * normal + vcp->tangentImpulse * tangent;
wA -= iA * b2Cross(vcp->rA, P);
vA -= mA * P;
wB += iB * b2Cross(vcp->rB, P);
vB += mB * P;
}
m_velocities[indexA].v = vA;
m_velocities[indexA].w = wA;
m_velocities[indexB].v = vB;
m_velocities[indexB].w = wB;
}
}
void b2ContactSolver::SolveVelocityConstraints()
{
for (int32 i = 0; i < m_count; ++i)
{
b2ContactVelocityConstraint* vc = m_velocityConstraints + i;
int32 indexA = vc->indexA;
int32 indexB = vc->indexB;
float32 mA = vc->invMassA;
float32 iA = vc->invIA;
float32 mB = vc->invMassB;
float32 iB = vc->invIB;
int32 pointCount = vc->pointCount;
b2Vec2 vA = m_velocities[indexA].v;
float32 wA = m_velocities[indexA].w;
b2Vec2 vB = m_velocities[indexB].v;
float32 wB = m_velocities[indexB].w;
b2Vec2 normal = vc->normal;
b2Vec2 tangent = b2Cross(normal, 1.0f);
float32 friction = vc->friction;
b2Assert(pointCount == 1 || pointCount == 2);
// Solve tangent constraints first because non-penetration is more important
// than friction.
for (int32 j = 0; j < pointCount; ++j)
{
b2VelocityConstraintPoint* vcp = vc->points + j;
// Relative velocity at contact
b2Vec2 dv = vB + b2Cross(wB, vcp->rB) - vA - b2Cross(wA, vcp->rA);
// Compute tangent force
float32 vt = b2Dot(dv, tangent);
float32 lambda = vcp->tangentMass * (-vt);
// b2Clamp the accumulated force
float32 maxFriction = friction * vcp->normalImpulse;
float32 newImpulse = b2Clamp(vcp->tangentImpulse + lambda, -maxFriction, maxFriction);
lambda = newImpulse - vcp->tangentImpulse;
vcp->tangentImpulse = newImpulse;
// Apply contact impulse
b2Vec2 P = lambda * tangent;
vA -= mA * P;
wA -= iA * b2Cross(vcp->rA, P);
vB += mB * P;
wB += iB * b2Cross(vcp->rB, P);
}
// Solve normal constraints
if (vc->pointCount == 1)
{
b2VelocityConstraintPoint* vcp = vc->points + 0;
// Relative velocity at contact
b2Vec2 dv = vB + b2Cross(wB, vcp->rB) - vA - b2Cross(wA, vcp->rA);
// Compute normal impulse
float32 vn = b2Dot(dv, normal);
float32 lambda = -vcp->normalMass * (vn - vcp->velocityBias);
// b2Clamp the accumulated impulse
float32 newImpulse = b2Max(vcp->normalImpulse + lambda, 0.0f);
lambda = newImpulse - vcp->normalImpulse;
vcp->normalImpulse = newImpulse;
// Apply contact impulse
b2Vec2 P = lambda * normal;
vA -= mA * P;
wA -= iA * b2Cross(vcp->rA, P);
vB += mB * P;
wB += iB * b2Cross(vcp->rB, P);
}
else
{
// Block solver developed in collaboration with Dirk Gregorius (back in 01/07 on Box2D_Lite).
// Build the mini LCP for this contact patch
//
// vn = A * x + b, vn >= 0, , vn >= 0, x >= 0 and vn_i * x_i = 0 with i = 1..2
//
// A = J * W * JT and J = ( -n, -r1 x n, n, r2 x n )
// b = vn0 - velocityBias
//
// The system is solved using the "Total enumeration method" (s. Murty). The complementary constraint vn_i * x_i
// implies that we must have in any solution either vn_i = 0 or x_i = 0. So for the 2D contact problem the cases
// vn1 = 0 and vn2 = 0, x1 = 0 and x2 = 0, x1 = 0 and vn2 = 0, x2 = 0 and vn1 = 0 need to be tested. The first valid
// solution that satisfies the problem is chosen.
//
// In order to account of the accumulated impulse 'a' (because of the iterative nature of the solver which only requires
// that the accumulated impulse is clamped and not the incremental impulse) we change the impulse variable (x_i).
//
// Substitute:
//
// x = a + d
//
// a := old total impulse
// x := new total impulse
// d := incremental impulse
//
// For the current iteration we extend the formula for the incremental impulse
// to compute the new total impulse:
//
// vn = A * d + b
// = A * (x - a) + b
// = A * x + b - A * a
// = A * x + b'
// b' = b - A * a;
b2VelocityConstraintPoint* cp1 = vc->points + 0;
b2VelocityConstraintPoint* cp2 = vc->points + 1;
b2Vec2 a(cp1->normalImpulse, cp2->normalImpulse);
b2Assert(a.x >= 0.0f && a.y >= 0.0f);
// Relative velocity at contact
b2Vec2 dv1 = vB + b2Cross(wB, cp1->rB) - vA - b2Cross(wA, cp1->rA);
b2Vec2 dv2 = vB + b2Cross(wB, cp2->rB) - vA - b2Cross(wA, cp2->rA);
// Compute normal velocity
float32 vn1 = b2Dot(dv1, normal);
float32 vn2 = b2Dot(dv2, normal);
b2Vec2 b;
b.x = vn1 - cp1->velocityBias;
b.y = vn2 - cp2->velocityBias;
// Compute b'
b -= b2Mul(vc->K, a);
const float32 k_errorTol = 1e-3f;
B2_NOT_USED(k_errorTol);
for (;;)
{
//
// Case 1: vn = 0
//
// 0 = A * x + b'
//
// Solve for x:
//
// x = - inv(A) * b'
//
b2Vec2 x = - b2Mul(vc->normalMass, b);
if (x.x >= 0.0f && x.y >= 0.0f)
{
// Get the incremental impulse
b2Vec2 d = x - a;
// Apply incremental impulse
b2Vec2 P1 = d.x * normal;
b2Vec2 P2 = d.y * normal;
vA -= mA * (P1 + P2);
wA -= iA * (b2Cross(cp1->rA, P1) + b2Cross(cp2->rA, P2));
vB += mB * (P1 + P2);
wB += iB * (b2Cross(cp1->rB, P1) + b2Cross(cp2->rB, P2));
// Accumulate
cp1->normalImpulse = x.x;
cp2->normalImpulse = x.y;
#if B2_DEBUG_SOLVER == 1
// Postconditions
dv1 = vB + b2Cross(wB, cp1->rB) - vA - b2Cross(wA, cp1->rA);
dv2 = vB + b2Cross(wB, cp2->rB) - vA - b2Cross(wA, cp2->rA);
// Compute normal velocity
vn1 = b2Dot(dv1, normal);
vn2 = b2Dot(dv2, normal);
b2Assert(b2Abs(vn1 - cp1->velocityBias) < k_errorTol);
b2Assert(b2Abs(vn2 - cp2->velocityBias) < k_errorTol);
#endif
break;
}
//
// Case 2: vn1 = 0 and x2 = 0
//
// 0 = a11 * x1 + a12 * 0 + b1'
// vn2 = a21 * x1 + a22 * 0 + b2'
//
x.x = - cp1->normalMass * b.x;
x.y = 0.0f;
//vn1 = 0.0f;
vn2 = vc->K.ex.y * x.x + b.y;
if (x.x >= 0.0f && vn2 >= 0.0f)
{
// Get the incremental impulse
b2Vec2 d = x - a;
// Apply incremental impulse
b2Vec2 P1 = d.x * normal;
b2Vec2 P2 = d.y * normal;
vA -= mA * (P1 + P2);
wA -= iA * (b2Cross(cp1->rA, P1) + b2Cross(cp2->rA, P2));
vB += mB * (P1 + P2);
wB += iB * (b2Cross(cp1->rB, P1) + b2Cross(cp2->rB, P2));
// Accumulate
cp1->normalImpulse = x.x;
cp2->normalImpulse = x.y;
#if B2_DEBUG_SOLVER == 1
// Postconditions
dv1 = vB + b2Cross(wB, cp1->rB) - vA - b2Cross(wA, cp1->rA);
// Compute normal velocity
vn1 = b2Dot(dv1, normal);
b2Assert(b2Abs(vn1 - cp1->velocityBias) < k_errorTol);
#endif
break;
}
//
// Case 3: vn2 = 0 and x1 = 0
//
// vn1 = a11 * 0 + a12 * x2 + b1'
// 0 = a21 * 0 + a22 * x2 + b2'
//
x.x = 0.0f;
x.y = - cp2->normalMass * b.y;
vn1 = vc->K.ey.x * x.y + b.x;
//vn2 = 0.0f;
if (x.y >= 0.0f && vn1 >= 0.0f)
{
// Resubstitute for the incremental impulse
b2Vec2 d = x - a;
// Apply incremental impulse
b2Vec2 P1 = d.x * normal;
b2Vec2 P2 = d.y * normal;
vA -= mA * (P1 + P2);
wA -= iA * (b2Cross(cp1->rA, P1) + b2Cross(cp2->rA, P2));
vB += mB * (P1 + P2);
wB += iB * (b2Cross(cp1->rB, P1) + b2Cross(cp2->rB, P2));
// Accumulate
cp1->normalImpulse = x.x;
cp2->normalImpulse = x.y;
#if B2_DEBUG_SOLVER == 1
// Postconditions
dv2 = vB + b2Cross(wB, cp2->rB) - vA - b2Cross(wA, cp2->rA);
// Compute normal velocity
vn2 = b2Dot(dv2, normal);
b2Assert(b2Abs(vn2 - cp2->velocityBias) < k_errorTol);
#endif
break;
}
//
// Case 4: x1 = 0 and x2 = 0
//
// vn1 = b1
// vn2 = b2;
x.x = 0.0f;
x.y = 0.0f;
vn1 = b.x;
vn2 = b.y;
if (vn1 >= 0.0f && vn2 >= 0.0f )
{
// Resubstitute for the incremental impulse
b2Vec2 d = x - a;
// Apply incremental impulse
b2Vec2 P1 = d.x * normal;
b2Vec2 P2 = d.y * normal;
vA -= mA * (P1 + P2);
wA -= iA * (b2Cross(cp1->rA, P1) + b2Cross(cp2->rA, P2));
vB += mB * (P1 + P2);
wB += iB * (b2Cross(cp1->rB, P1) + b2Cross(cp2->rB, P2));
// Accumulate
cp1->normalImpulse = x.x;
cp2->normalImpulse = x.y;
break;
}
// No solution, give up. This is hit sometimes, but it doesn't seem to matter.
break;
}
}
m_velocities[indexA].v = vA;
m_velocities[indexA].w = wA;
m_velocities[indexB].v = vB;
m_velocities[indexB].w = wB;
}
}
void b2ContactSolver::StoreImpulses()
{
for (int32 i = 0; i < m_count; ++i)
{
b2ContactVelocityConstraint* vc = m_velocityConstraints + i;
b2Manifold* manifold = m_contacts[vc->contactIndex]->GetManifold();
for (int32 j = 0; j < vc->pointCount; ++j)
{
manifold->points[j].normalImpulse = vc->points[j].normalImpulse;
manifold->points[j].tangentImpulse = vc->points[j].tangentImpulse;
}
}
}
struct b2PositionSolverManifold
{
void Initialize(b2ContactPositionConstraint* pc, const b2Transform& xfA, const b2Transform& xfB, int32 index)
{
b2Assert(pc->pointCount > 0);
switch (pc->type)
{
case b2Manifold::e_circles:
{
b2Vec2 pointA = b2Mul(xfA, pc->localPoint);
b2Vec2 pointB = b2Mul(xfB, pc->localPoints[0]);
normal = pointB - pointA;
normal.Normalize();
point = 0.5f * (pointA + pointB);
separation = b2Dot(pointB - pointA, normal) - pc->radiusA - pc->radiusB;
}
break;
case b2Manifold::e_faceA:
{
normal = b2Mul(xfA.q, pc->localNormal);
b2Vec2 planePoint = b2Mul(xfA, pc->localPoint);
b2Vec2 clipPoint = b2Mul(xfB, pc->localPoints[index]);
separation = b2Dot(clipPoint - planePoint, normal) - pc->radiusA - pc->radiusB;
point = clipPoint;
}
break;
case b2Manifold::e_faceB:
{
normal = b2Mul(xfB.q, pc->localNormal);
b2Vec2 planePoint = b2Mul(xfB, pc->localPoint);
b2Vec2 clipPoint = b2Mul(xfA, pc->localPoints[index]);
separation = b2Dot(clipPoint - planePoint, normal) - pc->radiusA - pc->radiusB;
point = clipPoint;
// Ensure normal points from A to B
normal = -normal;
}
break;
}
}
b2Vec2 normal;
b2Vec2 point;
float32 separation;
};
// Sequential solver.
bool b2ContactSolver::SolvePositionConstraints()
{
float32 minSeparation = 0.0f;
for (int32 i = 0; i < m_count; ++i)
{
b2ContactPositionConstraint* pc = m_positionConstraints + i;
int32 indexA = pc->indexA;
int32 indexB = pc->indexB;
b2Vec2 localCenterA = pc->localCenterA;
float32 mA = pc->invMassA;
float32 iA = pc->invIA;
b2Vec2 localCenterB = pc->localCenterB;
float32 mB = pc->invMassB;
float32 iB = pc->invIB;
int32 pointCount = pc->pointCount;
b2Vec2 cA = m_positions[indexA].c;
float32 aA = m_positions[indexA].a;
b2Vec2 cB = m_positions[indexB].c;
float32 aB = m_positions[indexB].a;
// Solve normal constraints
for (int32 j = 0; j < pointCount; ++j)
{
b2Transform xfA, xfB;
xfA.q.Set(aA);
xfB.q.Set(aB);
xfA.p = cA - b2Mul(xfA.q, localCenterA);
xfB.p = cB - b2Mul(xfB.q, localCenterB);
b2PositionSolverManifold psm;
psm.Initialize(pc, xfA, xfB, j);
b2Vec2 normal = psm.normal;
b2Vec2 point = psm.point;
float32 separation = psm.separation;
b2Vec2 rA = point - cA;
b2Vec2 rB = point - cB;
// Track max constraint error.
minSeparation = b2Min(minSeparation, separation);
// Prevent large corrections and allow slop.
float32 C = b2Clamp(b2_baumgarte * (separation + b2_linearSlop), -b2_maxLinearCorrection, 0.0f);
// Compute the effective mass.
float32 rnA = b2Cross(rA, normal);
float32 rnB = b2Cross(rB, normal);
float32 K = mA + mB + iA * rnA * rnA + iB * rnB * rnB;
// Compute normal impulse
float32 impulse = K > 0.0f ? - C / K : 0.0f;
b2Vec2 P = impulse * normal;
cA -= mA * P;
aA -= iA * b2Cross(rA, P);
cB += mB * P;
aB += iB * b2Cross(rB, P);
}
m_positions[indexA].c = cA;
m_positions[indexA].a = aA;
m_positions[indexB].c = cB;
m_positions[indexB].a = aB;
}
// We can't expect minSpeparation >= -b2_linearSlop because we don't
// push the separation above -b2_linearSlop.
return minSeparation >= -3.0f * b2_linearSlop;
}
// Sequential position solver for position constraints.
bool b2ContactSolver::SolveTOIPositionConstraints(int32 toiIndexA, int32 toiIndexB)
{
float32 minSeparation = 0.0f;
for (int32 i = 0; i < m_count; ++i)
{
b2ContactPositionConstraint* pc = m_positionConstraints + i;
int32 indexA = pc->indexA;
int32 indexB = pc->indexB;
b2Vec2 localCenterA = pc->localCenterA;
b2Vec2 localCenterB = pc->localCenterB;
int32 pointCount = pc->pointCount;
float32 mA = 0.0f;
float32 iA = 0.0f;
if (indexA == toiIndexA || indexA == toiIndexB)
{
mA = pc->invMassA;
iA = pc->invIA;
}
float32 mB = pc->invMassB;
float32 iB = pc->invIB;
if (indexB == toiIndexA || indexB == toiIndexB)
{
mB = pc->invMassB;
iB = pc->invIB;
}
b2Vec2 cA = m_positions[indexA].c;
float32 aA = m_positions[indexA].a;
b2Vec2 cB = m_positions[indexB].c;
float32 aB = m_positions[indexB].a;
// Solve normal constraints
for (int32 j = 0; j < pointCount; ++j)
{
b2Transform xfA, xfB;
xfA.q.Set(aA);
xfB.q.Set(aB);
xfA.p = cA - b2Mul(xfA.q, localCenterA);
xfB.p = cB - b2Mul(xfB.q, localCenterB);
b2PositionSolverManifold psm;
psm.Initialize(pc, xfA, xfB, j);
b2Vec2 normal = psm.normal;
b2Vec2 point = psm.point;
float32 separation = psm.separation;
b2Vec2 rA = point - cA;
b2Vec2 rB = point - cB;
// Track max constraint error.
minSeparation = b2Min(minSeparation, separation);
// Prevent large corrections and allow slop.
float32 C = b2Clamp(b2_toiBaugarte * (separation + b2_linearSlop), -b2_maxLinearCorrection, 0.0f);
// Compute the effective mass.
float32 rnA = b2Cross(rA, normal);
float32 rnB = b2Cross(rB, normal);
float32 K = mA + mB + iA * rnA * rnA + iB * rnB * rnB;
// Compute normal impulse
float32 impulse = K > 0.0f ? - C / K : 0.0f;
b2Vec2 P = impulse * normal;
cA -= mA * P;
aA -= iA * b2Cross(rA, P);
cB += mB * P;
aB += iB * b2Cross(rB, P);
}
m_positions[indexA].c = cA;
m_positions[indexA].a = aA;
m_positions[indexB].c = cB;
m_positions[indexB].a = aB;
}
// We can't expect minSpeparation >= -b2_linearSlop because we don't
// push the separation above -b2_linearSlop.
return minSeparation >= -1.5f * b2_linearSlop;
}

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_CONTACT_SOLVER_H
#define B2_CONTACT_SOLVER_H
#include "../../Common/b2Math.h"
#include "../../Collision/b2Collision.h"
#include "../b2TimeStep.h"
class b2Contact;
class b2Body;
class b2StackAllocator;
struct b2ContactPositionConstraint;
struct b2VelocityConstraintPoint
{
b2Vec2 rA;
b2Vec2 rB;
float32 normalImpulse;
float32 tangentImpulse;
float32 normalMass;
float32 tangentMass;
float32 velocityBias;
};
struct b2ContactVelocityConstraint
{
b2VelocityConstraintPoint points[b2_maxManifoldPoints];
b2Vec2 normal;
b2Mat22 normalMass;
b2Mat22 K;
int32 indexA;
int32 indexB;
float32 invMassA, invMassB;
float32 invIA, invIB;
float32 friction;
float32 restitution;
int32 pointCount;
int32 contactIndex;
};
struct b2ContactSolverDef
{
b2TimeStep step;
b2Contact** contacts;
int32 count;
b2Position* positions;
b2Velocity* velocities;
b2StackAllocator* allocator;
};
class b2ContactSolver
{
public:
b2ContactSolver(b2ContactSolverDef* def);
~b2ContactSolver();
void InitializeVelocityConstraints();
void WarmStart();
void SolveVelocityConstraints();
void StoreImpulses();
bool SolvePositionConstraints();
bool SolveTOIPositionConstraints(int32 toiIndexA, int32 toiIndexB);
b2TimeStep m_step;
b2Position* m_positions;
b2Velocity* m_velocities;
b2StackAllocator* m_allocator;
b2ContactPositionConstraint* m_positionConstraints;
b2ContactVelocityConstraint* m_velocityConstraints;
b2Contact** m_contacts;
int m_count;
};
#endif

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/*
* Copyright (c) 2006-2010 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2EdgeAndCircleContact.h"
#include "../../Common/b2BlockAllocator.h"
#include "../b2Fixture.h"
#include <new>
using namespace std;
b2Contact* b2EdgeAndCircleContact::Create(b2Fixture* fixtureA, int32, b2Fixture* fixtureB, int32, b2BlockAllocator* allocator)
{
void* mem = allocator->Allocate(sizeof(b2EdgeAndCircleContact));
return new (mem) b2EdgeAndCircleContact(fixtureA, fixtureB);
}
void b2EdgeAndCircleContact::Destroy(b2Contact* contact, b2BlockAllocator* allocator)
{
((b2EdgeAndCircleContact*)contact)->~b2EdgeAndCircleContact();
allocator->Free(contact, sizeof(b2EdgeAndCircleContact));
}
b2EdgeAndCircleContact::b2EdgeAndCircleContact(b2Fixture* fixtureA, b2Fixture* fixtureB)
: b2Contact(fixtureA, 0, fixtureB, 0)
{
b2Assert(m_fixtureA->GetType() == b2Shape::e_edge);
b2Assert(m_fixtureB->GetType() == b2Shape::e_circle);
}
void b2EdgeAndCircleContact::Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB)
{
b2CollideEdgeAndCircle( manifold,
(b2EdgeShape*)m_fixtureA->GetShape(), xfA,
(b2CircleShape*)m_fixtureB->GetShape(), xfB);
}

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_EDGE_AND_CIRCLE_CONTACT_H
#define B2_EDGE_AND_CIRCLE_CONTACT_H
#include "b2Contact.h"
class b2BlockAllocator;
class b2EdgeAndCircleContact : public b2Contact
{
public:
static b2Contact* Create( b2Fixture* fixtureA, int32 indexA,
b2Fixture* fixtureB, int32 indexB, b2BlockAllocator* allocator);
static void Destroy(b2Contact* contact, b2BlockAllocator* allocator);
b2EdgeAndCircleContact(b2Fixture* fixtureA, b2Fixture* fixtureB);
~b2EdgeAndCircleContact() {}
void Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB);
};
#endif

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/*
* Copyright (c) 2006-2010 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2EdgeAndPolygonContact.h"
#include "../../Common/b2BlockAllocator.h"
#include "../b2Fixture.h"
#include <new>
using namespace std;
b2Contact* b2EdgeAndPolygonContact::Create(b2Fixture* fixtureA, int32, b2Fixture* fixtureB, int32, b2BlockAllocator* allocator)
{
void* mem = allocator->Allocate(sizeof(b2EdgeAndPolygonContact));
return new (mem) b2EdgeAndPolygonContact(fixtureA, fixtureB);
}
void b2EdgeAndPolygonContact::Destroy(b2Contact* contact, b2BlockAllocator* allocator)
{
((b2EdgeAndPolygonContact*)contact)->~b2EdgeAndPolygonContact();
allocator->Free(contact, sizeof(b2EdgeAndPolygonContact));
}
b2EdgeAndPolygonContact::b2EdgeAndPolygonContact(b2Fixture* fixtureA, b2Fixture* fixtureB)
: b2Contact(fixtureA, 0, fixtureB, 0)
{
b2Assert(m_fixtureA->GetType() == b2Shape::e_edge);
b2Assert(m_fixtureB->GetType() == b2Shape::e_polygon);
}
void b2EdgeAndPolygonContact::Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB)
{
b2CollideEdgeAndPolygon( manifold,
(b2EdgeShape*)m_fixtureA->GetShape(), xfA,
(b2PolygonShape*)m_fixtureB->GetShape(), xfB);
}

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_EDGE_AND_POLYGON_CONTACT_H
#define B2_EDGE_AND_POLYGON_CONTACT_H
#include "b2Contact.h"
class b2BlockAllocator;
class b2EdgeAndPolygonContact : public b2Contact
{
public:
static b2Contact* Create( b2Fixture* fixtureA, int32 indexA,
b2Fixture* fixtureB, int32 indexB, b2BlockAllocator* allocator);
static void Destroy(b2Contact* contact, b2BlockAllocator* allocator);
b2EdgeAndPolygonContact(b2Fixture* fixtureA, b2Fixture* fixtureB);
~b2EdgeAndPolygonContact() {}
void Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB);
};
#endif

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2PolygonAndCircleContact.h"
#include "../../Common/b2BlockAllocator.h"
#include "../b2Fixture.h"
#include <new>
using namespace std;
b2Contact* b2PolygonAndCircleContact::Create(b2Fixture* fixtureA, int32, b2Fixture* fixtureB, int32, b2BlockAllocator* allocator)
{
void* mem = allocator->Allocate(sizeof(b2PolygonAndCircleContact));
return new (mem) b2PolygonAndCircleContact(fixtureA, fixtureB);
}
void b2PolygonAndCircleContact::Destroy(b2Contact* contact, b2BlockAllocator* allocator)
{
((b2PolygonAndCircleContact*)contact)->~b2PolygonAndCircleContact();
allocator->Free(contact, sizeof(b2PolygonAndCircleContact));
}
b2PolygonAndCircleContact::b2PolygonAndCircleContact(b2Fixture* fixtureA, b2Fixture* fixtureB)
: b2Contact(fixtureA, 0, fixtureB, 0)
{
b2Assert(m_fixtureA->GetType() == b2Shape::e_polygon);
b2Assert(m_fixtureB->GetType() == b2Shape::e_circle);
}
void b2PolygonAndCircleContact::Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB)
{
b2CollidePolygonAndCircle( manifold,
(b2PolygonShape*)m_fixtureA->GetShape(), xfA,
(b2CircleShape*)m_fixtureB->GetShape(), xfB);
}

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_POLYGON_AND_CIRCLE_CONTACT_H
#define B2_POLYGON_AND_CIRCLE_CONTACT_H
#include "b2Contact.h"
class b2BlockAllocator;
class b2PolygonAndCircleContact : public b2Contact
{
public:
static b2Contact* Create(b2Fixture* fixtureA, int32 indexA, b2Fixture* fixtureB, int32 indexB, b2BlockAllocator* allocator);
static void Destroy(b2Contact* contact, b2BlockAllocator* allocator);
b2PolygonAndCircleContact(b2Fixture* fixtureA, b2Fixture* fixtureB);
~b2PolygonAndCircleContact() {}
void Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB);
};
#endif

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2PolygonContact.h"
#include "../../Common/b2BlockAllocator.h"
#include "../../Collision/b2TimeOfImpact.h"
#include "../b2Body.h"
#include "../b2Fixture.h"
#include "../b2WorldCallbacks.h"
#include <new>
using namespace std;
b2Contact* b2PolygonContact::Create(b2Fixture* fixtureA, int32, b2Fixture* fixtureB, int32, b2BlockAllocator* allocator)
{
void* mem = allocator->Allocate(sizeof(b2PolygonContact));
return new (mem) b2PolygonContact(fixtureA, fixtureB);
}
void b2PolygonContact::Destroy(b2Contact* contact, b2BlockAllocator* allocator)
{
((b2PolygonContact*)contact)->~b2PolygonContact();
allocator->Free(contact, sizeof(b2PolygonContact));
}
b2PolygonContact::b2PolygonContact(b2Fixture* fixtureA, b2Fixture* fixtureB)
: b2Contact(fixtureA, 0, fixtureB, 0)
{
b2Assert(m_fixtureA->GetType() == b2Shape::e_polygon);
b2Assert(m_fixtureB->GetType() == b2Shape::e_polygon);
}
void b2PolygonContact::Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB)
{
b2CollidePolygons( manifold,
(b2PolygonShape*)m_fixtureA->GetShape(), xfA,
(b2PolygonShape*)m_fixtureB->GetShape(), xfB);
}

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_POLYGON_CONTACT_H
#define B2_POLYGON_CONTACT_H
#include "b2Contact.h"
class b2BlockAllocator;
class b2PolygonContact : public b2Contact
{
public:
static b2Contact* Create( b2Fixture* fixtureA, int32 indexA,
b2Fixture* fixtureB, int32 indexB, b2BlockAllocator* allocator);
static void Destroy(b2Contact* contact, b2BlockAllocator* allocator);
b2PolygonContact(b2Fixture* fixtureA, b2Fixture* fixtureB);
~b2PolygonContact() {}
void Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB);
};
#endif

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2DistanceJoint.h"
#include "../b2Body.h"
#include "../b2TimeStep.h"
// 1-D constrained system
// m (v2 - v1) = lambda
// v2 + (beta/h) * x1 + gamma * lambda = 0, gamma has units of inverse mass.
// x2 = x1 + h * v2
// 1-D mass-damper-spring system
// m (v2 - v1) + h * d * v2 + h * k *
// C = norm(p2 - p1) - L
// u = (p2 - p1) / norm(p2 - p1)
// Cdot = dot(u, v2 + cross(w2, r2) - v1 - cross(w1, r1))
// J = [-u -cross(r1, u) u cross(r2, u)]
// K = J * invM * JT
// = invMass1 + invI1 * cross(r1, u)^2 + invMass2 + invI2 * cross(r2, u)^2
void b2DistanceJointDef::Initialize(b2Body* b1, b2Body* b2,
const b2Vec2& anchor1, const b2Vec2& anchor2)
{
bodyA = b1;
bodyB = b2;
localAnchorA = bodyA->GetLocalPoint(anchor1);
localAnchorB = bodyB->GetLocalPoint(anchor2);
b2Vec2 d = anchor2 - anchor1;
length = d.Length();
}
b2DistanceJoint::b2DistanceJoint(const b2DistanceJointDef* def)
: b2Joint(def)
{
m_localAnchorA = def->localAnchorA;
m_localAnchorB = def->localAnchorB;
m_length = def->length;
m_frequencyHz = def->frequencyHz;
m_dampingRatio = def->dampingRatio;
m_impulse = 0.0f;
m_gamma = 0.0f;
m_bias = 0.0f;
}
void b2DistanceJoint::InitVelocityConstraints(const b2SolverData& data)
{
m_indexA = m_bodyA->m_islandIndex;
m_indexB = m_bodyB->m_islandIndex;
m_localCenterA = m_bodyA->m_sweep.localCenter;
m_localCenterB = m_bodyB->m_sweep.localCenter;
m_invMassA = m_bodyA->m_invMass;
m_invMassB = m_bodyB->m_invMass;
m_invIA = m_bodyA->m_invI;
m_invIB = m_bodyB->m_invI;
b2Vec2 cA = data.positions[m_indexA].c;
float32 aA = data.positions[m_indexA].a;
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
b2Rot qA(aA), qB(aB);
m_rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
m_rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
m_u = cB + m_rB - cA - m_rA;
// Handle singularity.
float32 length = m_u.Length();
if (length > b2_linearSlop)
{
m_u *= 1.0f / length;
}
else
{
m_u.Set(0.0f, 0.0f);
}
float32 crAu = b2Cross(m_rA, m_u);
float32 crBu = b2Cross(m_rB, m_u);
float32 invMass = m_invMassA + m_invIA * crAu * crAu + m_invMassB + m_invIB * crBu * crBu;
// Compute the effective mass matrix.
m_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
if (m_frequencyHz > 0.0f)
{
float32 C = length - m_length;
// Frequency
float32 omega = 2.0f * b2_pi * m_frequencyHz;
// Damping coefficient
float32 d = 2.0f * m_mass * m_dampingRatio * omega;
// Spring stiffness
float32 k = m_mass * omega * omega;
// magic formulas
float32 h = data.step.dt;
m_gamma = h * (d + h * k);
m_gamma = m_gamma != 0.0f ? 1.0f / m_gamma : 0.0f;
m_bias = C * h * k * m_gamma;
invMass += m_gamma;
m_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
}
else
{
m_gamma = 0.0f;
m_bias = 0.0f;
}
if (data.step.warmStarting)
{
// Scale the impulse to support a variable time step.
m_impulse *= data.step.dtRatio;
b2Vec2 P = m_impulse * m_u;
vA -= m_invMassA * P;
wA -= m_invIA * b2Cross(m_rA, P);
vB += m_invMassB * P;
wB += m_invIB * b2Cross(m_rB, P);
}
else
{
m_impulse = 0.0f;
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
void b2DistanceJoint::SolveVelocityConstraints(const b2SolverData& data)
{
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
// Cdot = dot(u, v + cross(w, r))
b2Vec2 vpA = vA + b2Cross(wA, m_rA);
b2Vec2 vpB = vB + b2Cross(wB, m_rB);
float32 Cdot = b2Dot(m_u, vpB - vpA);
float32 impulse = -m_mass * (Cdot + m_bias + m_gamma * m_impulse);
m_impulse += impulse;
b2Vec2 P = impulse * m_u;
vA -= m_invMassA * P;
wA -= m_invIA * b2Cross(m_rA, P);
vB += m_invMassB * P;
wB += m_invIB * b2Cross(m_rB, P);
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
bool b2DistanceJoint::SolvePositionConstraints(const b2SolverData& data)
{
if (m_frequencyHz > 0.0f)
{
// There is no position correction for soft distance constraints.
return true;
}
b2Vec2 cA = data.positions[m_indexA].c;
float32 aA = data.positions[m_indexA].a;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Rot qA(aA), qB(aB);
b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
b2Vec2 u = cB + rB - cA - rA;
float32 length = u.Normalize();
float32 C = length - m_length;
C = b2Clamp(C, -b2_maxLinearCorrection, b2_maxLinearCorrection);
float32 impulse = -m_mass * C;
b2Vec2 P = impulse * u;
cA -= m_invMassA * P;
aA -= m_invIA * b2Cross(rA, P);
cB += m_invMassB * P;
aB += m_invIB * b2Cross(rB, P);
data.positions[m_indexA].c = cA;
data.positions[m_indexA].a = aA;
data.positions[m_indexB].c = cB;
data.positions[m_indexB].a = aB;
return b2Abs(C) < b2_linearSlop;
}
b2Vec2 b2DistanceJoint::GetAnchorA() const
{
return m_bodyA->GetWorldPoint(m_localAnchorA);
}
b2Vec2 b2DistanceJoint::GetAnchorB() const
{
return m_bodyB->GetWorldPoint(m_localAnchorB);
}
b2Vec2 b2DistanceJoint::GetReactionForce(float32 inv_dt) const
{
b2Vec2 F = (inv_dt * m_impulse) * m_u;
return F;
}
float32 b2DistanceJoint::GetReactionTorque(float32 inv_dt) const
{
B2_NOT_USED(inv_dt);
return 0.0f;
}
void b2DistanceJoint::Dump()
{
int32 indexA = m_bodyA->m_islandIndex;
int32 indexB = m_bodyB->m_islandIndex;
b2Log(" b2DistanceJointDef jd;\n");
b2Log(" jd.bodyA = bodies[%d];\n", indexA);
b2Log(" jd.bodyB = bodies[%d];\n", indexB);
b2Log(" jd.collideConnected = bool(%d);\n", m_collideConnected);
b2Log(" jd.localAnchorA.Set(%.15lef, %.15lef);\n", m_localAnchorA.x, m_localAnchorA.y);
b2Log(" jd.localAnchorB.Set(%.15lef, %.15lef);\n", m_localAnchorB.x, m_localAnchorB.y);
b2Log(" jd.length = %.15lef;\n", m_length);
b2Log(" jd.frequencyHz = %.15lef;\n", m_frequencyHz);
b2Log(" jd.dampingRatio = %.15lef;\n", m_dampingRatio);
b2Log(" joints[%d] = m_world->CreateJoint(&jd);\n", m_index);
}

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/*
* Copyright (c) 2006-2007 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_DISTANCE_JOINT_H
#define B2_DISTANCE_JOINT_H
#include "b2Joint.h"
/// Distance joint definition. This requires defining an
/// anchor point on both bodies and the non-zero length of the
/// distance joint. The definition uses local anchor points
/// so that the initial configuration can violate the constraint
/// slightly. This helps when saving and loading a game.
/// @warning Do not use a zero or short length.
struct b2DistanceJointDef : public b2JointDef
{
b2DistanceJointDef()
{
type = e_distanceJoint;
localAnchorA.Set(0.0f, 0.0f);
localAnchorB.Set(0.0f, 0.0f);
length = 1.0f;
frequencyHz = 0.0f;
dampingRatio = 0.0f;
}
/// Initialize the bodies, anchors, and length using the world
/// anchors.
void Initialize(b2Body* bodyA, b2Body* bodyB,
const b2Vec2& anchorA, const b2Vec2& anchorB);
/// The local anchor point relative to bodyA's origin.
b2Vec2 localAnchorA;
/// The local anchor point relative to bodyB's origin.
b2Vec2 localAnchorB;
/// The natural length between the anchor points.
float32 length;
/// The mass-spring-damper frequency in Hertz. A value of 0
/// disables softness.
float32 frequencyHz;
/// The damping ratio. 0 = no damping, 1 = critical damping.
float32 dampingRatio;
};
/// A distance joint constrains two points on two bodies
/// to remain at a fixed distance from each other. You can view
/// this as a massless, rigid rod.
class b2DistanceJoint : public b2Joint
{
public:
b2Vec2 GetAnchorA() const;
b2Vec2 GetAnchorB() const;
/// Get the reaction force given the inverse time step.
/// Unit is N.
b2Vec2 GetReactionForce(float32 inv_dt) const;
/// Get the reaction torque given the inverse time step.
/// Unit is N*m. This is always zero for a distance joint.
float32 GetReactionTorque(float32 inv_dt) const;
/// The local anchor point relative to bodyA's origin.
const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
/// The local anchor point relative to bodyB's origin.
const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
/// Set/get the natural length.
/// Manipulating the length can lead to non-physical behavior when the frequency is zero.
void SetLength(float32 length);
float32 GetLength() const;
/// Set/get frequency in Hz.
void SetFrequency(float32 hz);
float32 GetFrequency() const;
/// Set/get damping ratio.
void SetDampingRatio(float32 ratio);
float32 GetDampingRatio() const;
/// Dump joint to dmLog
void Dump();
protected:
friend class b2Joint;
b2DistanceJoint(const b2DistanceJointDef* data);
void InitVelocityConstraints(const b2SolverData& data);
void SolveVelocityConstraints(const b2SolverData& data);
bool SolvePositionConstraints(const b2SolverData& data);
float32 m_frequencyHz;
float32 m_dampingRatio;
float32 m_bias;
// Solver shared
b2Vec2 m_localAnchorA;
b2Vec2 m_localAnchorB;
float32 m_gamma;
float32 m_impulse;
float32 m_length;
// Solver temp
juce::int32 m_indexA;
juce::int32 m_indexB;
b2Vec2 m_u;
b2Vec2 m_rA;
b2Vec2 m_rB;
b2Vec2 m_localCenterA;
b2Vec2 m_localCenterB;
float32 m_invMassA;
float32 m_invMassB;
float32 m_invIA;
float32 m_invIB;
float32 m_mass;
};
inline void b2DistanceJoint::SetLength(float32 length)
{
m_length = length;
}
inline float32 b2DistanceJoint::GetLength() const
{
return m_length;
}
inline void b2DistanceJoint::SetFrequency(float32 hz)
{
m_frequencyHz = hz;
}
inline float32 b2DistanceJoint::GetFrequency() const
{
return m_frequencyHz;
}
inline void b2DistanceJoint::SetDampingRatio(float32 ratio)
{
m_dampingRatio = ratio;
}
inline float32 b2DistanceJoint::GetDampingRatio() const
{
return m_dampingRatio;
}
#endif

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2FrictionJoint.h"
#include "../b2Body.h"
#include "../b2TimeStep.h"
// Point-to-point constraint
// Cdot = v2 - v1
// = v2 + cross(w2, r2) - v1 - cross(w1, r1)
// J = [-I -r1_skew I r2_skew ]
// Identity used:
// w k % (rx i + ry j) = w * (-ry i + rx j)
// Angle constraint
// Cdot = w2 - w1
// J = [0 0 -1 0 0 1]
// K = invI1 + invI2
void b2FrictionJointDef::Initialize(b2Body* bA, b2Body* bB, const b2Vec2& anchor)
{
bodyA = bA;
bodyB = bB;
localAnchorA = bodyA->GetLocalPoint(anchor);
localAnchorB = bodyB->GetLocalPoint(anchor);
}
b2FrictionJoint::b2FrictionJoint(const b2FrictionJointDef* def)
: b2Joint(def)
{
m_localAnchorA = def->localAnchorA;
m_localAnchorB = def->localAnchorB;
m_linearImpulse.SetZero();
m_angularImpulse = 0.0f;
m_maxForce = def->maxForce;
m_maxTorque = def->maxTorque;
}
void b2FrictionJoint::InitVelocityConstraints(const b2SolverData& data)
{
m_indexA = m_bodyA->m_islandIndex;
m_indexB = m_bodyB->m_islandIndex;
m_localCenterA = m_bodyA->m_sweep.localCenter;
m_localCenterB = m_bodyB->m_sweep.localCenter;
m_invMassA = m_bodyA->m_invMass;
m_invMassB = m_bodyB->m_invMass;
m_invIA = m_bodyA->m_invI;
m_invIB = m_bodyB->m_invI;
float32 aA = data.positions[m_indexA].a;
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
float32 aB = data.positions[m_indexB].a;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
b2Rot qA(aA), qB(aB);
// Compute the effective mass matrix.
m_rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
m_rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
// J = [-I -r1_skew I r2_skew]
// [ 0 -1 0 1]
// r_skew = [-ry; rx]
// Matlab
// K = [ mA+r1y^2*iA+mB+r2y^2*iB, -r1y*iA*r1x-r2y*iB*r2x, -r1y*iA-r2y*iB]
// [ -r1y*iA*r1x-r2y*iB*r2x, mA+r1x^2*iA+mB+r2x^2*iB, r1x*iA+r2x*iB]
// [ -r1y*iA-r2y*iB, r1x*iA+r2x*iB, iA+iB]
float32 mA = m_invMassA, mB = m_invMassB;
float32 iA = m_invIA, iB = m_invIB;
b2Mat22 K;
K.ex.x = mA + mB + iA * m_rA.y * m_rA.y + iB * m_rB.y * m_rB.y;
K.ex.y = -iA * m_rA.x * m_rA.y - iB * m_rB.x * m_rB.y;
K.ey.x = K.ex.y;
K.ey.y = mA + mB + iA * m_rA.x * m_rA.x + iB * m_rB.x * m_rB.x;
m_linearMass = K.GetInverse();
m_angularMass = iA + iB;
if (m_angularMass > 0.0f)
{
m_angularMass = 1.0f / m_angularMass;
}
if (data.step.warmStarting)
{
// Scale impulses to support a variable time step.
m_linearImpulse *= data.step.dtRatio;
m_angularImpulse *= data.step.dtRatio;
b2Vec2 P(m_linearImpulse.x, m_linearImpulse.y);
vA -= mA * P;
wA -= iA * (b2Cross(m_rA, P) + m_angularImpulse);
vB += mB * P;
wB += iB * (b2Cross(m_rB, P) + m_angularImpulse);
}
else
{
m_linearImpulse.SetZero();
m_angularImpulse = 0.0f;
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
void b2FrictionJoint::SolveVelocityConstraints(const b2SolverData& data)
{
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
float32 mA = m_invMassA, mB = m_invMassB;
float32 iA = m_invIA, iB = m_invIB;
float32 h = data.step.dt;
// Solve angular friction
{
float32 Cdot = wB - wA;
float32 impulse = -m_angularMass * Cdot;
float32 oldImpulse = m_angularImpulse;
float32 maxImpulse = h * m_maxTorque;
m_angularImpulse = b2Clamp(m_angularImpulse + impulse, -maxImpulse, maxImpulse);
impulse = m_angularImpulse - oldImpulse;
wA -= iA * impulse;
wB += iB * impulse;
}
// Solve linear friction
{
b2Vec2 Cdot = vB + b2Cross(wB, m_rB) - vA - b2Cross(wA, m_rA);
b2Vec2 impulse = -b2Mul(m_linearMass, Cdot);
b2Vec2 oldImpulse = m_linearImpulse;
m_linearImpulse += impulse;
float32 maxImpulse = h * m_maxForce;
if (m_linearImpulse.LengthSquared() > maxImpulse * maxImpulse)
{
m_linearImpulse.Normalize();
m_linearImpulse *= maxImpulse;
}
impulse = m_linearImpulse - oldImpulse;
vA -= mA * impulse;
wA -= iA * b2Cross(m_rA, impulse);
vB += mB * impulse;
wB += iB * b2Cross(m_rB, impulse);
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
bool b2FrictionJoint::SolvePositionConstraints(const b2SolverData& data)
{
B2_NOT_USED(data);
return true;
}
b2Vec2 b2FrictionJoint::GetAnchorA() const
{
return m_bodyA->GetWorldPoint(m_localAnchorA);
}
b2Vec2 b2FrictionJoint::GetAnchorB() const
{
return m_bodyB->GetWorldPoint(m_localAnchorB);
}
b2Vec2 b2FrictionJoint::GetReactionForce(float32 inv_dt) const
{
return inv_dt * m_linearImpulse;
}
float32 b2FrictionJoint::GetReactionTorque(float32 inv_dt) const
{
return inv_dt * m_angularImpulse;
}
void b2FrictionJoint::SetMaxForce(float32 force)
{
b2Assert(b2IsValid(force) && force >= 0.0f);
m_maxForce = force;
}
float32 b2FrictionJoint::GetMaxForce() const
{
return m_maxForce;
}
void b2FrictionJoint::SetMaxTorque(float32 torque)
{
b2Assert(b2IsValid(torque) && torque >= 0.0f);
m_maxTorque = torque;
}
float32 b2FrictionJoint::GetMaxTorque() const
{
return m_maxTorque;
}
void b2FrictionJoint::Dump()
{
int32 indexA = m_bodyA->m_islandIndex;
int32 indexB = m_bodyB->m_islandIndex;
b2Log(" b2FrictionJointDef jd;\n");
b2Log(" jd.bodyA = bodies[%d];\n", indexA);
b2Log(" jd.bodyB = bodies[%d];\n", indexB);
b2Log(" jd.collideConnected = bool(%d);\n", m_collideConnected);
b2Log(" jd.localAnchorA.Set(%.15lef, %.15lef);\n", m_localAnchorA.x, m_localAnchorA.y);
b2Log(" jd.localAnchorB.Set(%.15lef, %.15lef);\n", m_localAnchorB.x, m_localAnchorB.y);
b2Log(" jd.maxForce = %.15lef;\n", m_maxForce);
b2Log(" jd.maxTorque = %.15lef;\n", m_maxTorque);
b2Log(" joints[%d] = m_world->CreateJoint(&jd);\n", m_index);
}

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/*
* Copyright (c) 2006-2007 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_FRICTION_JOINT_H
#define B2_FRICTION_JOINT_H
#include "b2Joint.h"
/// Friction joint definition.
struct b2FrictionJointDef : public b2JointDef
{
b2FrictionJointDef()
{
type = e_frictionJoint;
localAnchorA.SetZero();
localAnchorB.SetZero();
maxForce = 0.0f;
maxTorque = 0.0f;
}
/// Initialize the bodies, anchors, axis, and reference angle using the world
/// anchor and world axis.
void Initialize(b2Body* bodyA, b2Body* bodyB, const b2Vec2& anchor);
/// The local anchor point relative to bodyA's origin.
b2Vec2 localAnchorA;
/// The local anchor point relative to bodyB's origin.
b2Vec2 localAnchorB;
/// The maximum friction force in N.
float32 maxForce;
/// The maximum friction torque in N-m.
float32 maxTorque;
};
/// Friction joint. This is used for top-down friction.
/// It provides 2D translational friction and angular friction.
class b2FrictionJoint : public b2Joint
{
public:
b2Vec2 GetAnchorA() const;
b2Vec2 GetAnchorB() const;
b2Vec2 GetReactionForce(float32 inv_dt) const;
float32 GetReactionTorque(float32 inv_dt) const;
/// The local anchor point relative to bodyA's origin.
const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
/// The local anchor point relative to bodyB's origin.
const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
/// Set the maximum friction force in N.
void SetMaxForce(float32 force);
/// Get the maximum friction force in N.
float32 GetMaxForce() const;
/// Set the maximum friction torque in N*m.
void SetMaxTorque(float32 torque);
/// Get the maximum friction torque in N*m.
float32 GetMaxTorque() const;
/// Dump joint to dmLog
void Dump();
protected:
friend class b2Joint;
b2FrictionJoint(const b2FrictionJointDef* def);
void InitVelocityConstraints(const b2SolverData& data);
void SolveVelocityConstraints(const b2SolverData& data);
bool SolvePositionConstraints(const b2SolverData& data);
b2Vec2 m_localAnchorA;
b2Vec2 m_localAnchorB;
// Solver shared
b2Vec2 m_linearImpulse;
float32 m_angularImpulse;
float32 m_maxForce;
float32 m_maxTorque;
// Solver temp
juce::int32 m_indexA;
juce::int32 m_indexB;
b2Vec2 m_rA;
b2Vec2 m_rB;
b2Vec2 m_localCenterA;
b2Vec2 m_localCenterB;
float32 m_invMassA;
float32 m_invMassB;
float32 m_invIA;
float32 m_invIB;
b2Mat22 m_linearMass;
float32 m_angularMass;
};
#endif

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/*
* Copyright (c) 2007-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2GearJoint.h"
#include "b2RevoluteJoint.h"
#include "b2PrismaticJoint.h"
#include "../b2Body.h"
#include "../b2TimeStep.h"
// Gear Joint:
// C0 = (coordinate1 + ratio * coordinate2)_initial
// C = (coordinate1 + ratio * coordinate2) - C0 = 0
// J = [J1 ratio * J2]
// K = J * invM * JT
// = J1 * invM1 * J1T + ratio * ratio * J2 * invM2 * J2T
//
// Revolute:
// coordinate = rotation
// Cdot = angularVelocity
// J = [0 0 1]
// K = J * invM * JT = invI
//
// Prismatic:
// coordinate = dot(p - pg, ug)
// Cdot = dot(v + cross(w, r), ug)
// J = [ug cross(r, ug)]
// K = J * invM * JT = invMass + invI * cross(r, ug)^2
b2GearJoint::b2GearJoint(const b2GearJointDef* def)
: b2Joint(def)
{
m_joint1 = def->joint1;
m_joint2 = def->joint2;
m_typeA = m_joint1->GetType();
m_typeB = m_joint2->GetType();
b2Assert(m_typeA == e_revoluteJoint || m_typeA == e_prismaticJoint);
b2Assert(m_typeB == e_revoluteJoint || m_typeB == e_prismaticJoint);
float32 coordinateA, coordinateB;
// TODO_ERIN there might be some problem with the joint edges in b2Joint.
m_bodyC = m_joint1->GetBodyA();
m_bodyA = m_joint1->GetBodyB();
// Get geometry of joint1
b2Transform xfA = m_bodyA->m_xf;
float32 aA = m_bodyA->m_sweep.a;
b2Transform xfC = m_bodyC->m_xf;
float32 aC = m_bodyC->m_sweep.a;
if (m_typeA == e_revoluteJoint)
{
b2RevoluteJoint* revolute = (b2RevoluteJoint*)def->joint1;
m_localAnchorC = revolute->m_localAnchorA;
m_localAnchorA = revolute->m_localAnchorB;
m_referenceAngleA = revolute->m_referenceAngle;
m_localAxisC.SetZero();
coordinateA = aA - aC - m_referenceAngleA;
}
else
{
b2PrismaticJoint* prismatic = (b2PrismaticJoint*)def->joint1;
m_localAnchorC = prismatic->m_localAnchorA;
m_localAnchorA = prismatic->m_localAnchorB;
m_referenceAngleA = prismatic->m_referenceAngle;
m_localAxisC = prismatic->m_localXAxisA;
b2Vec2 pC = m_localAnchorC;
b2Vec2 pA = b2MulT(xfC.q, b2Mul(xfA.q, m_localAnchorA) + (xfA.p - xfC.p));
coordinateA = b2Dot(pA - pC, m_localAxisC);
}
m_bodyD = m_joint2->GetBodyA();
m_bodyB = m_joint2->GetBodyB();
// Get geometry of joint2
b2Transform xfB = m_bodyB->m_xf;
float32 aB = m_bodyB->m_sweep.a;
b2Transform xfD = m_bodyD->m_xf;
float32 aD = m_bodyD->m_sweep.a;
if (m_typeB == e_revoluteJoint)
{
b2RevoluteJoint* revolute = (b2RevoluteJoint*)def->joint2;
m_localAnchorD = revolute->m_localAnchorA;
m_localAnchorB = revolute->m_localAnchorB;
m_referenceAngleB = revolute->m_referenceAngle;
m_localAxisD.SetZero();
coordinateB = aB - aD - m_referenceAngleB;
}
else
{
b2PrismaticJoint* prismatic = (b2PrismaticJoint*)def->joint2;
m_localAnchorD = prismatic->m_localAnchorA;
m_localAnchorB = prismatic->m_localAnchorB;
m_referenceAngleB = prismatic->m_referenceAngle;
m_localAxisD = prismatic->m_localXAxisA;
b2Vec2 pD = m_localAnchorD;
b2Vec2 pB = b2MulT(xfD.q, b2Mul(xfB.q, m_localAnchorB) + (xfB.p - xfD.p));
coordinateB = b2Dot(pB - pD, m_localAxisD);
}
m_ratio = def->ratio;
m_constant = coordinateA + m_ratio * coordinateB;
m_impulse = 0.0f;
}
void b2GearJoint::InitVelocityConstraints(const b2SolverData& data)
{
m_indexA = m_bodyA->m_islandIndex;
m_indexB = m_bodyB->m_islandIndex;
m_indexC = m_bodyC->m_islandIndex;
m_indexD = m_bodyD->m_islandIndex;
m_lcA = m_bodyA->m_sweep.localCenter;
m_lcB = m_bodyB->m_sweep.localCenter;
m_lcC = m_bodyC->m_sweep.localCenter;
m_lcD = m_bodyD->m_sweep.localCenter;
m_mA = m_bodyA->m_invMass;
m_mB = m_bodyB->m_invMass;
m_mC = m_bodyC->m_invMass;
m_mD = m_bodyD->m_invMass;
m_iA = m_bodyA->m_invI;
m_iB = m_bodyB->m_invI;
m_iC = m_bodyC->m_invI;
m_iD = m_bodyD->m_invI;
float32 aA = data.positions[m_indexA].a;
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
float32 aB = data.positions[m_indexB].a;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
float32 aC = data.positions[m_indexC].a;
b2Vec2 vC = data.velocities[m_indexC].v;
float32 wC = data.velocities[m_indexC].w;
float32 aD = data.positions[m_indexD].a;
b2Vec2 vD = data.velocities[m_indexD].v;
float32 wD = data.velocities[m_indexD].w;
b2Rot qA(aA), qB(aB), qC(aC), qD(aD);
m_mass = 0.0f;
if (m_typeA == e_revoluteJoint)
{
m_JvAC.SetZero();
m_JwA = 1.0f;
m_JwC = 1.0f;
m_mass += m_iA + m_iC;
}
else
{
b2Vec2 u = b2Mul(qC, m_localAxisC);
b2Vec2 rC = b2Mul(qC, m_localAnchorC - m_lcC);
b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_lcA);
m_JvAC = u;
m_JwC = b2Cross(rC, u);
m_JwA = b2Cross(rA, u);
m_mass += m_mC + m_mA + m_iC * m_JwC * m_JwC + m_iA * m_JwA * m_JwA;
}
if (m_typeB == e_revoluteJoint)
{
m_JvBD.SetZero();
m_JwB = m_ratio;
m_JwD = m_ratio;
m_mass += m_ratio * m_ratio * (m_iB + m_iD);
}
else
{
b2Vec2 u = b2Mul(qD, m_localAxisD);
b2Vec2 rD = b2Mul(qD, m_localAnchorD - m_lcD);
b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_lcB);
m_JvBD = m_ratio * u;
m_JwD = m_ratio * b2Cross(rD, u);
m_JwB = m_ratio * b2Cross(rB, u);
m_mass += m_ratio * m_ratio * (m_mD + m_mB) + m_iD * m_JwD * m_JwD + m_iB * m_JwB * m_JwB;
}
// Compute effective mass.
m_mass = m_mass > 0.0f ? 1.0f / m_mass : 0.0f;
if (data.step.warmStarting)
{
vA += (m_mA * m_impulse) * m_JvAC;
wA += m_iA * m_impulse * m_JwA;
vB += (m_mB * m_impulse) * m_JvBD;
wB += m_iB * m_impulse * m_JwB;
vC -= (m_mC * m_impulse) * m_JvAC;
wC -= m_iC * m_impulse * m_JwC;
vD -= (m_mD * m_impulse) * m_JvBD;
wD -= m_iD * m_impulse * m_JwD;
}
else
{
m_impulse = 0.0f;
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
data.velocities[m_indexC].v = vC;
data.velocities[m_indexC].w = wC;
data.velocities[m_indexD].v = vD;
data.velocities[m_indexD].w = wD;
}
void b2GearJoint::SolveVelocityConstraints(const b2SolverData& data)
{
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
b2Vec2 vC = data.velocities[m_indexC].v;
float32 wC = data.velocities[m_indexC].w;
b2Vec2 vD = data.velocities[m_indexD].v;
float32 wD = data.velocities[m_indexD].w;
float32 Cdot = b2Dot(m_JvAC, vA - vC) + b2Dot(m_JvBD, vB - vD);
Cdot += (m_JwA * wA - m_JwC * wC) + (m_JwB * wB - m_JwD * wD);
float32 impulse = -m_mass * Cdot;
m_impulse += impulse;
vA += (m_mA * impulse) * m_JvAC;
wA += m_iA * impulse * m_JwA;
vB += (m_mB * impulse) * m_JvBD;
wB += m_iB * impulse * m_JwB;
vC -= (m_mC * impulse) * m_JvAC;
wC -= m_iC * impulse * m_JwC;
vD -= (m_mD * impulse) * m_JvBD;
wD -= m_iD * impulse * m_JwD;
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
data.velocities[m_indexC].v = vC;
data.velocities[m_indexC].w = wC;
data.velocities[m_indexD].v = vD;
data.velocities[m_indexD].w = wD;
}
bool b2GearJoint::SolvePositionConstraints(const b2SolverData& data)
{
b2Vec2 cA = data.positions[m_indexA].c;
float32 aA = data.positions[m_indexA].a;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Vec2 cC = data.positions[m_indexC].c;
float32 aC = data.positions[m_indexC].a;
b2Vec2 cD = data.positions[m_indexD].c;
float32 aD = data.positions[m_indexD].a;
b2Rot qA(aA), qB(aB), qC(aC), qD(aD);
float32 linearError = 0.0f;
float32 coordinateA, coordinateB;
b2Vec2 JvAC, JvBD;
float32 JwA, JwB, JwC, JwD;
float32 mass = 0.0f;
if (m_typeA == e_revoluteJoint)
{
JvAC.SetZero();
JwA = 1.0f;
JwC = 1.0f;
mass += m_iA + m_iC;
coordinateA = aA - aC - m_referenceAngleA;
}
else
{
b2Vec2 u = b2Mul(qC, m_localAxisC);
b2Vec2 rC = b2Mul(qC, m_localAnchorC - m_lcC);
b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_lcA);
JvAC = u;
JwC = b2Cross(rC, u);
JwA = b2Cross(rA, u);
mass += m_mC + m_mA + m_iC * JwC * JwC + m_iA * JwA * JwA;
b2Vec2 pC = m_localAnchorC - m_lcC;
b2Vec2 pA = b2MulT(qC, rA + (cA - cC));
coordinateA = b2Dot(pA - pC, m_localAxisC);
}
if (m_typeB == e_revoluteJoint)
{
JvBD.SetZero();
JwB = m_ratio;
JwD = m_ratio;
mass += m_ratio * m_ratio * (m_iB + m_iD);
coordinateB = aB - aD - m_referenceAngleB;
}
else
{
b2Vec2 u = b2Mul(qD, m_localAxisD);
b2Vec2 rD = b2Mul(qD, m_localAnchorD - m_lcD);
b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_lcB);
JvBD = m_ratio * u;
JwD = m_ratio * b2Cross(rD, u);
JwB = m_ratio * b2Cross(rB, u);
mass += m_ratio * m_ratio * (m_mD + m_mB) + m_iD * JwD * JwD + m_iB * JwB * JwB;
b2Vec2 pD = m_localAnchorD - m_lcD;
b2Vec2 pB = b2MulT(qD, rB + (cB - cD));
coordinateB = b2Dot(pB - pD, m_localAxisD);
}
float32 C = (coordinateA + m_ratio * coordinateB) - m_constant;
float32 impulse = 0.0f;
if (mass > 0.0f)
{
impulse = -C / mass;
}
cA += m_mA * impulse * JvAC;
aA += m_iA * impulse * JwA;
cB += m_mB * impulse * JvBD;
aB += m_iB * impulse * JwB;
cC -= m_mC * impulse * JvAC;
aC -= m_iC * impulse * JwC;
cD -= m_mD * impulse * JvBD;
aD -= m_iD * impulse * JwD;
data.positions[m_indexA].c = cA;
data.positions[m_indexA].a = aA;
data.positions[m_indexB].c = cB;
data.positions[m_indexB].a = aB;
data.positions[m_indexC].c = cC;
data.positions[m_indexC].a = aC;
data.positions[m_indexD].c = cD;
data.positions[m_indexD].a = aD;
// TODO_ERIN not implemented
return linearError < b2_linearSlop;
}
b2Vec2 b2GearJoint::GetAnchorA() const
{
return m_bodyA->GetWorldPoint(m_localAnchorA);
}
b2Vec2 b2GearJoint::GetAnchorB() const
{
return m_bodyB->GetWorldPoint(m_localAnchorB);
}
b2Vec2 b2GearJoint::GetReactionForce(float32 inv_dt) const
{
b2Vec2 P = m_impulse * m_JvAC;
return inv_dt * P;
}
float32 b2GearJoint::GetReactionTorque(float32 inv_dt) const
{
float32 L = m_impulse * m_JwA;
return inv_dt * L;
}
void b2GearJoint::SetRatio(float32 ratio)
{
b2Assert(b2IsValid(ratio));
m_ratio = ratio;
}
float32 b2GearJoint::GetRatio() const
{
return m_ratio;
}
void b2GearJoint::Dump()
{
int32 indexA = m_bodyA->m_islandIndex;
int32 indexB = m_bodyB->m_islandIndex;
int32 index1 = m_joint1->m_index;
int32 index2 = m_joint2->m_index;
b2Log(" b2GearJointDef jd;\n");
b2Log(" jd.bodyA = bodies[%d];\n", indexA);
b2Log(" jd.bodyB = bodies[%d];\n", indexB);
b2Log(" jd.collideConnected = bool(%d);\n", m_collideConnected);
b2Log(" jd.joint1 = joints[%d];\n", index1);
b2Log(" jd.joint2 = joints[%d];\n", index2);
b2Log(" jd.ratio = %.15lef;\n", m_ratio);
b2Log(" joints[%d] = m_world->CreateJoint(&jd);\n", m_index);
}

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_GEAR_JOINT_H
#define B2_GEAR_JOINT_H
#include "b2Joint.h"
/// Gear joint definition. This definition requires two existing
/// revolute or prismatic joints (any combination will work).
struct b2GearJointDef : public b2JointDef
{
b2GearJointDef()
{
type = e_gearJoint;
joint1 = NULL;
joint2 = NULL;
ratio = 1.0f;
}
/// The first revolute/prismatic joint attached to the gear joint.
b2Joint* joint1;
/// The second revolute/prismatic joint attached to the gear joint.
b2Joint* joint2;
/// The gear ratio.
/// @see b2GearJoint for explanation.
float32 ratio;
};
/// A gear joint is used to connect two joints together. Either joint
/// can be a revolute or prismatic joint. You specify a gear ratio
/// to bind the motions together:
/// coordinate1 + ratio * coordinate2 = constant
/// The ratio can be negative or positive. If one joint is a revolute joint
/// and the other joint is a prismatic joint, then the ratio will have units
/// of length or units of 1/length.
/// @warning You have to manually destroy the gear joint if joint1 or joint2
/// is destroyed.
class b2GearJoint : public b2Joint
{
public:
b2Vec2 GetAnchorA() const;
b2Vec2 GetAnchorB() const;
b2Vec2 GetReactionForce(float32 inv_dt) const;
float32 GetReactionTorque(float32 inv_dt) const;
/// Get the first joint.
b2Joint* GetJoint1() { return m_joint1; }
/// Get the second joint.
b2Joint* GetJoint2() { return m_joint2; }
/// Set/Get the gear ratio.
void SetRatio(float32 ratio);
float32 GetRatio() const;
/// Dump joint to dmLog
void Dump();
protected:
friend class b2Joint;
b2GearJoint(const b2GearJointDef* data);
void InitVelocityConstraints(const b2SolverData& data);
void SolveVelocityConstraints(const b2SolverData& data);
bool SolvePositionConstraints(const b2SolverData& data);
b2Joint* m_joint1;
b2Joint* m_joint2;
b2JointType m_typeA;
b2JointType m_typeB;
// Body A is connected to body C
// Body B is connected to body D
b2Body* m_bodyC;
b2Body* m_bodyD;
// Solver shared
b2Vec2 m_localAnchorA;
b2Vec2 m_localAnchorB;
b2Vec2 m_localAnchorC;
b2Vec2 m_localAnchorD;
b2Vec2 m_localAxisC;
b2Vec2 m_localAxisD;
float32 m_referenceAngleA;
float32 m_referenceAngleB;
float32 m_constant;
float32 m_ratio;
float32 m_impulse;
// Solver temp
juce::int32 m_indexA, m_indexB, m_indexC, m_indexD;
b2Vec2 m_lcA, m_lcB, m_lcC, m_lcD;
float32 m_mA, m_mB, m_mC, m_mD;
float32 m_iA, m_iB, m_iC, m_iD;
b2Vec2 m_JvAC, m_JvBD;
float32 m_JwA, m_JwB, m_JwC, m_JwD;
float32 m_mass;
};
#endif

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/*
* Copyright (c) 2006-2007 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2Joint.h"
#include "b2DistanceJoint.h"
#include "b2WheelJoint.h"
#include "b2MouseJoint.h"
#include "b2RevoluteJoint.h"
#include "b2PrismaticJoint.h"
#include "b2PulleyJoint.h"
#include "b2GearJoint.h"
#include "b2WeldJoint.h"
#include "b2FrictionJoint.h"
#include "b2RopeJoint.h"
#include "../b2Body.h"
#include "../b2World.h"
#include "../../Common/b2BlockAllocator.h"
#include <new>
b2Joint* b2Joint::Create(const b2JointDef* def, b2BlockAllocator* allocator)
{
b2Joint* joint = NULL;
switch (def->type)
{
case e_distanceJoint:
{
void* mem = allocator->Allocate(sizeof(b2DistanceJoint));
joint = new (mem) b2DistanceJoint((b2DistanceJointDef*)def);
}
break;
case e_mouseJoint:
{
void* mem = allocator->Allocate(sizeof(b2MouseJoint));
joint = new (mem) b2MouseJoint((b2MouseJointDef*)def);
}
break;
case e_prismaticJoint:
{
void* mem = allocator->Allocate(sizeof(b2PrismaticJoint));
joint = new (mem) b2PrismaticJoint((b2PrismaticJointDef*)def);
}
break;
case e_revoluteJoint:
{
void* mem = allocator->Allocate(sizeof(b2RevoluteJoint));
joint = new (mem) b2RevoluteJoint((b2RevoluteJointDef*)def);
}
break;
case e_pulleyJoint:
{
void* mem = allocator->Allocate(sizeof(b2PulleyJoint));
joint = new (mem) b2PulleyJoint((b2PulleyJointDef*)def);
}
break;
case e_gearJoint:
{
void* mem = allocator->Allocate(sizeof(b2GearJoint));
joint = new (mem) b2GearJoint((b2GearJointDef*)def);
}
break;
case e_wheelJoint:
{
void* mem = allocator->Allocate(sizeof(b2WheelJoint));
joint = new (mem) b2WheelJoint((b2WheelJointDef*)def);
}
break;
case e_weldJoint:
{
void* mem = allocator->Allocate(sizeof(b2WeldJoint));
joint = new (mem) b2WeldJoint((b2WeldJointDef*)def);
}
break;
case e_frictionJoint:
{
void* mem = allocator->Allocate(sizeof(b2FrictionJoint));
joint = new (mem) b2FrictionJoint((b2FrictionJointDef*)def);
}
break;
case e_ropeJoint:
{
void* mem = allocator->Allocate(sizeof(b2RopeJoint));
joint = new (mem) b2RopeJoint((b2RopeJointDef*)def);
}
break;
default:
b2Assert(false);
break;
}
return joint;
}
void b2Joint::Destroy(b2Joint* joint, b2BlockAllocator* allocator)
{
joint->~b2Joint();
switch (joint->m_type)
{
case e_distanceJoint:
allocator->Free(joint, sizeof(b2DistanceJoint));
break;
case e_mouseJoint:
allocator->Free(joint, sizeof(b2MouseJoint));
break;
case e_prismaticJoint:
allocator->Free(joint, sizeof(b2PrismaticJoint));
break;
case e_revoluteJoint:
allocator->Free(joint, sizeof(b2RevoluteJoint));
break;
case e_pulleyJoint:
allocator->Free(joint, sizeof(b2PulleyJoint));
break;
case e_gearJoint:
allocator->Free(joint, sizeof(b2GearJoint));
break;
case e_wheelJoint:
allocator->Free(joint, sizeof(b2WheelJoint));
break;
case e_weldJoint:
allocator->Free(joint, sizeof(b2WeldJoint));
break;
case e_frictionJoint:
allocator->Free(joint, sizeof(b2FrictionJoint));
break;
case e_ropeJoint:
allocator->Free(joint, sizeof(b2RopeJoint));
break;
default:
b2Assert(false);
break;
}
}
b2Joint::b2Joint(const b2JointDef* def)
{
b2Assert(def->bodyA != def->bodyB);
m_type = def->type;
m_prev = NULL;
m_next = NULL;
m_bodyA = def->bodyA;
m_bodyB = def->bodyB;
m_index = 0;
m_collideConnected = def->collideConnected;
m_islandFlag = false;
m_userData = def->userData;
m_edgeA.joint = NULL;
m_edgeA.other = NULL;
m_edgeA.prev = NULL;
m_edgeA.next = NULL;
m_edgeB.joint = NULL;
m_edgeB.other = NULL;
m_edgeB.prev = NULL;
m_edgeB.next = NULL;
}
bool b2Joint::IsActive() const
{
return m_bodyA->IsActive() && m_bodyB->IsActive();
}

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/*
* Copyright (c) 2006-2007 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_JOINT_H
#define B2_JOINT_H
#include "../../Common/b2Math.h"
class b2Body;
class b2Joint;
struct b2SolverData;
class b2BlockAllocator;
enum b2JointType
{
e_unknownJoint,
e_revoluteJoint,
e_prismaticJoint,
e_distanceJoint,
e_pulleyJoint,
e_mouseJoint,
e_gearJoint,
e_wheelJoint,
e_weldJoint,
e_frictionJoint,
e_ropeJoint
};
enum b2LimitState
{
e_inactiveLimit,
e_atLowerLimit,
e_atUpperLimit,
e_equalLimits
};
struct b2Jacobian
{
b2Vec2 linear;
float32 angularA;
float32 angularB;
};
/// A joint edge is used to connect bodies and joints together
/// in a joint graph where each body is a node and each joint
/// is an edge. A joint edge belongs to a doubly linked list
/// maintained in each attached body. Each joint has two joint
/// nodes, one for each attached body.
struct b2JointEdge
{
b2Body* other; ///< provides quick access to the other body attached.
b2Joint* joint; ///< the joint
b2JointEdge* prev; ///< the previous joint edge in the body's joint list
b2JointEdge* next; ///< the next joint edge in the body's joint list
};
/// Joint definitions are used to construct joints.
struct b2JointDef
{
b2JointDef()
{
type = e_unknownJoint;
userData = NULL;
bodyA = NULL;
bodyB = NULL;
collideConnected = false;
}
/// The joint type is set automatically for concrete joint types.
b2JointType type;
/// Use this to attach application specific data to your joints.
void* userData;
/// The first attached body.
b2Body* bodyA;
/// The second attached body.
b2Body* bodyB;
/// Set this flag to true if the attached bodies should collide.
bool collideConnected;
};
/// The base joint class. Joints are used to constraint two bodies together in
/// various fashions. Some joints also feature limits and motors.
class b2Joint
{
public:
/// Get the type of the concrete joint.
b2JointType GetType() const;
/// Get the first body attached to this joint.
b2Body* GetBodyA();
/// Get the second body attached to this joint.
b2Body* GetBodyB();
/// Get the anchor point on bodyA in world coordinates.
virtual b2Vec2 GetAnchorA() const = 0;
/// Get the anchor point on bodyB in world coordinates.
virtual b2Vec2 GetAnchorB() const = 0;
/// Get the reaction force on bodyB at the joint anchor in Newtons.
virtual b2Vec2 GetReactionForce(float32 inv_dt) const = 0;
/// Get the reaction torque on bodyB in N*m.
virtual float32 GetReactionTorque(float32 inv_dt) const = 0;
/// Get the next joint the world joint list.
b2Joint* GetNext();
const b2Joint* GetNext() const;
/// Get the user data pointer.
void* GetUserData() const;
/// Set the user data pointer.
void SetUserData(void* data);
/// Short-cut function to determine if either body is inactive.
bool IsActive() const;
/// Get collide connected.
/// Note: modifying the collide connect flag won't work correctly because
/// the flag is only checked when fixture AABBs begin to overlap.
bool GetCollideConnected() const;
/// Dump this joint to the log file.
virtual void Dump() { b2Log("// Dump is not supported for this joint type.\n"); }
protected:
friend class b2World;
friend class b2Body;
friend class b2Island;
friend class b2GearJoint;
static b2Joint* Create(const b2JointDef* def, b2BlockAllocator* allocator);
static void Destroy(b2Joint* joint, b2BlockAllocator* allocator);
b2Joint(const b2JointDef* def);
virtual ~b2Joint() {}
virtual void InitVelocityConstraints(const b2SolverData& data) = 0;
virtual void SolveVelocityConstraints(const b2SolverData& data) = 0;
// This returns true if the position errors are within tolerance.
virtual bool SolvePositionConstraints(const b2SolverData& data) = 0;
b2JointType m_type;
b2Joint* m_prev;
b2Joint* m_next;
b2JointEdge m_edgeA;
b2JointEdge m_edgeB;
b2Body* m_bodyA;
b2Body* m_bodyB;
juce::int32 m_index;
bool m_islandFlag;
bool m_collideConnected;
void* m_userData;
};
inline b2JointType b2Joint::GetType() const
{
return m_type;
}
inline b2Body* b2Joint::GetBodyA()
{
return m_bodyA;
}
inline b2Body* b2Joint::GetBodyB()
{
return m_bodyB;
}
inline b2Joint* b2Joint::GetNext()
{
return m_next;
}
inline const b2Joint* b2Joint::GetNext() const
{
return m_next;
}
inline void* b2Joint::GetUserData() const
{
return m_userData;
}
inline void b2Joint::SetUserData(void* data)
{
m_userData = data;
}
inline bool b2Joint::GetCollideConnected() const
{
return m_collideConnected;
}
#endif

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/*
* Copyright (c) 2006-2007 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2MouseJoint.h"
#include "../b2Body.h"
#include "../b2TimeStep.h"
// p = attached point, m = mouse point
// C = p - m
// Cdot = v
// = v + cross(w, r)
// J = [I r_skew]
// Identity used:
// w k % (rx i + ry j) = w * (-ry i + rx j)
b2MouseJoint::b2MouseJoint(const b2MouseJointDef* def)
: b2Joint(def)
{
b2Assert(def->target.IsValid());
b2Assert(b2IsValid(def->maxForce) && def->maxForce >= 0.0f);
b2Assert(b2IsValid(def->frequencyHz) && def->frequencyHz >= 0.0f);
b2Assert(b2IsValid(def->dampingRatio) && def->dampingRatio >= 0.0f);
m_targetA = def->target;
m_localAnchorB = b2MulT(m_bodyB->GetTransform(), m_targetA);
m_maxForce = def->maxForce;
m_impulse.SetZero();
m_frequencyHz = def->frequencyHz;
m_dampingRatio = def->dampingRatio;
m_beta = 0.0f;
m_gamma = 0.0f;
}
void b2MouseJoint::SetTarget(const b2Vec2& target)
{
if (m_bodyB->IsAwake() == false)
{
m_bodyB->SetAwake(true);
}
m_targetA = target;
}
const b2Vec2& b2MouseJoint::GetTarget() const
{
return m_targetA;
}
void b2MouseJoint::SetMaxForce(float32 force)
{
m_maxForce = force;
}
float32 b2MouseJoint::GetMaxForce() const
{
return m_maxForce;
}
void b2MouseJoint::SetFrequency(float32 hz)
{
m_frequencyHz = hz;
}
float32 b2MouseJoint::GetFrequency() const
{
return m_frequencyHz;
}
void b2MouseJoint::SetDampingRatio(float32 ratio)
{
m_dampingRatio = ratio;
}
float32 b2MouseJoint::GetDampingRatio() const
{
return m_dampingRatio;
}
void b2MouseJoint::InitVelocityConstraints(const b2SolverData& data)
{
m_indexB = m_bodyB->m_islandIndex;
m_localCenterB = m_bodyB->m_sweep.localCenter;
m_invMassB = m_bodyB->m_invMass;
m_invIB = m_bodyB->m_invI;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
b2Rot qB(aB);
float32 mass = m_bodyB->GetMass();
// Frequency
float32 omega = 2.0f * b2_pi * m_frequencyHz;
// Damping coefficient
float32 d = 2.0f * mass * m_dampingRatio * omega;
// Spring stiffness
float32 k = mass * (omega * omega);
// magic formulas
// gamma has units of inverse mass.
// beta has units of inverse time.
float32 h = data.step.dt;
b2Assert(d + h * k > b2_epsilon);
m_gamma = h * (d + h * k);
if (m_gamma != 0.0f)
{
m_gamma = 1.0f / m_gamma;
}
m_beta = h * k * m_gamma;
// Compute the effective mass matrix.
m_rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
// K = [(1/m1 + 1/m2) * eye(2) - skew(r1) * invI1 * skew(r1) - skew(r2) * invI2 * skew(r2)]
// = [1/m1+1/m2 0 ] + invI1 * [r1.y*r1.y -r1.x*r1.y] + invI2 * [r1.y*r1.y -r1.x*r1.y]
// [ 0 1/m1+1/m2] [-r1.x*r1.y r1.x*r1.x] [-r1.x*r1.y r1.x*r1.x]
b2Mat22 K;
K.ex.x = m_invMassB + m_invIB * m_rB.y * m_rB.y + m_gamma;
K.ex.y = -m_invIB * m_rB.x * m_rB.y;
K.ey.x = K.ex.y;
K.ey.y = m_invMassB + m_invIB * m_rB.x * m_rB.x + m_gamma;
m_mass = K.GetInverse();
m_C = cB + m_rB - m_targetA;
m_C *= m_beta;
// Cheat with some damping
wB *= 0.98f;
if (data.step.warmStarting)
{
m_impulse *= data.step.dtRatio;
vB += m_invMassB * m_impulse;
wB += m_invIB * b2Cross(m_rB, m_impulse);
}
else
{
m_impulse.SetZero();
}
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
void b2MouseJoint::SolveVelocityConstraints(const b2SolverData& data)
{
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
// Cdot = v + cross(w, r)
b2Vec2 Cdot = vB + b2Cross(wB, m_rB);
b2Vec2 impulse = b2Mul(m_mass, -(Cdot + m_C + m_gamma * m_impulse));
b2Vec2 oldImpulse = m_impulse;
m_impulse += impulse;
float32 maxImpulse = data.step.dt * m_maxForce;
if (m_impulse.LengthSquared() > maxImpulse * maxImpulse)
{
m_impulse *= maxImpulse / m_impulse.Length();
}
impulse = m_impulse - oldImpulse;
vB += m_invMassB * impulse;
wB += m_invIB * b2Cross(m_rB, impulse);
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
bool b2MouseJoint::SolvePositionConstraints(const b2SolverData& data)
{
B2_NOT_USED(data);
return true;
}
b2Vec2 b2MouseJoint::GetAnchorA() const
{
return m_targetA;
}
b2Vec2 b2MouseJoint::GetAnchorB() const
{
return m_bodyB->GetWorldPoint(m_localAnchorB);
}
b2Vec2 b2MouseJoint::GetReactionForce(float32 inv_dt) const
{
return inv_dt * m_impulse;
}
float32 b2MouseJoint::GetReactionTorque(float32 inv_dt) const
{
return inv_dt * 0.0f;
}

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/*
* Copyright (c) 2006-2007 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_MOUSE_JOINT_H
#define B2_MOUSE_JOINT_H
#include "b2Joint.h"
/// Mouse joint definition. This requires a world target point,
/// tuning parameters, and the time step.
struct b2MouseJointDef : public b2JointDef
{
b2MouseJointDef()
{
type = e_mouseJoint;
target.Set(0.0f, 0.0f);
maxForce = 0.0f;
frequencyHz = 5.0f;
dampingRatio = 0.7f;
}
/// The initial world target point. This is assumed
/// to coincide with the body anchor initially.
b2Vec2 target;
/// The maximum constraint force that can be exerted
/// to move the candidate body. Usually you will express
/// as some multiple of the weight (multiplier * mass * gravity).
float32 maxForce;
/// The response speed.
float32 frequencyHz;
/// The damping ratio. 0 = no damping, 1 = critical damping.
float32 dampingRatio;
};
/// A mouse joint is used to make a point on a body track a
/// specified world point. This a soft constraint with a maximum
/// force. This allows the constraint to stretch and without
/// applying huge forces.
/// NOTE: this joint is not documented in the manual because it was
/// developed to be used in the testbed. If you want to learn how to
/// use the mouse joint, look at the testbed.
class b2MouseJoint : public b2Joint
{
public:
/// Implements b2Joint.
b2Vec2 GetAnchorA() const;
/// Implements b2Joint.
b2Vec2 GetAnchorB() const;
/// Implements b2Joint.
b2Vec2 GetReactionForce(float32 inv_dt) const;
/// Implements b2Joint.
float32 GetReactionTorque(float32 inv_dt) const;
/// Use this to update the target point.
void SetTarget(const b2Vec2& target);
const b2Vec2& GetTarget() const;
/// Set/get the maximum force in Newtons.
void SetMaxForce(float32 force);
float32 GetMaxForce() const;
/// Set/get the frequency in Hertz.
void SetFrequency(float32 hz);
float32 GetFrequency() const;
/// Set/get the damping ratio (dimensionless).
void SetDampingRatio(float32 ratio);
float32 GetDampingRatio() const;
/// The mouse joint does not support dumping.
void Dump() { b2Log("Mouse joint dumping is not supported.\n"); }
protected:
friend class b2Joint;
b2MouseJoint(const b2MouseJointDef* def);
void InitVelocityConstraints(const b2SolverData& data);
void SolveVelocityConstraints(const b2SolverData& data);
bool SolvePositionConstraints(const b2SolverData& data);
b2Vec2 m_localAnchorB;
b2Vec2 m_targetA;
float32 m_frequencyHz;
float32 m_dampingRatio;
float32 m_beta;
// Solver shared
b2Vec2 m_impulse;
float32 m_maxForce;
float32 m_gamma;
// Solver temp
juce::int32 m_indexA;
juce::int32 m_indexB;
b2Vec2 m_rB;
b2Vec2 m_localCenterB;
float32 m_invMassB;
float32 m_invIB;
b2Mat22 m_mass;
b2Vec2 m_C;
};
#endif

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2PrismaticJoint.h"
#include "../b2Body.h"
#include "../b2TimeStep.h"
// Linear constraint (point-to-line)
// d = p2 - p1 = x2 + r2 - x1 - r1
// C = dot(perp, d)
// Cdot = dot(d, cross(w1, perp)) + dot(perp, v2 + cross(w2, r2) - v1 - cross(w1, r1))
// = -dot(perp, v1) - dot(cross(d + r1, perp), w1) + dot(perp, v2) + dot(cross(r2, perp), v2)
// J = [-perp, -cross(d + r1, perp), perp, cross(r2,perp)]
//
// Angular constraint
// C = a2 - a1 + a_initial
// Cdot = w2 - w1
// J = [0 0 -1 0 0 1]
//
// K = J * invM * JT
//
// J = [-a -s1 a s2]
// [0 -1 0 1]
// a = perp
// s1 = cross(d + r1, a) = cross(p2 - x1, a)
// s2 = cross(r2, a) = cross(p2 - x2, a)
// Motor/Limit linear constraint
// C = dot(ax1, d)
// Cdot = = -dot(ax1, v1) - dot(cross(d + r1, ax1), w1) + dot(ax1, v2) + dot(cross(r2, ax1), v2)
// J = [-ax1 -cross(d+r1,ax1) ax1 cross(r2,ax1)]
// Block Solver
// We develop a block solver that includes the joint limit. This makes the limit stiff (inelastic) even
// when the mass has poor distribution (leading to large torques about the joint anchor points).
//
// The Jacobian has 3 rows:
// J = [-uT -s1 uT s2] // linear
// [0 -1 0 1] // angular
// [-vT -a1 vT a2] // limit
//
// u = perp
// v = axis
// s1 = cross(d + r1, u), s2 = cross(r2, u)
// a1 = cross(d + r1, v), a2 = cross(r2, v)
// M * (v2 - v1) = JT * df
// J * v2 = bias
//
// v2 = v1 + invM * JT * df
// J * (v1 + invM * JT * df) = bias
// K * df = bias - J * v1 = -Cdot
// K = J * invM * JT
// Cdot = J * v1 - bias
//
// Now solve for f2.
// df = f2 - f1
// K * (f2 - f1) = -Cdot
// f2 = invK * (-Cdot) + f1
//
// Clamp accumulated limit impulse.
// lower: f2(3) = max(f2(3), 0)
// upper: f2(3) = min(f2(3), 0)
//
// Solve for correct f2(1:2)
// K(1:2, 1:2) * f2(1:2) = -Cdot(1:2) - K(1:2,3) * f2(3) + K(1:2,1:3) * f1
// = -Cdot(1:2) - K(1:2,3) * f2(3) + K(1:2,1:2) * f1(1:2) + K(1:2,3) * f1(3)
// K(1:2, 1:2) * f2(1:2) = -Cdot(1:2) - K(1:2,3) * (f2(3) - f1(3)) + K(1:2,1:2) * f1(1:2)
// f2(1:2) = invK(1:2,1:2) * (-Cdot(1:2) - K(1:2,3) * (f2(3) - f1(3))) + f1(1:2)
//
// Now compute impulse to be applied:
// df = f2 - f1
void b2PrismaticJointDef::Initialize(b2Body* bA, b2Body* bB, const b2Vec2& anchor, const b2Vec2& axis)
{
bodyA = bA;
bodyB = bB;
localAnchorA = bodyA->GetLocalPoint(anchor);
localAnchorB = bodyB->GetLocalPoint(anchor);
localAxisA = bodyA->GetLocalVector(axis);
referenceAngle = bodyB->GetAngle() - bodyA->GetAngle();
}
b2PrismaticJoint::b2PrismaticJoint(const b2PrismaticJointDef* def)
: b2Joint(def)
{
m_localAnchorA = def->localAnchorA;
m_localAnchorB = def->localAnchorB;
m_localXAxisA = def->localAxisA;
m_localXAxisA.Normalize();
m_localYAxisA = b2Cross(1.0f, m_localXAxisA);
m_referenceAngle = def->referenceAngle;
m_impulse.SetZero();
m_motorMass = 0.0f;
m_motorImpulse = 0.0f;
m_lowerTranslation = def->lowerTranslation;
m_upperTranslation = def->upperTranslation;
m_maxMotorForce = def->maxMotorForce;
m_motorSpeed = def->motorSpeed;
m_enableLimit = def->enableLimit;
m_enableMotor = def->enableMotor;
m_limitState = e_inactiveLimit;
m_axis.SetZero();
m_perp.SetZero();
}
void b2PrismaticJoint::InitVelocityConstraints(const b2SolverData& data)
{
m_indexA = m_bodyA->m_islandIndex;
m_indexB = m_bodyB->m_islandIndex;
m_localCenterA = m_bodyA->m_sweep.localCenter;
m_localCenterB = m_bodyB->m_sweep.localCenter;
m_invMassA = m_bodyA->m_invMass;
m_invMassB = m_bodyB->m_invMass;
m_invIA = m_bodyA->m_invI;
m_invIB = m_bodyB->m_invI;
b2Vec2 cA = data.positions[m_indexA].c;
float32 aA = data.positions[m_indexA].a;
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
b2Rot qA(aA), qB(aB);
// Compute the effective masses.
b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
b2Vec2 d = (cB - cA) + rB - rA;
float32 mA = m_invMassA, mB = m_invMassB;
float32 iA = m_invIA, iB = m_invIB;
// Compute motor Jacobian and effective mass.
{
m_axis = b2Mul(qA, m_localXAxisA);
m_a1 = b2Cross(d + rA, m_axis);
m_a2 = b2Cross(rB, m_axis);
m_motorMass = mA + mB + iA * m_a1 * m_a1 + iB * m_a2 * m_a2;
if (m_motorMass > 0.0f)
{
m_motorMass = 1.0f / m_motorMass;
}
}
// Prismatic constraint.
{
m_perp = b2Mul(qA, m_localYAxisA);
m_s1 = b2Cross(d + rA, m_perp);
m_s2 = b2Cross(rB, m_perp);
float32 k11 = mA + mB + iA * m_s1 * m_s1 + iB * m_s2 * m_s2;
float32 k12 = iA * m_s1 + iB * m_s2;
float32 k13 = iA * m_s1 * m_a1 + iB * m_s2 * m_a2;
float32 k22 = iA + iB;
if (k22 == 0.0f)
{
// For bodies with fixed rotation.
k22 = 1.0f;
}
float32 k23 = iA * m_a1 + iB * m_a2;
float32 k33 = mA + mB + iA * m_a1 * m_a1 + iB * m_a2 * m_a2;
m_K.ex.Set(k11, k12, k13);
m_K.ey.Set(k12, k22, k23);
m_K.ez.Set(k13, k23, k33);
}
// Compute motor and limit terms.
if (m_enableLimit)
{
float32 jointTranslation = b2Dot(m_axis, d);
if (b2Abs(m_upperTranslation - m_lowerTranslation) < 2.0f * b2_linearSlop)
{
m_limitState = e_equalLimits;
}
else if (jointTranslation <= m_lowerTranslation)
{
if (m_limitState != e_atLowerLimit)
{
m_limitState = e_atLowerLimit;
m_impulse.z = 0.0f;
}
}
else if (jointTranslation >= m_upperTranslation)
{
if (m_limitState != e_atUpperLimit)
{
m_limitState = e_atUpperLimit;
m_impulse.z = 0.0f;
}
}
else
{
m_limitState = e_inactiveLimit;
m_impulse.z = 0.0f;
}
}
else
{
m_limitState = e_inactiveLimit;
m_impulse.z = 0.0f;
}
if (m_enableMotor == false)
{
m_motorImpulse = 0.0f;
}
if (data.step.warmStarting)
{
// Account for variable time step.
m_impulse *= data.step.dtRatio;
m_motorImpulse *= data.step.dtRatio;
b2Vec2 P = m_impulse.x * m_perp + (m_motorImpulse + m_impulse.z) * m_axis;
float32 LA = m_impulse.x * m_s1 + m_impulse.y + (m_motorImpulse + m_impulse.z) * m_a1;
float32 LB = m_impulse.x * m_s2 + m_impulse.y + (m_motorImpulse + m_impulse.z) * m_a2;
vA -= mA * P;
wA -= iA * LA;
vB += mB * P;
wB += iB * LB;
}
else
{
m_impulse.SetZero();
m_motorImpulse = 0.0f;
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
void b2PrismaticJoint::SolveVelocityConstraints(const b2SolverData& data)
{
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
float32 mA = m_invMassA, mB = m_invMassB;
float32 iA = m_invIA, iB = m_invIB;
// Solve linear motor constraint.
if (m_enableMotor && m_limitState != e_equalLimits)
{
float32 Cdot = b2Dot(m_axis, vB - vA) + m_a2 * wB - m_a1 * wA;
float32 impulse = m_motorMass * (m_motorSpeed - Cdot);
float32 oldImpulse = m_motorImpulse;
float32 maxImpulse = data.step.dt * m_maxMotorForce;
m_motorImpulse = b2Clamp(m_motorImpulse + impulse, -maxImpulse, maxImpulse);
impulse = m_motorImpulse - oldImpulse;
b2Vec2 P = impulse * m_axis;
float32 LA = impulse * m_a1;
float32 LB = impulse * m_a2;
vA -= mA * P;
wA -= iA * LA;
vB += mB * P;
wB += iB * LB;
}
b2Vec2 Cdot1;
Cdot1.x = b2Dot(m_perp, vB - vA) + m_s2 * wB - m_s1 * wA;
Cdot1.y = wB - wA;
if (m_enableLimit && m_limitState != e_inactiveLimit)
{
// Solve prismatic and limit constraint in block form.
float32 Cdot2;
Cdot2 = b2Dot(m_axis, vB - vA) + m_a2 * wB - m_a1 * wA;
b2Vec3 Cdot(Cdot1.x, Cdot1.y, Cdot2);
b2Vec3 f1 = m_impulse;
b2Vec3 df = m_K.Solve33(-Cdot);
m_impulse += df;
if (m_limitState == e_atLowerLimit)
{
m_impulse.z = b2Max(m_impulse.z, 0.0f);
}
else if (m_limitState == e_atUpperLimit)
{
m_impulse.z = b2Min(m_impulse.z, 0.0f);
}
// f2(1:2) = invK(1:2,1:2) * (-Cdot(1:2) - K(1:2,3) * (f2(3) - f1(3))) + f1(1:2)
b2Vec2 b = -Cdot1 - (m_impulse.z - f1.z) * b2Vec2(m_K.ez.x, m_K.ez.y);
b2Vec2 f2r = m_K.Solve22(b) + b2Vec2(f1.x, f1.y);
m_impulse.x = f2r.x;
m_impulse.y = f2r.y;
df = m_impulse - f1;
b2Vec2 P = df.x * m_perp + df.z * m_axis;
float32 LA = df.x * m_s1 + df.y + df.z * m_a1;
float32 LB = df.x * m_s2 + df.y + df.z * m_a2;
vA -= mA * P;
wA -= iA * LA;
vB += mB * P;
wB += iB * LB;
}
else
{
// Limit is inactive, just solve the prismatic constraint in block form.
b2Vec2 df = m_K.Solve22(-Cdot1);
m_impulse.x += df.x;
m_impulse.y += df.y;
b2Vec2 P = df.x * m_perp;
float32 LA = df.x * m_s1 + df.y;
float32 LB = df.x * m_s2 + df.y;
vA -= mA * P;
wA -= iA * LA;
vB += mB * P;
wB += iB * LB;
Cdot1.x = b2Dot(m_perp, vB - vA) + m_s2 * wB - m_s1 * wA;
Cdot1.y = wB - wA;
/*if (b2Abs(Cdot1.x) > 0.01f || b2Abs(Cdot1.y) > 0.01f)
{
b2Vec2 test = b2Mul22(m_K, df);
Cdot1.x += 0.0f;
}*/
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
bool b2PrismaticJoint::SolvePositionConstraints(const b2SolverData& data)
{
b2Vec2 cA = data.positions[m_indexA].c;
float32 aA = data.positions[m_indexA].a;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Rot qA(aA), qB(aB);
float32 mA = m_invMassA, mB = m_invMassB;
float32 iA = m_invIA, iB = m_invIB;
// Compute fresh Jacobians
b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
b2Vec2 d = cB + rB - cA - rA;
b2Vec2 axis = b2Mul(qA, m_localXAxisA);
float32 a1 = b2Cross(d + rA, axis);
float32 a2 = b2Cross(rB, axis);
b2Vec2 perp = b2Mul(qA, m_localYAxisA);
float32 s1 = b2Cross(d + rA, perp);
float32 s2 = b2Cross(rB, perp);
b2Vec3 impulse;
b2Vec2 C1;
C1.x = b2Dot(perp, d);
C1.y = aB - aA - m_referenceAngle;
float32 linearError = b2Abs(C1.x);
float32 angularError = b2Abs(C1.y);
bool active = false;
float32 C2 = 0.0f;
if (m_enableLimit)
{
float32 translation = b2Dot(axis, d);
if (b2Abs(m_upperTranslation - m_lowerTranslation) < 2.0f * b2_linearSlop)
{
// Prevent large angular corrections
C2 = b2Clamp(translation, -b2_maxLinearCorrection, b2_maxLinearCorrection);
linearError = b2Max(linearError, b2Abs(translation));
active = true;
}
else if (translation <= m_lowerTranslation)
{
// Prevent large linear corrections and allow some slop.
C2 = b2Clamp(translation - m_lowerTranslation + b2_linearSlop, -b2_maxLinearCorrection, 0.0f);
linearError = b2Max(linearError, m_lowerTranslation - translation);
active = true;
}
else if (translation >= m_upperTranslation)
{
// Prevent large linear corrections and allow some slop.
C2 = b2Clamp(translation - m_upperTranslation - b2_linearSlop, 0.0f, b2_maxLinearCorrection);
linearError = b2Max(linearError, translation - m_upperTranslation);
active = true;
}
}
if (active)
{
float32 k11 = mA + mB + iA * s1 * s1 + iB * s2 * s2;
float32 k12 = iA * s1 + iB * s2;
float32 k13 = iA * s1 * a1 + iB * s2 * a2;
float32 k22 = iA + iB;
if (k22 == 0.0f)
{
// For fixed rotation
k22 = 1.0f;
}
float32 k23 = iA * a1 + iB * a2;
float32 k33 = mA + mB + iA * a1 * a1 + iB * a2 * a2;
b2Mat33 K;
K.ex.Set(k11, k12, k13);
K.ey.Set(k12, k22, k23);
K.ez.Set(k13, k23, k33);
b2Vec3 C;
C.x = C1.x;
C.y = C1.y;
C.z = C2;
impulse = K.Solve33(-C);
}
else
{
float32 k11 = mA + mB + iA * s1 * s1 + iB * s2 * s2;
float32 k12 = iA * s1 + iB * s2;
float32 k22 = iA + iB;
if (k22 == 0.0f)
{
k22 = 1.0f;
}
b2Mat22 K;
K.ex.Set(k11, k12);
K.ey.Set(k12, k22);
b2Vec2 impulse1 = K.Solve(-C1);
impulse.x = impulse1.x;
impulse.y = impulse1.y;
impulse.z = 0.0f;
}
b2Vec2 P = impulse.x * perp + impulse.z * axis;
float32 LA = impulse.x * s1 + impulse.y + impulse.z * a1;
float32 LB = impulse.x * s2 + impulse.y + impulse.z * a2;
cA -= mA * P;
aA -= iA * LA;
cB += mB * P;
aB += iB * LB;
data.positions[m_indexA].c = cA;
data.positions[m_indexA].a = aA;
data.positions[m_indexB].c = cB;
data.positions[m_indexB].a = aB;
return linearError <= b2_linearSlop && angularError <= b2_angularSlop;
}
b2Vec2 b2PrismaticJoint::GetAnchorA() const
{
return m_bodyA->GetWorldPoint(m_localAnchorA);
}
b2Vec2 b2PrismaticJoint::GetAnchorB() const
{
return m_bodyB->GetWorldPoint(m_localAnchorB);
}
b2Vec2 b2PrismaticJoint::GetReactionForce(float32 inv_dt) const
{
return inv_dt * (m_impulse.x * m_perp + (m_motorImpulse + m_impulse.z) * m_axis);
}
float32 b2PrismaticJoint::GetReactionTorque(float32 inv_dt) const
{
return inv_dt * m_impulse.y;
}
float32 b2PrismaticJoint::GetJointTranslation() const
{
b2Vec2 pA = m_bodyA->GetWorldPoint(m_localAnchorA);
b2Vec2 pB = m_bodyB->GetWorldPoint(m_localAnchorB);
b2Vec2 d = pB - pA;
b2Vec2 axis = m_bodyA->GetWorldVector(m_localXAxisA);
float32 translation = b2Dot(d, axis);
return translation;
}
float32 b2PrismaticJoint::GetJointSpeed() const
{
b2Body* bA = m_bodyA;
b2Body* bB = m_bodyB;
b2Vec2 rA = b2Mul(bA->m_xf.q, m_localAnchorA - bA->m_sweep.localCenter);
b2Vec2 rB = b2Mul(bB->m_xf.q, m_localAnchorB - bB->m_sweep.localCenter);
b2Vec2 p1 = bA->m_sweep.c + rA;
b2Vec2 p2 = bB->m_sweep.c + rB;
b2Vec2 d = p2 - p1;
b2Vec2 axis = b2Mul(bA->m_xf.q, m_localXAxisA);
b2Vec2 vA = bA->m_linearVelocity;
b2Vec2 vB = bB->m_linearVelocity;
float32 wA = bA->m_angularVelocity;
float32 wB = bB->m_angularVelocity;
float32 speed = b2Dot(d, b2Cross(wA, axis)) + b2Dot(axis, vB + b2Cross(wB, rB) - vA - b2Cross(wA, rA));
return speed;
}
bool b2PrismaticJoint::IsLimitEnabled() const
{
return m_enableLimit;
}
void b2PrismaticJoint::EnableLimit(bool flag)
{
if (flag != m_enableLimit)
{
m_bodyA->SetAwake(true);
m_bodyB->SetAwake(true);
m_enableLimit = flag;
m_impulse.z = 0.0f;
}
}
float32 b2PrismaticJoint::GetLowerLimit() const
{
return m_lowerTranslation;
}
float32 b2PrismaticJoint::GetUpperLimit() const
{
return m_upperTranslation;
}
void b2PrismaticJoint::SetLimits(float32 lower, float32 upper)
{
b2Assert(lower <= upper);
if (lower != m_lowerTranslation || upper != m_upperTranslation)
{
m_bodyA->SetAwake(true);
m_bodyB->SetAwake(true);
m_lowerTranslation = lower;
m_upperTranslation = upper;
m_impulse.z = 0.0f;
}
}
bool b2PrismaticJoint::IsMotorEnabled() const
{
return m_enableMotor;
}
void b2PrismaticJoint::EnableMotor(bool flag)
{
m_bodyA->SetAwake(true);
m_bodyB->SetAwake(true);
m_enableMotor = flag;
}
void b2PrismaticJoint::SetMotorSpeed(float32 speed)
{
m_bodyA->SetAwake(true);
m_bodyB->SetAwake(true);
m_motorSpeed = speed;
}
void b2PrismaticJoint::SetMaxMotorForce(float32 force)
{
m_bodyA->SetAwake(true);
m_bodyB->SetAwake(true);
m_maxMotorForce = force;
}
float32 b2PrismaticJoint::GetMotorForce(float32 inv_dt) const
{
return inv_dt * m_motorImpulse;
}
void b2PrismaticJoint::Dump()
{
int32 indexA = m_bodyA->m_islandIndex;
int32 indexB = m_bodyB->m_islandIndex;
b2Log(" b2PrismaticJointDef jd;\n");
b2Log(" jd.bodyA = bodies[%d];\n", indexA);
b2Log(" jd.bodyB = bodies[%d];\n", indexB);
b2Log(" jd.collideConnected = bool(%d);\n", m_collideConnected);
b2Log(" jd.localAnchorA.Set(%.15lef, %.15lef);\n", m_localAnchorA.x, m_localAnchorA.y);
b2Log(" jd.localAnchorB.Set(%.15lef, %.15lef);\n", m_localAnchorB.x, m_localAnchorB.y);
b2Log(" jd.localAxisA.Set(%.15lef, %.15lef);\n", m_localXAxisA.x, m_localXAxisA.y);
b2Log(" jd.referenceAngle = %.15lef;\n", m_referenceAngle);
b2Log(" jd.enableLimit = bool(%d);\n", m_enableLimit);
b2Log(" jd.lowerTranslation = %.15lef;\n", m_lowerTranslation);
b2Log(" jd.upperTranslation = %.15lef;\n", m_upperTranslation);
b2Log(" jd.enableMotor = bool(%d);\n", m_enableMotor);
b2Log(" jd.motorSpeed = %.15lef;\n", m_motorSpeed);
b2Log(" jd.maxMotorForce = %.15lef;\n", m_maxMotorForce);
b2Log(" joints[%d] = m_world->CreateJoint(&jd);\n", m_index);
}

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_PRISMATIC_JOINT_H
#define B2_PRISMATIC_JOINT_H
#include "b2Joint.h"
/// Prismatic joint definition. This requires defining a line of
/// motion using an axis and an anchor point. The definition uses local
/// anchor points and a local axis so that the initial configuration
/// can violate the constraint slightly. The joint translation is zero
/// when the local anchor points coincide in world space. Using local
/// anchors and a local axis helps when saving and loading a game.
struct b2PrismaticJointDef : public b2JointDef
{
b2PrismaticJointDef()
{
type = e_prismaticJoint;
localAnchorA.SetZero();
localAnchorB.SetZero();
localAxisA.Set(1.0f, 0.0f);
referenceAngle = 0.0f;
enableLimit = false;
lowerTranslation = 0.0f;
upperTranslation = 0.0f;
enableMotor = false;
maxMotorForce = 0.0f;
motorSpeed = 0.0f;
}
/// Initialize the bodies, anchors, axis, and reference angle using the world
/// anchor and unit world axis.
void Initialize(b2Body* bodyA, b2Body* bodyB, const b2Vec2& anchor, const b2Vec2& axis);
/// The local anchor point relative to bodyA's origin.
b2Vec2 localAnchorA;
/// The local anchor point relative to bodyB's origin.
b2Vec2 localAnchorB;
/// The local translation unit axis in bodyA.
b2Vec2 localAxisA;
/// The constrained angle between the bodies: bodyB_angle - bodyA_angle.
float32 referenceAngle;
/// Enable/disable the joint limit.
bool enableLimit;
/// The lower translation limit, usually in meters.
float32 lowerTranslation;
/// The upper translation limit, usually in meters.
float32 upperTranslation;
/// Enable/disable the joint motor.
bool enableMotor;
/// The maximum motor torque, usually in N-m.
float32 maxMotorForce;
/// The desired motor speed in radians per second.
float32 motorSpeed;
};
/// A prismatic joint. This joint provides one degree of freedom: translation
/// along an axis fixed in bodyA. Relative rotation is prevented. You can
/// use a joint limit to restrict the range of motion and a joint motor to
/// drive the motion or to model joint friction.
class b2PrismaticJoint : public b2Joint
{
public:
b2Vec2 GetAnchorA() const;
b2Vec2 GetAnchorB() const;
b2Vec2 GetReactionForce(float32 inv_dt) const;
float32 GetReactionTorque(float32 inv_dt) const;
/// The local anchor point relative to bodyA's origin.
const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
/// The local anchor point relative to bodyB's origin.
const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
/// The local joint axis relative to bodyA.
const b2Vec2& GetLocalAxisA() const { return m_localXAxisA; }
/// Get the reference angle.
float32 GetReferenceAngle() const { return m_referenceAngle; }
/// Get the current joint translation, usually in meters.
float32 GetJointTranslation() const;
/// Get the current joint translation speed, usually in meters per second.
float32 GetJointSpeed() const;
/// Is the joint limit enabled?
bool IsLimitEnabled() const;
/// Enable/disable the joint limit.
void EnableLimit(bool flag);
/// Get the lower joint limit, usually in meters.
float32 GetLowerLimit() const;
/// Get the upper joint limit, usually in meters.
float32 GetUpperLimit() const;
/// Set the joint limits, usually in meters.
void SetLimits(float32 lower, float32 upper);
/// Is the joint motor enabled?
bool IsMotorEnabled() const;
/// Enable/disable the joint motor.
void EnableMotor(bool flag);
/// Set the motor speed, usually in meters per second.
void SetMotorSpeed(float32 speed);
/// Get the motor speed, usually in meters per second.
float32 GetMotorSpeed() const;
/// Set the maximum motor force, usually in N.
void SetMaxMotorForce(float32 force);
float32 GetMaxMotorForce() const { return m_maxMotorForce; }
/// Get the current motor force given the inverse time step, usually in N.
float32 GetMotorForce(float32 inv_dt) const;
/// Dump to b2Log
void Dump();
protected:
friend class b2Joint;
friend class b2GearJoint;
b2PrismaticJoint(const b2PrismaticJointDef* def);
void InitVelocityConstraints(const b2SolverData& data);
void SolveVelocityConstraints(const b2SolverData& data);
bool SolvePositionConstraints(const b2SolverData& data);
// Solver shared
b2Vec2 m_localAnchorA;
b2Vec2 m_localAnchorB;
b2Vec2 m_localXAxisA;
b2Vec2 m_localYAxisA;
float32 m_referenceAngle;
b2Vec3 m_impulse;
float32 m_motorImpulse;
float32 m_lowerTranslation;
float32 m_upperTranslation;
float32 m_maxMotorForce;
float32 m_motorSpeed;
bool m_enableLimit;
bool m_enableMotor;
b2LimitState m_limitState;
// Solver temp
juce::int32 m_indexA;
juce::int32 m_indexB;
b2Vec2 m_localCenterA;
b2Vec2 m_localCenterB;
float32 m_invMassA;
float32 m_invMassB;
float32 m_invIA;
float32 m_invIB;
b2Vec2 m_axis, m_perp;
float32 m_s1, m_s2;
float32 m_a1, m_a2;
b2Mat33 m_K;
float32 m_motorMass;
};
inline float32 b2PrismaticJoint::GetMotorSpeed() const
{
return m_motorSpeed;
}
#endif

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/*
* Copyright (c) 2007 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2PulleyJoint.h"
#include "../b2Body.h"
#include "../b2TimeStep.h"
// Pulley:
// length1 = norm(p1 - s1)
// length2 = norm(p2 - s2)
// C0 = (length1 + ratio * length2)_initial
// C = C0 - (length1 + ratio * length2)
// u1 = (p1 - s1) / norm(p1 - s1)
// u2 = (p2 - s2) / norm(p2 - s2)
// Cdot = -dot(u1, v1 + cross(w1, r1)) - ratio * dot(u2, v2 + cross(w2, r2))
// J = -[u1 cross(r1, u1) ratio * u2 ratio * cross(r2, u2)]
// K = J * invM * JT
// = invMass1 + invI1 * cross(r1, u1)^2 + ratio^2 * (invMass2 + invI2 * cross(r2, u2)^2)
void b2PulleyJointDef::Initialize(b2Body* bA, b2Body* bB,
const b2Vec2& groundA, const b2Vec2& groundB,
const b2Vec2& anchorA, const b2Vec2& anchorB,
float32 r)
{
bodyA = bA;
bodyB = bB;
groundAnchorA = groundA;
groundAnchorB = groundB;
localAnchorA = bodyA->GetLocalPoint(anchorA);
localAnchorB = bodyB->GetLocalPoint(anchorB);
b2Vec2 dA = anchorA - groundA;
lengthA = dA.Length();
b2Vec2 dB = anchorB - groundB;
lengthB = dB.Length();
ratio = r;
b2Assert(ratio > b2_epsilon);
}
b2PulleyJoint::b2PulleyJoint(const b2PulleyJointDef* def)
: b2Joint(def)
{
m_groundAnchorA = def->groundAnchorA;
m_groundAnchorB = def->groundAnchorB;
m_localAnchorA = def->localAnchorA;
m_localAnchorB = def->localAnchorB;
m_lengthA = def->lengthA;
m_lengthB = def->lengthB;
b2Assert(def->ratio != 0.0f);
m_ratio = def->ratio;
m_constant = def->lengthA + m_ratio * def->lengthB;
m_impulse = 0.0f;
}
void b2PulleyJoint::InitVelocityConstraints(const b2SolverData& data)
{
m_indexA = m_bodyA->m_islandIndex;
m_indexB = m_bodyB->m_islandIndex;
m_localCenterA = m_bodyA->m_sweep.localCenter;
m_localCenterB = m_bodyB->m_sweep.localCenter;
m_invMassA = m_bodyA->m_invMass;
m_invMassB = m_bodyB->m_invMass;
m_invIA = m_bodyA->m_invI;
m_invIB = m_bodyB->m_invI;
b2Vec2 cA = data.positions[m_indexA].c;
float32 aA = data.positions[m_indexA].a;
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
b2Rot qA(aA), qB(aB);
m_rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
m_rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
// Get the pulley axes.
m_uA = cA + m_rA - m_groundAnchorA;
m_uB = cB + m_rB - m_groundAnchorB;
float32 lengthA = m_uA.Length();
float32 lengthB = m_uB.Length();
if (lengthA > 10.0f * b2_linearSlop)
{
m_uA *= 1.0f / lengthA;
}
else
{
m_uA.SetZero();
}
if (lengthB > 10.0f * b2_linearSlop)
{
m_uB *= 1.0f / lengthB;
}
else
{
m_uB.SetZero();
}
// Compute effective mass.
float32 ruA = b2Cross(m_rA, m_uA);
float32 ruB = b2Cross(m_rB, m_uB);
float32 mA = m_invMassA + m_invIA * ruA * ruA;
float32 mB = m_invMassB + m_invIB * ruB * ruB;
m_mass = mA + m_ratio * m_ratio * mB;
if (m_mass > 0.0f)
{
m_mass = 1.0f / m_mass;
}
if (data.step.warmStarting)
{
// Scale impulses to support variable time steps.
m_impulse *= data.step.dtRatio;
// Warm starting.
b2Vec2 PA = -(m_impulse) * m_uA;
b2Vec2 PB = (-m_ratio * m_impulse) * m_uB;
vA += m_invMassA * PA;
wA += m_invIA * b2Cross(m_rA, PA);
vB += m_invMassB * PB;
wB += m_invIB * b2Cross(m_rB, PB);
}
else
{
m_impulse = 0.0f;
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
void b2PulleyJoint::SolveVelocityConstraints(const b2SolverData& data)
{
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
b2Vec2 vpA = vA + b2Cross(wA, m_rA);
b2Vec2 vpB = vB + b2Cross(wB, m_rB);
float32 Cdot = -b2Dot(m_uA, vpA) - m_ratio * b2Dot(m_uB, vpB);
float32 impulse = -m_mass * Cdot;
m_impulse += impulse;
b2Vec2 PA = -impulse * m_uA;
b2Vec2 PB = -m_ratio * impulse * m_uB;
vA += m_invMassA * PA;
wA += m_invIA * b2Cross(m_rA, PA);
vB += m_invMassB * PB;
wB += m_invIB * b2Cross(m_rB, PB);
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
bool b2PulleyJoint::SolvePositionConstraints(const b2SolverData& data)
{
b2Vec2 cA = data.positions[m_indexA].c;
float32 aA = data.positions[m_indexA].a;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Rot qA(aA), qB(aB);
b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
// Get the pulley axes.
b2Vec2 uA = cA + rA - m_groundAnchorA;
b2Vec2 uB = cB + rB - m_groundAnchorB;
float32 lengthA = uA.Length();
float32 lengthB = uB.Length();
if (lengthA > 10.0f * b2_linearSlop)
{
uA *= 1.0f / lengthA;
}
else
{
uA.SetZero();
}
if (lengthB > 10.0f * b2_linearSlop)
{
uB *= 1.0f / lengthB;
}
else
{
uB.SetZero();
}
// Compute effective mass.
float32 ruA = b2Cross(rA, uA);
float32 ruB = b2Cross(rB, uB);
float32 mA = m_invMassA + m_invIA * ruA * ruA;
float32 mB = m_invMassB + m_invIB * ruB * ruB;
float32 mass = mA + m_ratio * m_ratio * mB;
if (mass > 0.0f)
{
mass = 1.0f / mass;
}
float32 C = m_constant - lengthA - m_ratio * lengthB;
float32 linearError = b2Abs(C);
float32 impulse = -mass * C;
b2Vec2 PA = -impulse * uA;
b2Vec2 PB = -m_ratio * impulse * uB;
cA += m_invMassA * PA;
aA += m_invIA * b2Cross(rA, PA);
cB += m_invMassB * PB;
aB += m_invIB * b2Cross(rB, PB);
data.positions[m_indexA].c = cA;
data.positions[m_indexA].a = aA;
data.positions[m_indexB].c = cB;
data.positions[m_indexB].a = aB;
return linearError < b2_linearSlop;
}
b2Vec2 b2PulleyJoint::GetAnchorA() const
{
return m_bodyA->GetWorldPoint(m_localAnchorA);
}
b2Vec2 b2PulleyJoint::GetAnchorB() const
{
return m_bodyB->GetWorldPoint(m_localAnchorB);
}
b2Vec2 b2PulleyJoint::GetReactionForce(float32 inv_dt) const
{
b2Vec2 P = m_impulse * m_uB;
return inv_dt * P;
}
float32 b2PulleyJoint::GetReactionTorque(float32 inv_dt) const
{
B2_NOT_USED(inv_dt);
return 0.0f;
}
b2Vec2 b2PulleyJoint::GetGroundAnchorA() const
{
return m_groundAnchorA;
}
b2Vec2 b2PulleyJoint::GetGroundAnchorB() const
{
return m_groundAnchorB;
}
float32 b2PulleyJoint::GetLengthA() const
{
b2Vec2 p = m_bodyA->GetWorldPoint(m_localAnchorA);
b2Vec2 s = m_groundAnchorA;
b2Vec2 d = p - s;
return d.Length();
}
float32 b2PulleyJoint::GetLengthB() const
{
b2Vec2 p = m_bodyB->GetWorldPoint(m_localAnchorB);
b2Vec2 s = m_groundAnchorB;
b2Vec2 d = p - s;
return d.Length();
}
float32 b2PulleyJoint::GetRatio() const
{
return m_ratio;
}
void b2PulleyJoint::Dump()
{
int32 indexA = m_bodyA->m_islandIndex;
int32 indexB = m_bodyB->m_islandIndex;
b2Log(" b2PulleyJointDef jd;\n");
b2Log(" jd.bodyA = bodies[%d];\n", indexA);
b2Log(" jd.bodyB = bodies[%d];\n", indexB);
b2Log(" jd.collideConnected = bool(%d);\n", m_collideConnected);
b2Log(" jd.groundAnchorA.Set(%.15lef, %.15lef);\n", m_groundAnchorA.x, m_groundAnchorA.y);
b2Log(" jd.groundAnchorB.Set(%.15lef, %.15lef);\n", m_groundAnchorB.x, m_groundAnchorB.y);
b2Log(" jd.localAnchorA.Set(%.15lef, %.15lef);\n", m_localAnchorA.x, m_localAnchorA.y);
b2Log(" jd.localAnchorB.Set(%.15lef, %.15lef);\n", m_localAnchorB.x, m_localAnchorB.y);
b2Log(" jd.lengthA = %.15lef;\n", m_lengthA);
b2Log(" jd.lengthB = %.15lef;\n", m_lengthB);
b2Log(" jd.ratio = %.15lef;\n", m_ratio);
b2Log(" joints[%d] = m_world->CreateJoint(&jd);\n", m_index);
}

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_PULLEY_JOINT_H
#define B2_PULLEY_JOINT_H
#include "b2Joint.h"
const float32 b2_minPulleyLength = 2.0f;
/// Pulley joint definition. This requires two ground anchors,
/// two dynamic body anchor points, and a pulley ratio.
struct b2PulleyJointDef : public b2JointDef
{
b2PulleyJointDef()
{
type = e_pulleyJoint;
groundAnchorA.Set(-1.0f, 1.0f);
groundAnchorB.Set(1.0f, 1.0f);
localAnchorA.Set(-1.0f, 0.0f);
localAnchorB.Set(1.0f, 0.0f);
lengthA = 0.0f;
lengthB = 0.0f;
ratio = 1.0f;
collideConnected = true;
}
/// Initialize the bodies, anchors, lengths, max lengths, and ratio using the world anchors.
void Initialize(b2Body* bodyA, b2Body* bodyB,
const b2Vec2& groundAnchorA, const b2Vec2& groundAnchorB,
const b2Vec2& anchorA, const b2Vec2& anchorB,
float32 ratio);
/// The first ground anchor in world coordinates. This point never moves.
b2Vec2 groundAnchorA;
/// The second ground anchor in world coordinates. This point never moves.
b2Vec2 groundAnchorB;
/// The local anchor point relative to bodyA's origin.
b2Vec2 localAnchorA;
/// The local anchor point relative to bodyB's origin.
b2Vec2 localAnchorB;
/// The a reference length for the segment attached to bodyA.
float32 lengthA;
/// The a reference length for the segment attached to bodyB.
float32 lengthB;
/// The pulley ratio, used to simulate a block-and-tackle.
float32 ratio;
};
/// The pulley joint is connected to two bodies and two fixed ground points.
/// The pulley supports a ratio such that:
/// length1 + ratio * length2 <= constant
/// Yes, the force transmitted is scaled by the ratio.
/// Warning: the pulley joint can get a bit squirrelly by itself. They often
/// work better when combined with prismatic joints. You should also cover the
/// the anchor points with static shapes to prevent one side from going to
/// zero length.
class b2PulleyJoint : public b2Joint
{
public:
b2Vec2 GetAnchorA() const;
b2Vec2 GetAnchorB() const;
b2Vec2 GetReactionForce(float32 inv_dt) const;
float32 GetReactionTorque(float32 inv_dt) const;
/// Get the first ground anchor.
b2Vec2 GetGroundAnchorA() const;
/// Get the second ground anchor.
b2Vec2 GetGroundAnchorB() const;
/// Get the current length of the segment attached to bodyA.
float32 GetLengthA() const;
/// Get the current length of the segment attached to bodyB.
float32 GetLengthB() const;
/// Get the pulley ratio.
float32 GetRatio() const;
/// Dump joint to dmLog
void Dump();
protected:
friend class b2Joint;
b2PulleyJoint(const b2PulleyJointDef* data);
void InitVelocityConstraints(const b2SolverData& data);
void SolveVelocityConstraints(const b2SolverData& data);
bool SolvePositionConstraints(const b2SolverData& data);
b2Vec2 m_groundAnchorA;
b2Vec2 m_groundAnchorB;
float32 m_lengthA;
float32 m_lengthB;
// Solver shared
b2Vec2 m_localAnchorA;
b2Vec2 m_localAnchorB;
float32 m_constant;
float32 m_ratio;
float32 m_impulse;
// Solver temp
juce::int32 m_indexA;
juce::int32 m_indexB;
b2Vec2 m_uA;
b2Vec2 m_uB;
b2Vec2 m_rA;
b2Vec2 m_rB;
b2Vec2 m_localCenterA;
b2Vec2 m_localCenterB;
float32 m_invMassA;
float32 m_invMassB;
float32 m_invIA;
float32 m_invIB;
float32 m_mass;
};
#endif

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2RevoluteJoint.h"
#include "../b2Body.h"
#include "../b2TimeStep.h"
// Point-to-point constraint
// C = p2 - p1
// Cdot = v2 - v1
// = v2 + cross(w2, r2) - v1 - cross(w1, r1)
// J = [-I -r1_skew I r2_skew ]
// Identity used:
// w k % (rx i + ry j) = w * (-ry i + rx j)
// Motor constraint
// Cdot = w2 - w1
// J = [0 0 -1 0 0 1]
// K = invI1 + invI2
void b2RevoluteJointDef::Initialize(b2Body* bA, b2Body* bB, const b2Vec2& anchor)
{
bodyA = bA;
bodyB = bB;
localAnchorA = bodyA->GetLocalPoint(anchor);
localAnchorB = bodyB->GetLocalPoint(anchor);
referenceAngle = bodyB->GetAngle() - bodyA->GetAngle();
}
b2RevoluteJoint::b2RevoluteJoint(const b2RevoluteJointDef* def)
: b2Joint(def)
{
m_localAnchorA = def->localAnchorA;
m_localAnchorB = def->localAnchorB;
m_referenceAngle = def->referenceAngle;
m_impulse.SetZero();
m_motorImpulse = 0.0f;
m_lowerAngle = def->lowerAngle;
m_upperAngle = def->upperAngle;
m_maxMotorTorque = def->maxMotorTorque;
m_motorSpeed = def->motorSpeed;
m_enableLimit = def->enableLimit;
m_enableMotor = def->enableMotor;
m_limitState = e_inactiveLimit;
}
void b2RevoluteJoint::InitVelocityConstraints(const b2SolverData& data)
{
m_indexA = m_bodyA->m_islandIndex;
m_indexB = m_bodyB->m_islandIndex;
m_localCenterA = m_bodyA->m_sweep.localCenter;
m_localCenterB = m_bodyB->m_sweep.localCenter;
m_invMassA = m_bodyA->m_invMass;
m_invMassB = m_bodyB->m_invMass;
m_invIA = m_bodyA->m_invI;
m_invIB = m_bodyB->m_invI;
float32 aA = data.positions[m_indexA].a;
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
float32 aB = data.positions[m_indexB].a;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
b2Rot qA(aA), qB(aB);
m_rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
m_rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
// J = [-I -r1_skew I r2_skew]
// [ 0 -1 0 1]
// r_skew = [-ry; rx]
// Matlab
// K = [ mA+r1y^2*iA+mB+r2y^2*iB, -r1y*iA*r1x-r2y*iB*r2x, -r1y*iA-r2y*iB]
// [ -r1y*iA*r1x-r2y*iB*r2x, mA+r1x^2*iA+mB+r2x^2*iB, r1x*iA+r2x*iB]
// [ -r1y*iA-r2y*iB, r1x*iA+r2x*iB, iA+iB]
float32 mA = m_invMassA, mB = m_invMassB;
float32 iA = m_invIA, iB = m_invIB;
bool fixedRotation = (iA + iB == 0.0f);
m_mass.ex.x = mA + mB + m_rA.y * m_rA.y * iA + m_rB.y * m_rB.y * iB;
m_mass.ey.x = -m_rA.y * m_rA.x * iA - m_rB.y * m_rB.x * iB;
m_mass.ez.x = -m_rA.y * iA - m_rB.y * iB;
m_mass.ex.y = m_mass.ey.x;
m_mass.ey.y = mA + mB + m_rA.x * m_rA.x * iA + m_rB.x * m_rB.x * iB;
m_mass.ez.y = m_rA.x * iA + m_rB.x * iB;
m_mass.ex.z = m_mass.ez.x;
m_mass.ey.z = m_mass.ez.y;
m_mass.ez.z = iA + iB;
m_motorMass = iA + iB;
if (m_motorMass > 0.0f)
{
m_motorMass = 1.0f / m_motorMass;
}
if (m_enableMotor == false || fixedRotation)
{
m_motorImpulse = 0.0f;
}
if (m_enableLimit && fixedRotation == false)
{
float32 jointAngle = aB - aA - m_referenceAngle;
if (b2Abs(m_upperAngle - m_lowerAngle) < 2.0f * b2_angularSlop)
{
m_limitState = e_equalLimits;
}
else if (jointAngle <= m_lowerAngle)
{
if (m_limitState != e_atLowerLimit)
{
m_impulse.z = 0.0f;
}
m_limitState = e_atLowerLimit;
}
else if (jointAngle >= m_upperAngle)
{
if (m_limitState != e_atUpperLimit)
{
m_impulse.z = 0.0f;
}
m_limitState = e_atUpperLimit;
}
else
{
m_limitState = e_inactiveLimit;
m_impulse.z = 0.0f;
}
}
else
{
m_limitState = e_inactiveLimit;
}
if (data.step.warmStarting)
{
// Scale impulses to support a variable time step.
m_impulse *= data.step.dtRatio;
m_motorImpulse *= data.step.dtRatio;
b2Vec2 P(m_impulse.x, m_impulse.y);
vA -= mA * P;
wA -= iA * (b2Cross(m_rA, P) + m_motorImpulse + m_impulse.z);
vB += mB * P;
wB += iB * (b2Cross(m_rB, P) + m_motorImpulse + m_impulse.z);
}
else
{
m_impulse.SetZero();
m_motorImpulse = 0.0f;
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
void b2RevoluteJoint::SolveVelocityConstraints(const b2SolverData& data)
{
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
float32 mA = m_invMassA, mB = m_invMassB;
float32 iA = m_invIA, iB = m_invIB;
bool fixedRotation = (iA + iB == 0.0f);
// Solve motor constraint.
if (m_enableMotor && m_limitState != e_equalLimits && fixedRotation == false)
{
float32 Cdot = wB - wA - m_motorSpeed;
float32 impulse = -m_motorMass * Cdot;
float32 oldImpulse = m_motorImpulse;
float32 maxImpulse = data.step.dt * m_maxMotorTorque;
m_motorImpulse = b2Clamp(m_motorImpulse + impulse, -maxImpulse, maxImpulse);
impulse = m_motorImpulse - oldImpulse;
wA -= iA * impulse;
wB += iB * impulse;
}
// Solve limit constraint.
if (m_enableLimit && m_limitState != e_inactiveLimit && fixedRotation == false)
{
b2Vec2 Cdot1 = vB + b2Cross(wB, m_rB) - vA - b2Cross(wA, m_rA);
float32 Cdot2 = wB - wA;
b2Vec3 Cdot(Cdot1.x, Cdot1.y, Cdot2);
b2Vec3 impulse = -m_mass.Solve33(Cdot);
if (m_limitState == e_equalLimits)
{
m_impulse += impulse;
}
else if (m_limitState == e_atLowerLimit)
{
float32 newImpulse = m_impulse.z + impulse.z;
if (newImpulse < 0.0f)
{
b2Vec2 rhs = -Cdot1 + m_impulse.z * b2Vec2(m_mass.ez.x, m_mass.ez.y);
b2Vec2 reduced = m_mass.Solve22(rhs);
impulse.x = reduced.x;
impulse.y = reduced.y;
impulse.z = -m_impulse.z;
m_impulse.x += reduced.x;
m_impulse.y += reduced.y;
m_impulse.z = 0.0f;
}
else
{
m_impulse += impulse;
}
}
else if (m_limitState == e_atUpperLimit)
{
float32 newImpulse = m_impulse.z + impulse.z;
if (newImpulse > 0.0f)
{
b2Vec2 rhs = -Cdot1 + m_impulse.z * b2Vec2(m_mass.ez.x, m_mass.ez.y);
b2Vec2 reduced = m_mass.Solve22(rhs);
impulse.x = reduced.x;
impulse.y = reduced.y;
impulse.z = -m_impulse.z;
m_impulse.x += reduced.x;
m_impulse.y += reduced.y;
m_impulse.z = 0.0f;
}
else
{
m_impulse += impulse;
}
}
b2Vec2 P(impulse.x, impulse.y);
vA -= mA * P;
wA -= iA * (b2Cross(m_rA, P) + impulse.z);
vB += mB * P;
wB += iB * (b2Cross(m_rB, P) + impulse.z);
}
else
{
// Solve point-to-point constraint
b2Vec2 Cdot = vB + b2Cross(wB, m_rB) - vA - b2Cross(wA, m_rA);
b2Vec2 impulse = m_mass.Solve22(-Cdot);
m_impulse.x += impulse.x;
m_impulse.y += impulse.y;
vA -= mA * impulse;
wA -= iA * b2Cross(m_rA, impulse);
vB += mB * impulse;
wB += iB * b2Cross(m_rB, impulse);
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
bool b2RevoluteJoint::SolvePositionConstraints(const b2SolverData& data)
{
b2Vec2 cA = data.positions[m_indexA].c;
float32 aA = data.positions[m_indexA].a;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Rot qA(aA), qB(aB);
float32 angularError = 0.0f;
float32 positionError = 0.0f;
bool fixedRotation = (m_invIA + m_invIB == 0.0f);
// Solve angular limit constraint.
if (m_enableLimit && m_limitState != e_inactiveLimit && fixedRotation == false)
{
float32 angle = aB - aA - m_referenceAngle;
float32 limitImpulse = 0.0f;
if (m_limitState == e_equalLimits)
{
// Prevent large angular corrections
float32 C = b2Clamp(angle - m_lowerAngle, -b2_maxAngularCorrection, b2_maxAngularCorrection);
limitImpulse = -m_motorMass * C;
angularError = b2Abs(C);
}
else if (m_limitState == e_atLowerLimit)
{
float32 C = angle - m_lowerAngle;
angularError = -C;
// Prevent large angular corrections and allow some slop.
C = b2Clamp(C + b2_angularSlop, -b2_maxAngularCorrection, 0.0f);
limitImpulse = -m_motorMass * C;
}
else if (m_limitState == e_atUpperLimit)
{
float32 C = angle - m_upperAngle;
angularError = C;
// Prevent large angular corrections and allow some slop.
C = b2Clamp(C - b2_angularSlop, 0.0f, b2_maxAngularCorrection);
limitImpulse = -m_motorMass * C;
}
aA -= m_invIA * limitImpulse;
aB += m_invIB * limitImpulse;
}
// Solve point-to-point constraint.
{
qA.Set(aA);
qB.Set(aB);
b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
b2Vec2 C = cB + rB - cA - rA;
positionError = C.Length();
float32 mA = m_invMassA, mB = m_invMassB;
float32 iA = m_invIA, iB = m_invIB;
b2Mat22 K;
K.ex.x = mA + mB + iA * rA.y * rA.y + iB * rB.y * rB.y;
K.ex.y = -iA * rA.x * rA.y - iB * rB.x * rB.y;
K.ey.x = K.ex.y;
K.ey.y = mA + mB + iA * rA.x * rA.x + iB * rB.x * rB.x;
b2Vec2 impulse = -K.Solve(C);
cA -= mA * impulse;
aA -= iA * b2Cross(rA, impulse);
cB += mB * impulse;
aB += iB * b2Cross(rB, impulse);
}
data.positions[m_indexA].c = cA;
data.positions[m_indexA].a = aA;
data.positions[m_indexB].c = cB;
data.positions[m_indexB].a = aB;
return positionError <= b2_linearSlop && angularError <= b2_angularSlop;
}
b2Vec2 b2RevoluteJoint::GetAnchorA() const
{
return m_bodyA->GetWorldPoint(m_localAnchorA);
}
b2Vec2 b2RevoluteJoint::GetAnchorB() const
{
return m_bodyB->GetWorldPoint(m_localAnchorB);
}
b2Vec2 b2RevoluteJoint::GetReactionForce(float32 inv_dt) const
{
b2Vec2 P(m_impulse.x, m_impulse.y);
return inv_dt * P;
}
float32 b2RevoluteJoint::GetReactionTorque(float32 inv_dt) const
{
return inv_dt * m_impulse.z;
}
float32 b2RevoluteJoint::GetJointAngle() const
{
b2Body* bA = m_bodyA;
b2Body* bB = m_bodyB;
return bB->m_sweep.a - bA->m_sweep.a - m_referenceAngle;
}
float32 b2RevoluteJoint::GetJointSpeed() const
{
b2Body* bA = m_bodyA;
b2Body* bB = m_bodyB;
return bB->m_angularVelocity - bA->m_angularVelocity;
}
bool b2RevoluteJoint::IsMotorEnabled() const
{
return m_enableMotor;
}
void b2RevoluteJoint::EnableMotor(bool flag)
{
m_bodyA->SetAwake(true);
m_bodyB->SetAwake(true);
m_enableMotor = flag;
}
float32 b2RevoluteJoint::GetMotorTorque(float32 inv_dt) const
{
return inv_dt * m_motorImpulse;
}
void b2RevoluteJoint::SetMotorSpeed(float32 speed)
{
m_bodyA->SetAwake(true);
m_bodyB->SetAwake(true);
m_motorSpeed = speed;
}
void b2RevoluteJoint::SetMaxMotorTorque(float32 torque)
{
m_bodyA->SetAwake(true);
m_bodyB->SetAwake(true);
m_maxMotorTorque = torque;
}
bool b2RevoluteJoint::IsLimitEnabled() const
{
return m_enableLimit;
}
void b2RevoluteJoint::EnableLimit(bool flag)
{
if (flag != m_enableLimit)
{
m_bodyA->SetAwake(true);
m_bodyB->SetAwake(true);
m_enableLimit = flag;
m_impulse.z = 0.0f;
}
}
float32 b2RevoluteJoint::GetLowerLimit() const
{
return m_lowerAngle;
}
float32 b2RevoluteJoint::GetUpperLimit() const
{
return m_upperAngle;
}
void b2RevoluteJoint::SetLimits(float32 lower, float32 upper)
{
b2Assert(lower <= upper);
if (lower != m_lowerAngle || upper != m_upperAngle)
{
m_bodyA->SetAwake(true);
m_bodyB->SetAwake(true);
m_impulse.z = 0.0f;
m_lowerAngle = lower;
m_upperAngle = upper;
}
}
void b2RevoluteJoint::Dump()
{
int32 indexA = m_bodyA->m_islandIndex;
int32 indexB = m_bodyB->m_islandIndex;
b2Log(" b2RevoluteJointDef jd;\n");
b2Log(" jd.bodyA = bodies[%d];\n", indexA);
b2Log(" jd.bodyB = bodies[%d];\n", indexB);
b2Log(" jd.collideConnected = bool(%d);\n", m_collideConnected);
b2Log(" jd.localAnchorA.Set(%.15lef, %.15lef);\n", m_localAnchorA.x, m_localAnchorA.y);
b2Log(" jd.localAnchorB.Set(%.15lef, %.15lef);\n", m_localAnchorB.x, m_localAnchorB.y);
b2Log(" jd.referenceAngle = %.15lef;\n", m_referenceAngle);
b2Log(" jd.enableLimit = bool(%d);\n", m_enableLimit);
b2Log(" jd.lowerAngle = %.15lef;\n", m_lowerAngle);
b2Log(" jd.upperAngle = %.15lef;\n", m_upperAngle);
b2Log(" jd.enableMotor = bool(%d);\n", m_enableMotor);
b2Log(" jd.motorSpeed = %.15lef;\n", m_motorSpeed);
b2Log(" jd.maxMotorTorque = %.15lef;\n", m_maxMotorTorque);
b2Log(" joints[%d] = m_world->CreateJoint(&jd);\n", m_index);
}

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_REVOLUTE_JOINT_H
#define B2_REVOLUTE_JOINT_H
#include "b2Joint.h"
/// Revolute joint definition. This requires defining an
/// anchor point where the bodies are joined. The definition
/// uses local anchor points so that the initial configuration
/// can violate the constraint slightly. You also need to
/// specify the initial relative angle for joint limits. This
/// helps when saving and loading a game.
/// The local anchor points are measured from the body's origin
/// rather than the center of mass because:
/// 1. you might not know where the center of mass will be.
/// 2. if you add/remove shapes from a body and recompute the mass,
/// the joints will be broken.
struct b2RevoluteJointDef : public b2JointDef
{
b2RevoluteJointDef()
{
type = e_revoluteJoint;
localAnchorA.Set(0.0f, 0.0f);
localAnchorB.Set(0.0f, 0.0f);
referenceAngle = 0.0f;
lowerAngle = 0.0f;
upperAngle = 0.0f;
maxMotorTorque = 0.0f;
motorSpeed = 0.0f;
enableLimit = false;
enableMotor = false;
}
/// Initialize the bodies, anchors, and reference angle using a world
/// anchor point.
void Initialize(b2Body* bodyA, b2Body* bodyB, const b2Vec2& anchor);
/// The local anchor point relative to bodyA's origin.
b2Vec2 localAnchorA;
/// The local anchor point relative to bodyB's origin.
b2Vec2 localAnchorB;
/// The bodyB angle minus bodyA angle in the reference state (radians).
float32 referenceAngle;
/// A flag to enable joint limits.
bool enableLimit;
/// The lower angle for the joint limit (radians).
float32 lowerAngle;
/// The upper angle for the joint limit (radians).
float32 upperAngle;
/// A flag to enable the joint motor.
bool enableMotor;
/// The desired motor speed. Usually in radians per second.
float32 motorSpeed;
/// The maximum motor torque used to achieve the desired motor speed.
/// Usually in N-m.
float32 maxMotorTorque;
};
/// A revolute joint constrains two bodies to share a common point while they
/// are free to rotate about the point. The relative rotation about the shared
/// point is the joint angle. You can limit the relative rotation with
/// a joint limit that specifies a lower and upper angle. You can use a motor
/// to drive the relative rotation about the shared point. A maximum motor torque
/// is provided so that infinite forces are not generated.
class b2RevoluteJoint : public b2Joint
{
public:
b2Vec2 GetAnchorA() const;
b2Vec2 GetAnchorB() const;
/// The local anchor point relative to bodyA's origin.
const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
/// The local anchor point relative to bodyB's origin.
const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
/// Get the reference angle.
float32 GetReferenceAngle() const { return m_referenceAngle; }
/// Get the current joint angle in radians.
float32 GetJointAngle() const;
/// Get the current joint angle speed in radians per second.
float32 GetJointSpeed() const;
/// Is the joint limit enabled?
bool IsLimitEnabled() const;
/// Enable/disable the joint limit.
void EnableLimit(bool flag);
/// Get the lower joint limit in radians.
float32 GetLowerLimit() const;
/// Get the upper joint limit in radians.
float32 GetUpperLimit() const;
/// Set the joint limits in radians.
void SetLimits(float32 lower, float32 upper);
/// Is the joint motor enabled?
bool IsMotorEnabled() const;
/// Enable/disable the joint motor.
void EnableMotor(bool flag);
/// Set the motor speed in radians per second.
void SetMotorSpeed(float32 speed);
/// Get the motor speed in radians per second.
float32 GetMotorSpeed() const;
/// Set the maximum motor torque, usually in N-m.
void SetMaxMotorTorque(float32 torque);
float32 GetMaxMotorTorque() const { return m_maxMotorTorque; }
/// Get the reaction force given the inverse time step.
/// Unit is N.
b2Vec2 GetReactionForce(float32 inv_dt) const;
/// Get the reaction torque due to the joint limit given the inverse time step.
/// Unit is N*m.
float32 GetReactionTorque(float32 inv_dt) const;
/// Get the current motor torque given the inverse time step.
/// Unit is N*m.
float32 GetMotorTorque(float32 inv_dt) const;
/// Dump to b2Log.
void Dump();
protected:
friend class b2Joint;
friend class b2GearJoint;
b2RevoluteJoint(const b2RevoluteJointDef* def);
void InitVelocityConstraints(const b2SolverData& data);
void SolveVelocityConstraints(const b2SolverData& data);
bool SolvePositionConstraints(const b2SolverData& data);
// Solver shared
b2Vec2 m_localAnchorA;
b2Vec2 m_localAnchorB;
b2Vec3 m_impulse;
float32 m_motorImpulse;
bool m_enableMotor;
float32 m_maxMotorTorque;
float32 m_motorSpeed;
bool m_enableLimit;
float32 m_referenceAngle;
float32 m_lowerAngle;
float32 m_upperAngle;
// Solver temp
juce::int32 m_indexA;
juce::int32 m_indexB;
b2Vec2 m_rA;
b2Vec2 m_rB;
b2Vec2 m_localCenterA;
b2Vec2 m_localCenterB;
float32 m_invMassA;
float32 m_invMassB;
float32 m_invIA;
float32 m_invIB;
b2Mat33 m_mass; // effective mass for point-to-point constraint.
float32 m_motorMass; // effective mass for motor/limit angular constraint.
b2LimitState m_limitState;
};
inline float32 b2RevoluteJoint::GetMotorSpeed() const
{
return m_motorSpeed;
}
#endif

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/*
* Copyright (c) 2007-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2RopeJoint.h"
#include "../b2Body.h"
#include "../b2TimeStep.h"
// Limit:
// C = norm(pB - pA) - L
// u = (pB - pA) / norm(pB - pA)
// Cdot = dot(u, vB + cross(wB, rB) - vA - cross(wA, rA))
// J = [-u -cross(rA, u) u cross(rB, u)]
// K = J * invM * JT
// = invMassA + invIA * cross(rA, u)^2 + invMassB + invIB * cross(rB, u)^2
b2RopeJoint::b2RopeJoint(const b2RopeJointDef* def)
: b2Joint(def)
{
m_localAnchorA = def->localAnchorA;
m_localAnchorB = def->localAnchorB;
m_maxLength = def->maxLength;
m_mass = 0.0f;
m_impulse = 0.0f;
m_state = e_inactiveLimit;
m_length = 0.0f;
}
void b2RopeJoint::InitVelocityConstraints(const b2SolverData& data)
{
m_indexA = m_bodyA->m_islandIndex;
m_indexB = m_bodyB->m_islandIndex;
m_localCenterA = m_bodyA->m_sweep.localCenter;
m_localCenterB = m_bodyB->m_sweep.localCenter;
m_invMassA = m_bodyA->m_invMass;
m_invMassB = m_bodyB->m_invMass;
m_invIA = m_bodyA->m_invI;
m_invIB = m_bodyB->m_invI;
b2Vec2 cA = data.positions[m_indexA].c;
float32 aA = data.positions[m_indexA].a;
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
b2Rot qA(aA), qB(aB);
m_rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
m_rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
m_u = cB + m_rB - cA - m_rA;
m_length = m_u.Length();
float32 C = m_length - m_maxLength;
if (C > 0.0f)
{
m_state = e_atUpperLimit;
}
else
{
m_state = e_inactiveLimit;
}
if (m_length > b2_linearSlop)
{
m_u *= 1.0f / m_length;
}
else
{
m_u.SetZero();
m_mass = 0.0f;
m_impulse = 0.0f;
return;
}
// Compute effective mass.
float32 crA = b2Cross(m_rA, m_u);
float32 crB = b2Cross(m_rB, m_u);
float32 invMass = m_invMassA + m_invIA * crA * crA + m_invMassB + m_invIB * crB * crB;
m_mass = invMass != 0.0f ? 1.0f / invMass : 0.0f;
if (data.step.warmStarting)
{
// Scale the impulse to support a variable time step.
m_impulse *= data.step.dtRatio;
b2Vec2 P = m_impulse * m_u;
vA -= m_invMassA * P;
wA -= m_invIA * b2Cross(m_rA, P);
vB += m_invMassB * P;
wB += m_invIB * b2Cross(m_rB, P);
}
else
{
m_impulse = 0.0f;
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
void b2RopeJoint::SolveVelocityConstraints(const b2SolverData& data)
{
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
// Cdot = dot(u, v + cross(w, r))
b2Vec2 vpA = vA + b2Cross(wA, m_rA);
b2Vec2 vpB = vB + b2Cross(wB, m_rB);
float32 C = m_length - m_maxLength;
float32 Cdot = b2Dot(m_u, vpB - vpA);
// Predictive constraint.
if (C < 0.0f)
{
Cdot += data.step.inv_dt * C;
}
float32 impulse = -m_mass * Cdot;
float32 oldImpulse = m_impulse;
m_impulse = b2Min(0.0f, m_impulse + impulse);
impulse = m_impulse - oldImpulse;
b2Vec2 P = impulse * m_u;
vA -= m_invMassA * P;
wA -= m_invIA * b2Cross(m_rA, P);
vB += m_invMassB * P;
wB += m_invIB * b2Cross(m_rB, P);
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
bool b2RopeJoint::SolvePositionConstraints(const b2SolverData& data)
{
b2Vec2 cA = data.positions[m_indexA].c;
float32 aA = data.positions[m_indexA].a;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Rot qA(aA), qB(aB);
b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
b2Vec2 u = cB + rB - cA - rA;
float32 length = u.Normalize();
float32 C = length - m_maxLength;
C = b2Clamp(C, 0.0f, b2_maxLinearCorrection);
float32 impulse = -m_mass * C;
b2Vec2 P = impulse * u;
cA -= m_invMassA * P;
aA -= m_invIA * b2Cross(rA, P);
cB += m_invMassB * P;
aB += m_invIB * b2Cross(rB, P);
data.positions[m_indexA].c = cA;
data.positions[m_indexA].a = aA;
data.positions[m_indexB].c = cB;
data.positions[m_indexB].a = aB;
return length - m_maxLength < b2_linearSlop;
}
b2Vec2 b2RopeJoint::GetAnchorA() const
{
return m_bodyA->GetWorldPoint(m_localAnchorA);
}
b2Vec2 b2RopeJoint::GetAnchorB() const
{
return m_bodyB->GetWorldPoint(m_localAnchorB);
}
b2Vec2 b2RopeJoint::GetReactionForce(float32 inv_dt) const
{
b2Vec2 F = (inv_dt * m_impulse) * m_u;
return F;
}
float32 b2RopeJoint::GetReactionTorque(float32 inv_dt) const
{
B2_NOT_USED(inv_dt);
return 0.0f;
}
float32 b2RopeJoint::GetMaxLength() const
{
return m_maxLength;
}
b2LimitState b2RopeJoint::GetLimitState() const
{
return m_state;
}
void b2RopeJoint::Dump()
{
int32 indexA = m_bodyA->m_islandIndex;
int32 indexB = m_bodyB->m_islandIndex;
b2Log(" b2RopeJointDef jd;\n");
b2Log(" jd.bodyA = bodies[%d];\n", indexA);
b2Log(" jd.bodyB = bodies[%d];\n", indexB);
b2Log(" jd.collideConnected = bool(%d);\n", m_collideConnected);
b2Log(" jd.localAnchorA.Set(%.15lef, %.15lef);\n", m_localAnchorA.x, m_localAnchorA.y);
b2Log(" jd.localAnchorB.Set(%.15lef, %.15lef);\n", m_localAnchorB.x, m_localAnchorB.y);
b2Log(" jd.maxLength = %.15lef;\n", m_maxLength);
b2Log(" joints[%d] = m_world->CreateJoint(&jd);\n", m_index);
}

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_ROPE_JOINT_H
#define B2_ROPE_JOINT_H
#include "b2Joint.h"
/// Rope joint definition. This requires two body anchor points and
/// a maximum lengths.
/// Note: by default the connected objects will not collide.
/// see collideConnected in b2JointDef.
struct b2RopeJointDef : public b2JointDef
{
b2RopeJointDef()
{
type = e_ropeJoint;
localAnchorA.Set(-1.0f, 0.0f);
localAnchorB.Set(1.0f, 0.0f);
maxLength = 0.0f;
}
/// The local anchor point relative to bodyA's origin.
b2Vec2 localAnchorA;
/// The local anchor point relative to bodyB's origin.
b2Vec2 localAnchorB;
/// The maximum length of the rope.
/// Warning: this must be larger than b2_linearSlop or
/// the joint will have no effect.
float32 maxLength;
};
/// A rope joint enforces a maximum distance between two points
/// on two bodies. It has no other effect.
/// Warning: if you attempt to change the maximum length during
/// the simulation you will get some non-physical behavior.
/// A model that would allow you to dynamically modify the length
/// would have some sponginess, so I chose not to implement it
/// that way. See b2DistanceJoint if you want to dynamically
/// control length.
class b2RopeJoint : public b2Joint
{
public:
b2Vec2 GetAnchorA() const;
b2Vec2 GetAnchorB() const;
b2Vec2 GetReactionForce(float32 inv_dt) const;
float32 GetReactionTorque(float32 inv_dt) const;
/// The local anchor point relative to bodyA's origin.
const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
/// The local anchor point relative to bodyB's origin.
const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
/// Set/Get the maximum length of the rope.
void SetMaxLength(float32 length) { m_maxLength = length; }
float32 GetMaxLength() const;
b2LimitState GetLimitState() const;
/// Dump joint to dmLog
void Dump();
protected:
friend class b2Joint;
b2RopeJoint(const b2RopeJointDef* data);
void InitVelocityConstraints(const b2SolverData& data);
void SolveVelocityConstraints(const b2SolverData& data);
bool SolvePositionConstraints(const b2SolverData& data);
// Solver shared
b2Vec2 m_localAnchorA;
b2Vec2 m_localAnchorB;
float32 m_maxLength;
float32 m_length;
float32 m_impulse;
// Solver temp
juce::int32 m_indexA;
juce::int32 m_indexB;
b2Vec2 m_u;
b2Vec2 m_rA;
b2Vec2 m_rB;
b2Vec2 m_localCenterA;
b2Vec2 m_localCenterB;
float32 m_invMassA;
float32 m_invMassB;
float32 m_invIA;
float32 m_invIB;
float32 m_mass;
b2LimitState m_state;
};
#endif

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2WeldJoint.h"
#include "../b2Body.h"
#include "../b2TimeStep.h"
// Point-to-point constraint
// C = p2 - p1
// Cdot = v2 - v1
// = v2 + cross(w2, r2) - v1 - cross(w1, r1)
// J = [-I -r1_skew I r2_skew ]
// Identity used:
// w k % (rx i + ry j) = w * (-ry i + rx j)
// Angle constraint
// C = angle2 - angle1 - referenceAngle
// Cdot = w2 - w1
// J = [0 0 -1 0 0 1]
// K = invI1 + invI2
void b2WeldJointDef::Initialize(b2Body* bA, b2Body* bB, const b2Vec2& anchor)
{
bodyA = bA;
bodyB = bB;
localAnchorA = bodyA->GetLocalPoint(anchor);
localAnchorB = bodyB->GetLocalPoint(anchor);
referenceAngle = bodyB->GetAngle() - bodyA->GetAngle();
}
b2WeldJoint::b2WeldJoint(const b2WeldJointDef* def)
: b2Joint(def)
{
m_localAnchorA = def->localAnchorA;
m_localAnchorB = def->localAnchorB;
m_referenceAngle = def->referenceAngle;
m_frequencyHz = def->frequencyHz;
m_dampingRatio = def->dampingRatio;
m_impulse.SetZero();
}
void b2WeldJoint::InitVelocityConstraints(const b2SolverData& data)
{
m_indexA = m_bodyA->m_islandIndex;
m_indexB = m_bodyB->m_islandIndex;
m_localCenterA = m_bodyA->m_sweep.localCenter;
m_localCenterB = m_bodyB->m_sweep.localCenter;
m_invMassA = m_bodyA->m_invMass;
m_invMassB = m_bodyB->m_invMass;
m_invIA = m_bodyA->m_invI;
m_invIB = m_bodyB->m_invI;
float32 aA = data.positions[m_indexA].a;
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
float32 aB = data.positions[m_indexB].a;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
b2Rot qA(aA), qB(aB);
m_rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
m_rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
// J = [-I -r1_skew I r2_skew]
// [ 0 -1 0 1]
// r_skew = [-ry; rx]
// Matlab
// K = [ mA+r1y^2*iA+mB+r2y^2*iB, -r1y*iA*r1x-r2y*iB*r2x, -r1y*iA-r2y*iB]
// [ -r1y*iA*r1x-r2y*iB*r2x, mA+r1x^2*iA+mB+r2x^2*iB, r1x*iA+r2x*iB]
// [ -r1y*iA-r2y*iB, r1x*iA+r2x*iB, iA+iB]
float32 mA = m_invMassA, mB = m_invMassB;
float32 iA = m_invIA, iB = m_invIB;
b2Mat33 K;
K.ex.x = mA + mB + m_rA.y * m_rA.y * iA + m_rB.y * m_rB.y * iB;
K.ey.x = -m_rA.y * m_rA.x * iA - m_rB.y * m_rB.x * iB;
K.ez.x = -m_rA.y * iA - m_rB.y * iB;
K.ex.y = K.ey.x;
K.ey.y = mA + mB + m_rA.x * m_rA.x * iA + m_rB.x * m_rB.x * iB;
K.ez.y = m_rA.x * iA + m_rB.x * iB;
K.ex.z = K.ez.x;
K.ey.z = K.ez.y;
K.ez.z = iA + iB;
if (m_frequencyHz > 0.0f)
{
K.GetInverse22(&m_mass);
float32 invM = iA + iB;
float32 m = invM > 0.0f ? 1.0f / invM : 0.0f;
float32 C = aB - aA - m_referenceAngle;
// Frequency
float32 omega = 2.0f * b2_pi * m_frequencyHz;
// Damping coefficient
float32 d = 2.0f * m * m_dampingRatio * omega;
// Spring stiffness
float32 k = m * omega * omega;
// magic formulas
float32 h = data.step.dt;
m_gamma = h * (d + h * k);
m_gamma = m_gamma != 0.0f ? 1.0f / m_gamma : 0.0f;
m_bias = C * h * k * m_gamma;
invM += m_gamma;
m_mass.ez.z = invM != 0.0f ? 1.0f / invM : 0.0f;
}
else
{
K.GetSymInverse33(&m_mass);
m_gamma = 0.0f;
m_bias = 0.0f;
}
if (data.step.warmStarting)
{
// Scale impulses to support a variable time step.
m_impulse *= data.step.dtRatio;
b2Vec2 P(m_impulse.x, m_impulse.y);
vA -= mA * P;
wA -= iA * (b2Cross(m_rA, P) + m_impulse.z);
vB += mB * P;
wB += iB * (b2Cross(m_rB, P) + m_impulse.z);
}
else
{
m_impulse.SetZero();
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
void b2WeldJoint::SolveVelocityConstraints(const b2SolverData& data)
{
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
float32 mA = m_invMassA, mB = m_invMassB;
float32 iA = m_invIA, iB = m_invIB;
if (m_frequencyHz > 0.0f)
{
float32 Cdot2 = wB - wA;
float32 impulse2 = -m_mass.ez.z * (Cdot2 + m_bias + m_gamma * m_impulse.z);
m_impulse.z += impulse2;
wA -= iA * impulse2;
wB += iB * impulse2;
b2Vec2 Cdot1 = vB + b2Cross(wB, m_rB) - vA - b2Cross(wA, m_rA);
b2Vec2 impulse1 = -b2Mul22(m_mass, Cdot1);
m_impulse.x += impulse1.x;
m_impulse.y += impulse1.y;
b2Vec2 P = impulse1;
vA -= mA * P;
wA -= iA * b2Cross(m_rA, P);
vB += mB * P;
wB += iB * b2Cross(m_rB, P);
}
else
{
b2Vec2 Cdot1 = vB + b2Cross(wB, m_rB) - vA - b2Cross(wA, m_rA);
float32 Cdot2 = wB - wA;
b2Vec3 Cdot(Cdot1.x, Cdot1.y, Cdot2);
b2Vec3 impulse = -b2Mul(m_mass, Cdot);
m_impulse += impulse;
b2Vec2 P(impulse.x, impulse.y);
vA -= mA * P;
wA -= iA * (b2Cross(m_rA, P) + impulse.z);
vB += mB * P;
wB += iB * (b2Cross(m_rB, P) + impulse.z);
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
bool b2WeldJoint::SolvePositionConstraints(const b2SolverData& data)
{
b2Vec2 cA = data.positions[m_indexA].c;
float32 aA = data.positions[m_indexA].a;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Rot qA(aA), qB(aB);
float32 mA = m_invMassA, mB = m_invMassB;
float32 iA = m_invIA, iB = m_invIB;
b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
float32 positionError, angularError;
b2Mat33 K;
K.ex.x = mA + mB + rA.y * rA.y * iA + rB.y * rB.y * iB;
K.ey.x = -rA.y * rA.x * iA - rB.y * rB.x * iB;
K.ez.x = -rA.y * iA - rB.y * iB;
K.ex.y = K.ey.x;
K.ey.y = mA + mB + rA.x * rA.x * iA + rB.x * rB.x * iB;
K.ez.y = rA.x * iA + rB.x * iB;
K.ex.z = K.ez.x;
K.ey.z = K.ez.y;
K.ez.z = iA + iB;
if (m_frequencyHz > 0.0f)
{
b2Vec2 C1 = cB + rB - cA - rA;
positionError = C1.Length();
angularError = 0.0f;
b2Vec2 P = -K.Solve22(C1);
cA -= mA * P;
aA -= iA * b2Cross(rA, P);
cB += mB * P;
aB += iB * b2Cross(rB, P);
}
else
{
b2Vec2 C1 = cB + rB - cA - rA;
float32 C2 = aB - aA - m_referenceAngle;
positionError = C1.Length();
angularError = b2Abs(C2);
b2Vec3 C(C1.x, C1.y, C2);
b2Vec3 impulse = -K.Solve33(C);
b2Vec2 P(impulse.x, impulse.y);
cA -= mA * P;
aA -= iA * (b2Cross(rA, P) + impulse.z);
cB += mB * P;
aB += iB * (b2Cross(rB, P) + impulse.z);
}
data.positions[m_indexA].c = cA;
data.positions[m_indexA].a = aA;
data.positions[m_indexB].c = cB;
data.positions[m_indexB].a = aB;
return positionError <= b2_linearSlop && angularError <= b2_angularSlop;
}
b2Vec2 b2WeldJoint::GetAnchorA() const
{
return m_bodyA->GetWorldPoint(m_localAnchorA);
}
b2Vec2 b2WeldJoint::GetAnchorB() const
{
return m_bodyB->GetWorldPoint(m_localAnchorB);
}
b2Vec2 b2WeldJoint::GetReactionForce(float32 inv_dt) const
{
b2Vec2 P(m_impulse.x, m_impulse.y);
return inv_dt * P;
}
float32 b2WeldJoint::GetReactionTorque(float32 inv_dt) const
{
return inv_dt * m_impulse.z;
}
void b2WeldJoint::Dump()
{
int32 indexA = m_bodyA->m_islandIndex;
int32 indexB = m_bodyB->m_islandIndex;
b2Log(" b2WeldJointDef jd;\n");
b2Log(" jd.bodyA = bodies[%d];\n", indexA);
b2Log(" jd.bodyB = bodies[%d];\n", indexB);
b2Log(" jd.collideConnected = bool(%d);\n", m_collideConnected);
b2Log(" jd.localAnchorA.Set(%.15lef, %.15lef);\n", m_localAnchorA.x, m_localAnchorA.y);
b2Log(" jd.localAnchorB.Set(%.15lef, %.15lef);\n", m_localAnchorB.x, m_localAnchorB.y);
b2Log(" jd.referenceAngle = %.15lef;\n", m_referenceAngle);
b2Log(" jd.frequencyHz = %.15lef;\n", m_frequencyHz);
b2Log(" jd.dampingRatio = %.15lef;\n", m_dampingRatio);
b2Log(" joints[%d] = m_world->CreateJoint(&jd);\n", m_index);
}

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_WELD_JOINT_H
#define B2_WELD_JOINT_H
#include "b2Joint.h"
/// Weld joint definition. You need to specify local anchor points
/// where they are attached and the relative body angle. The position
/// of the anchor points is important for computing the reaction torque.
struct b2WeldJointDef : public b2JointDef
{
b2WeldJointDef()
{
type = e_weldJoint;
localAnchorA.Set(0.0f, 0.0f);
localAnchorB.Set(0.0f, 0.0f);
referenceAngle = 0.0f;
frequencyHz = 0.0f;
dampingRatio = 0.0f;
}
/// Initialize the bodies, anchors, and reference angle using a world
/// anchor point.
void Initialize(b2Body* bodyA, b2Body* bodyB, const b2Vec2& anchor);
/// The local anchor point relative to bodyA's origin.
b2Vec2 localAnchorA;
/// The local anchor point relative to bodyB's origin.
b2Vec2 localAnchorB;
/// The bodyB angle minus bodyA angle in the reference state (radians).
float32 referenceAngle;
/// The mass-spring-damper frequency in Hertz. Rotation only.
/// Disable softness with a value of 0.
float32 frequencyHz;
/// The damping ratio. 0 = no damping, 1 = critical damping.
float32 dampingRatio;
};
/// A weld joint essentially glues two bodies together. A weld joint may
/// distort somewhat because the island constraint solver is approximate.
class b2WeldJoint : public b2Joint
{
public:
b2Vec2 GetAnchorA() const;
b2Vec2 GetAnchorB() const;
b2Vec2 GetReactionForce(float32 inv_dt) const;
float32 GetReactionTorque(float32 inv_dt) const;
/// The local anchor point relative to bodyA's origin.
const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
/// The local anchor point relative to bodyB's origin.
const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
/// Get the reference angle.
float32 GetReferenceAngle() const { return m_referenceAngle; }
/// Set/get frequency in Hz.
void SetFrequency(float32 hz) { m_frequencyHz = hz; }
float32 GetFrequency() const { return m_frequencyHz; }
/// Set/get damping ratio.
void SetDampingRatio(float32 ratio) { m_dampingRatio = ratio; }
float32 GetDampingRatio() const { return m_dampingRatio; }
/// Dump to b2Log
void Dump();
protected:
friend class b2Joint;
b2WeldJoint(const b2WeldJointDef* def);
void InitVelocityConstraints(const b2SolverData& data);
void SolveVelocityConstraints(const b2SolverData& data);
bool SolvePositionConstraints(const b2SolverData& data);
float32 m_frequencyHz;
float32 m_dampingRatio;
float32 m_bias;
// Solver shared
b2Vec2 m_localAnchorA;
b2Vec2 m_localAnchorB;
float32 m_referenceAngle;
float32 m_gamma;
b2Vec3 m_impulse;
// Solver temp
juce::int32 m_indexA;
juce::int32 m_indexB;
b2Vec2 m_rA;
b2Vec2 m_rB;
b2Vec2 m_localCenterA;
b2Vec2 m_localCenterB;
float32 m_invMassA;
float32 m_invMassB;
float32 m_invIA;
float32 m_invIB;
b2Mat33 m_mass;
};
#endif

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/*
* Copyright (c) 2006-2007 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2WheelJoint.h"
#include "../b2Body.h"
#include "../b2TimeStep.h"
// Linear constraint (point-to-line)
// d = pB - pA = xB + rB - xA - rA
// C = dot(ay, d)
// Cdot = dot(d, cross(wA, ay)) + dot(ay, vB + cross(wB, rB) - vA - cross(wA, rA))
// = -dot(ay, vA) - dot(cross(d + rA, ay), wA) + dot(ay, vB) + dot(cross(rB, ay), vB)
// J = [-ay, -cross(d + rA, ay), ay, cross(rB, ay)]
// Spring linear constraint
// C = dot(ax, d)
// Cdot = = -dot(ax, vA) - dot(cross(d + rA, ax), wA) + dot(ax, vB) + dot(cross(rB, ax), vB)
// J = [-ax -cross(d+rA, ax) ax cross(rB, ax)]
// Motor rotational constraint
// Cdot = wB - wA
// J = [0 0 -1 0 0 1]
void b2WheelJointDef::Initialize(b2Body* bA, b2Body* bB, const b2Vec2& anchor, const b2Vec2& axis)
{
bodyA = bA;
bodyB = bB;
localAnchorA = bodyA->GetLocalPoint(anchor);
localAnchorB = bodyB->GetLocalPoint(anchor);
localAxisA = bodyA->GetLocalVector(axis);
}
b2WheelJoint::b2WheelJoint(const b2WheelJointDef* def)
: b2Joint(def)
{
m_localAnchorA = def->localAnchorA;
m_localAnchorB = def->localAnchorB;
m_localXAxisA = def->localAxisA;
m_localYAxisA = b2Cross(1.0f, m_localXAxisA);
m_mass = 0.0f;
m_impulse = 0.0f;
m_motorMass = 0.0f;
m_motorImpulse = 0.0f;
m_springMass = 0.0f;
m_springImpulse = 0.0f;
m_maxMotorTorque = def->maxMotorTorque;
m_motorSpeed = def->motorSpeed;
m_enableMotor = def->enableMotor;
m_frequencyHz = def->frequencyHz;
m_dampingRatio = def->dampingRatio;
m_bias = 0.0f;
m_gamma = 0.0f;
m_ax.SetZero();
m_ay.SetZero();
}
void b2WheelJoint::InitVelocityConstraints(const b2SolverData& data)
{
m_indexA = m_bodyA->m_islandIndex;
m_indexB = m_bodyB->m_islandIndex;
m_localCenterA = m_bodyA->m_sweep.localCenter;
m_localCenterB = m_bodyB->m_sweep.localCenter;
m_invMassA = m_bodyA->m_invMass;
m_invMassB = m_bodyB->m_invMass;
m_invIA = m_bodyA->m_invI;
m_invIB = m_bodyB->m_invI;
float32 mA = m_invMassA, mB = m_invMassB;
float32 iA = m_invIA, iB = m_invIB;
b2Vec2 cA = data.positions[m_indexA].c;
float32 aA = data.positions[m_indexA].a;
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
b2Rot qA(aA), qB(aB);
// Compute the effective masses.
b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
b2Vec2 d = cB + rB - cA - rA;
// Point to line constraint
{
m_ay = b2Mul(qA, m_localYAxisA);
m_sAy = b2Cross(d + rA, m_ay);
m_sBy = b2Cross(rB, m_ay);
m_mass = mA + mB + iA * m_sAy * m_sAy + iB * m_sBy * m_sBy;
if (m_mass > 0.0f)
{
m_mass = 1.0f / m_mass;
}
}
// Spring constraint
m_springMass = 0.0f;
m_bias = 0.0f;
m_gamma = 0.0f;
if (m_frequencyHz > 0.0f)
{
m_ax = b2Mul(qA, m_localXAxisA);
m_sAx = b2Cross(d + rA, m_ax);
m_sBx = b2Cross(rB, m_ax);
float32 invMass = mA + mB + iA * m_sAx * m_sAx + iB * m_sBx * m_sBx;
if (invMass > 0.0f)
{
m_springMass = 1.0f / invMass;
float32 C = b2Dot(d, m_ax);
// Frequency
float32 omega = 2.0f * b2_pi * m_frequencyHz;
// Damping coefficient
float32 damp = 2.0f * m_springMass * m_dampingRatio * omega;
// Spring stiffness
float32 k = m_springMass * omega * omega;
// magic formulas
float32 h = data.step.dt;
m_gamma = h * (damp + h * k);
if (m_gamma > 0.0f)
{
m_gamma = 1.0f / m_gamma;
}
m_bias = C * h * k * m_gamma;
m_springMass = invMass + m_gamma;
if (m_springMass > 0.0f)
{
m_springMass = 1.0f / m_springMass;
}
}
}
else
{
m_springImpulse = 0.0f;
}
// Rotational motor
if (m_enableMotor)
{
m_motorMass = iA + iB;
if (m_motorMass > 0.0f)
{
m_motorMass = 1.0f / m_motorMass;
}
}
else
{
m_motorMass = 0.0f;
m_motorImpulse = 0.0f;
}
if (data.step.warmStarting)
{
// Account for variable time step.
m_impulse *= data.step.dtRatio;
m_springImpulse *= data.step.dtRatio;
m_motorImpulse *= data.step.dtRatio;
b2Vec2 P = m_impulse * m_ay + m_springImpulse * m_ax;
float32 LA = m_impulse * m_sAy + m_springImpulse * m_sAx + m_motorImpulse;
float32 LB = m_impulse * m_sBy + m_springImpulse * m_sBx + m_motorImpulse;
vA -= m_invMassA * P;
wA -= m_invIA * LA;
vB += m_invMassB * P;
wB += m_invIB * LB;
}
else
{
m_impulse = 0.0f;
m_springImpulse = 0.0f;
m_motorImpulse = 0.0f;
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
void b2WheelJoint::SolveVelocityConstraints(const b2SolverData& data)
{
float32 mA = m_invMassA, mB = m_invMassB;
float32 iA = m_invIA, iB = m_invIB;
b2Vec2 vA = data.velocities[m_indexA].v;
float32 wA = data.velocities[m_indexA].w;
b2Vec2 vB = data.velocities[m_indexB].v;
float32 wB = data.velocities[m_indexB].w;
// Solve spring constraint
{
float32 Cdot = b2Dot(m_ax, vB - vA) + m_sBx * wB - m_sAx * wA;
float32 impulse = -m_springMass * (Cdot + m_bias + m_gamma * m_springImpulse);
m_springImpulse += impulse;
b2Vec2 P = impulse * m_ax;
float32 LA = impulse * m_sAx;
float32 LB = impulse * m_sBx;
vA -= mA * P;
wA -= iA * LA;
vB += mB * P;
wB += iB * LB;
}
// Solve rotational motor constraint
{
float32 Cdot = wB - wA - m_motorSpeed;
float32 impulse = -m_motorMass * Cdot;
float32 oldImpulse = m_motorImpulse;
float32 maxImpulse = data.step.dt * m_maxMotorTorque;
m_motorImpulse = b2Clamp(m_motorImpulse + impulse, -maxImpulse, maxImpulse);
impulse = m_motorImpulse - oldImpulse;
wA -= iA * impulse;
wB += iB * impulse;
}
// Solve point to line constraint
{
float32 Cdot = b2Dot(m_ay, vB - vA) + m_sBy * wB - m_sAy * wA;
float32 impulse = -m_mass * Cdot;
m_impulse += impulse;
b2Vec2 P = impulse * m_ay;
float32 LA = impulse * m_sAy;
float32 LB = impulse * m_sBy;
vA -= mA * P;
wA -= iA * LA;
vB += mB * P;
wB += iB * LB;
}
data.velocities[m_indexA].v = vA;
data.velocities[m_indexA].w = wA;
data.velocities[m_indexB].v = vB;
data.velocities[m_indexB].w = wB;
}
bool b2WheelJoint::SolvePositionConstraints(const b2SolverData& data)
{
b2Vec2 cA = data.positions[m_indexA].c;
float32 aA = data.positions[m_indexA].a;
b2Vec2 cB = data.positions[m_indexB].c;
float32 aB = data.positions[m_indexB].a;
b2Rot qA(aA), qB(aB);
b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
b2Vec2 d = (cB - cA) + rB - rA;
b2Vec2 ay = b2Mul(qA, m_localYAxisA);
float32 sAy = b2Cross(d + rA, ay);
float32 sBy = b2Cross(rB, ay);
float32 C = b2Dot(d, ay);
float32 k = m_invMassA + m_invMassB + m_invIA * m_sAy * m_sAy + m_invIB * m_sBy * m_sBy;
float32 impulse;
if (k != 0.0f)
{
impulse = - C / k;
}
else
{
impulse = 0.0f;
}
b2Vec2 P = impulse * ay;
float32 LA = impulse * sAy;
float32 LB = impulse * sBy;
cA -= m_invMassA * P;
aA -= m_invIA * LA;
cB += m_invMassB * P;
aB += m_invIB * LB;
data.positions[m_indexA].c = cA;
data.positions[m_indexA].a = aA;
data.positions[m_indexB].c = cB;
data.positions[m_indexB].a = aB;
return b2Abs(C) <= b2_linearSlop;
}
b2Vec2 b2WheelJoint::GetAnchorA() const
{
return m_bodyA->GetWorldPoint(m_localAnchorA);
}
b2Vec2 b2WheelJoint::GetAnchorB() const
{
return m_bodyB->GetWorldPoint(m_localAnchorB);
}
b2Vec2 b2WheelJoint::GetReactionForce(float32 inv_dt) const
{
return inv_dt * (m_impulse * m_ay + m_springImpulse * m_ax);
}
float32 b2WheelJoint::GetReactionTorque(float32 inv_dt) const
{
return inv_dt * m_motorImpulse;
}
float32 b2WheelJoint::GetJointTranslation() const
{
b2Body* bA = m_bodyA;
b2Body* bB = m_bodyB;
b2Vec2 pA = bA->GetWorldPoint(m_localAnchorA);
b2Vec2 pB = bB->GetWorldPoint(m_localAnchorB);
b2Vec2 d = pB - pA;
b2Vec2 axis = bA->GetWorldVector(m_localXAxisA);
float32 translation = b2Dot(d, axis);
return translation;
}
float32 b2WheelJoint::GetJointSpeed() const
{
float32 wA = m_bodyA->m_angularVelocity;
float32 wB = m_bodyB->m_angularVelocity;
return wB - wA;
}
bool b2WheelJoint::IsMotorEnabled() const
{
return m_enableMotor;
}
void b2WheelJoint::EnableMotor(bool flag)
{
m_bodyA->SetAwake(true);
m_bodyB->SetAwake(true);
m_enableMotor = flag;
}
void b2WheelJoint::SetMotorSpeed(float32 speed)
{
m_bodyA->SetAwake(true);
m_bodyB->SetAwake(true);
m_motorSpeed = speed;
}
void b2WheelJoint::SetMaxMotorTorque(float32 torque)
{
m_bodyA->SetAwake(true);
m_bodyB->SetAwake(true);
m_maxMotorTorque = torque;
}
float32 b2WheelJoint::GetMotorTorque(float32 inv_dt) const
{
return inv_dt * m_motorImpulse;
}
void b2WheelJoint::Dump()
{
int32 indexA = m_bodyA->m_islandIndex;
int32 indexB = m_bodyB->m_islandIndex;
b2Log(" b2WheelJointDef jd;\n");
b2Log(" jd.bodyA = bodies[%d];\n", indexA);
b2Log(" jd.bodyB = bodies[%d];\n", indexB);
b2Log(" jd.collideConnected = bool(%d);\n", m_collideConnected);
b2Log(" jd.localAnchorA.Set(%.15lef, %.15lef);\n", m_localAnchorA.x, m_localAnchorA.y);
b2Log(" jd.localAnchorB.Set(%.15lef, %.15lef);\n", m_localAnchorB.x, m_localAnchorB.y);
b2Log(" jd.localAxisA.Set(%.15lef, %.15lef);\n", m_localXAxisA.x, m_localXAxisA.y);
b2Log(" jd.enableMotor = bool(%d);\n", m_enableMotor);
b2Log(" jd.motorSpeed = %.15lef;\n", m_motorSpeed);
b2Log(" jd.maxMotorTorque = %.15lef;\n", m_maxMotorTorque);
b2Log(" jd.frequencyHz = %.15lef;\n", m_frequencyHz);
b2Log(" jd.dampingRatio = %.15lef;\n", m_dampingRatio);
b2Log(" joints[%d] = m_world->CreateJoint(&jd);\n", m_index);
}

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_WHEEL_JOINT_H
#define B2_WHEEL_JOINT_H
#include "b2Joint.h"
/// Wheel joint definition. This requires defining a line of
/// motion using an axis and an anchor point. The definition uses local
/// anchor points and a local axis so that the initial configuration
/// can violate the constraint slightly. The joint translation is zero
/// when the local anchor points coincide in world space. Using local
/// anchors and a local axis helps when saving and loading a game.
struct b2WheelJointDef : public b2JointDef
{
b2WheelJointDef()
{
type = e_wheelJoint;
localAnchorA.SetZero();
localAnchorB.SetZero();
localAxisA.Set(1.0f, 0.0f);
enableMotor = false;
maxMotorTorque = 0.0f;
motorSpeed = 0.0f;
frequencyHz = 2.0f;
dampingRatio = 0.7f;
}
/// Initialize the bodies, anchors, axis, and reference angle using the world
/// anchor and world axis.
void Initialize(b2Body* bodyA, b2Body* bodyB, const b2Vec2& anchor, const b2Vec2& axis);
/// The local anchor point relative to bodyA's origin.
b2Vec2 localAnchorA;
/// The local anchor point relative to bodyB's origin.
b2Vec2 localAnchorB;
/// The local translation axis in bodyA.
b2Vec2 localAxisA;
/// Enable/disable the joint motor.
bool enableMotor;
/// The maximum motor torque, usually in N-m.
float32 maxMotorTorque;
/// The desired motor speed in radians per second.
float32 motorSpeed;
/// Suspension frequency, zero indicates no suspension
float32 frequencyHz;
/// Suspension damping ratio, one indicates critical damping
float32 dampingRatio;
};
/// A wheel joint. This joint provides two degrees of freedom: translation
/// along an axis fixed in bodyA and rotation in the plane. You can use a
/// joint limit to restrict the range of motion and a joint motor to drive
/// the rotation or to model rotational friction.
/// This joint is designed for vehicle suspensions.
class b2WheelJoint : public b2Joint
{
public:
void GetDefinition(b2WheelJointDef* def) const;
b2Vec2 GetAnchorA() const;
b2Vec2 GetAnchorB() const;
b2Vec2 GetReactionForce(float32 inv_dt) const;
float32 GetReactionTorque(float32 inv_dt) const;
/// The local anchor point relative to bodyA's origin.
const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
/// The local anchor point relative to bodyB's origin.
const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
/// The local joint axis relative to bodyA.
const b2Vec2& GetLocalAxisA() const { return m_localXAxisA; }
/// Get the current joint translation, usually in meters.
float32 GetJointTranslation() const;
/// Get the current joint translation speed, usually in meters per second.
float32 GetJointSpeed() const;
/// Is the joint motor enabled?
bool IsMotorEnabled() const;
/// Enable/disable the joint motor.
void EnableMotor(bool flag);
/// Set the motor speed, usually in radians per second.
void SetMotorSpeed(float32 speed);
/// Get the motor speed, usually in radians per second.
float32 GetMotorSpeed() const;
/// Set/Get the maximum motor force, usually in N-m.
void SetMaxMotorTorque(float32 torque);
float32 GetMaxMotorTorque() const;
/// Get the current motor torque given the inverse time step, usually in N-m.
float32 GetMotorTorque(float32 inv_dt) const;
/// Set/Get the spring frequency in hertz. Setting the frequency to zero disables the spring.
void SetSpringFrequencyHz(float32 hz);
float32 GetSpringFrequencyHz() const;
/// Set/Get the spring damping ratio
void SetSpringDampingRatio(float32 ratio);
float32 GetSpringDampingRatio() const;
/// Dump to b2Log
void Dump();
protected:
friend class b2Joint;
b2WheelJoint(const b2WheelJointDef* def);
void InitVelocityConstraints(const b2SolverData& data);
void SolveVelocityConstraints(const b2SolverData& data);
bool SolvePositionConstraints(const b2SolverData& data);
float32 m_frequencyHz;
float32 m_dampingRatio;
// Solver shared
b2Vec2 m_localAnchorA;
b2Vec2 m_localAnchorB;
b2Vec2 m_localXAxisA;
b2Vec2 m_localYAxisA;
float32 m_impulse;
float32 m_motorImpulse;
float32 m_springImpulse;
float32 m_maxMotorTorque;
float32 m_motorSpeed;
bool m_enableMotor;
// Solver temp
juce::int32 m_indexA;
juce::int32 m_indexB;
b2Vec2 m_localCenterA;
b2Vec2 m_localCenterB;
float32 m_invMassA;
float32 m_invMassB;
float32 m_invIA;
float32 m_invIB;
b2Vec2 m_ax, m_ay;
float32 m_sAx, m_sBx;
float32 m_sAy, m_sBy;
float32 m_mass;
float32 m_motorMass;
float32 m_springMass;
float32 m_bias;
float32 m_gamma;
};
inline float32 b2WheelJoint::GetMotorSpeed() const
{
return m_motorSpeed;
}
inline float32 b2WheelJoint::GetMaxMotorTorque() const
{
return m_maxMotorTorque;
}
inline void b2WheelJoint::SetSpringFrequencyHz(float32 hz)
{
m_frequencyHz = hz;
}
inline float32 b2WheelJoint::GetSpringFrequencyHz() const
{
return m_frequencyHz;
}
inline void b2WheelJoint::SetSpringDampingRatio(float32 ratio)
{
m_dampingRatio = ratio;
}
inline float32 b2WheelJoint::GetSpringDampingRatio() const
{
return m_dampingRatio;
}
#endif

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/*
* Copyright (c) 2006-2007 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2Body.h"
#include "b2Fixture.h"
#include "b2World.h"
#include "Contacts/b2Contact.h"
#include "Joints/b2Joint.h"
b2Body::b2Body(const b2BodyDef* bd, b2World* world)
{
b2Assert(bd->position.IsValid());
b2Assert(bd->linearVelocity.IsValid());
b2Assert(b2IsValid(bd->angle));
b2Assert(b2IsValid(bd->angularVelocity));
b2Assert(b2IsValid(bd->angularDamping) && bd->angularDamping >= 0.0f);
b2Assert(b2IsValid(bd->linearDamping) && bd->linearDamping >= 0.0f);
m_flags = 0;
if (bd->bullet)
{
m_flags |= e_bulletFlag;
}
if (bd->fixedRotation)
{
m_flags |= e_fixedRotationFlag;
}
if (bd->allowSleep)
{
m_flags |= e_autoSleepFlag;
}
if (bd->awake)
{
m_flags |= e_awakeFlag;
}
if (bd->active)
{
m_flags |= e_activeFlag;
}
m_world = world;
m_xf.p = bd->position;
m_xf.q.Set(bd->angle);
m_sweep.localCenter.SetZero();
m_sweep.c0 = m_xf.p;
m_sweep.c = m_xf.p;
m_sweep.a0 = bd->angle;
m_sweep.a = bd->angle;
m_sweep.alpha0 = 0.0f;
m_jointList = NULL;
m_contactList = NULL;
m_prev = NULL;
m_next = NULL;
m_linearVelocity = bd->linearVelocity;
m_angularVelocity = bd->angularVelocity;
m_linearDamping = bd->linearDamping;
m_angularDamping = bd->angularDamping;
m_gravityScale = bd->gravityScale;
m_force.SetZero();
m_torque = 0.0f;
m_sleepTime = 0.0f;
m_type = bd->type;
if (m_type == b2_dynamicBody)
{
m_mass = 1.0f;
m_invMass = 1.0f;
}
else
{
m_mass = 0.0f;
m_invMass = 0.0f;
}
m_I = 0.0f;
m_invI = 0.0f;
m_userData = bd->userData;
m_fixtureList = NULL;
m_fixtureCount = 0;
}
b2Body::~b2Body()
{
// shapes and joints are destroyed in b2World::Destroy
}
void b2Body::SetType(b2BodyType type)
{
b2Assert(m_world->IsLocked() == false);
if (m_world->IsLocked() == true)
{
return;
}
if (m_type == type)
{
return;
}
m_type = type;
ResetMassData();
if (m_type == b2_staticBody)
{
m_linearVelocity.SetZero();
m_angularVelocity = 0.0f;
m_sweep.a0 = m_sweep.a;
m_sweep.c0 = m_sweep.c;
SynchronizeFixtures();
}
SetAwake(true);
m_force.SetZero();
m_torque = 0.0f;
// Since the body type changed, we need to flag contacts for filtering.
for (b2Fixture* f = m_fixtureList; f; f = f->m_next)
{
f->Refilter();
}
}
b2Fixture* b2Body::CreateFixture(const b2FixtureDef* def)
{
b2Assert(m_world->IsLocked() == false);
if (m_world->IsLocked() == true)
{
return NULL;
}
b2BlockAllocator* allocator = &m_world->m_blockAllocator;
void* memory = allocator->Allocate(sizeof(b2Fixture));
b2Fixture* fixture = new (memory) b2Fixture;
fixture->Create(allocator, this, def);
if (m_flags & e_activeFlag)
{
b2BroadPhase* broadPhase = &m_world->m_contactManager.m_broadPhase;
fixture->CreateProxies(broadPhase, m_xf);
}
fixture->m_next = m_fixtureList;
m_fixtureList = fixture;
++m_fixtureCount;
fixture->m_body = this;
// Adjust mass properties if needed.
if (fixture->m_density > 0.0f)
{
ResetMassData();
}
// Let the world know we have a new fixture. This will cause new contacts
// to be created at the beginning of the next time step.
m_world->m_flags |= b2World::e_newFixture;
return fixture;
}
b2Fixture* b2Body::CreateFixture(const b2Shape* shape, float32 density)
{
b2FixtureDef def;
def.shape = shape;
def.density = density;
return CreateFixture(&def);
}
void b2Body::DestroyFixture(b2Fixture* fixture)
{
b2Assert(m_world->IsLocked() == false);
if (m_world->IsLocked() == true)
{
return;
}
b2Assert(fixture->m_body == this);
// Remove the fixture from this body's singly linked list.
b2Assert(m_fixtureCount > 0);
b2Fixture** node = &m_fixtureList;
bool found = false;
while (*node != NULL)
{
if (*node == fixture)
{
*node = fixture->m_next;
found = true;
break;
}
node = &(*node)->m_next;
}
// You tried to remove a shape that is not attached to this body.
b2Assert(found);
juce::ignoreUnused (found);
// Destroy any contacts associated with the fixture.
b2ContactEdge* edge = m_contactList;
while (edge)
{
b2Contact* c = edge->contact;
edge = edge->next;
b2Fixture* fixtureA = c->GetFixtureA();
b2Fixture* fixtureB = c->GetFixtureB();
if (fixture == fixtureA || fixture == fixtureB)
{
// This destroys the contact and removes it from
// this body's contact list.
m_world->m_contactManager.Destroy(c);
}
}
b2BlockAllocator* allocator = &m_world->m_blockAllocator;
if (m_flags & e_activeFlag)
{
b2BroadPhase* broadPhase = &m_world->m_contactManager.m_broadPhase;
fixture->DestroyProxies(broadPhase);
}
fixture->Destroy(allocator);
fixture->m_body = NULL;
fixture->m_next = NULL;
fixture->~b2Fixture();
allocator->Free(fixture, sizeof(b2Fixture));
--m_fixtureCount;
// Reset the mass data.
ResetMassData();
}
void b2Body::ResetMassData()
{
// Compute mass data from shapes. Each shape has its own density.
m_mass = 0.0f;
m_invMass = 0.0f;
m_I = 0.0f;
m_invI = 0.0f;
m_sweep.localCenter.SetZero();
// Static and kinematic bodies have zero mass.
if (m_type == b2_staticBody || m_type == b2_kinematicBody)
{
m_sweep.c0 = m_xf.p;
m_sweep.c = m_xf.p;
m_sweep.a0 = m_sweep.a;
return;
}
b2Assert(m_type == b2_dynamicBody);
// Accumulate mass over all fixtures.
b2Vec2 localCenter = b2Vec2_zero;
for (b2Fixture* f = m_fixtureList; f; f = f->m_next)
{
if (f->m_density == 0.0f)
{
continue;
}
b2MassData massData;
f->GetMassData(&massData);
m_mass += massData.mass;
localCenter += massData.mass * massData.center;
m_I += massData.I;
}
// Compute center of mass.
if (m_mass > 0.0f)
{
m_invMass = 1.0f / m_mass;
localCenter *= m_invMass;
}
else
{
// Force all dynamic bodies to have a positive mass.
m_mass = 1.0f;
m_invMass = 1.0f;
}
if (m_I > 0.0f && (m_flags & e_fixedRotationFlag) == 0)
{
// Center the inertia about the center of mass.
m_I -= m_mass * b2Dot(localCenter, localCenter);
b2Assert(m_I > 0.0f);
m_invI = 1.0f / m_I;
}
else
{
m_I = 0.0f;
m_invI = 0.0f;
}
// Move center of mass.
b2Vec2 oldCenter = m_sweep.c;
m_sweep.localCenter = localCenter;
m_sweep.c0 = m_sweep.c = b2Mul(m_xf, m_sweep.localCenter);
// Update center of mass velocity.
m_linearVelocity += b2Cross(m_angularVelocity, m_sweep.c - oldCenter);
}
void b2Body::SetMassData(const b2MassData* massData)
{
b2Assert(m_world->IsLocked() == false);
if (m_world->IsLocked() == true)
{
return;
}
if (m_type != b2_dynamicBody)
{
return;
}
m_invMass = 0.0f;
m_I = 0.0f;
m_invI = 0.0f;
m_mass = massData->mass;
if (m_mass <= 0.0f)
{
m_mass = 1.0f;
}
m_invMass = 1.0f / m_mass;
if (massData->I > 0.0f && (m_flags & b2Body::e_fixedRotationFlag) == 0)
{
m_I = massData->I - m_mass * b2Dot(massData->center, massData->center);
b2Assert(m_I > 0.0f);
m_invI = 1.0f / m_I;
}
// Move center of mass.
b2Vec2 oldCenter = m_sweep.c;
m_sweep.localCenter = massData->center;
m_sweep.c0 = m_sweep.c = b2Mul(m_xf, m_sweep.localCenter);
// Update center of mass velocity.
m_linearVelocity += b2Cross(m_angularVelocity, m_sweep.c - oldCenter);
}
bool b2Body::ShouldCollide(const b2Body* other) const
{
// At least one body should be dynamic.
if (m_type != b2_dynamicBody && other->m_type != b2_dynamicBody)
{
return false;
}
// Does a joint prevent collision?
for (b2JointEdge* jn = m_jointList; jn; jn = jn->next)
{
if (jn->other == other)
{
if (jn->joint->m_collideConnected == false)
{
return false;
}
}
}
return true;
}
void b2Body::SetTransform(const b2Vec2& position, float32 angle)
{
b2Assert(m_world->IsLocked() == false);
if (m_world->IsLocked() == true)
{
return;
}
m_xf.q.Set(angle);
m_xf.p = position;
m_sweep.c = b2Mul(m_xf, m_sweep.localCenter);
m_sweep.a = angle;
m_sweep.c0 = m_sweep.c;
m_sweep.a0 = angle;
b2BroadPhase* broadPhase = &m_world->m_contactManager.m_broadPhase;
for (b2Fixture* f = m_fixtureList; f; f = f->m_next)
{
f->Synchronize(broadPhase, m_xf, m_xf);
}
m_world->m_contactManager.FindNewContacts();
}
void b2Body::SynchronizeFixtures()
{
b2Transform xf1;
xf1.q.Set(m_sweep.a0);
xf1.p = m_sweep.c0 - b2Mul(xf1.q, m_sweep.localCenter);
b2BroadPhase* broadPhase = &m_world->m_contactManager.m_broadPhase;
for (b2Fixture* f = m_fixtureList; f; f = f->m_next)
{
f->Synchronize(broadPhase, xf1, m_xf);
}
}
void b2Body::SetActive(bool flag)
{
b2Assert(m_world->IsLocked() == false);
if (flag == IsActive())
{
return;
}
if (flag)
{
m_flags |= e_activeFlag;
// Create all proxies.
b2BroadPhase* broadPhase = &m_world->m_contactManager.m_broadPhase;
for (b2Fixture* f = m_fixtureList; f; f = f->m_next)
{
f->CreateProxies(broadPhase, m_xf);
}
// Contacts are created the next time step.
}
else
{
m_flags &= ~e_activeFlag;
// Destroy all proxies.
b2BroadPhase* broadPhase = &m_world->m_contactManager.m_broadPhase;
for (b2Fixture* f = m_fixtureList; f; f = f->m_next)
{
f->DestroyProxies(broadPhase);
}
// Destroy the attached contacts.
b2ContactEdge* ce = m_contactList;
while (ce)
{
b2ContactEdge* ce0 = ce;
ce = ce->next;
m_world->m_contactManager.Destroy(ce0->contact);
}
m_contactList = NULL;
}
}
void b2Body::Dump()
{
int32 bodyIndex = m_islandIndex;
b2Log("{\n");
b2Log(" b2BodyDef bd;\n");
b2Log(" bd.type = b2BodyType(%d);\n", m_type);
b2Log(" bd.position.Set(%.15lef, %.15lef);\n", m_xf.p.x, m_xf.p.y);
b2Log(" bd.angle = %.15lef;\n", m_sweep.a);
b2Log(" bd.linearVelocity.Set(%.15lef, %.15lef);\n", m_linearVelocity.x, m_linearVelocity.y);
b2Log(" bd.angularVelocity = %.15lef;\n", m_angularVelocity);
b2Log(" bd.linearDamping = %.15lef;\n", m_linearDamping);
b2Log(" bd.angularDamping = %.15lef;\n", m_angularDamping);
b2Log(" bd.allowSleep = bool(%d);\n", m_flags & e_autoSleepFlag);
b2Log(" bd.awake = bool(%d);\n", m_flags & e_awakeFlag);
b2Log(" bd.fixedRotation = bool(%d);\n", m_flags & e_fixedRotationFlag);
b2Log(" bd.bullet = bool(%d);\n", m_flags & e_bulletFlag);
b2Log(" bd.active = bool(%d);\n", m_flags & e_activeFlag);
b2Log(" bd.gravityScale = %.15lef;\n", m_gravityScale);
b2Log(" bodies[%d] = m_world->CreateBody(&bd);\n", m_islandIndex);
b2Log("\n");
for (b2Fixture* f = m_fixtureList; f; f = f->m_next)
{
b2Log(" {\n");
f->Dump(bodyIndex);
b2Log(" }\n");
}
b2Log("}\n");
}

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@ -0,0 +1,845 @@
/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_BODY_H
#define B2_BODY_H
#include "../Common/b2Math.h"
#include "../Collision/Shapes/b2Shape.h"
class b2Fixture;
class b2Joint;
class b2Contact;
class b2Controller;
class b2World;
struct b2FixtureDef;
struct b2JointEdge;
struct b2ContactEdge;
/// The body type.
/// static: zero mass, zero velocity, may be manually moved
/// kinematic: zero mass, non-zero velocity set by user, moved by solver
/// dynamic: positive mass, non-zero velocity determined by forces, moved by solver
enum b2BodyType
{
b2_staticBody = 0,
b2_kinematicBody,
b2_dynamicBody
// TODO_ERIN
//b2_bulletBody,
};
/// A body definition holds all the data needed to construct a rigid body.
/// You can safely re-use body definitions. Shapes are added to a body after construction.
struct b2BodyDef
{
/// This constructor sets the body definition default values.
b2BodyDef()
{
userData = NULL;
position.Set(0.0f, 0.0f);
angle = 0.0f;
linearVelocity.Set(0.0f, 0.0f);
angularVelocity = 0.0f;
linearDamping = 0.0f;
angularDamping = 0.0f;
allowSleep = true;
awake = true;
fixedRotation = false;
bullet = false;
type = b2_staticBody;
active = true;
gravityScale = 1.0f;
}
/// The body type: static, kinematic, or dynamic.
/// Note: if a dynamic body would have zero mass, the mass is set to one.
b2BodyType type;
/// The world position of the body. Avoid creating bodies at the origin
/// since this can lead to many overlapping shapes.
b2Vec2 position;
/// The world angle of the body in radians.
float32 angle;
/// The linear velocity of the body's origin in world co-ordinates.
b2Vec2 linearVelocity;
/// The angular velocity of the body.
float32 angularVelocity;
/// Linear damping is use to reduce the linear velocity. The damping parameter
/// can be larger than 1.0f but the damping effect becomes sensitive to the
/// time step when the damping parameter is large.
float32 linearDamping;
/// Angular damping is use to reduce the angular velocity. The damping parameter
/// can be larger than 1.0f but the damping effect becomes sensitive to the
/// time step when the damping parameter is large.
float32 angularDamping;
/// Set this flag to false if this body should never fall asleep. Note that
/// this increases CPU usage.
bool allowSleep;
/// Is this body initially awake or sleeping?
bool awake;
/// Should this body be prevented from rotating? Useful for characters.
bool fixedRotation;
/// Is this a fast moving body that should be prevented from tunneling through
/// other moving bodies? Note that all bodies are prevented from tunneling through
/// kinematic and static bodies. This setting is only considered on dynamic bodies.
/// @warning You should use this flag sparingly since it increases processing time.
bool bullet;
/// Does this body start out active?
bool active;
/// Use this to store application specific body data.
void* userData;
/// Scale the gravity applied to this body.
float32 gravityScale;
};
/// A rigid body. These are created via b2World::CreateBody.
class b2Body
{
public:
/// Creates a fixture and attach it to this body. Use this function if you need
/// to set some fixture parameters, like friction. Otherwise you can create the
/// fixture directly from a shape.
/// If the density is non-zero, this function automatically updates the mass of the body.
/// Contacts are not created until the next time step.
/// @param def the fixture definition.
/// @warning This function is locked during callbacks.
b2Fixture* CreateFixture(const b2FixtureDef* def);
/// Creates a fixture from a shape and attach it to this body.
/// This is a convenience function. Use b2FixtureDef if you need to set parameters
/// like friction, restitution, user data, or filtering.
/// If the density is non-zero, this function automatically updates the mass of the body.
/// @param shape the shape to be cloned.
/// @param density the shape density (set to zero for static bodies).
/// @warning This function is locked during callbacks.
b2Fixture* CreateFixture(const b2Shape* shape, float32 density);
/// Destroy a fixture. This removes the fixture from the broad-phase and
/// destroys all contacts associated with this fixture. This will
/// automatically adjust the mass of the body if the body is dynamic and the
/// fixture has positive density.
/// All fixtures attached to a body are implicitly destroyed when the body is destroyed.
/// @param fixture the fixture to be removed.
/// @warning This function is locked during callbacks.
void DestroyFixture(b2Fixture* fixture);
/// Set the position of the body's origin and rotation.
/// This breaks any contacts and wakes the other bodies.
/// Manipulating a body's transform may cause non-physical behavior.
/// @param position the world position of the body's local origin.
/// @param angle the world rotation in radians.
void SetTransform(const b2Vec2& position, float32 angle);
/// Get the body transform for the body's origin.
/// @return the world transform of the body's origin.
const b2Transform& GetTransform() const;
/// Get the world body origin position.
/// @return the world position of the body's origin.
const b2Vec2& GetPosition() const;
/// Get the angle in radians.
/// @return the current world rotation angle in radians.
float32 GetAngle() const;
/// Get the world position of the center of mass.
const b2Vec2& GetWorldCenter() const;
/// Get the local position of the center of mass.
const b2Vec2& GetLocalCenter() const;
/// Set the linear velocity of the center of mass.
/// @param v the new linear velocity of the center of mass.
void SetLinearVelocity(const b2Vec2& v);
/// Get the linear velocity of the center of mass.
/// @return the linear velocity of the center of mass.
b2Vec2 GetLinearVelocity() const;
/// Set the angular velocity.
/// @param omega the new angular velocity in radians/second.
void SetAngularVelocity(float32 omega);
/// Get the angular velocity.
/// @return the angular velocity in radians/second.
float32 GetAngularVelocity() const;
/// Apply a force at a world point. If the force is not
/// applied at the center of mass, it will generate a torque and
/// affect the angular velocity. This wakes up the body.
/// @param force the world force vector, usually in Newtons (N).
/// @param point the world position of the point of application.
void ApplyForce(const b2Vec2& force, const b2Vec2& point);
/// Apply a force to the center of mass. This wakes up the body.
/// @param force the world force vector, usually in Newtons (N).
void ApplyForceToCenter(const b2Vec2& force);
/// Apply a torque. This affects the angular velocity
/// without affecting the linear velocity of the center of mass.
/// This wakes up the body.
/// @param torque about the z-axis (out of the screen), usually in N-m.
void ApplyTorque(float32 torque);
/// Apply an impulse at a point. This immediately modifies the velocity.
/// It also modifies the angular velocity if the point of application
/// is not at the center of mass. This wakes up the body.
/// @param impulse the world impulse vector, usually in N-seconds or kg-m/s.
/// @param point the world position of the point of application.
void ApplyLinearImpulse(const b2Vec2& impulse, const b2Vec2& point);
/// Apply an angular impulse.
/// @param impulse the angular impulse in units of kg*m*m/s
void ApplyAngularImpulse(float32 impulse);
/// Get the total mass of the body.
/// @return the mass, usually in kilograms (kg).
float32 GetMass() const;
/// Get the rotational inertia of the body about the local origin.
/// @return the rotational inertia, usually in kg-m^2.
float32 GetInertia() const;
/// Get the mass data of the body.
/// @return a struct containing the mass, inertia and center of the body.
void GetMassData(b2MassData* data) const;
/// Set the mass properties to override the mass properties of the fixtures.
/// Note that this changes the center of mass position.
/// Note that creating or destroying fixtures can also alter the mass.
/// This function has no effect if the body isn't dynamic.
/// @param massData the mass properties.
void SetMassData(const b2MassData* data);
/// This resets the mass properties to the sum of the mass properties of the fixtures.
/// This normally does not need to be called unless you called SetMassData to override
/// the mass and you later want to reset the mass.
void ResetMassData();
/// Get the world coordinates of a point given the local coordinates.
/// @param localPoint a point on the body measured relative the the body's origin.
/// @return the same point expressed in world coordinates.
b2Vec2 GetWorldPoint(const b2Vec2& localPoint) const;
/// Get the world coordinates of a vector given the local coordinates.
/// @param localVector a vector fixed in the body.
/// @return the same vector expressed in world coordinates.
b2Vec2 GetWorldVector(const b2Vec2& localVector) const;
/// Gets a local point relative to the body's origin given a world point.
/// @param a point in world coordinates.
/// @return the corresponding local point relative to the body's origin.
b2Vec2 GetLocalPoint(const b2Vec2& worldPoint) const;
/// Gets a local vector given a world vector.
/// @param a vector in world coordinates.
/// @return the corresponding local vector.
b2Vec2 GetLocalVector(const b2Vec2& worldVector) const;
/// Get the world linear velocity of a world point attached to this body.
/// @param a point in world coordinates.
/// @return the world velocity of a point.
b2Vec2 GetLinearVelocityFromWorldPoint(const b2Vec2& worldPoint) const;
/// Get the world velocity of a local point.
/// @param a point in local coordinates.
/// @return the world velocity of a point.
b2Vec2 GetLinearVelocityFromLocalPoint(const b2Vec2& localPoint) const;
/// Get the linear damping of the body.
float32 GetLinearDamping() const;
/// Set the linear damping of the body.
void SetLinearDamping(float32 linearDamping);
/// Get the angular damping of the body.
float32 GetAngularDamping() const;
/// Set the angular damping of the body.
void SetAngularDamping(float32 angularDamping);
/// Get the gravity scale of the body.
float32 GetGravityScale() const;
/// Set the gravity scale of the body.
void SetGravityScale(float32 scale);
/// Set the type of this body. This may alter the mass and velocity.
void SetType(b2BodyType type);
/// Get the type of this body.
b2BodyType GetType() const;
/// Should this body be treated like a bullet for continuous collision detection?
void SetBullet(bool flag);
/// Is this body treated like a bullet for continuous collision detection?
bool IsBullet() const;
/// You can disable sleeping on this body. If you disable sleeping, the
/// body will be woken.
void SetSleepingAllowed(bool flag);
/// Is this body allowed to sleep
bool IsSleepingAllowed() const;
/// Set the sleep state of the body. A sleeping body has very
/// low CPU cost.
/// @param flag set to true to put body to sleep, false to wake it.
void SetAwake(bool flag);
/// Get the sleeping state of this body.
/// @return true if the body is sleeping.
bool IsAwake() const;
/// Set the active state of the body. An inactive body is not
/// simulated and cannot be collided with or woken up.
/// If you pass a flag of true, all fixtures will be added to the
/// broad-phase.
/// If you pass a flag of false, all fixtures will be removed from
/// the broad-phase and all contacts will be destroyed.
/// Fixtures and joints are otherwise unaffected. You may continue
/// to create/destroy fixtures and joints on inactive bodies.
/// Fixtures on an inactive body are implicitly inactive and will
/// not participate in collisions, ray-casts, or queries.
/// Joints connected to an inactive body are implicitly inactive.
/// An inactive body is still owned by a b2World object and remains
/// in the body list.
void SetActive(bool flag);
/// Get the active state of the body.
bool IsActive() const;
/// Set this body to have fixed rotation. This causes the mass
/// to be reset.
void SetFixedRotation(bool flag);
/// Does this body have fixed rotation?
bool IsFixedRotation() const;
/// Get the list of all fixtures attached to this body.
b2Fixture* GetFixtureList();
const b2Fixture* GetFixtureList() const;
/// Get the list of all joints attached to this body.
b2JointEdge* GetJointList();
const b2JointEdge* GetJointList() const;
/// Get the list of all contacts attached to this body.
/// @warning this list changes during the time step and you may
/// miss some collisions if you don't use b2ContactListener.
b2ContactEdge* GetContactList();
const b2ContactEdge* GetContactList() const;
/// Get the next body in the world's body list.
b2Body* GetNext();
const b2Body* GetNext() const;
/// Get the user data pointer that was provided in the body definition.
void* GetUserData() const;
/// Set the user data. Use this to store your application specific data.
void SetUserData(void* data);
/// Get the parent world of this body.
b2World* GetWorld();
const b2World* GetWorld() const;
/// Dump this body to a log file
void Dump();
private:
friend class b2World;
friend class b2Island;
friend class b2ContactManager;
friend class b2ContactSolver;
friend class b2Contact;
friend class b2DistanceJoint;
friend class b2GearJoint;
friend class b2WheelJoint;
friend class b2MouseJoint;
friend class b2PrismaticJoint;
friend class b2PulleyJoint;
friend class b2RevoluteJoint;
friend class b2WeldJoint;
friend class b2FrictionJoint;
friend class b2RopeJoint;
// m_flags
enum
{
e_islandFlag = 0x0001,
e_awakeFlag = 0x0002,
e_autoSleepFlag = 0x0004,
e_bulletFlag = 0x0008,
e_fixedRotationFlag = 0x0010,
e_activeFlag = 0x0020,
e_toiFlag = 0x0040
};
b2Body(const b2BodyDef* bd, b2World* world);
~b2Body();
void SynchronizeFixtures();
void SynchronizeTransform();
// This is used to prevent connected bodies from colliding.
// It may lie, depending on the collideConnected flag.
bool ShouldCollide(const b2Body* other) const;
void Advance(float32 t);
b2BodyType m_type;
juce::uint16 m_flags;
juce::int32 m_islandIndex;
b2Transform m_xf; // the body origin transform
b2Sweep m_sweep; // the swept motion for CCD
b2Vec2 m_linearVelocity;
float32 m_angularVelocity;
b2Vec2 m_force;
float32 m_torque;
b2World* m_world;
b2Body* m_prev;
b2Body* m_next;
b2Fixture* m_fixtureList;
juce::int32 m_fixtureCount;
b2JointEdge* m_jointList;
b2ContactEdge* m_contactList;
float32 m_mass, m_invMass;
// Rotational inertia about the center of mass.
float32 m_I, m_invI;
float32 m_linearDamping;
float32 m_angularDamping;
float32 m_gravityScale;
float32 m_sleepTime;
void* m_userData;
};
inline b2BodyType b2Body::GetType() const
{
return m_type;
}
inline const b2Transform& b2Body::GetTransform() const
{
return m_xf;
}
inline const b2Vec2& b2Body::GetPosition() const
{
return m_xf.p;
}
inline float32 b2Body::GetAngle() const
{
return m_sweep.a;
}
inline const b2Vec2& b2Body::GetWorldCenter() const
{
return m_sweep.c;
}
inline const b2Vec2& b2Body::GetLocalCenter() const
{
return m_sweep.localCenter;
}
inline void b2Body::SetLinearVelocity(const b2Vec2& v)
{
if (m_type == b2_staticBody)
{
return;
}
if (b2Dot(v,v) > 0.0f)
{
SetAwake(true);
}
m_linearVelocity = v;
}
inline b2Vec2 b2Body::GetLinearVelocity() const
{
return m_linearVelocity;
}
inline void b2Body::SetAngularVelocity(float32 w)
{
if (m_type == b2_staticBody)
{
return;
}
if (w * w > 0.0f)
{
SetAwake(true);
}
m_angularVelocity = w;
}
inline float32 b2Body::GetAngularVelocity() const
{
return m_angularVelocity;
}
inline float32 b2Body::GetMass() const
{
return m_mass;
}
inline float32 b2Body::GetInertia() const
{
return m_I + m_mass * b2Dot(m_sweep.localCenter, m_sweep.localCenter);
}
inline void b2Body::GetMassData(b2MassData* data) const
{
data->mass = m_mass;
data->I = m_I + m_mass * b2Dot(m_sweep.localCenter, m_sweep.localCenter);
data->center = m_sweep.localCenter;
}
inline b2Vec2 b2Body::GetWorldPoint(const b2Vec2& localPoint) const
{
return b2Mul(m_xf, localPoint);
}
inline b2Vec2 b2Body::GetWorldVector(const b2Vec2& localVector) const
{
return b2Mul(m_xf.q, localVector);
}
inline b2Vec2 b2Body::GetLocalPoint(const b2Vec2& worldPoint) const
{
return b2MulT(m_xf, worldPoint);
}
inline b2Vec2 b2Body::GetLocalVector(const b2Vec2& worldVector) const
{
return b2MulT(m_xf.q, worldVector);
}
inline b2Vec2 b2Body::GetLinearVelocityFromWorldPoint(const b2Vec2& worldPoint) const
{
return m_linearVelocity + b2Cross(m_angularVelocity, worldPoint - m_sweep.c);
}
inline b2Vec2 b2Body::GetLinearVelocityFromLocalPoint(const b2Vec2& localPoint) const
{
return GetLinearVelocityFromWorldPoint(GetWorldPoint(localPoint));
}
inline float32 b2Body::GetLinearDamping() const
{
return m_linearDamping;
}
inline void b2Body::SetLinearDamping(float32 linearDamping)
{
m_linearDamping = linearDamping;
}
inline float32 b2Body::GetAngularDamping() const
{
return m_angularDamping;
}
inline void b2Body::SetAngularDamping(float32 angularDamping)
{
m_angularDamping = angularDamping;
}
inline float32 b2Body::GetGravityScale() const
{
return m_gravityScale;
}
inline void b2Body::SetGravityScale(float32 scale)
{
m_gravityScale = scale;
}
inline void b2Body::SetBullet(bool flag)
{
if (flag)
{
m_flags |= e_bulletFlag;
}
else
{
m_flags &= ~e_bulletFlag;
}
}
inline bool b2Body::IsBullet() const
{
return (m_flags & e_bulletFlag) == e_bulletFlag;
}
inline void b2Body::SetAwake(bool flag)
{
if (flag)
{
if ((m_flags & e_awakeFlag) == 0)
{
m_flags |= e_awakeFlag;
m_sleepTime = 0.0f;
}
}
else
{
m_flags &= ~e_awakeFlag;
m_sleepTime = 0.0f;
m_linearVelocity.SetZero();
m_angularVelocity = 0.0f;
m_force.SetZero();
m_torque = 0.0f;
}
}
inline bool b2Body::IsAwake() const
{
return (m_flags & e_awakeFlag) == e_awakeFlag;
}
inline bool b2Body::IsActive() const
{
return (m_flags & e_activeFlag) == e_activeFlag;
}
inline void b2Body::SetFixedRotation(bool flag)
{
if (flag)
{
m_flags |= e_fixedRotationFlag;
}
else
{
m_flags &= ~e_fixedRotationFlag;
}
ResetMassData();
}
inline bool b2Body::IsFixedRotation() const
{
return (m_flags & e_fixedRotationFlag) == e_fixedRotationFlag;
}
inline void b2Body::SetSleepingAllowed(bool flag)
{
if (flag)
{
m_flags |= e_autoSleepFlag;
}
else
{
m_flags &= ~e_autoSleepFlag;
SetAwake(true);
}
}
inline bool b2Body::IsSleepingAllowed() const
{
return (m_flags & e_autoSleepFlag) == e_autoSleepFlag;
}
inline b2Fixture* b2Body::GetFixtureList()
{
return m_fixtureList;
}
inline const b2Fixture* b2Body::GetFixtureList() const
{
return m_fixtureList;
}
inline b2JointEdge* b2Body::GetJointList()
{
return m_jointList;
}
inline const b2JointEdge* b2Body::GetJointList() const
{
return m_jointList;
}
inline b2ContactEdge* b2Body::GetContactList()
{
return m_contactList;
}
inline const b2ContactEdge* b2Body::GetContactList() const
{
return m_contactList;
}
inline b2Body* b2Body::GetNext()
{
return m_next;
}
inline const b2Body* b2Body::GetNext() const
{
return m_next;
}
inline void b2Body::SetUserData(void* data)
{
m_userData = data;
}
inline void* b2Body::GetUserData() const
{
return m_userData;
}
inline void b2Body::ApplyForce(const b2Vec2& force, const b2Vec2& point)
{
if (m_type != b2_dynamicBody)
{
return;
}
if (IsAwake() == false)
{
SetAwake(true);
}
m_force += force;
m_torque += b2Cross(point - m_sweep.c, force);
}
inline void b2Body::ApplyForceToCenter(const b2Vec2& force)
{
if (m_type != b2_dynamicBody)
{
return;
}
if (IsAwake() == false)
{
SetAwake(true);
}
m_force += force;
}
inline void b2Body::ApplyTorque(float32 torque)
{
if (m_type != b2_dynamicBody)
{
return;
}
if (IsAwake() == false)
{
SetAwake(true);
}
m_torque += torque;
}
inline void b2Body::ApplyLinearImpulse(const b2Vec2& impulse, const b2Vec2& point)
{
if (m_type != b2_dynamicBody)
{
return;
}
if (IsAwake() == false)
{
SetAwake(true);
}
m_linearVelocity += m_invMass * impulse;
m_angularVelocity += m_invI * b2Cross(point - m_sweep.c, impulse);
}
inline void b2Body::ApplyAngularImpulse(float32 impulse)
{
if (m_type != b2_dynamicBody)
{
return;
}
if (IsAwake() == false)
{
SetAwake(true);
}
m_angularVelocity += m_invI * impulse;
}
inline void b2Body::SynchronizeTransform()
{
m_xf.q.Set(m_sweep.a);
m_xf.p = m_sweep.c - b2Mul(m_xf.q, m_sweep.localCenter);
}
inline void b2Body::Advance(float32 alpha)
{
// Advance to the new safe time. This doesn't sync the broad-phase.
m_sweep.Advance(alpha);
m_sweep.c = m_sweep.c0;
m_sweep.a = m_sweep.a0;
m_xf.q.Set(m_sweep.a);
m_xf.p = m_sweep.c - b2Mul(m_xf.q, m_sweep.localCenter);
}
inline b2World* b2Body::GetWorld()
{
return m_world;
}
inline const b2World* b2Body::GetWorld() const
{
return m_world;
}
#endif

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2ContactManager.h"
#include "b2Body.h"
#include "b2Fixture.h"
#include "b2WorldCallbacks.h"
#include "Contacts/b2Contact.h"
b2ContactFilter b2_defaultFilter;
b2ContactListener b2_defaultListener;
b2ContactManager::b2ContactManager()
{
m_contactList = NULL;
m_contactCount = 0;
m_contactFilter = &b2_defaultFilter;
m_contactListener = &b2_defaultListener;
m_allocator = NULL;
}
void b2ContactManager::Destroy(b2Contact* c)
{
b2Fixture* fixtureA = c->GetFixtureA();
b2Fixture* fixtureB = c->GetFixtureB();
b2Body* bodyA = fixtureA->GetBody();
b2Body* bodyB = fixtureB->GetBody();
if (m_contactListener && c->IsTouching())
{
m_contactListener->EndContact(c);
}
// Remove from the world.
if (c->m_prev)
{
c->m_prev->m_next = c->m_next;
}
if (c->m_next)
{
c->m_next->m_prev = c->m_prev;
}
if (c == m_contactList)
{
m_contactList = c->m_next;
}
// Remove from body 1
if (c->m_nodeA.prev)
{
c->m_nodeA.prev->next = c->m_nodeA.next;
}
if (c->m_nodeA.next)
{
c->m_nodeA.next->prev = c->m_nodeA.prev;
}
if (&c->m_nodeA == bodyA->m_contactList)
{
bodyA->m_contactList = c->m_nodeA.next;
}
// Remove from body 2
if (c->m_nodeB.prev)
{
c->m_nodeB.prev->next = c->m_nodeB.next;
}
if (c->m_nodeB.next)
{
c->m_nodeB.next->prev = c->m_nodeB.prev;
}
if (&c->m_nodeB == bodyB->m_contactList)
{
bodyB->m_contactList = c->m_nodeB.next;
}
// Call the factory.
b2Contact::Destroy(c, m_allocator);
--m_contactCount;
}
// This is the top level collision call for the time step. Here
// all the narrow phase collision is processed for the world
// contact list.
void b2ContactManager::Collide()
{
// Update awake contacts.
b2Contact* c = m_contactList;
while (c)
{
b2Fixture* fixtureA = c->GetFixtureA();
b2Fixture* fixtureB = c->GetFixtureB();
int32 indexA = c->GetChildIndexA();
int32 indexB = c->GetChildIndexB();
b2Body* bodyA = fixtureA->GetBody();
b2Body* bodyB = fixtureB->GetBody();
// Is this contact flagged for filtering?
if (c->m_flags & b2Contact::e_filterFlag)
{
// Should these bodies collide?
if (bodyB->ShouldCollide(bodyA) == false)
{
b2Contact* cNuke = c;
c = cNuke->GetNext();
Destroy(cNuke);
continue;
}
// Check user filtering.
if (m_contactFilter && m_contactFilter->ShouldCollide(fixtureA, fixtureB) == false)
{
b2Contact* cNuke = c;
c = cNuke->GetNext();
Destroy(cNuke);
continue;
}
// Clear the filtering flag.
c->m_flags &= ~b2Contact::e_filterFlag;
}
bool activeA = bodyA->IsAwake() && bodyA->m_type != b2_staticBody;
bool activeB = bodyB->IsAwake() && bodyB->m_type != b2_staticBody;
// At least one body must be awake and it must be dynamic or kinematic.
if (activeA == false && activeB == false)
{
c = c->GetNext();
continue;
}
int32 proxyIdA = fixtureA->m_proxies[indexA].proxyId;
int32 proxyIdB = fixtureB->m_proxies[indexB].proxyId;
bool overlap = m_broadPhase.TestOverlap(proxyIdA, proxyIdB);
// Here we destroy contacts that cease to overlap in the broad-phase.
if (overlap == false)
{
b2Contact* cNuke = c;
c = cNuke->GetNext();
Destroy(cNuke);
continue;
}
// The contact persists.
c->Update(m_contactListener);
c = c->GetNext();
}
}
void b2ContactManager::FindNewContacts()
{
m_broadPhase.UpdatePairs(this);
}
void b2ContactManager::AddPair(void* proxyUserDataA, void* proxyUserDataB)
{
b2FixtureProxy* proxyA = (b2FixtureProxy*)proxyUserDataA;
b2FixtureProxy* proxyB = (b2FixtureProxy*)proxyUserDataB;
b2Fixture* fixtureA = proxyA->fixture;
b2Fixture* fixtureB = proxyB->fixture;
int32 indexA = proxyA->childIndex;
int32 indexB = proxyB->childIndex;
b2Body* bodyA = fixtureA->GetBody();
b2Body* bodyB = fixtureB->GetBody();
// Are the fixtures on the same body?
if (bodyA == bodyB)
{
return;
}
// TODO_ERIN use a hash table to remove a potential bottleneck when both
// bodies have a lot of contacts.
// Does a contact already exist?
b2ContactEdge* edge = bodyB->GetContactList();
while (edge)
{
if (edge->other == bodyA)
{
b2Fixture* fA = edge->contact->GetFixtureA();
b2Fixture* fB = edge->contact->GetFixtureB();
int32 iA = edge->contact->GetChildIndexA();
int32 iB = edge->contact->GetChildIndexB();
if (fA == fixtureA && fB == fixtureB && iA == indexA && iB == indexB)
{
// A contact already exists.
return;
}
if (fA == fixtureB && fB == fixtureA && iA == indexB && iB == indexA)
{
// A contact already exists.
return;
}
}
edge = edge->next;
}
// Does a joint override collision? Is at least one body dynamic?
if (bodyB->ShouldCollide(bodyA) == false)
{
return;
}
// Check user filtering.
if (m_contactFilter && m_contactFilter->ShouldCollide(fixtureA, fixtureB) == false)
{
return;
}
// Call the factory.
b2Contact* c = b2Contact::Create(fixtureA, indexA, fixtureB, indexB, m_allocator);
if (c == NULL)
{
return;
}
// Contact creation may swap fixtures.
fixtureA = c->GetFixtureA();
fixtureB = c->GetFixtureB();
// indexA = c->GetChildIndexA();
// indexB = c->GetChildIndexB();
bodyA = fixtureA->GetBody();
bodyB = fixtureB->GetBody();
// Insert into the world.
c->m_prev = NULL;
c->m_next = m_contactList;
if (m_contactList != NULL)
{
m_contactList->m_prev = c;
}
m_contactList = c;
// Connect to island graph.
// Connect to body A
c->m_nodeA.contact = c;
c->m_nodeA.other = bodyB;
c->m_nodeA.prev = NULL;
c->m_nodeA.next = bodyA->m_contactList;
if (bodyA->m_contactList != NULL)
{
bodyA->m_contactList->prev = &c->m_nodeA;
}
bodyA->m_contactList = &c->m_nodeA;
// Connect to body B
c->m_nodeB.contact = c;
c->m_nodeB.other = bodyA;
c->m_nodeB.prev = NULL;
c->m_nodeB.next = bodyB->m_contactList;
if (bodyB->m_contactList != NULL)
{
bodyB->m_contactList->prev = &c->m_nodeB;
}
bodyB->m_contactList = &c->m_nodeB;
// Wake up the bodies
bodyA->SetAwake(true);
bodyB->SetAwake(true);
++m_contactCount;
}

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_CONTACT_MANAGER_H
#define B2_CONTACT_MANAGER_H
#include "../Collision/b2BroadPhase.h"
class b2Contact;
class b2ContactFilter;
class b2ContactListener;
class b2BlockAllocator;
// Delegate of b2World.
class b2ContactManager
{
public:
b2ContactManager();
// Broad-phase callback.
void AddPair(void* proxyUserDataA, void* proxyUserDataB);
void FindNewContacts();
void Destroy(b2Contact* c);
void Collide();
b2BroadPhase m_broadPhase;
b2Contact* m_contactList;
juce::int32 m_contactCount;
b2ContactFilter* m_contactFilter;
b2ContactListener* m_contactListener;
b2BlockAllocator* m_allocator;
};
#endif

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2Fixture.h"
#include "Contacts/b2Contact.h"
#include "b2World.h"
#include "../Collision/Shapes/b2CircleShape.h"
#include "../Collision/Shapes/b2EdgeShape.h"
#include "../Collision/Shapes/b2PolygonShape.h"
#include "../Collision/Shapes/b2ChainShape.h"
#include "../Collision/b2BroadPhase.h"
#include "../Collision/b2Collision.h"
#include "../Common/b2BlockAllocator.h"
b2Fixture::b2Fixture()
{
m_userData = NULL;
m_body = NULL;
m_next = NULL;
m_proxies = NULL;
m_proxyCount = 0;
m_shape = NULL;
m_density = 0.0f;
}
void b2Fixture::Create(b2BlockAllocator* allocator, b2Body* body, const b2FixtureDef* def)
{
m_userData = def->userData;
m_friction = def->friction;
m_restitution = def->restitution;
m_body = body;
m_next = NULL;
m_filter = def->filter;
m_isSensor = def->isSensor;
m_shape = def->shape->Clone(allocator);
// Reserve proxy space
int32 childCount = m_shape->GetChildCount();
m_proxies = (b2FixtureProxy*)allocator->Allocate(childCount * sizeof(b2FixtureProxy));
for (int32 i = 0; i < childCount; ++i)
{
m_proxies[i].fixture = NULL;
m_proxies[i].proxyId = b2BroadPhase::e_nullProxy;
}
m_proxyCount = 0;
m_density = def->density;
}
void b2Fixture::Destroy(b2BlockAllocator* allocator)
{
// The proxies must be destroyed before calling this.
b2Assert(m_proxyCount == 0);
// Free the proxy array.
int32 childCount = m_shape->GetChildCount();
allocator->Free(m_proxies, childCount * sizeof(b2FixtureProxy));
m_proxies = NULL;
// Free the child shape.
switch (m_shape->m_type)
{
case b2Shape::e_circle:
{
b2CircleShape* s = (b2CircleShape*)m_shape;
s->~b2CircleShape();
allocator->Free(s, sizeof(b2CircleShape));
}
break;
case b2Shape::e_edge:
{
b2EdgeShape* s = (b2EdgeShape*)m_shape;
s->~b2EdgeShape();
allocator->Free(s, sizeof(b2EdgeShape));
}
break;
case b2Shape::e_polygon:
{
b2PolygonShape* s = (b2PolygonShape*)m_shape;
s->~b2PolygonShape();
allocator->Free(s, sizeof(b2PolygonShape));
}
break;
case b2Shape::e_chain:
{
b2ChainShape* s = (b2ChainShape*)m_shape;
s->~b2ChainShape();
allocator->Free(s, sizeof(b2ChainShape));
}
break;
default:
b2Assert(false);
break;
}
m_shape = NULL;
}
void b2Fixture::CreateProxies(b2BroadPhase* broadPhase, const b2Transform& xf)
{
b2Assert(m_proxyCount == 0);
// Create proxies in the broad-phase.
m_proxyCount = m_shape->GetChildCount();
for (int32 i = 0; i < m_proxyCount; ++i)
{
b2FixtureProxy* proxy = m_proxies + i;
m_shape->ComputeAABB(&proxy->aabb, xf, i);
proxy->proxyId = broadPhase->CreateProxy(proxy->aabb, proxy);
proxy->fixture = this;
proxy->childIndex = i;
}
}
void b2Fixture::DestroyProxies(b2BroadPhase* broadPhase)
{
// Destroy proxies in the broad-phase.
for (int32 i = 0; i < m_proxyCount; ++i)
{
b2FixtureProxy* proxy = m_proxies + i;
broadPhase->DestroyProxy(proxy->proxyId);
proxy->proxyId = b2BroadPhase::e_nullProxy;
}
m_proxyCount = 0;
}
void b2Fixture::Synchronize(b2BroadPhase* broadPhase, const b2Transform& transform1, const b2Transform& transform2)
{
if (m_proxyCount == 0)
{
return;
}
for (int32 i = 0; i < m_proxyCount; ++i)
{
b2FixtureProxy* proxy = m_proxies + i;
// Compute an AABB that covers the swept shape (may miss some rotation effect).
b2AABB aabb1, aabb2;
m_shape->ComputeAABB(&aabb1, transform1, proxy->childIndex);
m_shape->ComputeAABB(&aabb2, transform2, proxy->childIndex);
proxy->aabb.Combine(aabb1, aabb2);
b2Vec2 displacement = transform2.p - transform1.p;
broadPhase->MoveProxy(proxy->proxyId, proxy->aabb, displacement);
}
}
void b2Fixture::SetFilterData(const b2Filter& filter)
{
m_filter = filter;
Refilter();
}
void b2Fixture::Refilter()
{
if (m_body == NULL)
{
return;
}
// Flag associated contacts for filtering.
b2ContactEdge* edge = m_body->GetContactList();
while (edge)
{
b2Contact* contact = edge->contact;
b2Fixture* fixtureA = contact->GetFixtureA();
b2Fixture* fixtureB = contact->GetFixtureB();
if (fixtureA == this || fixtureB == this)
{
contact->FlagForFiltering();
}
edge = edge->next;
}
b2World* world = m_body->GetWorld();
if (world == NULL)
{
return;
}
// Touch each proxy so that new pairs may be created
b2BroadPhase* broadPhase = &world->m_contactManager.m_broadPhase;
for (int32 i = 0; i < m_proxyCount; ++i)
{
broadPhase->TouchProxy(m_proxies[i].proxyId);
}
}
void b2Fixture::SetSensor(bool sensor)
{
if (sensor != m_isSensor)
{
m_body->SetAwake(true);
m_isSensor = sensor;
}
}
void b2Fixture::Dump(int32 bodyIndex)
{
b2Log(" b2FixtureDef fd;\n");
b2Log(" fd.friction = %.15lef;\n", m_friction);
b2Log(" fd.restitution = %.15lef;\n", m_restitution);
b2Log(" fd.density = %.15lef;\n", m_density);
b2Log(" fd.isSensor = bool(%d);\n", m_isSensor);
b2Log(" fd.filter.categoryBits = uint16(%d);\n", m_filter.categoryBits);
b2Log(" fd.filter.maskBits = uint16(%d);\n", m_filter.maskBits);
b2Log(" fd.filter.groupIndex = int16(%d);\n", m_filter.groupIndex);
switch (m_shape->m_type)
{
case b2Shape::e_circle:
{
b2CircleShape* s = (b2CircleShape*)m_shape;
b2Log(" b2CircleShape shape;\n");
b2Log(" shape.m_radius = %.15lef;\n", s->m_radius);
b2Log(" shape.m_p.Set(%.15lef, %.15lef);\n", s->m_p.x, s->m_p.y);
}
break;
case b2Shape::e_edge:
{
b2EdgeShape* s = (b2EdgeShape*)m_shape;
b2Log(" b2EdgeShape shape;\n");
b2Log(" shape.m_radius = %.15lef;\n", s->m_radius);
b2Log(" shape.m_vertex0.Set(%.15lef, %.15lef);\n", s->m_vertex0.x, s->m_vertex0.y);
b2Log(" shape.m_vertex1.Set(%.15lef, %.15lef);\n", s->m_vertex1.x, s->m_vertex1.y);
b2Log(" shape.m_vertex2.Set(%.15lef, %.15lef);\n", s->m_vertex2.x, s->m_vertex2.y);
b2Log(" shape.m_vertex3.Set(%.15lef, %.15lef);\n", s->m_vertex3.x, s->m_vertex3.y);
b2Log(" shape.m_hasVertex0 = bool(%d);\n", s->m_hasVertex0);
b2Log(" shape.m_hasVertex3 = bool(%d);\n", s->m_hasVertex3);
}
break;
case b2Shape::e_polygon:
{
b2PolygonShape* s = (b2PolygonShape*)m_shape;
b2Log(" b2PolygonShape shape;\n");
b2Log(" b2Vec2 vs[%d];\n", b2_maxPolygonVertices);
for (int32 i = 0; i < s->m_vertexCount; ++i)
{
b2Log(" vs[%d].Set(%.15lef, %.15lef);\n", i, s->m_vertices[i].x, s->m_vertices[i].y);
}
b2Log(" shape.Set(vs, %d);\n", s->m_vertexCount);
}
break;
case b2Shape::e_chain:
{
b2ChainShape* s = (b2ChainShape*)m_shape;
b2Log(" b2ChainShape shape;\n");
b2Log(" b2Vec2 vs[%d];\n", s->m_count);
for (int32 i = 0; i < s->m_count; ++i)
{
b2Log(" vs[%d].Set(%.15lef, %.15lef);\n", i, s->m_vertices[i].x, s->m_vertices[i].y);
}
b2Log(" shape.CreateChain(vs, %d);\n", s->m_count);
b2Log(" shape.m_prevVertex.Set(%.15lef, %.15lef);\n", s->m_prevVertex.x, s->m_prevVertex.y);
b2Log(" shape.m_nextVertex.Set(%.15lef, %.15lef);\n", s->m_nextVertex.x, s->m_nextVertex.y);
b2Log(" shape.m_hasPrevVertex = bool(%d);\n", s->m_hasPrevVertex);
b2Log(" shape.m_hasNextVertex = bool(%d);\n", s->m_hasNextVertex);
}
break;
default:
return;
}
b2Log("\n");
b2Log(" fd.shape = &shape;\n");
b2Log("\n");
b2Log(" bodies[%d]->CreateFixture(&fd);\n", bodyIndex);
}

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_FIXTURE_H
#define B2_FIXTURE_H
#include "b2Body.h"
#include "../Collision/b2Collision.h"
#include "../Collision/Shapes/b2Shape.h"
class b2BlockAllocator;
class b2Body;
class b2BroadPhase;
class b2Fixture;
/// This holds contact filtering data.
struct b2Filter
{
b2Filter()
{
categoryBits = 0x0001;
maskBits = 0xFFFF;
groupIndex = 0;
}
/// The collision category bits. Normally you would just set one bit.
juce::uint16 categoryBits;
/// The collision mask bits. This states the categories that this
/// shape would accept for collision.
juce::uint16 maskBits;
/// Collision groups allow a certain group of objects to never collide (negative)
/// or always collide (positive). Zero means no collision group. Non-zero group
/// filtering always wins against the mask bits.
juce::int16 groupIndex;
};
/// A fixture definition is used to create a fixture. This class defines an
/// abstract fixture definition. You can reuse fixture definitions safely.
struct b2FixtureDef
{
/// The constructor sets the default fixture definition values.
b2FixtureDef()
{
shape = NULL;
userData = NULL;
friction = 0.2f;
restitution = 0.0f;
density = 0.0f;
isSensor = false;
}
/// The shape, this must be set. The shape will be cloned, so you
/// can create the shape on the stack.
const b2Shape* shape;
/// Use this to store application specific fixture data.
void* userData;
/// The friction coefficient, usually in the range [0,1].
float32 friction;
/// The restitution (elasticity) usually in the range [0,1].
float32 restitution;
/// The density, usually in kg/m^2.
float32 density;
/// A sensor shape collects contact information but never generates a collision
/// response.
bool isSensor;
/// Contact filtering data.
b2Filter filter;
};
/// This proxy is used internally to connect fixtures to the broad-phase.
struct b2FixtureProxy
{
b2AABB aabb;
b2Fixture* fixture;
juce::int32 childIndex;
juce::int32 proxyId;
};
/// A fixture is used to attach a shape to a body for collision detection. A fixture
/// inherits its transform from its parent. Fixtures hold additional non-geometric data
/// such as friction, collision filters, etc.
/// Fixtures are created via b2Body::CreateFixture.
/// @warning you cannot reuse fixtures.
class b2Fixture
{
public:
/// Get the type of the child shape. You can use this to down cast to the concrete shape.
/// @return the shape type.
b2Shape::Type GetType() const;
/// Get the child shape. You can modify the child shape, however you should not change the
/// number of vertices because this will crash some collision caching mechanisms.
/// Manipulating the shape may lead to non-physical behavior.
b2Shape* GetShape();
const b2Shape* GetShape() const;
/// Set if this fixture is a sensor.
void SetSensor(bool sensor);
/// Is this fixture a sensor (non-solid)?
/// @return the true if the shape is a sensor.
bool IsSensor() const;
/// Set the contact filtering data. This will not update contacts until the next time
/// step when either parent body is active and awake.
/// This automatically calls Refilter.
void SetFilterData(const b2Filter& filter);
/// Get the contact filtering data.
const b2Filter& GetFilterData() const;
/// Call this if you want to establish collision that was previously disabled by b2ContactFilter::ShouldCollide.
void Refilter();
/// Get the parent body of this fixture. This is NULL if the fixture is not attached.
/// @return the parent body.
b2Body* GetBody();
const b2Body* GetBody() const;
/// Get the next fixture in the parent body's fixture list.
/// @return the next shape.
b2Fixture* GetNext();
const b2Fixture* GetNext() const;
/// Get the user data that was assigned in the fixture definition. Use this to
/// store your application specific data.
void* GetUserData() const;
/// Set the user data. Use this to store your application specific data.
void SetUserData(void* data);
/// Test a point for containment in this fixture.
/// @param p a point in world coordinates.
bool TestPoint(const b2Vec2& p) const;
/// Cast a ray against this shape.
/// @param output the ray-cast results.
/// @param input the ray-cast input parameters.
bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input, juce::int32 childIndex) const;
/// Get the mass data for this fixture. The mass data is based on the density and
/// the shape. The rotational inertia is about the shape's origin. This operation
/// may be expensive.
void GetMassData(b2MassData* massData) const;
/// Set the density of this fixture. This will _not_ automatically adjust the mass
/// of the body. You must call b2Body::ResetMassData to update the body's mass.
void SetDensity(float32 density);
/// Get the density of this fixture.
float32 GetDensity() const;
/// Get the coefficient of friction.
float32 GetFriction() const;
/// Set the coefficient of friction. This will _not_ change the friction of
/// existing contacts.
void SetFriction(float32 friction);
/// Get the coefficient of restitution.
float32 GetRestitution() const;
/// Set the coefficient of restitution. This will _not_ change the restitution of
/// existing contacts.
void SetRestitution(float32 restitution);
/// Get the fixture's AABB. This AABB may be enlarge and/or stale.
/// If you need a more accurate AABB, compute it using the shape and
/// the body transform.
const b2AABB& GetAABB(juce::int32 childIndex) const;
/// Dump this fixture to the log file.
void Dump(juce::int32 bodyIndex);
protected:
friend class b2Body;
friend class b2World;
friend class b2Contact;
friend class b2ContactManager;
b2Fixture();
// We need separation create/destroy functions from the constructor/destructor because
// the destructor cannot access the allocator (no destructor arguments allowed by C++).
void Create(b2BlockAllocator* allocator, b2Body* body, const b2FixtureDef* def);
void Destroy(b2BlockAllocator* allocator);
// These support body activation/deactivation.
void CreateProxies(b2BroadPhase* broadPhase, const b2Transform& xf);
void DestroyProxies(b2BroadPhase* broadPhase);
void Synchronize(b2BroadPhase* broadPhase, const b2Transform& xf1, const b2Transform& xf2);
float32 m_density;
b2Fixture* m_next;
b2Body* m_body;
b2Shape* m_shape;
float32 m_friction;
float32 m_restitution;
b2FixtureProxy* m_proxies;
juce::int32 m_proxyCount;
b2Filter m_filter;
bool m_isSensor;
void* m_userData;
};
inline b2Shape::Type b2Fixture::GetType() const
{
return m_shape->GetType();
}
inline b2Shape* b2Fixture::GetShape()
{
return m_shape;
}
inline const b2Shape* b2Fixture::GetShape() const
{
return m_shape;
}
inline bool b2Fixture::IsSensor() const
{
return m_isSensor;
}
inline const b2Filter& b2Fixture::GetFilterData() const
{
return m_filter;
}
inline void* b2Fixture::GetUserData() const
{
return m_userData;
}
inline void b2Fixture::SetUserData(void* data)
{
m_userData = data;
}
inline b2Body* b2Fixture::GetBody()
{
return m_body;
}
inline const b2Body* b2Fixture::GetBody() const
{
return m_body;
}
inline b2Fixture* b2Fixture::GetNext()
{
return m_next;
}
inline const b2Fixture* b2Fixture::GetNext() const
{
return m_next;
}
inline void b2Fixture::SetDensity(float32 density)
{
b2Assert(b2IsValid(density) && density >= 0.0f);
m_density = density;
}
inline float32 b2Fixture::GetDensity() const
{
return m_density;
}
inline float32 b2Fixture::GetFriction() const
{
return m_friction;
}
inline void b2Fixture::SetFriction(float32 friction)
{
m_friction = friction;
}
inline float32 b2Fixture::GetRestitution() const
{
return m_restitution;
}
inline void b2Fixture::SetRestitution(float32 restitution)
{
m_restitution = restitution;
}
inline bool b2Fixture::TestPoint(const b2Vec2& p) const
{
return m_shape->TestPoint(m_body->GetTransform(), p);
}
inline bool b2Fixture::RayCast(b2RayCastOutput* output, const b2RayCastInput& input, juce::int32 childIndex) const
{
return m_shape->RayCast(output, input, m_body->GetTransform(), childIndex);
}
inline void b2Fixture::GetMassData(b2MassData* massData) const
{
m_shape->ComputeMass(massData, m_density);
}
inline const b2AABB& b2Fixture::GetAABB(juce::int32 childIndex) const
{
b2Assert(0 <= childIndex && childIndex < m_proxyCount);
return m_proxies[childIndex].aabb;
}
#endif

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "../Collision/b2Distance.h"
#include "b2Island.h"
#include "b2Body.h"
#include "b2Fixture.h"
#include "b2World.h"
#include "Contacts/b2Contact.h"
#include "Contacts/b2ContactSolver.h"
#include "Joints/b2Joint.h"
#include "../Common/b2StackAllocator.h"
#include "../Common/b2Timer.h"
/*
Position Correction Notes
=========================
I tried the several algorithms for position correction of the 2D revolute joint.
I looked at these systems:
- simple pendulum (1m diameter sphere on massless 5m stick) with initial angular velocity of 100 rad/s.
- suspension bridge with 30 1m long planks of length 1m.
- multi-link chain with 30 1m long links.
Here are the algorithms:
Baumgarte - A fraction of the position error is added to the velocity error. There is no
separate position solver.
Pseudo Velocities - After the velocity solver and position integration,
the position error, Jacobian, and effective mass are recomputed. Then
the velocity constraints are solved with pseudo velocities and a fraction
of the position error is added to the pseudo velocity error. The pseudo
velocities are initialized to zero and there is no warm-starting. After
the position solver, the pseudo velocities are added to the positions.
This is also called the First Order World method or the Position LCP method.
Modified Nonlinear Gauss-Seidel (NGS) - Like Pseudo Velocities except the
position error is re-computed for each constraint and the positions are updated
after the constraint is solved. The radius vectors (aka Jacobians) are
re-computed too (otherwise the algorithm has horrible instability). The pseudo
velocity states are not needed because they are effectively zero at the beginning
of each iteration. Since we have the current position error, we allow the
iterations to terminate early if the error becomes smaller than b2_linearSlop.
Full NGS or just NGS - Like Modified NGS except the effective mass are re-computed
each time a constraint is solved.
Here are the results:
Baumgarte - this is the cheapest algorithm but it has some stability problems,
especially with the bridge. The chain links separate easily close to the root
and they jitter as they struggle to pull together. This is one of the most common
methods in the field. The big drawback is that the position correction artificially
affects the momentum, thus leading to instabilities and false bounce. I used a
bias factor of 0.2. A larger bias factor makes the bridge less stable, a smaller
factor makes joints and contacts more spongy.
Pseudo Velocities - the is more stable than the Baumgarte method. The bridge is
stable. However, joints still separate with large angular velocities. Drag the
simple pendulum in a circle quickly and the joint will separate. The chain separates
easily and does not recover. I used a bias factor of 0.2. A larger value lead to
the bridge collapsing when a heavy cube drops on it.
Modified NGS - this algorithm is better in some ways than Baumgarte and Pseudo
Velocities, but in other ways it is worse. The bridge and chain are much more
stable, but the simple pendulum goes unstable at high angular velocities.
Full NGS - stable in all tests. The joints display good stiffness. The bridge
still sags, but this is better than infinite forces.
Recommendations
Pseudo Velocities are not really worthwhile because the bridge and chain cannot
recover from joint separation. In other cases the benefit over Baumgarte is small.
Modified NGS is not a robust method for the revolute joint due to the violent
instability seen in the simple pendulum. Perhaps it is viable with other constraint
types, especially scalar constraints where the effective mass is a scalar.
This leaves Baumgarte and Full NGS. Baumgarte has small, but manageable instabilities
and is very fast. I don't think we can escape Baumgarte, especially in highly
demanding cases where high constraint fidelity is not needed.
Full NGS is robust and easy on the eyes. I recommend this as an option for
higher fidelity simulation and certainly for suspension bridges and long chains.
Full NGS might be a good choice for ragdolls, especially motorized ragdolls where
joint separation can be problematic. The number of NGS iterations can be reduced
for better performance without harming robustness much.
Each joint in a can be handled differently in the position solver. So I recommend
a system where the user can select the algorithm on a per joint basis. I would
probably default to the slower Full NGS and let the user select the faster
Baumgarte method in performance critical scenarios.
*/
/*
Cache Performance
The Box2D solvers are dominated by cache misses. Data structures are designed
to increase the number of cache hits. Much of misses are due to random access
to body data. The constraint structures are iterated over linearly, which leads
to few cache misses.
The bodies are not accessed during iteration. Instead read only data, such as
the mass values are stored with the constraints. The mutable data are the constraint
impulses and the bodies velocities/positions. The impulses are held inside the
constraint structures. The body velocities/positions are held in compact, temporary
arrays to increase the number of cache hits. Linear and angular velocity are
stored in a single array since multiple arrays lead to multiple misses.
*/
/*
2D Rotation
R = [cos(theta) -sin(theta)]
[sin(theta) cos(theta) ]
thetaDot = omega
Let q1 = cos(theta), q2 = sin(theta).
R = [q1 -q2]
[q2 q1]
q1Dot = -thetaDot * q2
q2Dot = thetaDot * q1
q1_new = q1_old - dt * w * q2
q2_new = q2_old + dt * w * q1
then normalize.
This might be faster than computing sin+cos.
However, we can compute sin+cos of the same angle fast.
*/
b2Island::b2Island(
int32 bodyCapacity,
int32 contactCapacity,
int32 jointCapacity,
b2StackAllocator* allocator,
b2ContactListener* listener)
{
m_bodyCapacity = bodyCapacity;
m_contactCapacity = contactCapacity;
m_jointCapacity = jointCapacity;
m_bodyCount = 0;
m_contactCount = 0;
m_jointCount = 0;
m_allocator = allocator;
m_listener = listener;
m_bodies = (b2Body**)m_allocator->Allocate(bodyCapacity * sizeof(b2Body*));
m_contacts = (b2Contact**)m_allocator->Allocate(contactCapacity * sizeof(b2Contact*));
m_joints = (b2Joint**)m_allocator->Allocate(jointCapacity * sizeof(b2Joint*));
m_velocities = (b2Velocity*)m_allocator->Allocate(m_bodyCapacity * sizeof(b2Velocity));
m_positions = (b2Position*)m_allocator->Allocate(m_bodyCapacity * sizeof(b2Position));
}
b2Island::~b2Island()
{
// Warning: the order should reverse the constructor order.
m_allocator->Free(m_positions);
m_allocator->Free(m_velocities);
m_allocator->Free(m_joints);
m_allocator->Free(m_contacts);
m_allocator->Free(m_bodies);
}
void b2Island::Solve(b2Profile* profile, const b2TimeStep& step, const b2Vec2& gravity, bool allowSleep)
{
b2Timer timer;
float32 h = step.dt;
// Integrate velocities and apply damping. Initialize the body state.
for (int32 i = 0; i < m_bodyCount; ++i)
{
b2Body* b = m_bodies[i];
b2Vec2 c = b->m_sweep.c;
float32 a = b->m_sweep.a;
b2Vec2 v = b->m_linearVelocity;
float32 w = b->m_angularVelocity;
// Store positions for continuous collision.
b->m_sweep.c0 = b->m_sweep.c;
b->m_sweep.a0 = b->m_sweep.a;
if (b->m_type == b2_dynamicBody)
{
// Integrate velocities.
v += h * (b->m_gravityScale * gravity + b->m_invMass * b->m_force);
w += h * b->m_invI * b->m_torque;
// Apply damping.
// ODE: dv/dt + c * v = 0
// Solution: v(t) = v0 * exp(-c * t)
// Time step: v(t + dt) = v0 * exp(-c * (t + dt)) = v0 * exp(-c * t) * exp(-c * dt) = v * exp(-c * dt)
// v2 = exp(-c * dt) * v1
// Taylor expansion:
// v2 = (1.0f - c * dt) * v1
v *= b2Clamp(1.0f - h * b->m_linearDamping, 0.0f, 1.0f);
w *= b2Clamp(1.0f - h * b->m_angularDamping, 0.0f, 1.0f);
}
m_positions[i].c = c;
m_positions[i].a = a;
m_velocities[i].v = v;
m_velocities[i].w = w;
}
timer.Reset();
// Solver data
b2SolverData solverData;
solverData.step = step;
solverData.positions = m_positions;
solverData.velocities = m_velocities;
// Initialize velocity constraints.
b2ContactSolverDef contactSolverDef;
contactSolverDef.step = step;
contactSolverDef.contacts = m_contacts;
contactSolverDef.count = m_contactCount;
contactSolverDef.positions = m_positions;
contactSolverDef.velocities = m_velocities;
contactSolverDef.allocator = m_allocator;
b2ContactSolver contactSolver(&contactSolverDef);
contactSolver.InitializeVelocityConstraints();
if (step.warmStarting)
{
contactSolver.WarmStart();
}
for (int32 i = 0; i < m_jointCount; ++i)
{
m_joints[i]->InitVelocityConstraints(solverData);
}
profile->solveInit = timer.GetMilliseconds();
// Solve velocity constraints
timer.Reset();
for (int32 i = 0; i < step.velocityIterations; ++i)
{
for (int32 j = 0; j < m_jointCount; ++j)
{
m_joints[j]->SolveVelocityConstraints(solverData);
}
contactSolver.SolveVelocityConstraints();
}
// Store impulses for warm starting
contactSolver.StoreImpulses();
profile->solveVelocity = timer.GetMilliseconds();
// Integrate positions
for (int32 i = 0; i < m_bodyCount; ++i)
{
b2Vec2 c = m_positions[i].c;
float32 a = m_positions[i].a;
b2Vec2 v = m_velocities[i].v;
float32 w = m_velocities[i].w;
// Check for large velocities
b2Vec2 translation = h * v;
if (b2Dot(translation, translation) > b2_maxTranslationSquared)
{
float32 ratio = b2_maxTranslation / translation.Length();
v *= ratio;
}
float32 rotation = h * w;
if (rotation * rotation > b2_maxRotationSquared)
{
float32 ratio = b2_maxRotation / b2Abs(rotation);
w *= ratio;
}
// Integrate
c += h * v;
a += h * w;
m_positions[i].c = c;
m_positions[i].a = a;
m_velocities[i].v = v;
m_velocities[i].w = w;
}
// Solve position constraints
timer.Reset();
bool positionSolved = false;
for (int32 j = 0; j < step.positionIterations; ++j)
{
bool contactsOkay = contactSolver.SolvePositionConstraints();
bool jointsOkay = true;
for (int32 i = 0; i < m_jointCount; ++i)
{
bool jointOkay = m_joints[i]->SolvePositionConstraints(solverData);
jointsOkay = jointsOkay && jointOkay;
}
if (contactsOkay && jointsOkay)
{
// Exit early if the position errors are small.
positionSolved = true;
break;
}
}
// Copy state buffers back to the bodies
for (int32 i = 0; i < m_bodyCount; ++i)
{
b2Body* body = m_bodies[i];
body->m_sweep.c = m_positions[i].c;
body->m_sweep.a = m_positions[i].a;
body->m_linearVelocity = m_velocities[i].v;
body->m_angularVelocity = m_velocities[i].w;
body->SynchronizeTransform();
}
profile->solvePosition = timer.GetMilliseconds();
Report(contactSolver.m_velocityConstraints);
if (allowSleep)
{
float32 minSleepTime = b2_maxFloat;
const float32 linTolSqr = b2_linearSleepTolerance * b2_linearSleepTolerance;
const float32 angTolSqr = b2_angularSleepTolerance * b2_angularSleepTolerance;
for (int32 i = 0; i < m_bodyCount; ++i)
{
b2Body* b = m_bodies[i];
if (b->GetType() == b2_staticBody)
{
continue;
}
if ((b->m_flags & b2Body::e_autoSleepFlag) == 0 ||
b->m_angularVelocity * b->m_angularVelocity > angTolSqr ||
b2Dot(b->m_linearVelocity, b->m_linearVelocity) > linTolSqr)
{
b->m_sleepTime = 0.0f;
minSleepTime = 0.0f;
}
else
{
b->m_sleepTime += h;
minSleepTime = b2Min(minSleepTime, b->m_sleepTime);
}
}
if (minSleepTime >= b2_timeToSleep && positionSolved)
{
for (int32 i = 0; i < m_bodyCount; ++i)
{
b2Body* b = m_bodies[i];
b->SetAwake(false);
}
}
}
}
void b2Island::SolveTOI(const b2TimeStep& subStep, int32 toiIndexA, int32 toiIndexB)
{
b2Assert(toiIndexA < m_bodyCount);
b2Assert(toiIndexB < m_bodyCount);
// Initialize the body state.
for (int32 i = 0; i < m_bodyCount; ++i)
{
b2Body* b = m_bodies[i];
m_positions[i].c = b->m_sweep.c;
m_positions[i].a = b->m_sweep.a;
m_velocities[i].v = b->m_linearVelocity;
m_velocities[i].w = b->m_angularVelocity;
}
b2ContactSolverDef contactSolverDef;
contactSolverDef.contacts = m_contacts;
contactSolverDef.count = m_contactCount;
contactSolverDef.allocator = m_allocator;
contactSolverDef.step = subStep;
contactSolverDef.positions = m_positions;
contactSolverDef.velocities = m_velocities;
b2ContactSolver contactSolver(&contactSolverDef);
// Solve position constraints.
for (int32 i = 0; i < subStep.positionIterations; ++i)
{
bool contactsOkay = contactSolver.SolveTOIPositionConstraints(toiIndexA, toiIndexB);
if (contactsOkay)
{
break;
}
}
#if 0
// Is the new position really safe?
for (int32 i = 0; i < m_contactCount; ++i)
{
b2Contact* c = m_contacts[i];
b2Fixture* fA = c->GetFixtureA();
b2Fixture* fB = c->GetFixtureB();
b2Body* bA = fA->GetBody();
b2Body* bB = fB->GetBody();
int32 indexA = c->GetChildIndexA();
int32 indexB = c->GetChildIndexB();
b2DistanceInput input;
input.proxyA.Set(fA->GetShape(), indexA);
input.proxyB.Set(fB->GetShape(), indexB);
input.transformA = bA->GetTransform();
input.transformB = bB->GetTransform();
input.useRadii = false;
b2DistanceOutput output;
b2SimplexCache cache;
cache.count = 0;
b2Distance(&output, &cache, &input);
if (output.distance == 0 || cache.count == 3)
{
cache.count += 0;
}
}
#endif
// Leap of faith to new safe state.
m_bodies[toiIndexA]->m_sweep.c0 = m_positions[toiIndexA].c;
m_bodies[toiIndexA]->m_sweep.a0 = m_positions[toiIndexA].a;
m_bodies[toiIndexB]->m_sweep.c0 = m_positions[toiIndexB].c;
m_bodies[toiIndexB]->m_sweep.a0 = m_positions[toiIndexB].a;
// No warm starting is needed for TOI events because warm
// starting impulses were applied in the discrete solver.
contactSolver.InitializeVelocityConstraints();
// Solve velocity constraints.
for (int32 i = 0; i < subStep.velocityIterations; ++i)
{
contactSolver.SolveVelocityConstraints();
}
// Don't store the TOI contact forces for warm starting
// because they can be quite large.
float32 h = subStep.dt;
// Integrate positions
for (int32 i = 0; i < m_bodyCount; ++i)
{
b2Vec2 c = m_positions[i].c;
float32 a = m_positions[i].a;
b2Vec2 v = m_velocities[i].v;
float32 w = m_velocities[i].w;
// Check for large velocities
b2Vec2 translation = h * v;
if (b2Dot(translation, translation) > b2_maxTranslationSquared)
{
float32 ratio = b2_maxTranslation / translation.Length();
v *= ratio;
}
float32 rotation = h * w;
if (rotation * rotation > b2_maxRotationSquared)
{
float32 ratio = b2_maxRotation / b2Abs(rotation);
w *= ratio;
}
// Integrate
c += h * v;
a += h * w;
m_positions[i].c = c;
m_positions[i].a = a;
m_velocities[i].v = v;
m_velocities[i].w = w;
// Sync bodies
b2Body* body = m_bodies[i];
body->m_sweep.c = c;
body->m_sweep.a = a;
body->m_linearVelocity = v;
body->m_angularVelocity = w;
body->SynchronizeTransform();
}
Report(contactSolver.m_velocityConstraints);
}
void b2Island::Report(const b2ContactVelocityConstraint* constraints)
{
if (m_listener == NULL)
{
return;
}
for (int32 i = 0; i < m_contactCount; ++i)
{
b2Contact* c = m_contacts[i];
const b2ContactVelocityConstraint* vc = constraints + i;
b2ContactImpulse impulse;
impulse.count = vc->pointCount;
for (int32 j = 0; j < vc->pointCount; ++j)
{
impulse.normalImpulses[j] = vc->points[j].normalImpulse;
impulse.tangentImpulses[j] = vc->points[j].tangentImpulse;
}
m_listener->PostSolve(c, &impulse);
}
}

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_ISLAND_H
#define B2_ISLAND_H
#include "../Common/b2Math.h"
#include "b2Body.h"
#include "b2TimeStep.h"
class b2Contact;
class b2Joint;
class b2StackAllocator;
class b2ContactListener;
struct b2ContactVelocityConstraint;
struct b2Profile;
/// This is an internal class.
class b2Island
{
public:
b2Island(int32 bodyCapacity, int32 contactCapacity, int32 jointCapacity,
b2StackAllocator* allocator, b2ContactListener* listener);
~b2Island();
void Clear()
{
m_bodyCount = 0;
m_contactCount = 0;
m_jointCount = 0;
}
void Solve(b2Profile* profile, const b2TimeStep& step, const b2Vec2& gravity, bool allowSleep);
void SolveTOI(const b2TimeStep& subStep, int32 toiIndexA, int32 toiIndexB);
void Add(b2Body* body)
{
b2Assert(m_bodyCount < m_bodyCapacity);
body->m_islandIndex = m_bodyCount;
m_bodies[m_bodyCount] = body;
++m_bodyCount;
}
void Add(b2Contact* contact)
{
b2Assert(m_contactCount < m_contactCapacity);
m_contacts[m_contactCount++] = contact;
}
void Add(b2Joint* joint)
{
b2Assert(m_jointCount < m_jointCapacity);
m_joints[m_jointCount++] = joint;
}
void Report(const b2ContactVelocityConstraint* constraints);
b2StackAllocator* m_allocator;
b2ContactListener* m_listener;
b2Body** m_bodies;
b2Contact** m_contacts;
b2Joint** m_joints;
b2Position* m_positions;
b2Velocity* m_velocities;
int32 m_bodyCount;
int32 m_jointCount;
int32 m_contactCount;
int32 m_bodyCapacity;
int32 m_contactCapacity;
int32 m_jointCapacity;
};
#endif

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_TIME_STEP_H
#define B2_TIME_STEP_H
#include "../Common/b2Math.h"
/// Profiling data. Times are in milliseconds.
struct b2Profile
{
float32 step;
float32 collide;
float32 solve;
float32 solveInit;
float32 solveVelocity;
float32 solvePosition;
float32 broadphase;
float32 solveTOI;
};
/// This is an internal structure.
struct b2TimeStep
{
float32 dt; // time step
float32 inv_dt; // inverse time step (0 if dt == 0).
float32 dtRatio; // dt * inv_dt0
juce::int32 velocityIterations;
juce::int32 positionIterations;
bool warmStarting;
};
/// This is an internal structure.
struct b2Position
{
b2Vec2 c;
float32 a;
};
/// This is an internal structure.
struct b2Velocity
{
b2Vec2 v;
float32 w;
};
/// Solver Data
struct b2SolverData
{
b2TimeStep step;
b2Position* positions;
b2Velocity* velocities;
};
#endif

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/*
* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_WORLD_H
#define B2_WORLD_H
#include "../Common/b2Math.h"
#include "../Common/b2BlockAllocator.h"
#include "../Common/b2StackAllocator.h"
#include "b2ContactManager.h"
#include "b2WorldCallbacks.h"
#include "b2TimeStep.h"
struct b2AABB;
struct b2BodyDef;
struct b2Color;
struct b2JointDef;
class b2Body;
class b2Draw;
class b2Fixture;
class b2Joint;
/// The world class manages all physics entities, dynamic simulation,
/// and asynchronous queries. The world also contains efficient memory
/// management facilities.
class b2World
{
public:
/// Construct a world object.
/// @param gravity the world gravity vector.
b2World(const b2Vec2& gravity);
/// Destruct the world. All physics entities are destroyed and all heap memory is released.
~b2World();
/// Register a destruction listener. The listener is owned by you and must
/// remain in scope.
void SetDestructionListener(b2DestructionListener* listener);
/// Register a contact filter to provide specific control over collision.
/// Otherwise the default filter is used (b2_defaultFilter). The listener is
/// owned by you and must remain in scope.
void SetContactFilter(b2ContactFilter* filter);
/// Register a contact event listener. The listener is owned by you and must
/// remain in scope.
void SetContactListener(b2ContactListener* listener);
/// Register a routine for debug drawing. The debug draw functions are called
/// inside with b2World::DrawDebugData method. The debug draw object is owned
/// by you and must remain in scope.
void SetDebugDraw(b2Draw* debugDraw);
/// Create a rigid body given a definition. No reference to the definition
/// is retained.
/// @warning This function is locked during callbacks.
b2Body* CreateBody(const b2BodyDef* def);
/// Destroy a rigid body given a definition. No reference to the definition
/// is retained. This function is locked during callbacks.
/// @warning This automatically deletes all associated shapes and joints.
/// @warning This function is locked during callbacks.
void DestroyBody(b2Body* body);
/// Create a joint to constrain bodies together. No reference to the definition
/// is retained. This may cause the connected bodies to cease colliding.
/// @warning This function is locked during callbacks.
b2Joint* CreateJoint(const b2JointDef* def);
/// Destroy a joint. This may cause the connected bodies to begin colliding.
/// @warning This function is locked during callbacks.
void DestroyJoint(b2Joint* joint);
/// Take a time step. This performs collision detection, integration,
/// and constraint solution.
/// @param timeStep the amount of time to simulate, this should not vary.
/// @param velocityIterations for the velocity constraint solver.
/// @param positionIterations for the position constraint solver.
void Step( float32 timeStep,
juce::int32 velocityIterations,
juce::int32 positionIterations);
/// Manually clear the force buffer on all bodies. By default, forces are cleared automatically
/// after each call to Step. The default behavior is modified by calling SetAutoClearForces.
/// The purpose of this function is to support sub-stepping. Sub-stepping is often used to maintain
/// a fixed sized time step under a variable frame-rate.
/// When you perform sub-stepping you will disable auto clearing of forces and instead call
/// ClearForces after all sub-steps are complete in one pass of your game loop.
/// @see SetAutoClearForces
void ClearForces();
/// Call this to draw shapes and other debug draw data.
void DrawDebugData();
/// Query the world for all fixtures that potentially overlap the
/// provided AABB.
/// @param callback a user implemented callback class.
/// @param aabb the query box.
void QueryAABB(b2QueryCallback* callback, const b2AABB& aabb) const;
/// Ray-cast the world for all fixtures in the path of the ray. Your callback
/// controls whether you get the closest point, any point, or n-points.
/// The ray-cast ignores shapes that contain the starting point.
/// @param callback a user implemented callback class.
/// @param point1 the ray starting point
/// @param point2 the ray ending point
void RayCast(b2RayCastCallback* callback, const b2Vec2& point1, const b2Vec2& point2) const;
/// Get the world body list. With the returned body, use b2Body::GetNext to get
/// the next body in the world list. A NULL body indicates the end of the list.
/// @return the head of the world body list.
b2Body* GetBodyList();
const b2Body* GetBodyList() const;
/// Get the world joint list. With the returned joint, use b2Joint::GetNext to get
/// the next joint in the world list. A NULL joint indicates the end of the list.
/// @return the head of the world joint list.
b2Joint* GetJointList();
const b2Joint* GetJointList() const;
/// Get the world contact list. With the returned contact, use b2Contact::GetNext to get
/// the next contact in the world list. A NULL contact indicates the end of the list.
/// @return the head of the world contact list.
/// @warning contacts are created and destroyed in the middle of a time step.
/// Use b2ContactListener to avoid missing contacts.
b2Contact* GetContactList();
const b2Contact* GetContactList() const;
/// Enable/disable sleep.
void SetAllowSleeping(bool flag);
bool GetAllowSleeping() const { return m_allowSleep; }
/// Enable/disable warm starting. For testing.
void SetWarmStarting(bool flag) { m_warmStarting = flag; }
bool GetWarmStarting() const { return m_warmStarting; }
/// Enable/disable continuous physics. For testing.
void SetContinuousPhysics(bool flag) { m_continuousPhysics = flag; }
bool GetContinuousPhysics() const { return m_continuousPhysics; }
/// Enable/disable single stepped continuous physics. For testing.
void SetSubStepping(bool flag) { m_subStepping = flag; }
bool GetSubStepping() const { return m_subStepping; }
/// Get the number of broad-phase proxies.
juce::int32 GetProxyCount() const;
/// Get the number of bodies.
juce::int32 GetBodyCount() const;
/// Get the number of joints.
juce::int32 GetJointCount() const;
/// Get the number of contacts (each may have 0 or more contact points).
juce::int32 GetContactCount() const;
/// Get the height of the dynamic tree.
juce::int32 GetTreeHeight() const;
/// Get the balance of the dynamic tree.
juce::int32 GetTreeBalance() const;
/// Get the quality metric of the dynamic tree. The smaller the better.
/// The minimum is 1.
float32 GetTreeQuality() const;
/// Change the global gravity vector.
void SetGravity(const b2Vec2& gravity);
/// Get the global gravity vector.
b2Vec2 GetGravity() const;
/// Is the world locked (in the middle of a time step).
bool IsLocked() const;
/// Set flag to control automatic clearing of forces after each time step.
void SetAutoClearForces(bool flag);
/// Get the flag that controls automatic clearing of forces after each time step.
bool GetAutoClearForces() const;
/// Get the contact manager for testing.
const b2ContactManager& GetContactManager() const;
/// Get the current profile.
const b2Profile& GetProfile() const;
/// Dump the world into the log file.
/// @warning this should be called outside of a time step.
void Dump();
private:
// m_flags
enum
{
e_newFixture = 0x0001,
e_locked = 0x0002,
e_clearForces = 0x0004
};
friend class b2Body;
friend class b2Fixture;
friend class b2ContactManager;
friend class b2Controller;
void Solve(const b2TimeStep& step);
void SolveTOI(const b2TimeStep& step);
void DrawJoint(b2Joint* joint);
void DrawShape(b2Fixture* shape, const b2Transform& xf, const b2Color& color);
b2BlockAllocator m_blockAllocator;
b2StackAllocator m_stackAllocator;
juce::int32 m_flags;
b2ContactManager m_contactManager;
b2Body* m_bodyList;
b2Joint* m_jointList;
juce::int32 m_bodyCount;
juce::int32 m_jointCount;
b2Vec2 m_gravity;
bool m_allowSleep;
b2DestructionListener* m_destructionListener;
b2Draw* m_debugDraw;
// This is used to compute the time step ratio to
// support a variable time step.
float32 m_inv_dt0;
// These are for debugging the solver.
bool m_warmStarting;
bool m_continuousPhysics;
bool m_subStepping;
bool m_stepComplete;
b2Profile m_profile;
};
inline b2Body* b2World::GetBodyList()
{
return m_bodyList;
}
inline const b2Body* b2World::GetBodyList() const
{
return m_bodyList;
}
inline b2Joint* b2World::GetJointList()
{
return m_jointList;
}
inline const b2Joint* b2World::GetJointList() const
{
return m_jointList;
}
inline b2Contact* b2World::GetContactList()
{
return m_contactManager.m_contactList;
}
inline const b2Contact* b2World::GetContactList() const
{
return m_contactManager.m_contactList;
}
inline juce::int32 b2World::GetBodyCount() const
{
return m_bodyCount;
}
inline juce::int32 b2World::GetJointCount() const
{
return m_jointCount;
}
inline juce::int32 b2World::GetContactCount() const
{
return m_contactManager.m_contactCount;
}
inline void b2World::SetGravity(const b2Vec2& gravity)
{
m_gravity = gravity;
}
inline b2Vec2 b2World::GetGravity() const
{
return m_gravity;
}
inline bool b2World::IsLocked() const
{
return (m_flags & e_locked) == e_locked;
}
inline void b2World::SetAutoClearForces(bool flag)
{
if (flag)
{
m_flags |= e_clearForces;
}
else
{
m_flags &= ~e_clearForces;
}
}
/// Get the flag that controls automatic clearing of forces after each time step.
inline bool b2World::GetAutoClearForces() const
{
return (m_flags & e_clearForces) == e_clearForces;
}
inline const b2ContactManager& b2World::GetContactManager() const
{
return m_contactManager;
}
inline const b2Profile& b2World::GetProfile() const
{
return m_profile;
}
#endif

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "b2WorldCallbacks.h"
#include "b2Fixture.h"
// Return true if contact calculations should be performed between these two shapes.
// If you implement your own collision filter you may want to build from this implementation.
bool b2ContactFilter::ShouldCollide(b2Fixture* fixtureA, b2Fixture* fixtureB)
{
const b2Filter& filterA = fixtureA->GetFilterData();
const b2Filter& filterB = fixtureB->GetFilterData();
if (filterA.groupIndex == filterB.groupIndex && filterA.groupIndex != 0)
{
return filterA.groupIndex > 0;
}
bool collide = (filterA.maskBits & filterB.categoryBits) != 0 && (filterA.categoryBits & filterB.maskBits) != 0;
return collide;
}

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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_WORLD_CALLBACKS_H
#define B2_WORLD_CALLBACKS_H
#include "../Common/b2Settings.h"
struct b2Vec2;
struct b2Transform;
class b2Fixture;
class b2Body;
class b2Joint;
class b2Contact;
struct b2ContactResult;
struct b2Manifold;
/// Joints and fixtures are destroyed when their associated
/// body is destroyed. Implement this listener so that you
/// may nullify references to these joints and shapes.
class b2DestructionListener
{
public:
virtual ~b2DestructionListener() {}
/// Called when any joint is about to be destroyed due
/// to the destruction of one of its attached bodies.
virtual void SayGoodbye(b2Joint* joint) = 0;
/// Called when any fixture is about to be destroyed due
/// to the destruction of its parent body.
virtual void SayGoodbye(b2Fixture* fixture) = 0;
};
/// Implement this class to provide collision filtering. In other words, you can implement
/// this class if you want finer control over contact creation.
class b2ContactFilter
{
public:
virtual ~b2ContactFilter() {}
/// Return true if contact calculations should be performed between these two shapes.
/// @warning for performance reasons this is only called when the AABBs begin to overlap.
virtual bool ShouldCollide(b2Fixture* fixtureA, b2Fixture* fixtureB);
};
/// Contact impulses for reporting. Impulses are used instead of forces because
/// sub-step forces may approach infinity for rigid body collisions. These
/// match up one-to-one with the contact points in b2Manifold.
struct b2ContactImpulse
{
float32 normalImpulses[b2_maxManifoldPoints];
float32 tangentImpulses[b2_maxManifoldPoints];
juce::int32 count;
};
/// Implement this class to get contact information. You can use these results for
/// things like sounds and game logic. You can also get contact results by
/// traversing the contact lists after the time step. However, you might miss
/// some contacts because continuous physics leads to sub-stepping.
/// Additionally you may receive multiple callbacks for the same contact in a
/// single time step.
/// You should strive to make your callbacks efficient because there may be
/// many callbacks per time step.
/// @warning You cannot create/destroy Box2D entities inside these callbacks.
class b2ContactListener
{
public:
virtual ~b2ContactListener() {}
/// Called when two fixtures begin to touch.
virtual void BeginContact(b2Contact* contact) { B2_NOT_USED(contact); }
/// Called when two fixtures cease to touch.
virtual void EndContact(b2Contact* contact) { B2_NOT_USED(contact); }
/// This is called after a contact is updated. This allows you to inspect a
/// contact before it goes to the solver. If you are careful, you can modify the
/// contact manifold (e.g. disable contact).
/// A copy of the old manifold is provided so that you can detect changes.
/// Note: this is called only for awake bodies.
/// Note: this is called even when the number of contact points is zero.
/// Note: this is not called for sensors.
/// Note: if you set the number of contact points to zero, you will not
/// get an EndContact callback. However, you may get a BeginContact callback
/// the next step.
virtual void PreSolve(b2Contact* contact, const b2Manifold* oldManifold)
{
B2_NOT_USED(contact);
B2_NOT_USED(oldManifold);
}
/// This lets you inspect a contact after the solver is finished. This is useful
/// for inspecting impulses.
/// Note: the contact manifold does not include time of impact impulses, which can be
/// arbitrarily large if the sub-step is small. Hence the impulse is provided explicitly
/// in a separate data structure.
/// Note: this is only called for contacts that are touching, solid, and awake.
virtual void PostSolve(b2Contact* contact, const b2ContactImpulse* impulse)
{
B2_NOT_USED(contact);
B2_NOT_USED(impulse);
}
};
/// Callback class for AABB queries.
/// See b2World::Query
class b2QueryCallback
{
public:
virtual ~b2QueryCallback() {}
/// Called for each fixture found in the query AABB.
/// @return false to terminate the query.
virtual bool ReportFixture(b2Fixture* fixture) = 0;
};
/// Callback class for ray casts.
/// See b2World::RayCast
class b2RayCastCallback
{
public:
virtual ~b2RayCastCallback() {}
/// Called for each fixture found in the query. You control how the ray cast
/// proceeds by returning a float:
/// return -1: ignore this fixture and continue
/// return 0: terminate the ray cast
/// return fraction: clip the ray to this point
/// return 1: don't clip the ray and continue
/// @param fixture the fixture hit by the ray
/// @param point the point of initial intersection
/// @param normal the normal vector at the point of intersection
/// @return -1 to filter, 0 to terminate, fraction to clip the ray for
/// closest hit, 1 to continue
virtual float32 ReportFixture( b2Fixture* fixture, const b2Vec2& point,
const b2Vec2& normal, float32 fraction) = 0;
};
#endif