paulxstretch/deps/juce/examples/Assets/Box2DTests/PolyShapes.h
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2022-04-18 17:51:22 -04:00

296 lines
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C++

/*
* 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 POLY_SHAPES_H
#define POLY_SHAPES_H
/// This tests stacking. It also shows how to use b2World::Query
/// and b2TestOverlap.
const int32 k_maxBodies = 256;
/// This callback is called by b2World::QueryAABB. We find all the fixtures
/// that overlap an AABB. Of those, we use b2TestOverlap to determine which fixtures
/// overlap a circle. Up to 4 overlapped fixtures will be highlighted with a yellow border.
class PolyShapesCallback : public b2QueryCallback
{
public:
enum
{
e_maxCount = 4
};
PolyShapesCallback()
{
m_count = 0;
}
void DrawFixture(b2Fixture* fixture)
{
b2Color color(0.95f, 0.95f, 0.6f);
const b2Transform& xf = fixture->GetBody()->GetTransform();
switch (fixture->GetType())
{
case b2Shape::e_circle:
{
b2CircleShape* circle = (b2CircleShape*)fixture->GetShape();
b2Vec2 center = b2Mul(xf, circle->m_p);
float32 radius = circle->m_radius;
m_debugDraw->DrawCircle(center, radius, color);
}
break;
case b2Shape::e_polygon:
{
b2PolygonShape* poly = (b2PolygonShape*)fixture->GetShape();
int32 vertexCount = poly->m_vertexCount;
b2Assert(vertexCount <= b2_maxPolygonVertices);
b2Vec2 vertices[b2_maxPolygonVertices];
for (int32 i = 0; i < vertexCount; ++i)
{
vertices[i] = b2Mul(xf, poly->m_vertices[i]);
}
m_debugDraw->DrawPolygon(vertices, vertexCount, color);
}
break;
default:
break;
}
}
/// Called for each fixture found in the query AABB.
/// @return false to terminate the query.
bool ReportFixture(b2Fixture* fixture)
{
if (m_count == e_maxCount)
{
return false;
}
b2Body* body = fixture->GetBody();
b2Shape* shape = fixture->GetShape();
bool overlap = b2TestOverlap(shape, 0, &m_circle, 0, body->GetTransform(), m_transform);
if (overlap)
{
DrawFixture(fixture);
++m_count;
}
return true;
}
b2CircleShape m_circle;
b2Transform m_transform;
b2Draw* m_debugDraw;
int32 m_count;
};
class PolyShapes : public Test
{
public:
PolyShapes()
{
// Ground body
{
b2BodyDef bd;
b2Body* ground = m_world->CreateBody(&bd);
b2EdgeShape shape;
shape.Set(b2Vec2(-40.0f, 0.0f), b2Vec2(40.0f, 0.0f));
ground->CreateFixture(&shape, 0.0f);
}
{
b2Vec2 vertices[3];
vertices[0].Set(-0.5f, 0.0f);
vertices[1].Set(0.5f, 0.0f);
vertices[2].Set(0.0f, 1.5f);
m_polygons[0].Set(vertices, 3);
}
{
b2Vec2 vertices[3];
vertices[0].Set(-0.1f, 0.0f);
vertices[1].Set(0.1f, 0.0f);
vertices[2].Set(0.0f, 1.5f);
m_polygons[1].Set(vertices, 3);
}
{
float32 w = 1.0f;
float32 b = w / (2.0f + b2Sqrt(2.0f));
float32 s = b2Sqrt(2.0f) * b;
b2Vec2 vertices[8];
vertices[0].Set(0.5f * s, 0.0f);
vertices[1].Set(0.5f * w, b);
vertices[2].Set(0.5f * w, b + s);
vertices[3].Set(0.5f * s, w);
vertices[4].Set(-0.5f * s, w);
vertices[5].Set(-0.5f * w, b + s);
vertices[6].Set(-0.5f * w, b);
vertices[7].Set(-0.5f * s, 0.0f);
m_polygons[2].Set(vertices, 8);
}
{
m_polygons[3].SetAsBox(0.5f, 0.5f);
}
{
m_circle.m_radius = 0.5f;
}
m_bodyIndex = 0;
memset(m_bodies, 0, sizeof(m_bodies));
}
void Create(int32 index)
{
if (m_bodies[m_bodyIndex] != NULL)
{
m_world->DestroyBody(m_bodies[m_bodyIndex]);
m_bodies[m_bodyIndex] = NULL;
}
b2BodyDef bd;
bd.type = b2_dynamicBody;
float32 x = RandomFloat(-2.0f, 2.0f);
bd.position.Set(x, 10.0f);
bd.angle = RandomFloat(-b2_pi, b2_pi);
if (index == 4)
{
bd.angularDamping = 0.02f;
}
m_bodies[m_bodyIndex] = m_world->CreateBody(&bd);
if (index < 4)
{
b2FixtureDef fd;
fd.shape = m_polygons + index;
fd.density = 1.0f;
fd.friction = 0.3f;
m_bodies[m_bodyIndex]->CreateFixture(&fd);
}
else
{
b2FixtureDef fd;
fd.shape = &m_circle;
fd.density = 1.0f;
fd.friction = 0.3f;
m_bodies[m_bodyIndex]->CreateFixture(&fd);
}
m_bodyIndex = (m_bodyIndex + 1) % k_maxBodies;
}
void DestroyBody()
{
for (int32 i = 0; i < k_maxBodies; ++i)
{
if (m_bodies[i] != NULL)
{
m_world->DestroyBody(m_bodies[i]);
m_bodies[i] = NULL;
return;
}
}
}
void Keyboard(unsigned char key)
{
switch (key)
{
case '1':
case '2':
case '3':
case '4':
case '5':
Create(key - '1');
break;
case 'a':
for (int32 i = 0; i < k_maxBodies; i += 2)
{
if (m_bodies[i])
{
bool active = m_bodies[i]->IsActive();
m_bodies[i]->SetActive(!active);
}
}
break;
case 'd':
DestroyBody();
break;
}
}
void Step(Settings* settings)
{
Test::Step(settings);
PolyShapesCallback callback;
callback.m_circle.m_radius = 2.0f;
callback.m_circle.m_p.Set(0.0f, 1.1f);
callback.m_transform.SetIdentity();
callback.m_debugDraw = &m_debugDraw;
b2AABB aabb;
callback.m_circle.ComputeAABB(&aabb, callback.m_transform, 0);
m_world->QueryAABB(&callback, aabb);
b2Color color(0.4f, 0.7f, 0.8f);
m_debugDraw.DrawCircle(callback.m_circle.m_p, callback.m_circle.m_radius, color);
m_debugDraw.DrawString(5, m_textLine, "Press 1-5 to drop stuff");
m_textLine += 15;
m_debugDraw.DrawString(5, m_textLine, "Press 'a' to (de)activate some bodies");
m_textLine += 15;
m_debugDraw.DrawString(5, m_textLine, "Press 'd' to destroy a body");
m_textLine += 15;
}
static Test* Create()
{
return new PolyShapes;
}
int32 m_bodyIndex;
b2Body* m_bodies[k_maxBodies];
b2PolygonShape m_polygons[4];
b2CircleShape m_circle;
};
#endif