paulxstretch/deps/juce/examples/Assets/Box2DTests/RayCast.h

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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 RAY_CAST_H
#define RAY_CAST_H
// This test demonstrates how to use the world ray-cast feature.
// NOTE: we are intentionally filtering one of the polygons, therefore
// the ray will always miss one type of polygon.
// This callback finds the closest hit. Polygon 0 is filtered.
class RayCastClosestCallback : public b2RayCastCallback
{
public:
RayCastClosestCallback()
{
m_hit = false;
}
float32 ReportFixture( b2Fixture* fixture, const b2Vec2& point,
const b2Vec2& normal, float32 fraction)
{
b2Body* body = fixture->GetBody();
void* userData = body->GetUserData();
if (userData)
{
int32 index = *(int32*)userData;
if (index == 0)
{
// filter
return -1.0f;
}
}
m_hit = true;
m_point = point;
m_normal = normal;
return fraction;
}
bool m_hit;
b2Vec2 m_point;
b2Vec2 m_normal;
};
// This callback finds any hit. Polygon 0 is filtered.
class RayCastAnyCallback : public b2RayCastCallback
{
public:
RayCastAnyCallback()
{
m_hit = false;
}
float32 ReportFixture( b2Fixture* fixture, const b2Vec2& point,
const b2Vec2& normal, float32 fraction)
{
b2Body* body = fixture->GetBody();
void* userData = body->GetUserData();
if (userData)
{
int32 index = *(int32*)userData;
if (index == 0)
{
// filter
return -1.0f;
}
}
m_hit = true;
m_point = point;
m_normal = normal;
return 0.0f;
}
bool m_hit;
b2Vec2 m_point;
b2Vec2 m_normal;
};
// This ray cast collects multiple hits along the ray. Polygon 0 is filtered.
class RayCastMultipleCallback : public b2RayCastCallback
{
public:
enum
{
e_maxCount = 3
};
RayCastMultipleCallback()
{
m_count = 0;
}
float32 ReportFixture( b2Fixture* fixture, const b2Vec2& point,
const b2Vec2& normal, float32 fraction)
{
b2Body* body = fixture->GetBody();
void* userData = body->GetUserData();
if (userData)
{
int32 index = *(int32*)userData;
if (index == 0)
{
// filter
return -1.0f;
}
}
b2Assert(m_count < e_maxCount);
m_points[m_count] = point;
m_normals[m_count] = normal;
++m_count;
if (m_count == e_maxCount)
{
return 0.0f;
}
return 1.0f;
}
b2Vec2 m_points[e_maxCount];
b2Vec2 m_normals[e_maxCount];
int32 m_count;
};
class RayCast : public Test
{
public:
enum
{
e_maxBodies = 256
};
enum Mode
{
e_closest,
e_any,
e_multiple
};
RayCast()
{
// 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));
m_angle = 0.0f;
m_mode = e_closest;
}
void Create(int32 index)
{
if (m_bodies[m_bodyIndex] != NULL)
{
m_world->DestroyBody(m_bodies[m_bodyIndex]);
m_bodies[m_bodyIndex] = NULL;
}
b2BodyDef bd;
float32 x = RandomFloat(-10.0f, 10.0f);
float32 y = RandomFloat(0.0f, 20.0f);
bd.position.Set(x, y);
bd.angle = RandomFloat(-b2_pi, b2_pi);
m_userData[m_bodyIndex] = index;
bd.userData = m_userData + m_bodyIndex;
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.friction = 0.3f;
m_bodies[m_bodyIndex]->CreateFixture(&fd);
}
else
{
b2FixtureDef fd;
fd.shape = &m_circle;
fd.friction = 0.3f;
m_bodies[m_bodyIndex]->CreateFixture(&fd);
}
m_bodyIndex = (m_bodyIndex + 1) % e_maxBodies;
}
void DestroyBody()
{
for (int32 i = 0; i < e_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 'd':
DestroyBody();
break;
case 'm':
if (m_mode == e_closest)
{
m_mode = e_any;
}
else if (m_mode == e_any)
{
m_mode = e_multiple;
}
else if (m_mode == e_multiple)
{
m_mode = e_closest;
}
}
}
void Step(Settings* settings)
{
bool advanceRay = settings->pause == 0 || settings->singleStep;
Test::Step(settings);
m_debugDraw.DrawString(5, m_textLine, "Press 1-5 to drop stuff, m to change the mode");
m_textLine += 15;
m_debugDraw.DrawString(5, m_textLine, "Mode = %d", m_mode);
m_textLine += 15;
float32 L = 11.0f;
b2Vec2 point1(0.0f, 10.0f);
b2Vec2 d(L * cosf(m_angle), L * sinf(m_angle));
b2Vec2 point2 = point1 + d;
if (m_mode == e_closest)
{
RayCastClosestCallback callback;
m_world->RayCast(&callback, point1, point2);
if (callback.m_hit)
{
m_debugDraw.DrawPoint(callback.m_point, 5.0f, b2Color(0.4f, 0.9f, 0.4f));
m_debugDraw.DrawSegment(point1, callback.m_point, b2Color(0.8f, 0.8f, 0.8f));
b2Vec2 head = callback.m_point + 0.5f * callback.m_normal;
m_debugDraw.DrawSegment(callback.m_point, head, b2Color(0.9f, 0.9f, 0.4f));
}
else
{
m_debugDraw.DrawSegment(point1, point2, b2Color(0.8f, 0.8f, 0.8f));
}
}
else if (m_mode == e_any)
{
RayCastAnyCallback callback;
m_world->RayCast(&callback, point1, point2);
if (callback.m_hit)
{
m_debugDraw.DrawPoint(callback.m_point, 5.0f, b2Color(0.4f, 0.9f, 0.4f));
m_debugDraw.DrawSegment(point1, callback.m_point, b2Color(0.8f, 0.8f, 0.8f));
b2Vec2 head = callback.m_point + 0.5f * callback.m_normal;
m_debugDraw.DrawSegment(callback.m_point, head, b2Color(0.9f, 0.9f, 0.4f));
}
else
{
m_debugDraw.DrawSegment(point1, point2, b2Color(0.8f, 0.8f, 0.8f));
}
}
else if (m_mode == e_multiple)
{
RayCastMultipleCallback callback;
m_world->RayCast(&callback, point1, point2);
m_debugDraw.DrawSegment(point1, point2, b2Color(0.8f, 0.8f, 0.8f));
for (int32 i = 0; i < callback.m_count; ++i)
{
b2Vec2 p = callback.m_points[i];
b2Vec2 n = callback.m_normals[i];
m_debugDraw.DrawPoint(p, 5.0f, b2Color(0.4f, 0.9f, 0.4f));
m_debugDraw.DrawSegment(point1, p, b2Color(0.8f, 0.8f, 0.8f));
b2Vec2 head = p + 0.5f * n;
m_debugDraw.DrawSegment(p, head, b2Color(0.9f, 0.9f, 0.4f));
}
}
if (advanceRay)
{
m_angle += 0.25f * b2_pi / 180.0f;
}
#if 0
// This case was failing.
{
b2Vec2 vertices[4];
//vertices[0].Set(-22.875f, -3.0f);
//vertices[1].Set(22.875f, -3.0f);
//vertices[2].Set(22.875f, 3.0f);
//vertices[3].Set(-22.875f, 3.0f);
b2PolygonShape shape;
//shape.Set(vertices, 4);
shape.SetAsBox(22.875f, 3.0f);
b2RayCastInput input;
input.p1.Set(10.2725f,1.71372f);
input.p2.Set(10.2353f,2.21807f);
//input.maxFraction = 0.567623f;
input.maxFraction = 0.56762173f;
b2Transform xf;
xf.SetIdentity();
xf.position.Set(23.0f, 5.0f);
b2RayCastOutput output;
bool hit;
hit = shape.RayCast(&output, input, xf);
hit = false;
b2Color color(1.0f, 1.0f, 1.0f);
b2Vec2 vs[4];
for (int32 i = 0; i < 4; ++i)
{
vs[i] = b2Mul(xf, shape.m_vertices[i]);
}
m_debugDraw.DrawPolygon(vs, 4, color);
m_debugDraw.DrawSegment(input.p1, input.p2, color);
}
#endif
}
static Test* Create()
{
return new RayCast;
}
int32 m_bodyIndex;
b2Body* m_bodies[e_maxBodies];
int32 m_userData[e_maxBodies];
b2PolygonShape m_polygons[4];
b2CircleShape m_circle;
float32 m_angle;
Mode m_mode;
};
#endif