RayCast.h
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- /*
- * Copyright (c) 2006-2009 Erin Catto http://www.gphysics.com
- *
- * 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();
- int32 index = 0;
- 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);
- b2PolygonShape shape;
- shape.SetAsEdge(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 + sqrtf(2.0f));
- float32 s = sqrtf(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