1 /* 2 * Copyright (c) 2006-2009 Erin Catto http://www.box2d.org 3 * 4 * This software is provided 'as-is', without any express or implied 5 * warranty. In no event will the authors be held liable for any damages 6 * arising from the use of this software. 7 * Permission is granted to anyone to use this software for any purpose, 8 * including commercial applications, and to alter it and redistribute it 9 * freely, subject to the following restrictions: 10 * 1. The origin of this software must not be misrepresented; you must not 11 * claim that you wrote the original software. If you use this software 12 * in a product, an acknowledgment in the product documentation would be 13 * appreciated but is not required. 14 * 2. Altered source versions must be plainly marked as such, and must not be 15 * misrepresented as being the original software. 16 * 3. This notice may not be removed or altered from any source distribution. 17 */ 18 19 #ifndef POLY_SHAPES_H 20 #define POLY_SHAPES_H 21 22 /// This tests stacking. It also shows how to use b2World::Query 23 /// and b2TestOverlap. 24 25 const int32 k_maxBodies = 256; 26 27 /// This callback is called by b2World::QueryAABB. We find all the fixtures 28 /// that overlap an AABB. Of those, we use b2TestOverlap to determine which fixtures 29 /// overlap a circle. Up to 4 overlapped fixtures will be highlighted with a yellow border. 30 class PolyShapesCallback : public b2QueryCallback 31 { 32 public: 33 34 enum 35 { 36 e_maxCount = 4 37 }; 38 PolyShapesCallback()39 PolyShapesCallback() 40 { 41 m_count = 0; 42 } 43 DrawFixture(b2Fixture * fixture)44 void DrawFixture(b2Fixture* fixture) 45 { 46 b2Color color(0.95f, 0.95f, 0.6f); 47 const b2Transform& xf = fixture->GetBody()->GetTransform(); 48 49 switch (fixture->GetType()) 50 { 51 case b2Shape::e_circle: 52 { 53 b2CircleShape* circle = (b2CircleShape*)fixture->GetShape(); 54 55 b2Vec2 center = b2Mul(xf, circle->m_p); 56 float32 radius = circle->m_radius; 57 58 m_debugDraw->DrawCircle(center, radius, color); 59 } 60 break; 61 62 case b2Shape::e_polygon: 63 { 64 b2PolygonShape* poly = (b2PolygonShape*)fixture->GetShape(); 65 int32 vertexCount = poly->m_vertexCount; 66 b2Assert(vertexCount <= b2_maxPolygonVertices); 67 b2Vec2 vertices[b2_maxPolygonVertices]; 68 69 for (int32 i = 0; i < vertexCount; ++i) 70 { 71 vertices[i] = b2Mul(xf, poly->m_vertices[i]); 72 } 73 74 m_debugDraw->DrawPolygon(vertices, vertexCount, color); 75 } 76 break; 77 78 default: 79 break; 80 } 81 } 82 83 /// Called for each fixture found in the query AABB. 84 /// @return false to terminate the query. ReportFixture(b2Fixture * fixture)85 bool ReportFixture(b2Fixture* fixture) 86 { 87 if (m_count == e_maxCount) 88 { 89 return false; 90 } 91 92 b2Body* body = fixture->GetBody(); 93 b2Shape* shape = fixture->GetShape(); 94 95 bool overlap = b2TestOverlap(shape, 0, &m_circle, 0, body->GetTransform(), m_transform); 96 97 if (overlap) 98 { 99 DrawFixture(fixture); 100 ++m_count; 101 } 102 103 return true; 104 } 105 106 b2CircleShape m_circle; 107 b2Transform m_transform; 108 b2Draw* m_debugDraw; 109 int32 m_count; 110 }; 111 112 class PolyShapes : public Test 113 { 114 public: PolyShapes()115 PolyShapes() 116 { 117 // Ground body 118 { 119 b2BodyDef bd; 120 b2Body* ground = m_world->CreateBody(&bd); 121 122 b2EdgeShape shape; 123 shape.Set(b2Vec2(-40.0f, 0.0f), b2Vec2(40.0f, 0.0f)); 124 ground->CreateFixture(&shape, 0.0f); 125 } 126 127 { 128 b2Vec2 vertices[3]; 129 vertices[0].Set(-0.5f, 0.0f); 130 vertices[1].Set(0.5f, 0.0f); 131 vertices[2].Set(0.0f, 1.5f); 132 m_polygons[0].Set(vertices, 3); 133 } 134 135 { 136 b2Vec2 vertices[3]; 137 vertices[0].Set(-0.1f, 0.0f); 138 vertices[1].Set(0.1f, 0.0f); 139 vertices[2].Set(0.0f, 1.5f); 140 m_polygons[1].Set(vertices, 3); 141 } 142 143 { 144 float32 w = 1.0f; 145 float32 b = w / (2.0f + b2Sqrt(2.0f)); 146 float32 s = b2Sqrt(2.0f) * b; 147 148 b2Vec2 vertices[8]; 149 vertices[0].Set(0.5f * s, 0.0f); 150 vertices[1].Set(0.5f * w, b); 151 vertices[2].Set(0.5f * w, b + s); 152 vertices[3].Set(0.5f * s, w); 153 vertices[4].Set(-0.5f * s, w); 154 vertices[5].Set(-0.5f * w, b + s); 155 vertices[6].Set(-0.5f * w, b); 156 vertices[7].Set(-0.5f * s, 0.0f); 157 158 m_polygons[2].Set(vertices, 8); 159 } 160 161 { 162 m_polygons[3].SetAsBox(0.5f, 0.5f); 163 } 164 165 { 166 m_circle.m_radius = 0.5f; 167 } 168 169 m_bodyIndex = 0; 170 memset(m_bodies, 0, sizeof(m_bodies)); 171 } 172 Create(int32 index)173 void Create(int32 index) 174 { 175 if (m_bodies[m_bodyIndex] != NULL) 176 { 177 m_world->DestroyBody(m_bodies[m_bodyIndex]); 178 m_bodies[m_bodyIndex] = NULL; 179 } 180 181 b2BodyDef bd; 182 bd.type = b2_dynamicBody; 183 184 float32 x = RandomFloat(-2.0f, 2.0f); 185 bd.position.Set(x, 10.0f); 186 bd.angle = RandomFloat(-b2_pi, b2_pi); 187 188 if (index == 4) 189 { 190 bd.angularDamping = 0.02f; 191 } 192 193 m_bodies[m_bodyIndex] = m_world->CreateBody(&bd); 194 195 if (index < 4) 196 { 197 b2FixtureDef fd; 198 fd.shape = m_polygons + index; 199 fd.density = 1.0f; 200 fd.friction = 0.3f; 201 m_bodies[m_bodyIndex]->CreateFixture(&fd); 202 } 203 else 204 { 205 b2FixtureDef fd; 206 fd.shape = &m_circle; 207 fd.density = 1.0f; 208 fd.friction = 0.3f; 209 210 m_bodies[m_bodyIndex]->CreateFixture(&fd); 211 } 212 213 m_bodyIndex = (m_bodyIndex + 1) % k_maxBodies; 214 } 215 DestroyBody()216 void DestroyBody() 217 { 218 for (int32 i = 0; i < k_maxBodies; ++i) 219 { 220 if (m_bodies[i] != NULL) 221 { 222 m_world->DestroyBody(m_bodies[i]); 223 m_bodies[i] = NULL; 224 return; 225 } 226 } 227 } 228 Keyboard(unsigned char key)229 void Keyboard(unsigned char key) 230 { 231 switch (key) 232 { 233 case '1': 234 case '2': 235 case '3': 236 case '4': 237 case '5': 238 Create(key - '1'); 239 break; 240 241 case 'a': 242 for (int32 i = 0; i < k_maxBodies; i += 2) 243 { 244 if (m_bodies[i]) 245 { 246 bool active = m_bodies[i]->IsActive(); 247 m_bodies[i]->SetActive(!active); 248 } 249 } 250 break; 251 252 case 'd': 253 DestroyBody(); 254 break; 255 } 256 } 257 Step(Settings * settings)258 void Step(Settings* settings) 259 { 260 Test::Step(settings); 261 262 PolyShapesCallback callback; 263 callback.m_circle.m_radius = 2.0f; 264 callback.m_circle.m_p.Set(0.0f, 1.1f); 265 callback.m_transform.SetIdentity(); 266 callback.m_debugDraw = &m_debugDraw; 267 268 b2AABB aabb; 269 callback.m_circle.ComputeAABB(&aabb, callback.m_transform, 0); 270 271 m_world->QueryAABB(&callback, aabb); 272 273 b2Color color(0.4f, 0.7f, 0.8f); 274 m_debugDraw.DrawCircle(callback.m_circle.m_p, callback.m_circle.m_radius, color); 275 276 m_debugDraw.DrawString(5, m_textLine, "Press 1-5 to drop stuff"); 277 m_textLine += 15; 278 m_debugDraw.DrawString(5, m_textLine, "Press 'a' to (de)activate some bodies"); 279 m_textLine += 15; 280 m_debugDraw.DrawString(5, m_textLine, "Press 'd' to destroy a body"); 281 m_textLine += 15; 282 } 283 Create()284 static Test* Create() 285 { 286 return new PolyShapes; 287 } 288 289 int32 m_bodyIndex; 290 b2Body* m_bodies[k_maxBodies]; 291 b2PolygonShape m_polygons[4]; 292 b2CircleShape m_circle; 293 }; 294 295 #endif 296