| 1 | /* |
| 2 | * Copyright (C) 2008 Patrik Gornicz, Gornicz_P (at) hotmail (dot) com. |
| 3 | * |
| 4 | * This program is free software: you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation, either version 3 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 16 | */ |
| 17 | |
| 18 | #include "collisionManager.h" |
| 19 | #include "debug.h" |
| 20 | |
| 21 | #include "Vector2.h" |
| 22 | |
| 23 | #include "Entities/Ball.h" |
| 24 | #include "Entities/Polygon.h" |
| 25 | #include "Entities/PhysicsEntity.h" |
| 26 | |
| 27 | #include "CollisionInfo.h" |
| 28 | |
| 29 | #include "mathw.h" |
| 30 | |
| 31 | /// ***** Private Class Header ***** |
| 32 | |
| 33 | /// ***** Private Method Headers ***** |
| 34 | |
| 35 | void clearEntities(); |
| 36 | void placeEntity(PhysicsEntity* p); |
| 37 | void updateEntities(); |
| 38 | |
| 39 | void applyCollision(PhysicsEntity* p1, PhysicsEntity* p2); |
| 40 | void applyCollision(Ball* b1, Ball* b2); |
| 41 | void applyCollision(Polygon* pPoly, Ball* pBall); |
| 42 | |
| 43 | bool getInfo(const Ball* b1, const Ball* b2, CollisionInfo* cInfo); |
| 44 | bool getInfo(const Polygon* pPoly, const Ball* pBall, CollisionInfo* cInfo); |
| 45 | |
| 46 | /// ***** Private Variables ***** |
| 47 | |
| 48 | const int xDivisions = 20; |
| 49 | const int yDivisions = 16; |
| 50 | const int screenX = 800; |
| 51 | const int screenY = 600; |
| 52 | |
| 53 | setPhys divisions[xDivisions][yDivisions]; |
| 54 | |
| 55 | /// ***** Initializers/Cleaners ***** |
| 56 | |
| 57 | void collision::init() |
| 58 | { |
| 59 | |
| 60 | } |
| 61 | void collision::clean() |
| 62 | { |
| 63 | |
| 64 | } |
| 65 | |
| 66 | /// ***** Public Methods ***** |
| 67 | |
| 68 | void collision::update(setPhys& sp) |
| 69 | { |
| 70 | clearEntities(); |
| 71 | |
| 72 | for( setPhys::iterator it = sp.begin(); |
| 73 | it != sp.end(); |
| 74 | it++ ) |
| 75 | { |
| 76 | placeEntity(*it); |
| 77 | } |
| 78 | |
| 79 | updateEntities(); |
| 80 | } |
| 81 | |
| 82 | /// ***** Private Methods ***** |
| 83 | |
| 84 | void clearEntities() |
| 85 | { |
| 86 | for( int x = 0; |
| 87 | x < xDivisions; |
| 88 | x++ ) |
| 89 | { |
| 90 | for( int y = 0; |
| 91 | y < yDivisions; |
| 92 | y++ ) |
| 93 | { |
| 94 | divisions[x][y].clear(); |
| 95 | } |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | void placeEntity(PhysicsEntity* p) |
| 100 | { |
| 101 | Vector2 minP; |
| 102 | Vector2 maxP; |
| 103 | |
| 104 | { // Ball case |
| 105 | Ball* b = dynamic_cast<Ball*>(p); |
| 106 | |
| 107 | if( b != NULL ) |
| 108 | { |
| 109 | const float& xb = b->positionRaw().x; |
| 110 | const float& yb = b->positionRaw().y; |
| 111 | const float& rad = b->radius; |
| 112 | |
| 113 | minP.x = xb - rad; |
| 114 | minP.y = yb - rad; |
| 115 | maxP.x = xb + rad; |
| 116 | maxP.y = yb + rad; |
| 117 | |
| 118 | goto start; |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | { // Polygon case |
| 123 | Polygon* pPoly = dynamic_cast<Polygon*>(p); |
| 124 | |
| 125 | if( pPoly != NULL ) |
| 126 | { |
| 127 | minP = pPoly->minP; |
| 128 | maxP = pPoly->maxP; |
| 129 | |
| 130 | goto start; |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | DPF(0, "ENTITY TYPE NOT SUPPORTED BY placeEntity()!!"); |
| 135 | return; |
| 136 | |
| 137 | start: |
| 138 | for( int x = static_cast<int>( minP.x / (screenX / xDivisions) ); |
| 139 | x <= static_cast<int>( maxP.x / (screenX / xDivisions) ); |
| 140 | x++ ) |
| 141 | { |
| 142 | if(x < 0 || xDivisions <= x) |
| 143 | break; |
| 144 | |
| 145 | for( int y = static_cast<int>( minP.y / (screenY / yDivisions) ); |
| 146 | y <= static_cast<int>( maxP.y / (screenY / yDivisions) ); |
| 147 | y++ ) |
| 148 | { |
| 149 | if(y < 0 || yDivisions <= y) |
| 150 | break; |
| 151 | |
| 152 | divisions[x][y].insert(p); |
| 153 | } |
| 154 | } |
| 155 | } |
| 156 | |
| 157 | void updateEntities() |
| 158 | { |
| 159 | for( int x = 0; |
| 160 | x < xDivisions; |
| 161 | x++ ) |
| 162 | { |
| 163 | for( int y = 0; |
| 164 | y < yDivisions; |
| 165 | y++ ) |
| 166 | { |
| 167 | for( setPhys::iterator it1 = divisions[x][y].begin(); |
| 168 | it1 != divisions[x][y].end(); |
| 169 | it1++ ) |
| 170 | { |
| 171 | for( setPhys::iterator it2 = divisions[x][y].begin(); |
| 172 | it2 != divisions[x][y].end(); |
| 173 | it2++ ) |
| 174 | { |
| 175 | if( *it1 == *it2 ) |
| 176 | break; |
| 177 | |
| 178 | applyCollision(*it1, *it2); |
| 179 | } |
| 180 | } |
| 181 | } |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | void applyCollision(PhysicsEntity* p1, PhysicsEntity* p2) |
| 186 | { |
| 187 | { |
| 188 | Ball* b1 = dynamic_cast<Ball*>(p1); |
| 189 | Ball* b2 = dynamic_cast<Ball*>(p2); |
| 190 | |
| 191 | if( b1 != NULL && b2 != NULL ) |
| 192 | { |
| 193 | applyCollision(b1, b2); |
| 194 | return; |
| 195 | } |
| 196 | } |
| 197 | |
| 198 | { |
| 199 | Polygon* pPoly = dynamic_cast<Polygon*>(p1); |
| 200 | Ball* pBall = dynamic_cast<Ball*>(p2); |
| 201 | |
| 202 | if( pPoly != NULL && pBall != NULL ) |
| 203 | { |
| 204 | applyCollision(pPoly, pBall); |
| 205 | return; |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | { |
| 210 | Polygon* pPoly = dynamic_cast<Polygon*>(p2); |
| 211 | Ball* pBall = dynamic_cast<Ball*>(p1); |
| 212 | |
| 213 | if( pPoly != NULL && pBall != NULL ) |
| 214 | { |
| 215 | applyCollision(pPoly, pBall); |
| 216 | return; |
| 217 | } |
| 218 | } |
| 219 | |
| 220 | DPF(0, "ENTITY TYPE NOT SUPPORTED BY applyCollision()!!"); |
| 221 | } |
| 222 | |
| 223 | void applyCollision(Ball* b1, Ball* b2) |
| 224 | { |
| 225 | CollisionInfo cInfo; |
| 226 | |
| 227 | if(!getInfo(b1, b2, &cInfo)) |
| 228 | return; |
| 229 | |
| 230 | // a few values to simplify the equations |
| 231 | const Vector2& normal = cInfo.m_vecNormal; |
| 232 | const Vector2& point = cInfo.m_vecPoint; |
| 233 | |
| 234 | float m1 = b1->mass; |
| 235 | float m2 = b2->mass; |
| 236 | |
| 237 | float e = (b1->CoR + b2->CoR) / 2; |
| 238 | |
| 239 | Vector2 v1 = b1->velocityRaw(); |
| 240 | Vector2 v2 = b2->velocityRaw(); |
| 241 | |
| 242 | |
| 243 | float iTop = -(e + 1) * (v1 - v2).dot(normal); |
| 244 | |
| 245 | // otherwise the collision happened and we do the math the below assumes |
| 246 | // collisions have no friction |
| 247 | |
| 248 | float impulse = iTop / (normal.dot(normal) * (1 / m1 + 1 / m2)); |
| 249 | |
| 250 | b1->applyImpulse(impulse / m1 * normal, point); |
| 251 | b2->applyImpulse(-impulse / m2 * normal, point); |
| 252 | } |
| 253 | |
| 254 | void applyCollision(Polygon* pPoly, Ball* pBall) |
| 255 | { |
| 256 | CollisionInfo cInfo; |
| 257 | |
| 258 | if(!getInfo(pPoly, pBall, &cInfo)) |
| 259 | return; |
| 260 | |
| 261 | float fCoR = pBall->CoR; |
| 262 | Vector2 vecNorm = cInfo.m_vecNormal; |
| 263 | |
| 264 | Vector2 vecVelo = pBall->velocityRaw(); |
| 265 | |
| 266 | // impulse divided by mass |
| 267 | float idm = (-(fCoR + 1) * vecVelo.dot(vecNorm)) |
| 268 | / (vecNorm.dot(vecNorm)); |
| 269 | |
| 270 | pBall->applyImpulse(idm * vecNorm); |
| 271 | |
| 272 | // HACK |
| 273 | // CoR penetration fix, adds the jitters |
| 274 | |
| 275 | // from center to point |
| 276 | Vector2 vecCollP = vecNorm / vecNorm.length() * pBall->radius; |
| 277 | pBall->applyNudge(cInfo.m_vecPoint + vecCollP - pBall->positionRaw()); |
| 278 | } |
| 279 | |
| 280 | bool getInfo(const Ball* b1, const Ball* b2, CollisionInfo* pcInfo) |
| 281 | { |
| 282 | // a few values to simplify the equations |
| 283 | float r1 = b1->radius; |
| 284 | float r2 = b2->radius; |
| 285 | |
| 286 | Vector2 p1 = b1->positionRaw(); |
| 287 | Vector2 p2 = b2->positionRaw(); |
| 288 | Vector2 v1 = b1->velocityRaw(); |
| 289 | Vector2 v2 = b2->velocityRaw(); |
| 290 | |
| 291 | // quick binding box check |
| 292 | if (p1.x - r1 > p2.x + r2 |
| 293 | || p1.x + r1 < p2.x - r2 |
| 294 | || p1.y - r1 > p2.y + r2 |
| 295 | || p1.y + r1 < p2.y - r2) |
| 296 | return false; |
| 297 | |
| 298 | // test if not touching |
| 299 | if ((p1 - p2).sqrLength() >= (r1 + r2)*(r1 + r2)) |
| 300 | return false; |
| 301 | |
| 302 | // test if they are moving apart in some way if they aren't it's likely |
| 303 | // that they collided last frame and are still overlapping |
| 304 | |
| 305 | if ((v1 - v2).dot(p1 - p2) >= 0) |
| 306 | return false; |
| 307 | |
| 308 | pcInfo->m_vecPoint = p1 - (p1 - p2) * r1 / (r1 + r2); |
| 309 | pcInfo->m_vecNormal = p1 - p2; |
| 310 | |
| 311 | return true; |
| 312 | } |
| 313 | |
| 314 | bool getInfo(const Polygon* pPoly, const Ball* pBall, CollisionInfo* pcInfo) |
| 315 | { |
| 316 | // a few values to simplify the equations |
| 317 | float fRad = pBall->radius; |
| 318 | Vector2 vecPos = pBall->positionRaw(); |
| 319 | Vector2 vecVelo = pBall->velocityRaw(); |
| 320 | |
| 321 | float fMaxX = pPoly->maxP.x; |
| 322 | float fMinX = pPoly->minP.x; |
| 323 | float fMaxY = pPoly->maxP.y; |
| 324 | float fMinY = pPoly->minP.y; |
| 325 | |
| 326 | // quick binding box check |
| 327 | if (vecPos.x - fRad > fMaxX || vecPos.x + fRad < fMinX || |
| 328 | vecPos.y - fRad > fMaxY || vecPos.y + fRad < fMinY) |
| 329 | return false; |
| 330 | |
| 331 | |
| 332 | Vector2 vecTotVec; |
| 333 | int iTot = 0; |
| 334 | |
| 335 | { |
| 336 | const vector<Vector2>& pts = pPoly->points; |
| 337 | unsigned int num = pts.size(); |
| 338 | |
| 339 | for (unsigned int i = 0; i < num; i++) |
| 340 | { |
| 341 | Vector2 vec = vectorToLine(vecPos, |
| 342 | pts[i].x, |
| 343 | pts[i].y, |
| 344 | pts[(i + 1) % num].x, |
| 345 | pts[(i + 1) % num].y); |
| 346 | |
| 347 | if (vec.sqrLength() <= fRad*fRad && 0 < vec.dot(vecVelo)) |
| 348 | { |
| 349 | vecTotVec += vec; |
| 350 | iTot += 1; |
| 351 | } |
| 352 | } |
| 353 | } |
| 354 | |
| 355 | if (iTot <= 0) |
| 356 | return false; |
| 357 | |
| 358 | |
| 359 | pcInfo->m_vecPoint = vecTotVec / iTot + vecPos; |
| 360 | pcInfo->m_vecNormal = vecPos - pcInfo->m_vecPoint; |
| 361 | |
| 362 | return true; |
| 363 | } |