dali-physics/third-party/chipmunk2d/src/cpBody.c

   1 /* Copyright (c) 2013 Scott Lembcke and Howling Moon Software
   2  *
   3  * Permission is hereby granted, free of charge, to any person obtaining a copy
   4  * of this software and associated documentation files (the "Software"), to deal
   5  * in the Software without restriction, including without limitation the rights
   6  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   7  * copies of the Software, and to permit persons to whom the Software is
   8  * furnished to do so, subject to the following conditions:
   9  *
  10  * The above copyright notice and this permission notice shall be included in
  11  * all copies or substantial portions of the Software.
  12  *
  13  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  14  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  15  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  16  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  17  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  18  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  19  * SOFTWARE.
  20  */
  21
  22 #include <float.h>
  23 #include <stdarg.h>
  24
  25 #include "chipmunk/chipmunk_private.h"
  26
  27 cpBody*
  28 cpBodyAlloc(void)
  29 {
  30         return (cpBody *)cpcalloc(1, sizeof(cpBody));
  31 }
  32
  33 cpBody *
  34 cpBodyInit(cpBody *body, cpFloat mass, cpFloat moment)
  35 {
  36         body->space = NULL;
  37         body->shapeList = NULL;
  38         body->arbiterList = NULL;
  39         body->constraintList = NULL;
  40
  41         body->velocity_func = cpBodyUpdateVelocity;
  42         body->position_func = cpBodyUpdatePosition;
  43
  44         body->sleeping.root = NULL;
  45         body->sleeping.next = NULL;
  46         body->sleeping.idleTime = 0.0f;
  47
  48         body->p = cpvzero;
  49         body->v = cpvzero;
  50         body->f = cpvzero;
  51
  52         body->w = 0.0f;
  53         body->t = 0.0f;
  54
  55         body->v_bias = cpvzero;
  56         body->w_bias = 0.0f;
  57
  58         body->userData = NULL;
  59
  60         // Setters must be called after full initialization so the sanity checks don't assert on garbage data.
  61         cpBodySetMass(body, mass);
  62         cpBodySetMoment(body, moment);
  63         cpBodySetAngle(body, 0.0f);
  64
  65         return body;
  66 }
  67
  68 cpBody*
  69 cpBodyNew(cpFloat mass, cpFloat moment)
  70 {
  71         return cpBodyInit(cpBodyAlloc(), mass, moment);
  72 }
  73
  74 cpBody*
  75 cpBodyNewKinematic()
  76 {
  77         cpBody *body = cpBodyNew(0.0f, 0.0f);
  78         cpBodySetType(body, CP_BODY_TYPE_KINEMATIC);
  79
  80         return body;
  81 }
  82
  83 cpBody*
  84 cpBodyNewStatic()
  85 {
  86         cpBody *body = cpBodyNew(0.0f, 0.0f);
  87         cpBodySetType(body, CP_BODY_TYPE_STATIC);
  88
  89         return body;
  90 }
  91
  92 void cpBodyDestroy(cpBody *body){}
  93
  94 void
  95 cpBodyFree(cpBody *body)
  96 {
  97         if(body){
  98                 cpBodyDestroy(body);
  99                 cpfree(body);
 100         }
 101 }
 102
 103 #ifdef NDEBUG
 104         #define cpAssertSaneBody(body)
 105 #else
 106         static void cpv_assert_nan(cpVect v, char *message){cpAssertHard(v.x == v.x && v.y == v.y, message);}
 107         static void cpv_assert_infinite(cpVect v, char *message){cpAssertHard(cpfabs(v.x) != INFINITY && cpfabs(v.y) != INFINITY, message);}
 108         static void cpv_assert_sane(cpVect v, char *message){cpv_assert_nan(v, message); cpv_assert_infinite(v, message);}
 109
 110         static void
 111         cpBodySanityCheck(const cpBody *body)
 112         {
 113                 cpAssertHard(body->m == body->m && body->m_inv == body->m_inv, "Body's mass is NaN.");
 114                 cpAssertHard(body->i == body->i && body->i_inv == body->i_inv, "Body's moment is NaN.");
 115                 cpAssertHard(body->m >= 0.0f, "Body's mass is negative.");
 116                 cpAssertHard(body->i >= 0.0f, "Body's moment is negative.");
 117
 118                 cpv_assert_sane(body->p, "Body's position is invalid.");
 119                 cpv_assert_sane(body->v, "Body's velocity is invalid.");
 120                 cpv_assert_sane(body->f, "Body's force is invalid.");
 121
 122                 cpAssertHard(body->a == body->a && cpfabs(body->a) != INFINITY, "Body's angle is invalid.");
 123                 cpAssertHard(body->w == body->w && cpfabs(body->w) != INFINITY, "Body's angular velocity is invalid.");
 124                 cpAssertHard(body->t == body->t && cpfabs(body->t) != INFINITY, "Body's torque is invalid.");
 125         }
 126
 127         #define cpAssertSaneBody(body) cpBodySanityCheck(body)
 128 #endif
 129
 130 cpBool
 131 cpBodyIsSleeping(const cpBody *body)
 132 {
 133         return (body->sleeping.root != ((cpBody*)0));
 134 }
 135
 136 cpBodyType
 137 cpBodyGetType(cpBody *body)
 138 {
 139         if(body->sleeping.idleTime == INFINITY){
 140                 return CP_BODY_TYPE_STATIC;
 141         } else if(body->m == INFINITY){
 142                 return CP_BODY_TYPE_KINEMATIC;
 143         } else {
 144                 return CP_BODY_TYPE_DYNAMIC;
 145         }
 146 }
 147
 148 void
 149 cpBodySetType(cpBody *body, cpBodyType type)
 150 {
 151         cpBodyType oldType = cpBodyGetType(body);
 152         if(oldType == type) return;
 153
 154         // Static bodies have their idle timers set to infinity.
 155         // Non-static bodies should have their idle timer reset.
 156         body->sleeping.idleTime = (type == CP_BODY_TYPE_STATIC ? INFINITY : 0.0f);
 157
 158         if(type == CP_BODY_TYPE_DYNAMIC){
 159                 body->m = body->i = 0.0f;
 160                 body->m_inv = body->i_inv = INFINITY;
 161
 162                 cpBodyAccumulateMassFromShapes(body);
 163         } else {
 164                 body->m = body->i = INFINITY;
 165                 body->m_inv = body->i_inv = 0.0f;
 166
 167                 body->v = cpvzero;
 168                 body->w = 0.0f;
 169         }
 170
 171         // If the body is added to a space already, we'll need to update some space data structures.
 172         cpSpace *space = cpBodyGetSpace(body);
 173         if(space != NULL){
 174                 cpAssertSpaceUnlocked(space);
 175
 176                 if(oldType == CP_BODY_TYPE_STATIC){
 177                         // TODO This is probably not necessary
 178 //                      cpBodyActivateStatic(body, NULL);
 179                 } else {
 180                         cpBodyActivate(body);
 181                 }
 182
 183                 // Move the bodies to the correct array.
 184                 cpArray *fromArray = cpSpaceArrayForBodyType(space, oldType);
 185                 cpArray *toArray = cpSpaceArrayForBodyType(space, type);
 186                 if(fromArray != toArray){
 187                         cpArrayDeleteObj(fromArray, body);
 188                         cpArrayPush(toArray, body);
 189                 }
 190
 191                 // Move the body's shapes to the correct spatial index.
 192                 cpSpatialIndex *fromIndex = (oldType == CP_BODY_TYPE_STATIC ? space->staticShapes : space->dynamicShapes);
 193                 cpSpatialIndex *toIndex = (type == CP_BODY_TYPE_STATIC ? space->staticShapes : space->dynamicShapes);
 194                 if(fromIndex != toIndex){
 195                         CP_BODY_FOREACH_SHAPE(body, shape){
 196                                 cpSpatialIndexRemove(fromIndex, shape, shape->hashid);
 197                                 cpSpatialIndexInsert(toIndex, shape, shape->hashid);
 198                         }
 199                 }
 200         }
 201 }
 202
 203
 204
 205 // Should *only* be called when shapes with mass info are modified, added or removed.
 206 void
 207 cpBodyAccumulateMassFromShapes(cpBody *body)
 208 {
 209         if(body == NULL || cpBodyGetType(body) != CP_BODY_TYPE_DYNAMIC) return;
 210
 211         // Reset the body's mass data.
 212         body->m = body->i = 0.0f;
 213         body->cog = cpvzero;
 214
 215         // Cache the position to realign it at the end.
 216         cpVect pos = cpBodyGetPosition(body);
 217
 218         // Accumulate mass from shapes.
 219         CP_BODY_FOREACH_SHAPE(body, shape){
 220                 struct cpShapeMassInfo *info = &shape->massInfo;
 221                 cpFloat m = info->m;
 222
 223                 if(m > 0.0f){
 224                         cpFloat msum = body->m + m;
 225
 226                         body->i += m*info->i + cpvdistsq(body->cog, info->cog)*(m*body->m)/msum;
 227                         body->cog = cpvlerp(body->cog, info->cog, m/msum);
 228                         body->m = msum;
 229                 }
 230         }
 231
 232         // Recalculate the inverses.
 233         body->m_inv = 1.0f/body->m;
 234         body->i_inv = 1.0f/body->i;
 235
 236         // Realign the body since the CoG has probably moved.
 237         cpBodySetPosition(body, pos);
 238         cpAssertSaneBody(body);
 239 }
 240
 241 cpSpace *
 242 cpBodyGetSpace(const cpBody *body)
 243 {
 244         return body->space;
 245 }
 246
 247 cpFloat
 248 cpBodyGetMass(const cpBody *body)
 249 {
 250         return body->m;
 251 }
 252
 253 void
 254 cpBodySetMass(cpBody *body, cpFloat mass)
 255 {
 256         cpAssertHard(cpBodyGetType(body) == CP_BODY_TYPE_DYNAMIC, "You cannot set the mass of kinematic or static bodies.");
 257         cpAssertHard(0.0f <= mass && mass < INFINITY, "Mass must be positive and finite.");
 258
 259         cpBodyActivate(body);
 260         body->m = mass;
 261         body->m_inv = mass == 0.0f ? INFINITY : 1.0f/mass;
 262         cpAssertSaneBody(body);
 263 }
 264
 265 cpFloat
 266 cpBodyGetMoment(const cpBody *body)
 267 {
 268         return body->i;
 269 }
 270
 271 void
 272 cpBodySetMoment(cpBody *body, cpFloat moment)
 273 {
 274         cpAssertHard(moment >= 0.0f, "Moment of Inertia must be positive.");
 275
 276         cpBodyActivate(body);
 277         body->i = moment;
 278         body->i_inv = moment == 0.0f ? INFINITY : 1.0f/moment;
 279         cpAssertSaneBody(body);
 280 }
 281
 282 cpVect
 283 cpBodyGetRotation(const cpBody *body)
 284 {
 285         return cpv(body->transform.a, body->transform.b);
 286 }
 287
 288 void
 289 cpBodyAddShape(cpBody *body, cpShape *shape)
 290 {
 291         cpShape *next = body->shapeList;
 292         if(next) next->prev = shape;
 293
 294         shape->next = next;
 295         body->shapeList = shape;
 296
 297         if(shape->massInfo.m > 0.0f){
 298                 cpBodyAccumulateMassFromShapes(body);
 299         }
 300 }
 301
 302 void
 303 cpBodyRemoveShape(cpBody *body, cpShape *shape)
 304 {
 305   cpShape *prev = shape->prev;
 306   cpShape *next = shape->next;
 307
 308   if(prev){
 309                 prev->next = next;
 310   } else {
 311                 body->shapeList = next;
 312   }
 313
 314   if(next){
 315                 next->prev = prev;
 316         }
 317
 318   shape->prev = NULL;
 319   shape->next = NULL;
 320
 321         if(cpBodyGetType(body) == CP_BODY_TYPE_DYNAMIC && shape->massInfo.m > 0.0f){
 322                 cpBodyAccumulateMassFromShapes(body);
 323         }
 324 }
 325
 326 static cpConstraint *
 327 filterConstraints(cpConstraint *node, cpBody *body, cpConstraint *filter)
 328 {
 329         if(node == filter){
 330                 return cpConstraintNext(node, body);
 331         } else if(node->a == body){
 332                 node->next_a = filterConstraints(node->next_a, body, filter);
 333         } else {
 334                 node->next_b = filterConstraints(node->next_b, body, filter);
 335         }
 336
 337         return node;
 338 }
 339
 340 void
 341 cpBodyRemoveConstraint(cpBody *body, cpConstraint *constraint)
 342 {
 343         body->constraintList = filterConstraints(body->constraintList, body, constraint);
 344 }
 345
 346 // 'p' is the position of the CoG
 347 static void
 348 SetTransform(cpBody *body, cpVect p, cpFloat a)
 349 {
 350         cpVect rot = cpvforangle(a);
 351         cpVect c = body->cog;
 352
 353         body->transform = cpTransformNewTranspose(
 354                 rot.x, -rot.y, p.x - (c.x*rot.x - c.y*rot.y),
 355                 rot.y,  rot.x, p.y - (c.x*rot.y + c.y*rot.x)
 356         );
 357 }
 358
 359 static inline cpFloat
 360 SetAngle(cpBody *body, cpFloat a)
 361 {
 362         body->a = a;
 363         cpAssertSaneBody(body);
 364
 365         return a;
 366 }
 367
 368 cpVect
 369 cpBodyGetPosition(const cpBody *body)
 370 {
 371         return cpTransformPoint(body->transform, cpvzero);
 372 }
 373
 374 void
 375 cpBodySetPosition(cpBody *body, cpVect position)
 376 {
 377         cpBodyActivate(body);
 378         cpVect p = body->p = cpvadd(cpTransformVect(body->transform, body->cog), position);
 379         cpAssertSaneBody(body);
 380
 381         SetTransform(body, p, body->a);
 382 }
 383
 384 cpVect
 385 cpBodyGetCenterOfGravity(const cpBody *body)
 386 {
 387         return body->cog;
 388 }
 389
 390 void
 391 cpBodySetCenterOfGravity(cpBody *body, cpVect cog)
 392 {
 393         cpBodyActivate(body);
 394         body->cog = cog;
 395         cpAssertSaneBody(body);
 396 }
 397
 398 cpVect
 399 cpBodyGetVelocity(const cpBody *body)
 400 {
 401         return body->v;
 402 }
 403
 404 void
 405 cpBodySetVelocity(cpBody *body, cpVect velocity)
 406 {
 407         cpBodyActivate(body);
 408         body->v = velocity;
 409         cpAssertSaneBody(body);
 410 }
 411
 412 cpVect
 413 cpBodyGetForce(const cpBody *body)
 414 {
 415         return body->f;
 416 }
 417
 418 void
 419 cpBodySetForce(cpBody *body, cpVect force)
 420 {
 421         cpBodyActivate(body);
 422         body->f = force;
 423         cpAssertSaneBody(body);
 424 }
 425
 426 cpFloat
 427 cpBodyGetAngle(const cpBody *body)
 428 {
 429         return body->a;
 430 }
 431
 432 void
 433 cpBodySetAngle(cpBody *body, cpFloat angle)
 434 {
 435         cpBodyActivate(body);
 436         SetAngle(body, angle);
 437
 438         SetTransform(body, body->p, angle);
 439 }
 440
 441 cpFloat
 442 cpBodyGetAngularVelocity(const cpBody *body)
 443 {
 444         return body->w;
 445 }
 446
 447 void
 448 cpBodySetAngularVelocity(cpBody *body, cpFloat angularVelocity)
 449 {
 450         cpBodyActivate(body);
 451         body->w = angularVelocity;
 452         cpAssertSaneBody(body);
 453 }
 454
 455 cpFloat
 456 cpBodyGetTorque(const cpBody *body)
 457 {
 458         return body->t;
 459 }
 460
 461 void
 462 cpBodySetTorque(cpBody *body, cpFloat torque)
 463 {
 464         cpBodyActivate(body);
 465         body->t = torque;
 466         cpAssertSaneBody(body);
 467 }
 468
 469 cpDataPointer
 470 cpBodyGetUserData(const cpBody *body)
 471 {
 472         return body->userData;
 473 }
 474
 475 void
 476 cpBodySetUserData(cpBody *body, cpDataPointer userData)
 477 {
 478         body->userData = userData;
 479 }
 480
 481 void
 482 cpBodySetVelocityUpdateFunc(cpBody *body, cpBodyVelocityFunc velocityFunc)
 483 {
 484         body->velocity_func = velocityFunc;
 485 }
 486
 487 void
 488 cpBodySetPositionUpdateFunc(cpBody *body, cpBodyPositionFunc positionFunc)
 489 {
 490         body->position_func = positionFunc;
 491 }
 492
 493 void
 494 cpBodyUpdateVelocity(cpBody *body, cpVect gravity, cpFloat damping, cpFloat dt)
 495 {
 496         // Skip kinematic bodies.
 497         if(cpBodyGetType(body) == CP_BODY_TYPE_KINEMATIC) return;
 498
 499         cpAssertSoft(body->m > 0.0f && body->i > 0.0f, "Body's mass and moment must be positive to simulate. (Mass: %f Moment: %f)", body->m, body->i);
 500
 501         body->v = cpvadd(cpvmult(body->v, damping), cpvmult(cpvadd(gravity, cpvmult(body->f, body->m_inv)), dt));
 502         body->w = body->w*damping + body->t*body->i_inv*dt;
 503
 504         // Reset forces.
 505         body->f = cpvzero;
 506         body->t = 0.0f;
 507
 508         cpAssertSaneBody(body);
 509 }
 510
 511 void
 512 cpBodyUpdatePosition(cpBody *body, cpFloat dt)
 513 {
 514         cpVect p = body->p = cpvadd(body->p, cpvmult(cpvadd(body->v, body->v_bias), dt));
 515         cpFloat a = SetAngle(body, body->a + (body->w + body->w_bias)*dt);
 516         SetTransform(body, p, a);
 517
 518         body->v_bias = cpvzero;
 519         body->w_bias = 0.0f;
 520
 521         cpAssertSaneBody(body);
 522 }
 523
 524 cpVect
 525 cpBodyLocalToWorld(const cpBody *body, const cpVect point)
 526 {
 527         return cpTransformPoint(body->transform, point);
 528 }
 529
 530 cpVect
 531 cpBodyWorldToLocal(const cpBody *body, const cpVect point)
 532 {
 533         return cpTransformPoint(cpTransformRigidInverse(body->transform), point);
 534 }
 535
 536 void
 537 cpBodyApplyForceAtWorldPoint(cpBody *body, cpVect force, cpVect point)
 538 {
 539         cpBodyActivate(body);
 540         body->f = cpvadd(body->f, force);
 541
 542         cpVect r = cpvsub(point, cpTransformPoint(body->transform, body->cog));
 543         body->t += cpvcross(r, force);
 544 }
 545
 546 void
 547 cpBodyApplyForceAtLocalPoint(cpBody *body, cpVect force, cpVect point)
 548 {
 549         cpBodyApplyForceAtWorldPoint(body, cpTransformVect(body->transform, force), cpTransformPoint(body->transform, point));
 550 }
 551
 552 void
 553 cpBodyApplyImpulseAtWorldPoint(cpBody *body, cpVect impulse, cpVect point)
 554 {
 555         cpBodyActivate(body);
 556
 557         cpVect r = cpvsub(point, cpTransformPoint(body->transform, body->cog));
 558         apply_impulse(body, impulse, r);
 559 }
 560
 561 void
 562 cpBodyApplyImpulseAtLocalPoint(cpBody *body, cpVect impulse, cpVect point)
 563 {
 564         cpBodyApplyImpulseAtWorldPoint(body, cpTransformVect(body->transform, impulse), cpTransformPoint(body->transform, point));
 565 }
 566
 567 cpVect
 568 cpBodyGetVelocityAtLocalPoint(const cpBody *body, cpVect point)
 569 {
 570         cpVect r = cpTransformVect(body->transform, cpvsub(point, body->cog));
 571         return cpvadd(body->v, cpvmult(cpvperp(r), body->w));
 572 }
 573
 574 cpVect
 575 cpBodyGetVelocityAtWorldPoint(const cpBody *body, cpVect point)
 576 {
 577         cpVect r = cpvsub(point, cpTransformPoint(body->transform, body->cog));
 578         return cpvadd(body->v, cpvmult(cpvperp(r), body->w));
 579 }
 580
 581 cpFloat
 582 cpBodyKineticEnergy(const cpBody *body)
 583 {
 584         // Need to do some fudging to avoid NaNs
 585         cpFloat vsq = cpvdot(body->v, body->v);
 586         cpFloat wsq = body->w*body->w;
 587         return (vsq ? vsq*body->m : 0.0f) + (wsq ? wsq*body->i : 0.0f);
 588 }
 589
 590 void
 591 cpBodyEachShape(cpBody *body, cpBodyShapeIteratorFunc func, void *data)
 592 {
 593         cpShape *shape = body->shapeList;
 594         while(shape){
 595                 cpShape *next = shape->next;
 596                 func(body, shape, data);
 597                 shape = next;
 598         }
 599 }
 600
 601 void
 602 cpBodyEachConstraint(cpBody *body, cpBodyConstraintIteratorFunc func, void *data)
 603 {
 604         cpConstraint *constraint = body->constraintList;
 605         while(constraint){
 606                 cpConstraint *next = cpConstraintNext(constraint, body);
 607                 func(body, constraint, data);
 608                 constraint = next;
 609         }
 610 }
 611
 612 void
 613 cpBodyEachArbiter(cpBody *body, cpBodyArbiterIteratorFunc func, void *data)
 614 {
 615         cpArbiter *arb = body->arbiterList;
 616         while(arb){
 617                 cpArbiter *next = cpArbiterNext(arb, body);
 618
 619                 cpBool swapped = arb->swapped; {
 620                         arb->swapped = (body == arb->body_b);
 621                         func(body, arb, data);
 622                 } arb->swapped = swapped;
 623
 624                 arb = next;
 625         }
 626 }