446 lines
14 KiB
C
Executable file
446 lines
14 KiB
C
Executable file
/* Copyright (c) 2013 Scott Lembcke and Howling Moon Software
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include "chipmunk/chipmunk_private.h"
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//MARK: Post Step Callback Functions
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cpPostStepCallback *
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cpSpaceGetPostStepCallback(cpSpace *space, void *key)
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{
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cpArray *arr = space->postStepCallbacks;
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for(int i=0; i<arr->num; i++){
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cpPostStepCallback *callback = (cpPostStepCallback *)arr->arr[i];
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if(callback && callback->key == key) return callback;
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}
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return NULL;
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}
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static void PostStepDoNothing(cpSpace *space, void *obj, void *data){}
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cpBool
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cpSpaceAddPostStepCallback(cpSpace *space, cpPostStepFunc func, void *key, void *data)
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{
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cpAssertWarn(space->locked,
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"Adding a post-step callback when the space is not locked is unnecessary. "
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"Post-step callbacks will not called until the end of the next call to cpSpaceStep() or the next query.");
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if(!cpSpaceGetPostStepCallback(space, key)){
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cpPostStepCallback *callback = (cpPostStepCallback *)cpcalloc(1, sizeof(cpPostStepCallback));
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callback->func = (func ? func : PostStepDoNothing);
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callback->key = key;
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callback->data = data;
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cpArrayPush(space->postStepCallbacks, callback);
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return cpTrue;
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} else {
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return cpFalse;
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}
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}
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//MARK: Locking Functions
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void
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cpSpaceLock(cpSpace *space)
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{
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space->locked++;
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}
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void
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cpSpaceUnlock(cpSpace *space, cpBool runPostStep)
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{
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space->locked--;
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cpAssertHard(space->locked >= 0, "Internal Error: Space lock underflow.");
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if(space->locked == 0){
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cpArray *waking = space->rousedBodies;
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for(int i=0, count=waking->num; i<count; i++){
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cpSpaceActivateBody(space, (cpBody *)waking->arr[i]);
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waking->arr[i] = NULL;
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}
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waking->num = 0;
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if(space->locked == 0 && runPostStep && !space->skipPostStep){
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space->skipPostStep = cpTrue;
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cpArray *arr = space->postStepCallbacks;
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for(int i=0; i<arr->num; i++){
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cpPostStepCallback *callback = (cpPostStepCallback *)arr->arr[i];
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cpPostStepFunc func = callback->func;
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// Mark the func as NULL in case calling it calls cpSpaceRunPostStepCallbacks() again.
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// TODO: need more tests around this case I think.
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callback->func = NULL;
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if(func) func(space, callback->key, callback->data);
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arr->arr[i] = NULL;
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cpfree(callback);
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}
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arr->num = 0;
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space->skipPostStep = cpFalse;
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}
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}
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}
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//MARK: Contact Buffer Functions
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struct cpContactBufferHeader {
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cpTimestamp stamp;
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cpContactBufferHeader *next;
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unsigned int numContacts;
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};
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#define CP_CONTACTS_BUFFER_SIZE ((CP_BUFFER_BYTES - sizeof(cpContactBufferHeader))/sizeof(struct cpContact))
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typedef struct cpContactBuffer {
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cpContactBufferHeader header;
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struct cpContact contacts[CP_CONTACTS_BUFFER_SIZE];
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} cpContactBuffer;
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static cpContactBufferHeader *
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cpSpaceAllocContactBuffer(cpSpace *space)
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{
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cpContactBuffer *buffer = (cpContactBuffer *)cpcalloc(1, sizeof(cpContactBuffer));
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cpArrayPush(space->allocatedBuffers, buffer);
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return (cpContactBufferHeader *)buffer;
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}
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static cpContactBufferHeader *
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cpContactBufferHeaderInit(cpContactBufferHeader *header, cpTimestamp stamp, cpContactBufferHeader *splice)
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{
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header->stamp = stamp;
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header->next = (splice ? splice->next : header);
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header->numContacts = 0;
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return header;
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}
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void
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cpSpacePushFreshContactBuffer(cpSpace *space)
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{
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cpTimestamp stamp = space->stamp;
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cpContactBufferHeader *head = space->contactBuffersHead;
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if(!head){
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// No buffers have been allocated, make one
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space->contactBuffersHead = cpContactBufferHeaderInit(cpSpaceAllocContactBuffer(space), stamp, NULL);
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} else if(stamp - head->next->stamp > space->collisionPersistence){
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// The tail buffer is available, rotate the ring
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cpContactBufferHeader *tail = head->next;
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space->contactBuffersHead = cpContactBufferHeaderInit(tail, stamp, tail);
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} else {
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// Allocate a new buffer and push it into the ring
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cpContactBufferHeader *buffer = cpContactBufferHeaderInit(cpSpaceAllocContactBuffer(space), stamp, head);
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space->contactBuffersHead = head->next = buffer;
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}
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}
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struct cpContact *
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cpContactBufferGetArray(cpSpace *space)
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{
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if(space->contactBuffersHead->numContacts + CP_MAX_CONTACTS_PER_ARBITER > CP_CONTACTS_BUFFER_SIZE){
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// contact buffer could overflow on the next collision, push a fresh one.
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cpSpacePushFreshContactBuffer(space);
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}
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cpContactBufferHeader *head = space->contactBuffersHead;
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return ((cpContactBuffer *)head)->contacts + head->numContacts;
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}
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void
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cpSpacePushContacts(cpSpace *space, int count)
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{
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cpAssertHard(count <= CP_MAX_CONTACTS_PER_ARBITER, "Internal Error: Contact buffer overflow!");
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space->contactBuffersHead->numContacts += count;
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}
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static void
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cpSpacePopContacts(cpSpace *space, int count){
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space->contactBuffersHead->numContacts -= count;
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}
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//MARK: Collision Detection Functions
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static void *
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cpSpaceArbiterSetTrans(cpShape **shapes, cpSpace *space)
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{
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if(space->pooledArbiters->num == 0){
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// arbiter pool is exhausted, make more
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int count = CP_BUFFER_BYTES/sizeof(cpArbiter);
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cpAssertHard(count, "Internal Error: Buffer size too small.");
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cpArbiter *buffer = (cpArbiter *)cpcalloc(1, CP_BUFFER_BYTES);
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cpArrayPush(space->allocatedBuffers, buffer);
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for(int i=0; i<count; i++) cpArrayPush(space->pooledArbiters, buffer + i);
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}
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return cpArbiterInit((cpArbiter *)cpArrayPop(space->pooledArbiters), shapes[0], shapes[1]);
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}
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static inline cpBool
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QueryRejectConstraint(cpBody *a, cpBody *b)
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{
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CP_BODY_FOREACH_CONSTRAINT(a, constraint){
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if(
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!constraint->collideBodies && (
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(constraint->a == a && constraint->b == b) ||
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(constraint->a == b && constraint->b == a)
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)
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) return cpTrue;
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}
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return cpFalse;
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}
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static inline cpBool
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QueryReject(cpShape *a, cpShape *b)
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{
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return (
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// BBoxes must overlap
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!cpBBIntersects(a->bb, b->bb)
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// Don't collide shapes attached to the same body.
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|| a->body == b->body
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// Don't collide shapes that are filtered.
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|| cpShapeFilterReject(a->filter, b->filter)
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// Don't collide bodies if they have a constraint with collideBodies == cpFalse.
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|| QueryRejectConstraint(a->body, b->body)
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);
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}
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// Callback from the spatial hash.
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cpCollisionID
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cpSpaceCollideShapes(cpShape *a, cpShape *b, cpCollisionID id, cpSpace *space)
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{
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// Reject any of the simple cases
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if(QueryReject(a,b)) return id;
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// Narrow-phase collision detection.
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struct cpCollisionInfo info = cpCollide(a, b, id, cpContactBufferGetArray(space));
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if(info.count == 0) return info.id; // Shapes are not colliding.
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cpSpacePushContacts(space, info.count);
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// Get an arbiter from space->arbiterSet for the two shapes.
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// This is where the persistant contact magic comes from.
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const cpShape *shape_pair[] = {info.a, info.b};
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cpHashValue arbHashID = CP_HASH_PAIR((cpHashValue)info.a, (cpHashValue)info.b);
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cpArbiter *arb = (cpArbiter *)cpHashSetInsert(space->cachedArbiters, arbHashID, shape_pair, (cpHashSetTransFunc)cpSpaceArbiterSetTrans, space);
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cpArbiterUpdate(arb, &info, space);
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cpCollisionHandler *handler = arb->handler;
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// Call the begin function first if it's the first step
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if(arb->state == CP_ARBITER_STATE_FIRST_COLLISION && !handler->beginFunc(arb, space, handler->userData)){
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cpArbiterIgnore(arb); // permanently ignore the collision until separation
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}
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if(
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// Ignore the arbiter if it has been flagged
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(arb->state != CP_ARBITER_STATE_IGNORE) &&
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// Call preSolve
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handler->preSolveFunc(arb, space, handler->userData) &&
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// Check (again) in case the pre-solve() callback called cpArbiterIgnored().
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arb->state != CP_ARBITER_STATE_IGNORE &&
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// Process, but don't add collisions for sensors.
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!(a->sensor || b->sensor) &&
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// Don't process collisions between two infinite mass bodies.
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// This includes collisions between two kinematic bodies, or a kinematic body and a static body.
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!(a->body->m == INFINITY && b->body->m == INFINITY)
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){
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cpArrayPush(space->arbiters, arb);
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} else {
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cpSpacePopContacts(space, info.count);
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arb->contacts = NULL;
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arb->count = 0;
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// Normally arbiters are set as used after calling the post-solve callback.
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// However, post-solve() callbacks are not called for sensors or arbiters rejected from pre-solve.
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if(arb->state != CP_ARBITER_STATE_IGNORE) arb->state = CP_ARBITER_STATE_NORMAL;
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}
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// Time stamp the arbiter so we know it was used recently.
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arb->stamp = space->stamp;
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return info.id;
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}
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// Hashset filter func to throw away old arbiters.
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cpBool
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cpSpaceArbiterSetFilter(cpArbiter *arb, cpSpace *space)
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{
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cpTimestamp ticks = space->stamp - arb->stamp;
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cpBody *a = arb->body_a, *b = arb->body_b;
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// TODO: should make an arbiter state for this so it doesn't require filtering arbiters for dangling body pointers on body removal.
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// Preserve arbiters on sensors and rejected arbiters for sleeping objects.
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// This prevents errant separate callbacks from happenening.
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if(
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(cpBodyGetType(a) == CP_BODY_TYPE_STATIC || cpBodyIsSleeping(a)) &&
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(cpBodyGetType(b) == CP_BODY_TYPE_STATIC || cpBodyIsSleeping(b))
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){
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return cpTrue;
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}
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// Arbiter was used last frame, but not this one
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if(ticks >= 1 && arb->state != CP_ARBITER_STATE_CACHED){
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arb->state = CP_ARBITER_STATE_CACHED;
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cpCollisionHandler *handler = arb->handler;
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handler->separateFunc(arb, space, handler->userData);
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}
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if(ticks >= space->collisionPersistence){
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arb->contacts = NULL;
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arb->count = 0;
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cpArrayPush(space->pooledArbiters, arb);
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return cpFalse;
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}
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return cpTrue;
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}
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//MARK: All Important cpSpaceStep() Function
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void
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cpShapeUpdateFunc(cpShape *shape, void *unused)
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{
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cpShapeCacheBB(shape);
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}
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void
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cpSpaceStep(cpSpace *space, cpFloat dt)
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{
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// don't step if the timestep is 0!
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if(dt == 0.0f) return;
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space->stamp++;
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cpFloat prev_dt = space->curr_dt;
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space->curr_dt = dt;
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cpArray *bodies = space->dynamicBodies;
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cpArray *constraints = space->constraints;
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cpArray *arbiters = space->arbiters;
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// Reset and empty the arbiter lists.
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for(int i=0; i<arbiters->num; i++){
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cpArbiter *arb = (cpArbiter *)arbiters->arr[i];
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arb->state = CP_ARBITER_STATE_NORMAL;
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// If both bodies are awake, unthread the arbiter from the contact graph.
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if(!cpBodyIsSleeping(arb->body_a) && !cpBodyIsSleeping(arb->body_b)){
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cpArbiterUnthread(arb);
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}
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}
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arbiters->num = 0;
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cpSpaceLock(space); {
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// Integrate positions
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for(int i=0; i<bodies->num; i++){
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cpBody *body = (cpBody *)bodies->arr[i];
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body->position_func(body, dt);
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}
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// Find colliding pairs.
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cpSpacePushFreshContactBuffer(space);
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cpSpatialIndexEach(space->dynamicShapes, (cpSpatialIndexIteratorFunc)cpShapeUpdateFunc, NULL);
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cpSpatialIndexReindexQuery(space->dynamicShapes, (cpSpatialIndexQueryFunc)cpSpaceCollideShapes, space);
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} cpSpaceUnlock(space, cpFalse);
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// Rebuild the contact graph (and detect sleeping components if sleeping is enabled)
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cpSpaceProcessComponents(space, dt);
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cpSpaceLock(space); {
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// Clear out old cached arbiters and call separate callbacks
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cpHashSetFilter(space->cachedArbiters, (cpHashSetFilterFunc)cpSpaceArbiterSetFilter, space);
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// Prestep the arbiters and constraints.
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cpFloat slop = space->collisionSlop;
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cpFloat biasCoef = 1.0f - cpfpow(space->collisionBias, dt);
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for(int i=0; i<arbiters->num; i++){
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cpArbiterPreStep((cpArbiter *)arbiters->arr[i], dt, slop, biasCoef);
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}
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for(int i=0; i<constraints->num; i++){
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cpConstraint *constraint = (cpConstraint *)constraints->arr[i];
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cpConstraintPreSolveFunc preSolve = constraint->preSolve;
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if(preSolve) preSolve(constraint, space);
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constraint->klass->preStep(constraint, dt);
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}
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// Integrate velocities.
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cpFloat damping = cpfpow(space->damping, dt);
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cpVect gravity = space->gravity;
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for(int i=0; i<bodies->num; i++){
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cpBody *body = (cpBody *)bodies->arr[i];
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body->velocity_func(body, gravity, damping, dt);
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}
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// Apply cached impulses
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cpFloat dt_coef = (prev_dt == 0.0f ? 0.0f : dt/prev_dt);
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for(int i=0; i<arbiters->num; i++){
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cpArbiterApplyCachedImpulse((cpArbiter *)arbiters->arr[i], dt_coef);
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}
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for(int i=0; i<constraints->num; i++){
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cpConstraint *constraint = (cpConstraint *)constraints->arr[i];
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constraint->klass->applyCachedImpulse(constraint, dt_coef);
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}
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// Run the impulse solver.
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for(int i=0; i<space->iterations; i++){
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for(int j=0; j<arbiters->num; j++){
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cpArbiterApplyImpulse((cpArbiter *)arbiters->arr[j]);
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}
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for(int j=0; j<constraints->num; j++){
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cpConstraint *constraint = (cpConstraint *)constraints->arr[j];
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constraint->klass->applyImpulse(constraint, dt);
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}
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}
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// Run the constraint post-solve callbacks
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for(int i=0; i<constraints->num; i++){
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cpConstraint *constraint = (cpConstraint *)constraints->arr[i];
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cpConstraintPostSolveFunc postSolve = constraint->postSolve;
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if(postSolve) postSolve(constraint, space);
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}
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// run the post-solve callbacks
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for(int i=0; i<arbiters->num; i++){
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cpArbiter *arb = (cpArbiter *) arbiters->arr[i];
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cpCollisionHandler *handler = arb->handler;
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handler->postSolveFunc(arb, space, handler->userData);
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}
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} cpSpaceUnlock(space, cpTrue);
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}
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