// Portable static method: prerequisite call: m_dynamicsWorld.getBroadphase().getOverlappingPairCache().setInternalGhostPairCallback(new btGhostPairCallback()); public static void GetCollidingObjectsInsidePairCachingGhostObject(DiscreteDynamicsWorld m_dynamicsWorld, PairCachingGhostObject m_pairCachingGhostObject, ObjectArray<CollisionObject> collisionArrayOut) { bool addOnlyObjectsWithNegativeDistance = true; // With "false" things don't change much, and the code is a bit faster and cleaner... collisionArrayOut.Resize(0); if (m_pairCachingGhostObject == null || m_dynamicsWorld == null) return; //#define USE_PLAIN_COLLISION_WORLD // We dispatch all collision pairs of the ghost object every step (slow) #if USE_PLAIN_COLLISION_WORLD //====================================================================================================== // I thought this line was no longer needed, but it seems to be necessary (and I believe it's an expensive call): m_dynamicsWorld.getDispatcher().dispatchAllCollisionPairs(m_pairCachingGhostObject.getOverlappingPairCache(), m_dynamicsWorld.getDispatchInfo(), m_dynamicsWorld.getDispatcher()); // Maybe the call can be automatically triggered by some other Bullet call (I'm almost sure I could comment it out in another demo I made long ago...) // So by now the general rule is: in real projects, simply comment it out and see if it works! //====================================================================================================== // UPDATE: in dynamic worlds, the line above can be commented out and the broadphase pair can be retrieved through the call to findPair(...) below. // In collision worlds probably the above line is needed only if collision detection for all the bodies hasn't been made... This is something // I'm still not sure of... the general rule is to try to comment out the line above and try to use findPair(...) and see if it works whenever possible.... //====================================================================================================== #endif //USE_PLAIN_COLLISION_WORLD ObjectArray<BroadphasePair> collisionPairs = m_pairCachingGhostObject.GetOverlappingPairCache().GetOverlappingPairArray(); int numObjects = collisionPairs.Count; PersistentManifoldArray m_manifoldArray = new PersistentManifoldArray(); bool added; for (int i = 0; i < numObjects; i++) { m_manifoldArray.Resize(0); #if USE_PLAIN_COLLISION_WORLD const btBroadphasePair& collisionPair = collisionPairs[i]; if (collisionPair.m_algorithm) collisionPair.m_algorithm.getAllContactManifolds(m_manifoldArray); else { // THIS SHOULD NEVER HAPPEN, AND IF IT DOES, PLEASE RE-ENABLE the "call" a few lines above... printf("No collisionPair.m_algorithm - probably m_dynamicsWorld.getDispatcher().dispatchAllCollisionPairs(...) must be missing.\n"); } #else // USE_PLAIN_COLLISION_WORLD BroadphasePair cPair = collisionPairs[i]; //unless we manually perform collision detection on this pair, the contacts are in the dynamics world paircache: BroadphasePair collisionPair = m_dynamicsWorld.GetPairCache().FindPair(cPair.m_pProxy0, cPair.m_pProxy1); if (collisionPair == null) { continue; } if (collisionPair.m_algorithm != null) { collisionPair.m_algorithm.GetAllContactManifolds(m_manifoldArray); } else { // THIS SHOULD NEVER HAPPEN, AND IF IT DOES, PLEASE RE-ENABLE the "call" a few lines above... //printf("No collisionPair.m_algorithm - probably m_dynamicsWorld.getDispatcher().dispatchAllCollisionPairs(...) must be missing.\n"); } #endif //USE_PLAIN_COLLISION_WORLD added = false; for (int j = 0; j < m_manifoldArray.Count; j++) { PersistentManifold manifold = m_manifoldArray[j]; // Here we are in the narrowphase, but can happen that manifold.getNumContacts()==0: if (addOnlyObjectsWithNegativeDistance) { for (int p = 0, numContacts = manifold.GetNumContacts(); p < numContacts; p++) { ManifoldPoint pt = manifold.GetContactPoint(p); if (pt.GetDistance() < 0.0) { // How can I be sure that the colObjs are all distinct ? I use the "added" flag. collisionArrayOut.Add((CollisionObject)(manifold.GetBody0() == m_pairCachingGhostObject ? manifold.GetBody1() : manifold.GetBody0())); added = true; break; } } if (added) { break; } } else if (manifold.GetNumContacts() > 0) { collisionArrayOut.Add((CollisionObject)(manifold.GetBody0() == m_pairCachingGhostObject ? manifold.GetBody1() : manifold.GetBody0())); break; } } } }
// Portable static method: prerequisite call: m_dynamicsWorld.getBroadphase().getOverlappingPairCache().setInternalGhostPairCallback(new btGhostPairCallback()); public static void GetCollidingObjectsInsidePairCachingGhostObject(DiscreteDynamicsWorld m_dynamicsWorld, PairCachingGhostObject m_pairCachingGhostObject, ObjectArray <CollisionObject> collisionArrayOut) { bool addOnlyObjectsWithNegativeDistance = true; // With "false" things don't change much, and the code is a bit faster and cleaner... collisionArrayOut.Resize(0); if (m_pairCachingGhostObject == null || m_dynamicsWorld == null) { return; } //#define USE_PLAIN_COLLISION_WORLD // We dispatch all collision pairs of the ghost object every step (slow) #if USE_PLAIN_COLLISION_WORLD //====================================================================================================== // I thought this line was no longer needed, but it seems to be necessary (and I believe it's an expensive call): m_dynamicsWorld.getDispatcher().dispatchAllCollisionPairs(m_pairCachingGhostObject.getOverlappingPairCache(), m_dynamicsWorld.getDispatchInfo(), m_dynamicsWorld.getDispatcher()); // Maybe the call can be automatically triggered by some other Bullet call (I'm almost sure I could comment it out in another demo I made long ago...) // So by now the general rule is: in real projects, simply comment it out and see if it works! //====================================================================================================== // UPDATE: in dynamic worlds, the line above can be commented out and the broadphase pair can be retrieved through the call to findPair(...) below. // In collision worlds probably the above line is needed only if collision detection for all the bodies hasn't been made... This is something // I'm still not sure of... the general rule is to try to comment out the line above and try to use findPair(...) and see if it works whenever possible.... //====================================================================================================== #endif //USE_PLAIN_COLLISION_WORLD ObjectArray <BroadphasePair> collisionPairs = m_pairCachingGhostObject.GetOverlappingPairCache().GetOverlappingPairArray(); int numObjects = collisionPairs.Count; PersistentManifoldArray m_manifoldArray = new PersistentManifoldArray(); bool added; for (int i = 0; i < numObjects; i++) { m_manifoldArray.Resize(0); #if USE_PLAIN_COLLISION_WORLD const btBroadphasePair& collisionPair = collisionPairs[i]; if (collisionPair.m_algorithm) { collisionPair.m_algorithm.getAllContactManifolds(m_manifoldArray); } else // THIS SHOULD NEVER HAPPEN, AND IF IT DOES, PLEASE RE-ENABLE the "call" a few lines above... { printf("No collisionPair.m_algorithm - probably m_dynamicsWorld.getDispatcher().dispatchAllCollisionPairs(...) must be missing.\n"); } #else // USE_PLAIN_COLLISION_WORLD BroadphasePair cPair = collisionPairs[i]; //unless we manually perform collision detection on this pair, the contacts are in the dynamics world paircache: BroadphasePair collisionPair = m_dynamicsWorld.GetPairCache().FindPair(cPair.m_pProxy0, cPair.m_pProxy1); if (collisionPair == null) { continue; } if (collisionPair.m_algorithm != null) { collisionPair.m_algorithm.GetAllContactManifolds(m_manifoldArray); } else { // THIS SHOULD NEVER HAPPEN, AND IF IT DOES, PLEASE RE-ENABLE the "call" a few lines above... //printf("No collisionPair.m_algorithm - probably m_dynamicsWorld.getDispatcher().dispatchAllCollisionPairs(...) must be missing.\n"); } #endif //USE_PLAIN_COLLISION_WORLD added = false; for (int j = 0; j < m_manifoldArray.Count; j++) { PersistentManifold manifold = m_manifoldArray[j]; // Here we are in the narrowphase, but can happen that manifold.getNumContacts()==0: if (addOnlyObjectsWithNegativeDistance) { for (int p = 0, numContacts = manifold.GetNumContacts(); p < numContacts; p++) { ManifoldPoint pt = manifold.GetContactPoint(p); if (pt.GetDistance() < 0.0) { // How can I be sure that the colObjs are all distinct ? I use the "added" flag. collisionArrayOut.Add((CollisionObject)(manifold.GetBody0() == m_pairCachingGhostObject ? manifold.GetBody1() : manifold.GetBody0())); added = true; break; } } if (added) { break; } } else if (manifold.GetNumContacts() > 0) { collisionArrayOut.Add((CollisionObject)(manifold.GetBody0() == m_pairCachingGhostObject ? manifold.GetBody1() : manifold.GetBody0())); break; } } } }