text: /*
  Bullet Continuous Collision Detection and Physics Library
  Copyright (c) 2003-2013 Erwin Coumans  http://bulletphysics.org
  
  This software is provided 'as-is', without any express or implied warranty.
  In no event will the authors be held liable for any damages arising from the use of this software.
  Permission is granted to anyone to use this software for any purpose, 
  including commercial applications, and to alter it and redistribute it freely, 
  subject to the following restrictions:
  
  1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
  
  */
  
  #include "btCompoundCompoundCollisionAlgorithm.h"
  #include "LinearMath/btQuickprof.h"
  #include "BulletCollision/CollisionDispatch/btCollisionObject.h"
  #include "BulletCollision/CollisionShapes/btCompoundShape.h"
  #include "BulletCollision/BroadphaseCollision/btDbvt.h"
  #include "LinearMath/btIDebugDraw.h"
  #include "LinearMath/btAabbUtil2.h"
  #include "BulletCollision/CollisionDispatch/btManifoldResult.h"
  #include "BulletCollision/CollisionDispatch/btCollisionObjectWrapper.h"
  
  //USE_LOCAL_STACK will avoid most (often all) dynamic memory allocations due to resizing in processCollision and MycollideTT
  #define USE_LOCAL_STACK 1
  
  btShapePairCallback gCompoundCompoundChildShapePairCallback = 0;
  
  btCompoundCompoundCollisionAlgorithm::btCompoundCompoundCollisionAlgorithm( const btCollisionAlgorithmConstructionInfo& ci,const btCollisionObjectWrapper* body0Wrap,const btCollisionObjectWrapper* body1Wrap,bool isSwapped)
  :btCompoundCollisionAlgorithm(ci,body0Wrap,body1Wrap,isSwapped)
  {
  
  	void* ptr = btAlignedAlloc(sizeof(btHashedSimplePairCache),16);
  	m_childCollisionAlgorithmCache= new(ptr) btHashedSimplePairCache();
  
  	const btCollisionObjectWrapper* col0ObjWrap = body0Wrap;
  	btAssert (col0ObjWrap->getCollisionShape()->isCompound());
  
  	const btCollisionObjectWrapper* col1ObjWrap = body1Wrap;
  	btAssert (col1ObjWrap->getCollisionShape()->isCompound());
  	
  	const btCompoundShape* compoundShape0 = static_cast<const btCompoundShape*>(col0ObjWrap->getCollisionShape());
  	m_compoundShapeRevision0 = compoundShape0->getUpdateRevision();
  
  	const btCompoundShape* compoundShape1 = static_cast<const btCompoundShape*>(col1ObjWrap->getCollisionShape());
  	m_compoundShapeRevision1 = compoundShape1->getUpdateRevision();
  	
  	
  }
  
  
  btCompoundCompoundCollisionAlgorithm::~btCompoundCompoundCollisionAlgorithm()
  {
  	removeChildAlgorithms();
  	m_childCollisionAlgorithmCache->~btHashedSimplePairCache();
  	btAlignedFree(m_childCollisionAlgorithmCache);
  }
  
  void	btCompoundCompoundCollisionAlgorithm::getAllContactManifolds(btManifoldArray&	manifoldArray)
  {
  	int i;
  	btSimplePairArray& pairs = m_childCollisionAlgorithmCache->getOverlappingPairArray();
  	for (i=0;i<pairs.size();i++)
  	{
  		if (pairs[i].m_userPointer)
  		{
  			
  			((btCollisionAlgorithm*)pairs[i].m_userPointer)->getAllContactManifolds(manifoldArray);
  		}
  	}
  }
  
  
  void	btCompoundCompoundCollisionAlgorithm::removeChildAlgorithms()
  {
  	btSimplePairArray& pairs = m_childCollisionAlgorithmCache->getOverlappingPairArray();
  
  	int numChildren = pairs.size();
  	int i;
  	for (i=0;i<numChildren;i++)
  	{
  		if (pairs[i].m_userPointer)
  		{
  			btCollisionAlgorithm* algo = (btCollisionAlgorithm*) pairs[i].m_userPointer;
  			algo->~btCollisionAlgorithm();
  			m_dispatcher->freeCollisionAlgorithm(algo);
  		}
  	}
  	m_childCollisionAlgorithmCache->removeAllPairs();
  }
  
  struct	btCompoundCompoundLeafCallback : btDbvt::ICollide
  {
  	int m_numOverlapPairs;
  
  
  	const btCollisionObjectWrapper* m_compound0ColObjWrap;
  	const btCollisionObjectWrapper* m_compound1ColObjWrap;
  	btDispatcher* m_dispatcher;
  	const btDispatcherInfo& m_dispatchInfo;
  	btManifoldResult*	m_resultOut;
  	
  	
  	class btHashedSimplePairCache*	m_childCollisionAlgorithmCache;
  	
  	btPersistentManifold*	m_sharedManifold;
  	
  	btCompoundCompoundLeafCallback (const btCollisionObjectWrapper* compound1ObjWrap,
  									const btCollisionObjectWrapper* compound0ObjWrap,
  									btDispatcher* dispatcher,
  									const btDispatcherInfo& dispatchInfo,
  									btManifoldResult*	resultOut,
  									btHashedSimplePairCache* childAlgorithmsCache,
  									btPersistentManifold*	sharedManifold)
  		:m_numOverlapPairs(0),m_compound0ColObjWrap(compound1ObjWrap),m_compound1ColObjWrap(compound0ObjWrap),m_dispatcher(dispatcher),m_dispatchInfo(dispatchInfo),m_resultOut(resultOut),
  		m_childCollisionAlgorithmCache(childAlgorithmsCache),
  		m_sharedManifold(sharedManifold)
  	{
  
  	}
  
  
  
  	
  	void		Process(const btDbvtNode* leaf0,const btDbvtNode* leaf1)
  	{
  		BT_PROFILE("btCompoundCompoundLeafCallback::Process");
  		m_numOverlapPairs++;
  
  
  		int childIndex0 = leaf0->dataAsInt;
  		int childIndex1 = leaf1->dataAsInt;
  		
  
  		btAssert(childIndex0>=0);
  		btAssert(childIndex1>=0);
  
  
  		const btCompoundShape* compoundShape0 = static_cast<const btCompoundShape*>(m_compound0ColObjWrap->getCollisionShape());
  		btAssert(childIndex0<compoundShape0->getNumChildShapes());
  
  		const btCompoundShape* compoundShape1 = static_cast<const btCompoundShape*>(m_compound1ColObjWrap->getCollisionShape());
  		btAssert(childIndex1<compoundShape1->getNumChildShapes());
  
  		const btCollisionShape* childShape0 = compoundShape0->getChildShape(childIndex0);
  		const btCollisionShape* childShape1 = compoundShape1->getChildShape(childIndex1);
  
  		//backup
  		btTransform	orgTrans0 = m_compound0ColObjWrap->getWorldTransform();
  		const btTransform& childTrans0 = compoundShape0->getChildTransform(childIndex0);
  		btTransform	newChildWorldTrans0 = orgTrans0*childTrans0 ;
  		
  		btTransform	orgTrans1 = m_compound1ColObjWrap->getWorldTransform();
  		const btTransform& childTrans1 = compoundShape1->getChildTransform(childIndex1);
  		btTransform	newChildWorldTrans1 = orgTrans1*childTrans1 ;
  		
  
  		//perform an AABB check first
  		btVector3 aabbMin0,aabbMax0,aabbMin1,aabbMax1;
  		childShape0->getAabb(newChildWorldTrans0,aabbMin0,aabbMax0);
  		childShape1->getAabb(newChildWorldTrans1,aabbMin1,aabbMax1);
  		
  		btVector3 thresholdVec(m_resultOut->m_closestPointDistanceThreshold, m_resultOut->m_closestPointDistanceThreshold, m_resultOut->m_closestPointDistanceThreshold);
  
  		aabbMin0 -= thresholdVec;
  		aabbMax0 += thresholdVec;
  
  		if (gCompoundCompoundChildShapePairCallback)
  		{
  			if (!gCompoundCompoundChildShapePairCallback(childShape0,childShape1))
  				return;
  		}
  
  		if (TestAabbAgainstAabb2(aabbMin0,aabbMax0,aabbMin1,aabbMax1))
  		{
  			btCollisionObjectWrapper compoundWrap0(this->m_compound0ColObjWrap,childShape0, m_compound0ColObjWrap->getCollisionObject(),newChildWorldTrans0,-1,childIndex0);
  			btCollisionObjectWrapper compoundWrap1(this->m_compound1ColObjWrap,childShape1,m_compound1ColObjWrap->getCollisionObject(),newChildWorldTrans1,-1,childIndex1);
  			
  
  			btSimplePair* pair = m_childCollisionAlgorithmCache->findPair(childIndex0,childIndex1);
  
  			btCollisionAlgorithm* colAlgo = 0;
  			if (m_resultOut->m_closestPointDistanceThreshold > 0)
  			{
  				colAlgo = m_dispatcher->findAlgorithm(&compoundWrap0, &compoundWrap1, 0, BT_CLOSEST_POINT_ALGORITHMS);
  			}
  			else
  			{
  				if (pair)
  				{
  					colAlgo = (btCollisionAlgorithm*)pair->m_userPointer;
  
  				}
  				else
  				{
  					colAlgo = m_dispatcher->findAlgorithm(&compoundWrap0, &compoundWrap1, m_sharedManifold, BT_CONTACT_POINT_ALGORITHMS);
  					pair = m_childCollisionAlgorithmCache->addOverlappingPair(childIndex0, childIndex1);
  					btAssert(pair);
  					pair->m_userPointer = colAlgo;
  				}
  			}
  
  			btAssert(colAlgo);
  						
  			const btCollisionObjectWrapper* tmpWrap0 = 0;
  			const btCollisionObjectWrapper* tmpWrap1 = 0;
  
  			tmpWrap0 = m_resultOut->getBody0Wrap();
  			tmpWrap1 = m_resultOut->getBody1Wrap();
  
  			m_resultOut->setBody0Wrap(&compoundWrap0);
  			m_resultOut->setBody1Wrap(&compoundWrap1);
  
  			m_resultOut->setShapeIdentifiersA(-1,childIndex0);
  			m_resultOut->setShapeIdentifiersB(-1,childIndex1);
  
  
  			colAlgo->processCollision(&compoundWrap0,&compoundWrap1,m_dispatchInfo,m_resultOut);
  			
  			m_resultOut->setBody0Wrap(tmpWrap0);
  			m_resultOut->setBody1Wrap(tmpWrap1);
  			
  
  
  		}
  	}
  };
  
  
  static DBVT_INLINE bool		MyIntersect(	const btDbvtAabbMm& a,
  								  const btDbvtAabbMm& b, const btTransform& xform, btScalar distanceThreshold)
  {
  	btVector3 newmin,newmax;
  	btTransformAabb(b.Mins(),b.Maxs(),0.f,xform,newmin,newmax);
  	newmin -= btVector3(distanceThreshold, distanceThreshold, distanceThreshold);
  	newmax += btVector3(distanceThreshold, distanceThreshold, distanceThreshold);
  	btDbvtAabbMm newb = btDbvtAabbMm::FromMM(newmin,newmax);
  	return Intersect(a,newb);
  }
  
  
  static inline void		MycollideTT(	const btDbvtNode* root0,
  								  const btDbvtNode* root1,
  								  const btTransform& xform,
  								  btCompoundCompoundLeafCallback* callback, btScalar distanceThreshold)
  {
  
  		if(root0&&root1)
  		{
  			int								depth=1;
  			int								treshold=btDbvt::DOUBLE_STACKSIZE-4;
  			btAlignedObjectArray<btDbvt::sStkNN>	stkStack;
  #ifdef USE_LOCAL_STACK
  			ATTRIBUTE_ALIGNED16(btDbvt::sStkNN localStack[btDbvt::DOUBLE_STACKSIZE]);
  			stkStack.initializeFromBuffer(&localStack,btDbvt::DOUBLE_STACKSIZE,btDbvt::DOUBLE_STACKSIZE);
  #else
  			stkStack.resize(btDbvt::DOUBLE_STACKSIZE);
  #endif
  			stkStack[0]=btDbvt::sStkNN(root0,root1);
  			do	{
  				btDbvt::sStkNN	p=stkStack[--depth];
  				if(MyIntersect(p.a->volume,p.b->volume,xform, distanceThreshold))
  				{
  					if(depth>treshold)
  					{
  						stkStack.resize(stkStack.size()*2);
  						treshold=stkStack.size()-4;
  					}
  					if(p.a->isinternal())
  					{
  						if(p.b->isinternal())
  						{					
  							stkStack[depth++]=btDbvt::sStkNN(p.a->childs[0],p.b->childs[0]);
  							stkStack[depth++]=btDbvt::sStkNN(p.a->childs[1],p.b->childs[0]);
  							stkStack[depth++]=btDbvt::sStkNN(p.a->childs[0],p.b->childs[1]);
  							stkStack[depth++]=btDbvt::sStkNN(p.a->childs[1],p.b->childs[1]);
  						}
  						else
  						{
  							stkStack[depth++]=btDbvt::sStkNN(p.a->childs[0],p.b);
  							stkStack[depth++]=btDbvt::sStkNN(p.a->childs[1],p.b);
  						}
  					}
  					else
  					{
  						if(p.b->isinternal())
  						{
  							stkStack[depth++]=btDbvt::sStkNN(p.a,p.b->childs[0]);
  							stkStack[depth++]=btDbvt::sStkNN(p.a,p.b->childs[1]);
  						}
  						else
  						{
  							callback->Process(p.a,p.b);
  						}
  					}
  				}
  			} while(depth);
  		}
  }
  
  void btCompoundCompoundCollisionAlgorithm::processCollision (const btCollisionObjectWrapper* body0Wrap,const btCollisionObjectWrapper* body1Wrap,const btDispatcherInfo& dispatchInfo,btManifoldResult* resultOut)
  {
  
  	const btCollisionObjectWrapper* col0ObjWrap = body0Wrap;
  	const btCollisionObjectWrapper* col1ObjWrap= body1Wrap;
  
  	btAssert (col0ObjWrap->getCollisionShape()->isCompound());
  	btAssert (col1ObjWrap->getCollisionShape()->isCompound());
  	const btCompoundShape* compoundShape0 = static_cast<const btCompoundShape*>(col0ObjWrap->getCollisionShape());
  	const btCompoundShape* compoundShape1 = static_cast<const btCompoundShape*>(col1ObjWrap->getCollisionShape());
  
  	const btDbvt* tree0 = compoundShape0->getDynamicAabbTree();
  	const btDbvt* tree1 = compoundShape1->getDynamicAabbTree();
  	if (!tree0 || !tree1)
  	{
  		return btCompoundCollisionAlgorithm::processCollision(body0Wrap,body1Wrap,dispatchInfo,resultOut);
  	}
  	///btCompoundShape might have changed:
  	////make sure the internal child collision algorithm caches are still valid
  	if ((compoundShape0->getUpdateRevision() != m_compoundShapeRevision0) || (compoundShape1->getUpdateRevision() != m_compoundShapeRevision1))
  	{
  		///clear all
  		removeChildAlgorithms();
  		m_compoundShapeRevision0 = compoundShape0->getUpdateRevision();
  		m_compoundShapeRevision1 = compoundShape1->getUpdateRevision();
  
  	}
  
  
  	///we need to refresh all contact manifolds
  	///note that we should actually recursively traverse all children, btCompoundShape can nested more then 1 level deep
  	///so we should add a 'refreshManifolds' in the btCollisionAlgorithm
  	{
  		int i;
  		btManifoldArray manifoldArray;
  #ifdef USE_LOCAL_STACK 
  		btPersistentManifold localManifolds[4];
  		manifoldArray.initializeFromBuffer(&localManifolds,0,4);
  #endif
  		btSimplePairArray& pairs = m_childCollisionAlgorithmCache->getOverlappingPairArray();
  		for (i=0;i<pairs.size();i++)
  		{
  			if (pairs[i].m_userPointer)
  			{
  				btCollisionAlgorithm* algo = (btCollisionAlgorithm*) pairs[i].m_userPointer;
  				algo->getAllContactManifolds(manifoldArray);
  				for (int m=0;m<manifoldArray.size();m++)
  				{
  					if (manifoldArray[m]->getNumContacts())
  					{
  						resultOut->setPersistentManifold(manifoldArray[m]);
  						resultOut->refreshContactPoints();
  						resultOut->setPersistentManifold(0);
  					}
  				}
  				manifoldArray.resize(0);
  			}
  		}
  	}
  
  
  	
  
  	btCompoundCompoundLeafCallback callback(col0ObjWrap,col1ObjWrap,this->m_dispatcher,dispatchInfo,resultOut,this->m_childCollisionAlgorithmCache,m_sharedManifold);
  
  
  	const btTransform	xform=col0ObjWrap->getWorldTransform().inverse()*col1ObjWrap->getWorldTransform();
  	MycollideTT(tree0->m_root,tree1->m_root,xform,&callback, resultOut->m_closestPointDistanceThreshold);
  
  	//printf("#compound-compound child/leaf overlap =%d                      \r",callback.m_numOverlapPairs);
  
  	//remove non-overlapping child pairs
  
  	{
  		btAssert(m_removePairs.size()==0);
  
  		//iterate over all children, perform an AABB check inside ProcessChildShape
  		btSimplePairArray& pairs = m_childCollisionAlgorithmCache->getOverlappingPairArray();
  		
  		int i;
  		btManifoldArray	manifoldArray;
          
  		
  
          
          
          btVector3 aabbMin0,aabbMax0,aabbMin1,aabbMax1;        
          
  		for (i=0;i<pairs.size();i++)
  		{
  			if (pairs[i].m_userPointer)
  			{
  				btCollisionAlgorithm* algo = (btCollisionAlgorithm*)pairs[i].m_userPointer;
  
  				{
  					btTransform	orgTrans0;
  					const btCollisionShape* childShape0 = 0;
  					
  					btTransform	newChildWorldTrans0;
  					btTransform	orgInterpolationTrans0;
  					childShape0 = compoundShape0->getChildShape(pairs[i].m_indexA);
  					orgTrans0 = col0ObjWrap->getWorldTransform();
  					orgInterpolationTrans0 = col0ObjWrap->getWorldTransform();
  					const btTransform& childTrans0 = compoundShape0->getChildTransform(pairs[i].m_indexA);
  					newChildWorldTrans0 = orgTrans0*childTrans0 ;
  					childShape0->getAabb(newChildWorldTrans0,aabbMin0,aabbMax0);
  				}
  				btVector3 thresholdVec(resultOut->m_closestPointDistanceThreshold, resultOut->m_closestPointDistanceThreshold, resultOut->m_closestPointDistanceThreshold);
  				aabbMin0 -= thresholdVec;
  				aabbMax0 += thresholdVec;
  				{
  					btTransform	orgInterpolationTrans1;
  					const btCollisionShape* childShape1 = 0;
  					btTransform	orgTrans1;
  					btTransform	newChildWorldTrans1;
  
  					childShape1 = compoundShape1->getChildShape(pairs[i].m_indexB);
  					orgTrans1 = col1ObjWrap->getWorldTransform();
  					orgInterpolationTrans1 = col1ObjWrap->getWorldTransform();
  					const btTransform& childTrans1 = compoundShape1->getChildTransform(pairs[i].m_indexB);
  					newChildWorldTrans1 = orgTrans1*childTrans1 ;
  					childShape1->getAabb(newChildWorldTrans1,aabbMin1,aabbMax1);
  				}
  				
  				aabbMin1 -= thresholdVec;
  				aabbMax1 += thresholdVec;
  
  				if (!TestAabbAgainstAabb2(aabbMin0,aabbMax0,aabbMin1,aabbMax1))
  				{
  					algo->~btCollisionAlgorithm();
  					m_dispatcher->freeCollisionAlgorithm(algo);
  					m_removePairs.push_back(btSimplePair(pairs[i].m_indexA,pairs[i].m_indexB));
  				}
  			}
  		}
  		for (int i=0;i<m_removePairs.size();i++)
  		{
  			m_childCollisionAlgorithmCache->removeOverlappingPair(m_removePairs[i].m_indexA,m_removePairs[i].m_indexB);
  		}
  		m_removePairs.clear();
  	}
  
  }
  
  btScalar	btCompoundCompoundCollisionAlgorithm::calculateTimeOfImpact(btCollisionObject* body0,btCollisionObject* body1,const btDispatcherInfo& dispatchInfo,btManifoldResult* resultOut)
  {
  	btAssert(0);
  	return 0.f;
  
  }
  
  
  
  