MultiSource/Benchmarks/Bullet/btGjkPairDetector.cpp - llvm-test-suite - Git at Google

 /*
 Bullet Continuous Collision Detection and Physics Library
 Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/

 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 "BulletCollision/NarrowPhaseCollision/btGjkPairDetector.h"
 #include "BulletCollision/CollisionShapes/btConvexShape.h"
 #include "BulletCollision/NarrowPhaseCollision/btSimplexSolverInterface.h"
 #include "BulletCollision/NarrowPhaseCollision/btConvexPenetrationDepthSolver.h"


 #if defined(DEBUG) || defined (_DEBUG)
 //#define TEST_NON_VIRTUAL 1
 #include <stdio.h> //for debug printf
 #ifdef __SPU__
 #include <spu_printf.h>
 #define printf spu_printf
 //#define DEBUG_SPU_COLLISION_DETECTION 1
 #endif //__SPU__
 #endif

 //must be above the machine epsilon
 #define REL_ERROR2 btScalar(1.0e-6)

 //temp globals, to improve GJK/EPA/penetration calculations
 int gNumDeepPenetrationChecks = 0;
 int gNumGjkChecks = 0;


 btGjkPairDetector::btGjkPairDetector(const btConvexShape* objectA,const btConvexShape* objectB,btSimplexSolverInterface* simplexSolver,btConvexPenetrationDepthSolver*	penetrationDepthSolver)
 :m_cachedSeparatingAxis(btScalar(0.),btScalar(1.),btScalar(0.)),
 m_penetrationDepthSolver(penetrationDepthSolver),
 m_simplexSolver(simplexSolver),
 m_minkowskiA(objectA),
 m_minkowskiB(objectB),
 m_shapeTypeA(objectA->getShapeType()),
 m_shapeTypeB(objectB->getShapeType()),
 m_marginA(objectA->getMargin()),
 m_marginB(objectB->getMargin()),
 m_ignoreMargin(false),
 m_lastUsedMethod(-1),
 m_catchDegeneracies(1)
 {
 }
 btGjkPairDetector::btGjkPairDetector(const btConvexShape* objectA,const btConvexShape* objectB,int shapeTypeA,int shapeTypeB,btScalar marginA, btScalar marginB, btSimplexSolverInterface* simplexSolver,btConvexPenetrationDepthSolver*	penetrationDepthSolver)
 :m_cachedSeparatingAxis(btScalar(0.),btScalar(1.),btScalar(0.)),
 m_penetrationDepthSolver(penetrationDepthSolver),
 m_simplexSolver(simplexSolver),
 m_minkowskiA(objectA),
 m_minkowskiB(objectB),
 m_shapeTypeA(shapeTypeA),
 m_shapeTypeB(shapeTypeB),
 m_marginA(marginA),
 m_marginB(marginB),
 m_ignoreMargin(false),
 m_lastUsedMethod(-1),
 m_catchDegeneracies(1)
 {
 }

 void	btGjkPairDetector::getClosestPoints(const ClosestPointInput& input,Result& output,class btIDebugDraw* debugDraw,bool swapResults)
 {
 	(void)swapResults;

 	getClosestPointsNonVirtual(input,output,debugDraw);
 }

 #ifdef __SPU__
 void btGjkPairDetector::getClosestPointsNonVirtual(const ClosestPointInput& input,Result& output,class btIDebugDraw* debugDraw)
 #else
 void btGjkPairDetector::getClosestPointsNonVirtual(const ClosestPointInput& input,Result& output,class btIDebugDraw* debugDraw)
 #endif
 {
 	m_cachedSeparatingDistance = 0.f;

 	btScalar distance=btScalar(0.);
 	btVector3	normalInB(btScalar(0.),btScalar(0.),btScalar(0.));
 	btVector3 pointOnA,pointOnB;
 	btTransform	localTransA = input.m_transformA;
 	btTransform localTransB = input.m_transformB;
 	btVector3 positionOffset = (localTransA.getOrigin() + localTransB.getOrigin()) * btScalar(0.5);
 	localTransA.getOrigin() -= positionOffset;
 	localTransB.getOrigin() -= positionOffset;

 	bool check2d = m_minkowskiA->isConvex2d() && m_minkowskiB->isConvex2d();

 	btScalar marginA = m_marginA;
 	btScalar marginB = m_marginB;

 	gNumGjkChecks++;

 #ifdef DEBUG_SPU_COLLISION_DETECTION
 	spu_printf("inside gjk\n");
 #endif
 	//for CCD we don't use margins
 	if (m_ignoreMargin)
 	{
 		marginA = btScalar(0.);
 		marginB = btScalar(0.);
 #ifdef DEBUG_SPU_COLLISION_DETECTION
 		spu_printf("ignoring margin\n");
 #endif
 	}

 	m_curIter = 0;
 	int gGjkMaxIter = 1000;//this is to catch invalid input, perhaps check for #NaN?
 	m_cachedSeparatingAxis.setValue(0,1,0);

 	bool isValid = false;
 	bool checkSimplex = false;
 	bool checkPenetration = true;
 	m_degenerateSimplex = 0;

 	m_lastUsedMethod = -1;

 	{
 		btScalar squaredDistance = BT_LARGE_FLOAT;
 		btScalar delta = btScalar(0.);

 		btScalar margin = marginA + marginB;


 		m_simplexSolver->reset();

 		for ( ; ; )
 		//while (true)
 		{

 			btVector3 seperatingAxisInA = (-m_cachedSeparatingAxis)* input.m_transformA.getBasis();
 			btVector3 seperatingAxisInB = m_cachedSeparatingAxis* input.m_transformB.getBasis();

 #if 1

 			btVector3 pInA = m_minkowskiA->localGetSupportVertexWithoutMarginNonVirtual(seperatingAxisInA);
 			btVector3 qInB = m_minkowskiB->localGetSupportVertexWithoutMarginNonVirtual(seperatingAxisInB);

 //			btVector3 pInA  = localGetSupportingVertexWithoutMargin(m_shapeTypeA, m_minkowskiA, seperatingAxisInA,input.m_convexVertexData[0]);//, &featureIndexA);
 //			btVector3 qInB  = localGetSupportingVertexWithoutMargin(m_shapeTypeB, m_minkowskiB, seperatingAxisInB,input.m_convexVertexData[1]);//, &featureIndexB);

 #else
 #ifdef __SPU__
 			btVector3 pInA = m_minkowskiA->localGetSupportVertexWithoutMarginNonVirtual(seperatingAxisInA);
 			btVector3 qInB = m_minkowskiB->localGetSupportVertexWithoutMarginNonVirtual(seperatingAxisInB);
 #else
 			btVector3 pInA = m_minkowskiA->localGetSupportingVertexWithoutMargin(seperatingAxisInA);
 			btVector3 qInB = m_minkowskiB->localGetSupportingVertexWithoutMargin(seperatingAxisInB);
 #ifdef TEST_NON_VIRTUAL
 			btVector3 pInAv = m_minkowskiA->localGetSupportingVertexWithoutMargin(seperatingAxisInA);
 			btVector3 qInBv = m_minkowskiB->localGetSupportingVertexWithoutMargin(seperatingAxisInB);
 			btAssert((pInAv-pInA).length() < 0.0001);
 			btAssert((qInBv-qInB).length() < 0.0001);
 #endif //
 #endif //__SPU__
 #endif


 			btVector3  pWorld = localTransA(pInA);
 			btVector3  qWorld = localTransB(qInB);

 #ifdef DEBUG_SPU_COLLISION_DETECTION
 		spu_printf("got local supporting vertices\n");
 #endif

 			if (check2d)
 			{
 				pWorld[2] = 0.f;
 				qWorld[2] = 0.f;
 			}

 			btVector3 w	= pWorld - qWorld;
 			delta = m_cachedSeparatingAxis.dot(w);

 			// potential exit, they don't overlap
 			if ((delta > btScalar(0.0)) && (delta * delta > squaredDistance * input.m_maximumDistanceSquared))
 			{
 				m_degenerateSimplex = 10;
 				checkSimplex=true;
 				//checkPenetration = false;
 				break;
 			}

 			//exit 0: the new point is already in the simplex, or we didn't come any closer
 			if (m_simplexSolver->inSimplex(w))
 			{
 				m_degenerateSimplex = 1;
 				checkSimplex = true;
 				break;
 			}
 			// are we getting any closer ?
 			btScalar f0 = squaredDistance - delta;
 			btScalar f1 = squaredDistance * REL_ERROR2;

 			if (f0 <= f1)
 			{
 				if (f0 <= btScalar(0.))
 				{
 					m_degenerateSimplex = 2;
 				} else
 				{
 					m_degenerateSimplex = 11;
 				}
 				checkSimplex = true;
 				break;
 			}

 #ifdef DEBUG_SPU_COLLISION_DETECTION
 		spu_printf("addVertex 1\n");
 #endif
 			//add current vertex to simplex
 			m_simplexSolver->addVertex(w, pWorld, qWorld);
 #ifdef DEBUG_SPU_COLLISION_DETECTION
 		spu_printf("addVertex 2\n");
 #endif
 			btVector3 newCachedSeparatingAxis;

 			//calculate the closest point to the origin (update vector v)
 			if (!m_simplexSolver->closest(newCachedSeparatingAxis))
 			{
 				m_degenerateSimplex = 3;
 				checkSimplex = true;
 				break;
 			}

 			if(newCachedSeparatingAxis.length2()<REL_ERROR2)
             {
 				m_cachedSeparatingAxis = newCachedSeparatingAxis;
                 m_degenerateSimplex = 6;
                 checkSimplex = true;
                 break;
             }

 			btScalar previousSquaredDistance = squaredDistance;
 			squaredDistance = newCachedSeparatingAxis.length2();
 #if 0
 ///warning: this termination condition leads to some problems in 2d test case see Bullet/Demos/Box2dDemo
 			if (squaredDistance>previousSquaredDistance)
 			{
 				m_degenerateSimplex = 7;
 				squaredDistance = previousSquaredDistance;
                 checkSimplex = false;
                 break;
 			}
 #endif //

 			m_cachedSeparatingAxis = newCachedSeparatingAxis;

 			//redundant m_simplexSolver->compute_points(pointOnA, pointOnB);

 			//are we getting any closer ?
 			if (previousSquaredDistance - squaredDistance <= SIMD_EPSILON * previousSquaredDistance)
 			{
 				m_simplexSolver->backup_closest(m_cachedSeparatingAxis);
 				checkSimplex = true;
 				m_degenerateSimplex = 12;

 				break;
 			}

 			  //degeneracy, this is typically due to invalid/uninitialized worldtransforms for a btCollisionObject
               if (m_curIter++ > gGjkMaxIter)
               {
                       #if defined(DEBUG) || defined (_DEBUG) || defined (DEBUG_SPU_COLLISION_DETECTION)

                               printf("btGjkPairDetector maxIter exceeded:%i\n",m_curIter);
                               printf("sepAxis=(%f,%f,%f), squaredDistance = %f, shapeTypeA=%i,shapeTypeB=%i\n",
                               m_cachedSeparatingAxis.getX(),
                               m_cachedSeparatingAxis.getY(),
                               m_cachedSeparatingAxis.getZ(),
                               squaredDistance,
                               m_minkowskiA->getShapeType(),
                               m_minkowskiB->getShapeType());

                       #endif
                       break;

               }


 			bool check = (!m_simplexSolver->fullSimplex());
 			//bool check = (!m_simplexSolver->fullSimplex() && squaredDistance > SIMD_EPSILON * m_simplexSolver->maxVertex());

 			if (!check)
 			{
 				//do we need this backup_closest here ?
 				m_simplexSolver->backup_closest(m_cachedSeparatingAxis);
 				m_degenerateSimplex = 13;
 				break;
 			}
 		}

 		if (checkSimplex)
 		{
 			m_simplexSolver->compute_points(pointOnA, pointOnB);
 			normalInB = pointOnA-pointOnB;
 			btScalar lenSqr =m_cachedSeparatingAxis.length2();

 			//valid normal
 			if (lenSqr < 0.0001)
 			{
 				m_degenerateSimplex = 5;
 			}
 			if (lenSqr > SIMD_EPSILON*SIMD_EPSILON)
 			{
 				btScalar rlen = btScalar(1.) / btSqrt(lenSqr );
 				normalInB *= rlen; //normalize
 				btScalar s = btSqrt(squaredDistance);

 				btAssert(s > btScalar(0.0));
 				pointOnA -= m_cachedSeparatingAxis * (marginA / s);
 				pointOnB += m_cachedSeparatingAxis * (marginB / s);
 				distance = ((btScalar(1.)/rlen) - margin);
 				isValid = true;

 				m_lastUsedMethod = 1;
 			} else
 			{
 				m_lastUsedMethod = 2;
 			}
 		}

 		bool catchDegeneratePenetrationCase =
 			(m_catchDegeneracies && m_penetrationDepthSolver && m_degenerateSimplex && ((distance+margin) < 0.01));

 		//if (checkPenetration && !isValid)
 		if (checkPenetration && (!isValid || catchDegeneratePenetrationCase ))
 		{
 			//penetration case

 			//if there is no way to handle penetrations, bail out
 			if (m_penetrationDepthSolver)
 			{
 				// Penetration depth case.
 				btVector3 tmpPointOnA,tmpPointOnB;

 				gNumDeepPenetrationChecks++;
 				m_cachedSeparatingAxis.setZero();

 				bool isValid2 = m_penetrationDepthSolver->calcPenDepth(
 					*m_simplexSolver,
 					m_minkowskiA,m_minkowskiB,
 					localTransA,localTransB,
 					m_cachedSeparatingAxis, tmpPointOnA, tmpPointOnB,
 					debugDraw,input.m_stackAlloc
 					);


 				if (isValid2)
 				{
 					btVector3 tmpNormalInB = tmpPointOnB-tmpPointOnA;
 					btScalar lenSqr = tmpNormalInB.length2();
 					if (lenSqr <= (SIMD_EPSILON*SIMD_EPSILON))
 					{
 						tmpNormalInB = m_cachedSeparatingAxis;
 						lenSqr = m_cachedSeparatingAxis.length2();
 					}

 					if (lenSqr > (SIMD_EPSILON*SIMD_EPSILON))
 					{
 						tmpNormalInB /= btSqrt(lenSqr);
 						btScalar distance2 = -(tmpPointOnA-tmpPointOnB).length();
 						//only replace valid penetrations when the result is deeper (check)
 						if (!isValid || (distance2 < distance))
 						{
 							distance = distance2;
 							pointOnA = tmpPointOnA;
 							pointOnB = tmpPointOnB;
 							normalInB = tmpNormalInB;
 							isValid = true;
 							m_lastUsedMethod = 3;
 						} else
 						{
 							m_lastUsedMethod = 8;
 						}
 					} else
 					{
 						m_lastUsedMethod = 9;
 					}
 				} else

 				{
 					///this is another degenerate case, where the initial GJK calculation reports a degenerate case
 					///EPA reports no penetration, and the second GJK (using the supporting vector without margin)
 					///reports a valid positive distance. Use the results of the second GJK instead of failing.
 					///thanks to Jacob.Langford for the reproduction case
 					///http://code.google.com/p/bullet/issues/detail?id=250


 					if (m_cachedSeparatingAxis.length2() > btScalar(0.))
 					{
 						btScalar distance2 = (tmpPointOnA-tmpPointOnB).length()-margin;
 						//only replace valid distances when the distance is less
 						if (!isValid || (distance2 < distance))
 						{
 							distance = distance2;
 							pointOnA = tmpPointOnA;
 							pointOnB = tmpPointOnB;
 							pointOnA -= m_cachedSeparatingAxis * marginA ;
 							pointOnB += m_cachedSeparatingAxis * marginB ;
 							normalInB = m_cachedSeparatingAxis;
 							normalInB.normalize();
 							isValid = true;
 							m_lastUsedMethod = 6;
 						} else
 						{
 							m_lastUsedMethod = 5;
 						}
 					}
 				}

 			}

 		}
 	}


 	if (isValid && ((distance < 0) || (distance*distance < input.m_maximumDistanceSquared)))
 	{
 #if 0
 ///some debugging
 //		if (check2d)
 		{
 			printf("n = %2.3f,%2.3f,%2.3f. ",normalInB[0],normalInB[1],normalInB[2]);
 			printf("distance = %2.3f exit=%d deg=%d\n",distance,m_lastUsedMethod,m_degenerateSimplex);
 		}
 #endif

 		m_cachedSeparatingAxis = normalInB;
 		m_cachedSeparatingDistance = distance;

 		output.addContactPoint(
 			normalInB,
 			pointOnB+positionOffset,
 			distance);

 	}


 }
	/*
	Bullet Continuous Collision Detection and Physics Library
	Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/

	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 "BulletCollision/NarrowPhaseCollision/btGjkPairDetector.h"
	#include "BulletCollision/CollisionShapes/btConvexShape.h"
	#include "BulletCollision/NarrowPhaseCollision/btSimplexSolverInterface.h"
	#include "BulletCollision/NarrowPhaseCollision/btConvexPenetrationDepthSolver.h"



	#if defined(DEBUG) \|\| defined (_DEBUG)
	//#define TEST_NON_VIRTUAL 1
	#include <stdio.h> //for debug printf
	#ifdef __SPU__
	#include <spu_printf.h>
	#define printf spu_printf
	//#define DEBUG_SPU_COLLISION_DETECTION 1
	#endif //__SPU__
	#endif

	//must be above the machine epsilon
	#define REL_ERROR2 btScalar(1.0e-6)

	//temp globals, to improve GJK/EPA/penetration calculations
	int gNumDeepPenetrationChecks = 0;
	int gNumGjkChecks = 0;


	btGjkPairDetector::btGjkPairDetector(const btConvexShape* objectA,const btConvexShape* objectB,btSimplexSolverInterface* simplexSolver,btConvexPenetrationDepthSolver* penetrationDepthSolver)
	:m_cachedSeparatingAxis(btScalar(0.),btScalar(1.),btScalar(0.)),
	m_penetrationDepthSolver(penetrationDepthSolver),
	m_simplexSolver(simplexSolver),
	m_minkowskiA(objectA),
	m_minkowskiB(objectB),
	m_shapeTypeA(objectA->getShapeType()),
	m_shapeTypeB(objectB->getShapeType()),
	m_marginA(objectA->getMargin()),
	m_marginB(objectB->getMargin()),
	m_ignoreMargin(false),
	m_lastUsedMethod(-1),
	m_catchDegeneracies(1)
	{
	}
	btGjkPairDetector::btGjkPairDetector(const btConvexShape* objectA,const btConvexShape* objectB,int shapeTypeA,int shapeTypeB,btScalar marginA, btScalar marginB, btSimplexSolverInterface* simplexSolver,btConvexPenetrationDepthSolver* penetrationDepthSolver)
	:m_cachedSeparatingAxis(btScalar(0.),btScalar(1.),btScalar(0.)),
	m_penetrationDepthSolver(penetrationDepthSolver),
	m_simplexSolver(simplexSolver),
	m_minkowskiA(objectA),
	m_minkowskiB(objectB),
	m_shapeTypeA(shapeTypeA),
	m_shapeTypeB(shapeTypeB),
	m_marginA(marginA),
	m_marginB(marginB),
	m_ignoreMargin(false),
	m_lastUsedMethod(-1),
	m_catchDegeneracies(1)
	{
	}

	void btGjkPairDetector::getClosestPoints(const ClosestPointInput& input,Result& output,class btIDebugDraw* debugDraw,bool swapResults)
	{
	(void)swapResults;

	getClosestPointsNonVirtual(input,output,debugDraw);
	}

	#ifdef __SPU__
	void btGjkPairDetector::getClosestPointsNonVirtual(const ClosestPointInput& input,Result& output,class btIDebugDraw* debugDraw)
	#else
	void btGjkPairDetector::getClosestPointsNonVirtual(const ClosestPointInput& input,Result& output,class btIDebugDraw* debugDraw)
	#endif
	{
	m_cachedSeparatingDistance = 0.f;

	btScalar distance=btScalar(0.);
	btVector3 normalInB(btScalar(0.),btScalar(0.),btScalar(0.));
	btVector3 pointOnA,pointOnB;
	btTransform localTransA = input.m_transformA;
	btTransform localTransB = input.m_transformB;
	btVector3 positionOffset = (localTransA.getOrigin() + localTransB.getOrigin()) * btScalar(0.5);
	localTransA.getOrigin() -= positionOffset;
	localTransB.getOrigin() -= positionOffset;

	bool check2d = m_minkowskiA->isConvex2d() && m_minkowskiB->isConvex2d();

	btScalar marginA = m_marginA;
	btScalar marginB = m_marginB;

	gNumGjkChecks++;

	#ifdef DEBUG_SPU_COLLISION_DETECTION
	spu_printf("inside gjk\n");
	#endif
	//for CCD we don't use margins
	if (m_ignoreMargin)
	{
	marginA = btScalar(0.);
	marginB = btScalar(0.);
	#ifdef DEBUG_SPU_COLLISION_DETECTION
	spu_printf("ignoring margin\n");
	#endif
	}

	m_curIter = 0;
	int gGjkMaxIter = 1000;//this is to catch invalid input, perhaps check for #NaN?
	m_cachedSeparatingAxis.setValue(0,1,0);

	bool isValid = false;
	bool checkSimplex = false;
	bool checkPenetration = true;
	m_degenerateSimplex = 0;

	m_lastUsedMethod = -1;

	{
	btScalar squaredDistance = BT_LARGE_FLOAT;
	btScalar delta = btScalar(0.);

	btScalar margin = marginA + marginB;



	m_simplexSolver->reset();

	for ( ; ; )
	//while (true)
	{

	btVector3 seperatingAxisInA = (-m_cachedSeparatingAxis)* input.m_transformA.getBasis();
	btVector3 seperatingAxisInB = m_cachedSeparatingAxis* input.m_transformB.getBasis();

	#if 1

	btVector3 pInA = m_minkowskiA->localGetSupportVertexWithoutMarginNonVirtual(seperatingAxisInA);
	btVector3 qInB = m_minkowskiB->localGetSupportVertexWithoutMarginNonVirtual(seperatingAxisInB);

	// btVector3 pInA = localGetSupportingVertexWithoutMargin(m_shapeTypeA, m_minkowskiA, seperatingAxisInA,input.m_convexVertexData[0]);//, &featureIndexA);
	// btVector3 qInB = localGetSupportingVertexWithoutMargin(m_shapeTypeB, m_minkowskiB, seperatingAxisInB,input.m_convexVertexData[1]);//, &featureIndexB);

	#else
	#ifdef __SPU__
	btVector3 pInA = m_minkowskiA->localGetSupportVertexWithoutMarginNonVirtual(seperatingAxisInA);
	btVector3 qInB = m_minkowskiB->localGetSupportVertexWithoutMarginNonVirtual(seperatingAxisInB);
	#else
	btVector3 pInA = m_minkowskiA->localGetSupportingVertexWithoutMargin(seperatingAxisInA);
	btVector3 qInB = m_minkowskiB->localGetSupportingVertexWithoutMargin(seperatingAxisInB);
	#ifdef TEST_NON_VIRTUAL
	btVector3 pInAv = m_minkowskiA->localGetSupportingVertexWithoutMargin(seperatingAxisInA);
	btVector3 qInBv = m_minkowskiB->localGetSupportingVertexWithoutMargin(seperatingAxisInB);
	btAssert((pInAv-pInA).length() < 0.0001);
	btAssert((qInBv-qInB).length() < 0.0001);
	#endif //
	#endif //__SPU__
	#endif


	btVector3 pWorld = localTransA(pInA);
	btVector3 qWorld = localTransB(qInB);

	#ifdef DEBUG_SPU_COLLISION_DETECTION
	spu_printf("got local supporting vertices\n");
	#endif

	if (check2d)
	{
	pWorld[2] = 0.f;
	qWorld[2] = 0.f;
	}

	btVector3 w = pWorld - qWorld;
	delta = m_cachedSeparatingAxis.dot(w);

	// potential exit, they don't overlap
	if ((delta > btScalar(0.0)) && (delta * delta > squaredDistance * input.m_maximumDistanceSquared))
	{
	m_degenerateSimplex = 10;
	checkSimplex=true;
	//checkPenetration = false;
	break;
	}

	//exit 0: the new point is already in the simplex, or we didn't come any closer
	if (m_simplexSolver->inSimplex(w))
	{
	m_degenerateSimplex = 1;
	checkSimplex = true;
	break;
	}
	// are we getting any closer ?
	btScalar f0 = squaredDistance - delta;
	btScalar f1 = squaredDistance * REL_ERROR2;

	if (f0 <= f1)
	{
	if (f0 <= btScalar(0.))
	{
	m_degenerateSimplex = 2;
	} else
	{
	m_degenerateSimplex = 11;
	}
	checkSimplex = true;
	break;
	}

	#ifdef DEBUG_SPU_COLLISION_DETECTION
	spu_printf("addVertex 1\n");
	#endif
	//add current vertex to simplex
	m_simplexSolver->addVertex(w, pWorld, qWorld);
	#ifdef DEBUG_SPU_COLLISION_DETECTION
	spu_printf("addVertex 2\n");
	#endif
	btVector3 newCachedSeparatingAxis;

	//calculate the closest point to the origin (update vector v)
	if (!m_simplexSolver->closest(newCachedSeparatingAxis))
	{
	m_degenerateSimplex = 3;
	checkSimplex = true;
	break;
	}

	if(newCachedSeparatingAxis.length2()<REL_ERROR2)
	{
	m_cachedSeparatingAxis = newCachedSeparatingAxis;
	m_degenerateSimplex = 6;
	checkSimplex = true;
	break;
	}

	btScalar previousSquaredDistance = squaredDistance;
	squaredDistance = newCachedSeparatingAxis.length2();
	#if 0
	///warning: this termination condition leads to some problems in 2d test case see Bullet/Demos/Box2dDemo
	if (squaredDistance>previousSquaredDistance)
	{
	m_degenerateSimplex = 7;
	squaredDistance = previousSquaredDistance;
	checkSimplex = false;
	break;
	}
	#endif //

	m_cachedSeparatingAxis = newCachedSeparatingAxis;

	//redundant m_simplexSolver->compute_points(pointOnA, pointOnB);

	//are we getting any closer ?
	if (previousSquaredDistance - squaredDistance <= SIMD_EPSILON * previousSquaredDistance)
	{
	m_simplexSolver->backup_closest(m_cachedSeparatingAxis);
	checkSimplex = true;
	m_degenerateSimplex = 12;

	break;
	}

	//degeneracy, this is typically due to invalid/uninitialized worldtransforms for a btCollisionObject
	if (m_curIter++ > gGjkMaxIter)
	{
	#if defined(DEBUG) \|\| defined (_DEBUG) \|\| defined (DEBUG_SPU_COLLISION_DETECTION)

	printf("btGjkPairDetector maxIter exceeded:%i\n",m_curIter);
	printf("sepAxis=(%f,%f,%f), squaredDistance = %f, shapeTypeA=%i,shapeTypeB=%i\n",
	m_cachedSeparatingAxis.getX(),
	m_cachedSeparatingAxis.getY(),
	m_cachedSeparatingAxis.getZ(),
	squaredDistance,
	m_minkowskiA->getShapeType(),
	m_minkowskiB->getShapeType());

	#endif
	break;

	}


	bool check = (!m_simplexSolver->fullSimplex());
	//bool check = (!m_simplexSolver->fullSimplex() && squaredDistance > SIMD_EPSILON * m_simplexSolver->maxVertex());

	if (!check)
	{
	//do we need this backup_closest here ?
	m_simplexSolver->backup_closest(m_cachedSeparatingAxis);
	m_degenerateSimplex = 13;
	break;
	}
	}

	if (checkSimplex)
	{
	m_simplexSolver->compute_points(pointOnA, pointOnB);
	normalInB = pointOnA-pointOnB;
	btScalar lenSqr =m_cachedSeparatingAxis.length2();

	//valid normal
	if (lenSqr < 0.0001)
	{
	m_degenerateSimplex = 5;
	}
	if (lenSqr > SIMD_EPSILON*SIMD_EPSILON)
	{
	btScalar rlen = btScalar(1.) / btSqrt(lenSqr );
	normalInB *= rlen; //normalize
	btScalar s = btSqrt(squaredDistance);

	btAssert(s > btScalar(0.0));
	pointOnA -= m_cachedSeparatingAxis * (marginA / s);
	pointOnB += m_cachedSeparatingAxis * (marginB / s);
	distance = ((btScalar(1.)/rlen) - margin);
	isValid = true;

	m_lastUsedMethod = 1;
	} else
	{
	m_lastUsedMethod = 2;
	}
	}

	bool catchDegeneratePenetrationCase =
	(m_catchDegeneracies && m_penetrationDepthSolver && m_degenerateSimplex && ((distance+margin) < 0.01));

	//if (checkPenetration && !isValid)
	if (checkPenetration && (!isValid \|\| catchDegeneratePenetrationCase ))
	{
	//penetration case

	//if there is no way to handle penetrations, bail out
	if (m_penetrationDepthSolver)
	{
	// Penetration depth case.
	btVector3 tmpPointOnA,tmpPointOnB;

	gNumDeepPenetrationChecks++;
	m_cachedSeparatingAxis.setZero();

	bool isValid2 = m_penetrationDepthSolver->calcPenDepth(
	*m_simplexSolver,
	m_minkowskiA,m_minkowskiB,
	localTransA,localTransB,
	m_cachedSeparatingAxis, tmpPointOnA, tmpPointOnB,
	debugDraw,input.m_stackAlloc
	);


	if (isValid2)
	{
	btVector3 tmpNormalInB = tmpPointOnB-tmpPointOnA;
	btScalar lenSqr = tmpNormalInB.length2();
	if (lenSqr <= (SIMD_EPSILON*SIMD_EPSILON))
	{
	tmpNormalInB = m_cachedSeparatingAxis;
	lenSqr = m_cachedSeparatingAxis.length2();
	}

	if (lenSqr > (SIMD_EPSILON*SIMD_EPSILON))
	{
	tmpNormalInB /= btSqrt(lenSqr);
	btScalar distance2 = -(tmpPointOnA-tmpPointOnB).length();
	//only replace valid penetrations when the result is deeper (check)
	if (!isValid \|\| (distance2 < distance))
	{
	distance = distance2;
	pointOnA = tmpPointOnA;
	pointOnB = tmpPointOnB;
	normalInB = tmpNormalInB;
	isValid = true;
	m_lastUsedMethod = 3;
	} else
	{
	m_lastUsedMethod = 8;
	}
	} else
	{
	m_lastUsedMethod = 9;
	}
	} else

	{
	///this is another degenerate case, where the initial GJK calculation reports a degenerate case
	///EPA reports no penetration, and the second GJK (using the supporting vector without margin)
	///reports a valid positive distance. Use the results of the second GJK instead of failing.
	///thanks to Jacob.Langford for the reproduction case
	///http://code.google.com/p/bullet/issues/detail?id=250


	if (m_cachedSeparatingAxis.length2() > btScalar(0.))
	{
	btScalar distance2 = (tmpPointOnA-tmpPointOnB).length()-margin;
	//only replace valid distances when the distance is less
	if (!isValid \|\| (distance2 < distance))
	{
	distance = distance2;
	pointOnA = tmpPointOnA;
	pointOnB = tmpPointOnB;
	pointOnA -= m_cachedSeparatingAxis * marginA ;
	pointOnB += m_cachedSeparatingAxis * marginB ;
	normalInB = m_cachedSeparatingAxis;
	normalInB.normalize();
	isValid = true;
	m_lastUsedMethod = 6;
	} else
	{
	m_lastUsedMethod = 5;
	}
	}
	}

	}

	}
	}



	if (isValid && ((distance < 0) \|\| (distance*distance < input.m_maximumDistanceSquared)))
	{
	#if 0
	///some debugging
	// if (check2d)
	{
	printf("n = %2.3f,%2.3f,%2.3f. ",normalInB[0],normalInB[1],normalInB[2]);
	printf("distance = %2.3f exit=%d deg=%d\n",distance,m_lastUsedMethod,m_degenerateSimplex);
	}
	#endif

	m_cachedSeparatingAxis = normalInB;
	m_cachedSeparatingDistance = distance;

	output.addContactPoint(
	normalInB,
	pointOnB+positionOffset,
	distance);

	}


	}