Fix friction and restitution in BulletMultiThreaded (collision detection and parallel solver)

Thanks to lsgmasa for reporting, see http://www.bulletphysics.com/Bullet/phpBB3/viewtopic.php?f=9&t=1758

Extras/BulletMultiThreaded/SpuNarrowPhaseCollisionTask/SpuContactResult.cpp

@@ -31,13 +31,38 @@ SpuContactResult::SpuContactResult()
 	g_manifoldDmaExport.swapBuffers();
 }
 
- void	SpuContactResult::setContactInfo(btPersistentManifold* spuManifold, uint64_t	manifoldAddress,const btTransform& worldTrans0,const btTransform& worldTrans1, bool isSwapped)
+ 	///User can override this material combiner by implementing gContactAddedCallback and setting body0->m_collisionFlags |= btCollisionObject::customMaterialCallback;
+inline btScalar	calculateCombinedFriction(btScalar friction0,btScalar friction1)
+{
+	btScalar friction = friction0*friction1;
+
+	const btScalar MAX_FRICTION  = btScalar(10.);
+
+	if (friction < -MAX_FRICTION)
+		friction = -MAX_FRICTION;
+	if (friction > MAX_FRICTION)
+		friction = MAX_FRICTION;
+	return friction;
+
+}
+
+inline btScalar	calculateCombinedRestitution(btScalar restitution0,btScalar restitution1)
+{
+	return restitution0*restitution1;
+}
+
+
+
+ void	SpuContactResult::setContactInfo(btPersistentManifold* spuManifold, uint64_t	manifoldAddress,const btTransform& worldTrans0,const btTransform& worldTrans1, btScalar restitution0,btScalar restitution1, btScalar friction0,btScalar friction1, bool isSwapped)
  {
 	//spu_printf("SpuContactResult::setContactInfo ManifoldAddress: %lu\n", manifoldAddress);
 	m_rootWorldTransform0 = worldTrans0;
 	m_rootWorldTransform1 = worldTrans1;
 	m_manifoldAddress = manifoldAddress;    
 	m_spuManifold = spuManifold;
+
+	m_combinedFriction = calculateCombinedFriction(friction0,friction1);
+	m_combinedRestitution = calculateCombinedRestitution(restitution0,restitution1);
 	m_isSwapped = isSwapped;
  }
 
@@ -55,6 +80,8 @@ bool ManifoldResultAddContactPoint(const btVector3& normalOnBInWorld,
 								   btPersistentManifold* manifoldPtr,
 								   btTransform& transA,
 								   btTransform& transB,
+									btScalar	combinedFriction,
+									btScalar	combinedRestitution,
 								   bool isSwapped)
 {
 	
@@ -109,8 +136,8 @@ bool ManifoldResultAddContactPoint(const btVector3& normalOnBInWorld,
 	} else
 	{
 
-		newPt.m_combinedFriction = 0.25f;//calculateCombinedFriction(m_body0,m_body1);
+		newPt.m_combinedFriction = combinedFriction;
-		newPt.m_combinedRestitution = 0.0f;//calculateCombinedRestitution(m_body0,m_body1);
+		newPt.m_combinedRestitution = combinedRestitution;
 
 		/*
 		//potential TODO: SPU callbacks, either immediate (local on the SPU), or deferred
@@ -165,6 +192,8 @@ void SpuContactResult::addContactPoint(const btVector3& normalOnBInWorld,const b
 		localManifold,
 		m_rootWorldTransform0,
 		m_rootWorldTransform1,
+		m_combinedFriction,
+		m_combinedRestitution,
 		m_isSwapped);
 	m_RequiresWriteBack = m_RequiresWriteBack || retVal;
 }

Extras/BulletMultiThreaded/SpuNarrowPhaseCollisionTask/SpuContactResult.h

@@ -81,6 +81,9 @@ class SpuContactResult
 
     btPersistentManifold* m_spuManifold;
 	bool m_RequiresWriteBack;
+	btScalar	m_combinedFriction;
+	btScalar	m_combinedRestitution;
+	
 	bool m_isSwapped;
 
 	DoubleBuffer<btPersistentManifold, 1> g_manifoldDmaExport;
@@ -96,7 +99,8 @@ class SpuContactResult
 
 		virtual void setShapeIdentifiers(int partId0,int index0,	int partId1,int index1);
 
-        void	setContactInfo(btPersistentManifold* spuManifold, uint64_t	manifoldAddress,const btTransform& worldTrans0,const btTransform& worldTrans1, bool isSwapped = false);
+		void	setContactInfo(btPersistentManifold* spuManifold, uint64_t	manifoldAddress,const btTransform& worldTrans0,const btTransform& worldTrans1, btScalar restitution0,btScalar restitution1, btScalar friction0,btScalar friction01, bool isSwapped);
+
 
         void writeDoubleBufferedManifold(btPersistentManifold* lsManifold, btPersistentManifold* mmManifold);
 

Extras/BulletMultiThreaded/SpuNarrowPhaseCollisionTask/SpuGatheringCollisionTask.cpp

@@ -932,7 +932,11 @@ void	ProcessSpuConvexConvexCollision(SpuCollisionPairInput* wuInput, CollisionTa
 #endif
 		btPersistentManifold* spuManifold=&lsMemPtr->gPersistentManifold;
 		//spuContacts.setContactInfo(spuManifold,manifoldAddress,wuInput->m_worldTransform0,wuInput->m_worldTransform1,wuInput->m_isSwapped);
-		spuContacts.setContactInfo(spuManifold,manifoldAddress,lsMemPtr->getColObj0()->getWorldTransform(),lsMemPtr->getColObj1()->getWorldTransform(),wuInput->m_isSwapped);
+		spuContacts.setContactInfo(spuManifold,manifoldAddress,lsMemPtr->getColObj0()->getWorldTransform(),
+			lsMemPtr->getColObj1()->getWorldTransform(),
+			lsMemPtr->getColObj0()->getRestitution(),lsMemPtr->getColObj1()->getRestitution(),
+			lsMemPtr->getColObj0()->getFriction(),lsMemPtr->getColObj1()->getFriction(),
+			wuInput->m_isSwapped);
 
 		SpuGjkPairDetector gjk(shape0Ptr,shape1Ptr,shapeType0,shapeType1,marginA,marginB,&vsSolver,&penetrationSolver);
 		gjk.getClosestPoints(cpInput,spuContacts);//,debugDraw);

Extras/BulletMultiThreaded/SpuSolverTask/SpuParallellSolverTask.cpp

@@ -1062,15 +1062,14 @@ void processSolverTask(void* userPtr, void* lsMemory)
 									};
 
 									btScalar penVel = -constraint.m_penetration/taskDesc.m_commandData.m_manifoldSetup.m_solverInfo.m_timeStep;
-									if (rest > penVel)
-									{
-										rest = btScalar(0.);
-									}
-									constraint.m_restitution = rest;
-
 									constraint.m_penetration *= 
 										-(taskDesc.m_commandData.m_manifoldSetup.m_solverInfo.m_erp/taskDesc.m_commandData.m_manifoldSetup.m_solverInfo.m_timeStep);
 								
+									if (rest > penVel)
+									{
+										constraint.m_penetration = btScalar(0.);
+									}
+									constraint.m_restitution = rest;
 									constraint.m_appliedImpulse = 0.f;