added initial support for per-triangle material properties in a non-convex mesh. needs testing.

Bullet/CollisionDispatch/CollisionObject.h

@@ -45,7 +45,7 @@ struct	CollisionObject
 	{
 		isStatic = 1,
 		noContactResponse = 2,
-
+		customMaterialCallback = 4,//this allows per-triangle material (friction/restitution)
 	};
 
 	int				m_collisionFlags;
@@ -54,6 +54,9 @@ struct	CollisionObject
 	int				m_activationState1;
 	float			m_deactivationTime;
 
+	SimdScalar		m_friction;
+	SimdScalar		m_restitution;
+
 	BroadphaseProxy*	m_broadphaseHandle;
 	CollisionShape*		m_collisionShape;
 
@@ -102,6 +105,23 @@ struct	CollisionObject
 		return ((GetActivationState() != ISLAND_SLEEPING) && (GetActivationState() != DISABLE_SIMULATION));
 	}
 
+		void	setRestitution(float rest)
+	{
+		m_restitution = rest;
+	}
+	float	getRestitution() const
+	{
+		return m_restitution;
+	}
+	void	setFriction(float frict)
+	{
+		m_friction = frict;
+	}
+	float	getFriction() const
+	{
+		return m_friction;
+	}
+
 
 };
 

Bullet/CollisionDispatch/ConvexConcaveCollisionAlgorithm.cpp

@@ -112,6 +112,7 @@ void ConvexTriangleCallback::ProcessTriangle(SimdVector3* triangle,int partId, i
 		ob->m_collisionShape = &tm;
 		
 		ConvexConvexAlgorithm cvxcvxalgo(m_manifoldPtr,ci,m_convexProxy,&m_triangleProxy);
+		cvxcvxalgo.SetShapeIdentifiers(-1,-1,partId,triangleIndex);
 		cvxcvxalgo.ProcessCollision(m_convexProxy,&m_triangleProxy,*m_dispatchInfoPtr);
 		ob->m_collisionShape = tmpShape;
 

Bullet/CollisionDispatch/ConvexConvexAlgorithm.h

@@ -55,7 +55,13 @@ public:
 
 	void	SetLowLevelOfDetail(bool useLowLevel);
 
-	
+	virtual void SetShapeIdentifiers(int partId0,int index0,	int partId1,int index1)
+	{
+			m_gjkPairDetector.m_partId0=partId0;
+			m_gjkPairDetector.m_partId1=partId1;
+			m_gjkPairDetector.m_index0=index0;
+			m_gjkPairDetector.m_index1=index1;		
+	}
 
 	const PersistentManifold*	GetManifold()
 	{

Bullet/CollisionDispatch/ManifoldResult.cpp

@@ -18,6 +18,31 @@ subject to the following restrictions:
 #include "NarrowPhaseCollision/PersistentManifold.h"
 #include "CollisionDispatch/CollisionObject.h"
 
+
+///This is to allow MaterialCombiner/Custom Friction/Restitution values
+ContactAddedCallback		gContactAddedCallback=0;
+
+///User can override this material combiner by implementing gContactAddedCallback and setting body0->m_collisionFlags |= CollisionObject::customMaterialCallback;
+inline SimdScalar	calculateCombinedFriction(const CollisionObject* body0,const CollisionObject* body1)
+{
+	SimdScalar friction = body0->getFriction() * body1->getFriction();
+
+	const SimdScalar MAX_FRICTION  = 10.f;
+	if (friction < -MAX_FRICTION)
+		friction = -MAX_FRICTION;
+	if (friction > MAX_FRICTION)
+		friction = MAX_FRICTION;
+	return friction;
+
+}
+
+inline SimdScalar	calculateCombinedRestitution(const CollisionObject* body0,const CollisionObject* body1)
+{
+	return body0->getRestitution() * body1->getRestitution();
+}
+
+
+
 ManifoldResult::ManifoldResult(CollisionObject* body0,CollisionObject* body1,PersistentManifold* manifoldPtr)
 		:m_manifoldPtr(manifoldPtr),
 		m_body0(body0),
@@ -56,6 +81,20 @@ void ManifoldResult::AddContactPoint(const SimdVector3& normalOnBInWorld,const S
 
 	} else
 	{
+
+		newPt.m_combinedFriction = calculateCombinedFriction(m_body0,m_body1);
+		newPt.m_combinedRestitution = calculateCombinedRestitution(m_body0,m_body1);
+
+		//User can override friction and/or restitution
+		if (gContactAddedCallback &&
+			//and if either of the two bodies requires custom material
+			 ((m_body0->m_collisionFlags & CollisionObject::customMaterialCallback) ||
+			   (m_body1->m_collisionFlags & CollisionObject::customMaterialCallback)))
+		{
+			//experimental feature info, for per-triangle material etc.
+			(*gContactAddedCallback)(newPt,m_body0,m_partId0,m_index0,m_body1,m_partId1,m_index1);
+		}
+
 		m_manifoldPtr->AddManifoldPoint(newPt);
 	}
 }

Bullet/CollisionDispatch/ManifoldResult.h

@@ -20,8 +20,10 @@ subject to the following restrictions:
 #include "NarrowPhaseCollision/DiscreteCollisionDetectorInterface.h"
 struct CollisionObject;
 class PersistentManifold;
+class ManifoldPoint;
 
-
+typedef bool (*ContactAddedCallback)(ManifoldPoint& cp,	const CollisionObject* colObj0,int partId0,int index0,const CollisionObject* colObj1,int partId1,int index1);
+extern ContactAddedCallback		gContactAddedCallback;
 
 
 
@@ -31,15 +33,28 @@ class ManifoldResult : public DiscreteCollisionDetectorInterface::Result
 	PersistentManifold* m_manifoldPtr;
 	CollisionObject* m_body0;
 	CollisionObject* m_body1;
-
+	int	m_partId0;
+	int m_partId1;
+	int m_index0;
+	int m_index1;
 public:
 
 	ManifoldResult(CollisionObject* body0,CollisionObject* body1,PersistentManifold* manifoldPtr);
 
 	virtual ~ManifoldResult() {};
 
+	virtual void SetShapeIdentifiers(int partId0,int index0,	int partId1,int index1)
+	{
+			m_partId0=partId0;
+			m_partId1=partId1;
+			m_index0=index0;
+			m_index1=index1;		
+	}
+
 	virtual void AddContactPoint(const SimdVector3& normalOnBInWorld,const SimdVector3& pointInWorld,float depth);
 
+
+
 };
 
 #endif //MANIFOLD_RESULT_H