+ provide access to 'root' collision shape, in case the original collision shape is temporarily replaced by a child collision shape.

+ added MultiMaterialDemo showing how to use the new btTriangleIndexVertexMaterialArray.
Thanks to Alex Silverman for this contribution!

Demos/MultiMaterialDemo/Jamfile

@@ -0,0 +1,3 @@
+SubDir TOP Demos MultiMaterialDemo ;
+
+BulletDemo MultiMaterialDemo : [ Wildcard *.h *.cpp  ] ;

Demos/MultiMaterialDemo/MultiMaterialDemo.cpp

@@ -0,0 +1,382 @@
+/*
+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 "btBulletDynamicsCommon.h"
+#include "LinearMath/btIDebugDraw.h"
+#include "GLDebugDrawer.h"
+#include "MultiMaterialDemo.h"
+#include "GL_ShapeDrawer.h"
+#include "GlutStuff.h"
+
+#include "BulletCollision\CollisionShapes\btTriangleShape.h"
+#include "BulletCollision\CollisionShapes\btTriangleIndexVertexMaterialArray.h"
+#include "BulletCollision\CollisionShapes\btMultimaterialTriangleMeshShape.h"
+#include "BulletCollision\CollisionShapes\btMaterial.h"
+
+// Create a custom material, just because we can
+class CustomMaterial : public btMaterial
+{
+public:
+    int foo1;
+    int foo2;
+    CustomMaterial(){}
+    CustomMaterial(int a, int b) {foo1 = a; foo2 = b;}
+};
+
+// Storage for the vertex data
+static btVector3*	gVertices = 0;
+// Storage for the face data
+static int*	gIndices = 0;
+// Storage for the material data
+static CustomMaterial* gMaterials = 0;
+// Storage for the face -> material index data
+static int* gFaceMaterialIndices = 0;
+
+static btBvhTriangleMeshShape* trimeshShape =0;
+static btRigidBody* staticBody = 0;
+static float waveheight = 0.f;
+
+const float TRIANGLE_SIZE=1.f;
+
+
+///User can override this material combiner by implementing gContactAddedCallback and setting body0->m_collisionFlags |= btCollisionObject::customMaterialCallback;
+inline btScalar	calculateCombinedFriction(float friction0,float friction1)
+{
+    btScalar friction = friction0 * friction1;
+
+    const btScalar MAX_FRICTION  = 10.f;
+    if (friction < -MAX_FRICTION)
+        friction = -MAX_FRICTION;
+    if (friction > MAX_FRICTION)
+        friction = MAX_FRICTION;
+    return friction;
+
+}
+
+inline btScalar	calculateCombinedRestitution(float restitution0,float restitution1)
+{
+    return restitution0 * restitution1;
+}
+
+
+
+static bool CustomMaterialCombinerCallback(btManifoldPoint& cp,	const btCollisionObject* colObj0,int partId0,int index0,const btCollisionObject* colObj1,int partId1,int index1)
+{
+    
+    // Apply material properties
+    if (colObj0->getCollisionShape()->getShapeType() == TRIANGLE_SHAPE_PROXYTYPE)
+    {
+        const btCollisionShape* parent0 = colObj0->getRootCollisionShape();
+        if(parent0 != 0 && parent0->getShapeType() == MULTIMATERIAL_TRIANGLE_MESH_PROXYTYPE)
+        {
+            btMultimaterialTriangleMeshShape* shape = (btMultimaterialTriangleMeshShape*)parent0;
+            const btMaterial * props = shape->getMaterialProperties(partId0, index0);
+            cp.m_combinedFriction = calculateCombinedFriction(props->m_friction, colObj1->getFriction());
+            cp.m_combinedRestitution = props->m_restitution * colObj1->getRestitution();
+        }
+    }
+    else if (colObj1->getCollisionShape()->getShapeType() == TRIANGLE_SHAPE_PROXYTYPE)
+    {
+        const btCollisionShape* parent1 = colObj1->getRootCollisionShape();
+        if(parent1 != 0 && parent1->getShapeType() == MULTIMATERIAL_TRIANGLE_MESH_PROXYTYPE)
+        {
+            btMultimaterialTriangleMeshShape* shape = (btMultimaterialTriangleMeshShape*)parent1;
+            const btMaterial * props = shape->getMaterialProperties(partId1, index1);
+            cp.m_combinedFriction = calculateCombinedFriction(props->m_friction, colObj0->getFriction());
+            cp.m_combinedRestitution = props->m_restitution * colObj0->getRestitution();
+        }
+    }
+
+    //this return value is currently ignored, but to be on the safe side: return false if you don't calculate friction
+    return true;
+}
+
+extern ContactAddedCallback		gContactAddedCallback;
+
+const int NUM_VERTS_X = 20;
+const int NUM_VERTS_Y = 50;
+const int totalVerts = NUM_VERTS_X*NUM_VERTS_Y;
+
+void MultiMaterialDemo::setVertexPositions(float waveheight, float offset)
+{
+    int i;
+    int j;
+
+    for ( i=0;i<NUM_VERTS_X;i++)
+    {
+        for (j=0;j<NUM_VERTS_Y;j++)
+        {
+            gVertices[i+j*NUM_VERTS_X].setValue((i-NUM_VERTS_X*0.5f)*TRIANGLE_SIZE,
+                //0.f,
+                waveheight*sinf((float)i+offset)*cosf((float)j+offset),
+                (j-NUM_VERTS_Y*0.5f)*TRIANGLE_SIZE);
+        }
+    }
+}
+
+void MultiMaterialDemo::keyboardCallback(unsigned char key, int x, int y)
+{
+    if (key == 'g')
+    {
+        m_animatedMesh = !m_animatedMesh;
+        if (m_animatedMesh)
+        {
+            staticBody->setCollisionFlags( staticBody->getCollisionFlags() | btCollisionObject::CF_KINEMATIC_OBJECT);
+            staticBody->setActivationState(DISABLE_DEACTIVATION);
+        } else
+        {
+            staticBody->setCollisionFlags( staticBody->getCollisionFlags() & ~btCollisionObject::CF_KINEMATIC_OBJECT);
+            staticBody->forceActivationState(ACTIVE_TAG);
+        }
+    }
+
+    DemoApplication::keyboardCallback(key,x,y);
+
+}
+
+void	MultiMaterialDemo::initPhysics()
+{
+#define TRISIZE 50.f
+
+    gContactAddedCallback = CustomMaterialCombinerCallback;
+
+    // The number of triangles
+    const int totalTriangles = 2*(NUM_VERTS_X-1)*(NUM_VERTS_Y-1);
+    // The number of materials
+    const int totalMaterials = 2;
+
+    int vertStride = sizeof(btVector3);
+    int indexStride = 3*sizeof(int);
+    int materialStride = sizeof(CustomMaterial);
+    int triangleMaterialStride = sizeof(int);
+
+    gVertices = new btVector3[totalVerts];
+    gIndices = new int[totalTriangles*3];
+    gMaterials = new CustomMaterial[totalMaterials];
+    gFaceMaterialIndices = new int[totalTriangles];
+
+    // Explicitly set up the materials.  It's a small array so let's do it bit by bit.
+    gMaterials[0].m_friction = 0;
+    gMaterials[0].m_restitution = 0.9;
+    gMaterials[0].foo1 = 5;
+    gMaterials[0].foo2 = 7;
+    gMaterials[1].m_friction = 0.9;
+    gMaterials[1].m_restitution = 0.1;
+    gMaterials[1].foo1 = 53;
+    gMaterials[1].foo2 = 15;
+
+    int i;
+    // Set up the vertex data
+    setVertexPositions(waveheight,0.f);
+    int index=0;
+    // Set up the face data
+    for ( i=0;i<NUM_VERTS_X-1;i++)
+    {
+        for (int j=0;j<NUM_VERTS_Y-1;j++)
+        {
+            gIndices[index++] = j*NUM_VERTS_X+i;
+            gIndices[index++] = j*NUM_VERTS_X+i+1;
+            gIndices[index++] = (j+1)*NUM_VERTS_X+i+1;
+
+            gIndices[index++] = j*NUM_VERTS_X+i;
+            gIndices[index++] = (j+1)*NUM_VERTS_X+i+1;
+            gIndices[index++] = (j+1)*NUM_VERTS_X+i;
+        }
+    }
+
+    // Set up the face->material index data
+    for(int a = 0; a < totalTriangles; a++)
+    {
+        // This will give the first half of the faces low friction and high restitution
+        // and the second half of the faces high friction and low restitution
+        if(a > totalTriangles*0.5f)
+            gFaceMaterialIndices[a] = 0;
+        else
+            gFaceMaterialIndices[a] = 1;
+    }
+
+    // Create the array structure
+    m_indexVertexArrays = new btTriangleIndexVertexMaterialArray(
+        totalTriangles, gIndices, indexStride,
+        totalVerts,(btScalar*) &gVertices[0].x(),vertStride,
+        totalMaterials, (unsigned char *)gMaterials, sizeof(CustomMaterial),
+        gFaceMaterialIndices, sizeof(int));
+
+    bool useQuantizedAabbCompression = true;
+    // Create the multimaterial mesh shape
+    trimeshShape  = new btMultimaterialTriangleMeshShape((btTriangleIndexVertexMaterialArray*)m_indexVertexArrays,useQuantizedAabbCompression);
+    m_collisionShapes.push_back(trimeshShape);
+
+    btCollisionShape* groundShape = trimeshShape;
+
+    m_collisionConfiguration = new btDefaultCollisionConfiguration();
+
+    m_dispatcher = new	btCollisionDispatcher(m_collisionConfiguration);
+
+    btVector3 worldMin(-1000,-1000,-1000);
+    btVector3 worldMax(1000,1000,1000);
+    m_broadphase = new btAxisSweep3(worldMin,worldMax);
+    m_solver = new btSequentialImpulseConstraintSolver();
+    m_dynamicsWorld = new btDiscreteDynamicsWorld(m_dispatcher,m_broadphase,m_solver,m_collisionConfiguration);
+
+    float mass = 0.f;
+    btTransform	startTransform;
+    startTransform.setIdentity();
+    startTransform.setOrigin(btVector3(0,-2,0));
+
+    btCollisionShape* colShape = new btBoxShape(btVector3(0.5f,0.5f,0.5f));
+    m_collisionShapes.push_back(colShape);
+
+    {
+        for (int i=0;i<1;i++)
+        {
+            startTransform.setOrigin(btVector3(10,10,-20));
+            btRigidBody* body = localCreateRigidBody(1, startTransform,colShape);
+            body->setCollisionFlags(body->getCollisionFlags()  | btCollisionObject::CF_CUSTOM_MATERIAL_CALLBACK);
+            body->setFriction(0.9f);
+            body->setGravity(btVector3(0,-20.f,0));
+            body->applyCentralImpulse(btVector3(-7.7f,0,0));
+        }
+    }
+
+    startTransform.setIdentity();
+    staticBody = localCreateRigidBody(mass, startTransform,groundShape);
+
+    staticBody->setCollisionFlags(staticBody->getCollisionFlags() | btCollisionObject::CF_STATIC_OBJECT);
+
+    //enable custom material callback
+    staticBody->setCollisionFlags(staticBody->getCollisionFlags()  | btCollisionObject::CF_CUSTOM_MATERIAL_CALLBACK);
+}
+
+void MultiMaterialDemo::clientMoveAndDisplay()
+{
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
+
+    float dt = getDeltaTimeMicroseconds() * 0.000001f;
+
+    if (m_animatedMesh)
+    {
+        static float offset=0.f;
+        offset+=0.01f;
+
+        //	setVertexPositions(waveheight,offset);
+
+        int i;
+        int j;
+        btVector3 aabbMin(1e30,1e30,1e30);
+        btVector3 aabbMax(-1e30,-1e30,-1e30);
+
+        for ( i=NUM_VERTS_X/2-3;i<NUM_VERTS_X/2+2;i++)
+        {
+            for (j=NUM_VERTS_X/2-3;j<NUM_VERTS_Y/2+2;j++)
+            {
+
+                aabbMax.setMax(gVertices[i+j*NUM_VERTS_X]);
+                aabbMin.setMin(gVertices[i+j*NUM_VERTS_X]);
+
+                gVertices[i+j*NUM_VERTS_X].setValue((i-NUM_VERTS_X*0.5f)*TRIANGLE_SIZE,
+                    0.f,
+                    (j-NUM_VERTS_Y*0.5f)*TRIANGLE_SIZE);
+
+                aabbMin.setMin(gVertices[i+j*NUM_VERTS_X]);
+                aabbMax.setMax(gVertices[i+j*NUM_VERTS_X]);
+
+            }
+        }
+
+        trimeshShape->partialRefitTree(aabbMin,aabbMax);
+
+        //clear all contact points involving mesh proxy. Note: this is a slow/unoptimized operation.
+        m_dynamicsWorld->getBroadphase()->getOverlappingPairCache()->cleanProxyFromPairs(staticBody->getBroadphaseHandle(),getDynamicsWorld()->getDispatcher());
+    }
+
+    m_dynamicsWorld->stepSimulation(dt);
+
+    //optional but useful: debug drawing
+    m_dynamicsWorld->debugDrawWorld();
+
+    renderme();
+
+    glFlush();
+    glutSwapBuffers();
+
+}
+
+
+
+
+void MultiMaterialDemo::displayCallback(void) {
+
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
+
+    renderme();
+
+    glFlush();
+    glutSwapBuffers();
+}
+
+
+
+void	MultiMaterialDemo::exitPhysics()
+{
+
+
+
+    //cleanup in the reverse order of creation/initialization
+
+    //remove the rigidbodies from the dynamics world and delete them
+    int i;
+    for (i=m_dynamicsWorld->getNumCollisionObjects()-1; i>=0 ;i--)
+    {
+        btCollisionObject* obj = m_dynamicsWorld->getCollisionObjectArray()[i];
+        btRigidBody* body = btRigidBody::upcast(obj);
+        if (body && body->getMotionState())
+        {
+            delete body->getMotionState();
+        }
+        m_dynamicsWorld->removeCollisionObject( obj );
+        delete obj;
+    }
+
+    //delete collision shapes
+    for (int j=0;j<m_collisionShapes.size();j++)
+    {
+        btCollisionShape* shape = m_collisionShapes[j];
+        delete shape;
+    }
+
+    //delete dynamics world
+    delete m_dynamicsWorld;
+
+    if (m_indexVertexArrays)
+        delete m_indexVertexArrays;
+
+    //delete solver
+    delete m_solver;
+
+    //delete broadphase
+    delete m_broadphase;
+
+    //delete dispatcher
+    delete m_dispatcher;
+
+    delete m_collisionConfiguration;
+
+
+}
+
+
+
+

Demos/MultiMaterialDemo/MultiMaterialDemo.h

@@ -0,0 +1,84 @@
+/*
+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.
+*/
+#ifndef CONCAVE_DEMO_H
+#define CONCAVE_DEMO_H
+
+#include "DemoApplication.h"
+#include "LinearMath/btAlignedObjectArray.h"
+
+class btBroadphaseInterface;
+class btCollisionShape;
+class btOverlappingPairCache;
+class btCollisionDispatcher;
+class btConstraintSolver;
+struct btCollisionAlgorithmCreateFunc;
+class btDefaultCollisionConfiguration;
+class btTriangleIndexVertexArray;
+
+///MultiMaterialDemo shows usage of static concave triangle meshes
+///It also shows per-triangle material (friction/restitution) through CustomMaterialCombinerCallback
+class MultiMaterialDemo : public DemoApplication
+{
+
+	//keep the collision shapes, for deletion/cleanup
+	btAlignedObjectArray<btCollisionShape*>	m_collisionShapes;
+
+	btTriangleIndexVertexArray* m_indexVertexArrays;
+
+	btBroadphaseInterface*	m_broadphase;
+
+	btCollisionDispatcher*	m_dispatcher;
+
+	btConstraintSolver*	m_solver;
+
+	btDefaultCollisionConfiguration* m_collisionConfiguration;
+
+	bool	m_animatedMesh;
+
+	public:
+
+	MultiMaterialDemo() : m_animatedMesh(true)
+	{
+
+	}
+	void	initPhysics();
+
+	void	exitPhysics();
+
+	virtual ~MultiMaterialDemo()
+	{
+		exitPhysics();
+	}
+
+	virtual void clientMoveAndDisplay();
+
+	virtual void displayCallback();
+	
+	//to show refit works
+	void	setVertexPositions(float waveheight, float offset);
+	
+	virtual void keyboardCallback(unsigned char key, int x, int y);
+	
+	static DemoApplication* Create()
+	{
+		MultiMaterialDemo* demo = new MultiMaterialDemo();
+		demo->myinit();
+		demo->initPhysics();
+		return demo;
+	};
+};
+
+#endif //CONCAVE_DEMO_H
+

Demos/MultiMaterialDemo/main.cpp

@@ -0,0 +1,22 @@
+
+#include "MultiMaterialDemo.h"
+#include "GlutStuff.h"
+
+#include "GlutStuff.h"
+#include "GLDebugDrawer.h"
+#include "btBulletDynamicsCommon.h"
+
+GLDebugDrawer	gDebugDrawer;
+
+int main(int argc,char** argv)
+{
+
+        MultiMaterialDemo* multiMaterialDemo = new MultiMaterialDemo();
+        multiMaterialDemo->initPhysics();
+        multiMaterialDemo->setCameraDistance(30.f);
+        
+        multiMaterialDemo->getDynamicsWorld()->setDebugDrawer(&gDebugDrawer);
+
+        return glutmain(argc, argv,640,480,"Multimaterial Mesh Demo",multiMaterialDemo);
+}
+

src/BulletCollision/BroadphaseCollision/btBroadphaseProxy.h

@@ -52,6 +52,8 @@ CONCAVE_SHAPES_START_HERE,
 	TERRAIN_SHAPE_PROXYTYPE,
 ///Used for GIMPACT Trimesh integration
 	GIMPACT_SHAPE_PROXYTYPE,
+///Multimaterial mesh
+    MULTIMATERIAL_TRIANGLE_MESH_PROXYTYPE,
 	
 	EMPTY_SHAPE_PROXYTYPE,
 	STATIC_PLANE_PROXYTYPE,

src/BulletCollision/CollisionDispatch/btCollisionObject.cpp

@@ -19,6 +19,7 @@ subject to the following restrictions:
 btCollisionObject::btCollisionObject()
 	:	m_broadphaseHandle(0),
 		m_collisionShape(0),
+		m_rootCollisionShape(0),
 		m_collisionFlags(btCollisionObject::CF_STATIC_OBJECT),
 		m_islandTag1(-1),
 		m_companionId(-1),

src/BulletCollision/CollisionDispatch/btCollisionObject.h

@@ -52,6 +52,11 @@ protected:
 	btBroadphaseProxy*		m_broadphaseHandle;
 	btCollisionShape*		m_collisionShape;
 	
+	///m_rootCollisionShape is temporarily used to store the original collision shape
+	///The m_collisionShape might be temporarily replaced by a child collision shape during collision detection purposes
+	///If it is NULL, the m_collisionShape is not temporarily replaced.
+	btCollisionShape*		m_rootCollisionShape;
+
 	int				m_collisionFlags;
 
 	int				m_islandTag1;
@@ -141,6 +146,7 @@ public:
 	void	setCollisionShape(btCollisionShape* collisionShape)
 	{
 		m_collisionShape = collisionShape;
+		m_rootCollisionShape = collisionShape;
 	}
 
 	SIMD_FORCE_INLINE const btCollisionShape*	getCollisionShape() const
@@ -153,8 +159,22 @@ public:
 		return m_collisionShape;
 	}
 
+	SIMD_FORCE_INLINE const btCollisionShape*	getRootCollisionShape() const
+	{
+		return m_rootCollisionShape;
+	}
 
+	SIMD_FORCE_INLINE btCollisionShape*	getRootCollisionShape()
+	{
+		return m_rootCollisionShape;
+	}
 
+	///Avoid using this internal API call
+	///internalSetTemporaryCollisionShape is used to temporary replace the actual collision shape by a child collision shape.
+	void	internalSetTemporaryCollisionShape(btCollisionShape* collisionShape)
+	{
+		m_collisionShape = collisionShape;
+	}
 
 	int	getActivationState() const { return m_activationState1;}
 	

src/BulletCollision/CollisionDispatch/btCompoundCollisionAlgorithm.cpp

@@ -34,10 +34,9 @@ m_isSwapped(isSwapped)
 	for (i=0;i<numChildren;i++)
 	{
 		btCollisionShape* childShape = compoundShape->getChildShape(i);
-		btCollisionShape* orgShape = colObj->getCollisionShape();
+		colObj->internalSetTemporaryCollisionShape( childShape );
-		colObj->setCollisionShape( childShape );
 		m_childCollisionAlgorithms[i] = ci.m_dispatcher1->findAlgorithm(colObj,otherObj);
-		colObj->setCollisionShape( orgShape );
+		colObj->setCollisionShape( colObj->getRootCollisionShape());
 	}
 }
 

src/BulletCollision/CollisionDispatch/btConvexConcaveCollisionAlgorithm.cpp

@@ -116,13 +116,8 @@ void btConvexTriangleCallback::processTriangle(btVector3* triangle,int partId, i
 	{
 		btTriangleShape tm(triangle[0],triangle[1],triangle[2]);	
 		tm.setMargin(m_collisionMarginTriangle);
-		btCollisionShape* tmpShape = ob->getCollisionShape();
-
-		//copy over user pointers to temporary shape
-		tm.setUserPointer(tmpShape->getUserPointer());
-		
-		ob->setCollisionShape( &tm );
 		
+		ob->internalSetTemporaryCollisionShape( &tm );
 		
 		btCollisionAlgorithm* colAlgo = ci.m_dispatcher1->findAlgorithm(m_convexBody,m_triBody,m_manifoldPtr);
 		///this should use the btDispatcher, so the actual registered algorithm is used
@@ -134,12 +129,10 @@ void btConvexTriangleCallback::processTriangle(btVector3* triangle,int partId, i
 		colAlgo->processCollision(m_convexBody,m_triBody,*m_dispatchInfoPtr,m_resultOut);
 		colAlgo->~btCollisionAlgorithm();
 		ci.m_dispatcher1->freeCollisionAlgorithm(colAlgo);
-		ob->setCollisionShape( tmpShape );
+		ob->setCollisionShape( ob->getRootCollisionShape());
-
 	}
 
 
-
 }
 
 

src/BulletCollision/CollisionShapes/btMaterial.h

@@ -0,0 +1,34 @@
+/*
+Bullet Continuous Collision Detection and Physics Library
+Copyright (c) 2003-2008 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.
+*/
+
+/// This file was created by Alex Silverman
+
+#ifndef MATERIAL_H
+#define MATERIAL_H
+
+// Material class to be used by btMultimaterialTriangleMeshShape to store triangle properties
+class btMaterial
+{
+    // public members so that materials can change due to world events
+public:
+    btScalar m_friction;
+    btScalar m_restitution;
+    int pad[2];
+
+    btMaterial(){}
+    btMaterial(btScalar fric, btScalar rest) { m_friction = fric; m_restitution = rest; }
+};
+
+#endif // MATERIAL_H

src/BulletCollision/CollisionShapes/btMultimaterialTriangleMeshShape.cpp

@@ -0,0 +1,45 @@
+/*
+Bullet Continuous Collision Detection and Physics Library
+Copyright (c) 2003-2008 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.
+*/
+
+/// This file was created by Alex Silverman
+
+#include "BulletCollision/CollisionShapes/btMultimaterialTriangleMeshShape.h"
+#include "BulletCollision/CollisionShapes/btTriangleIndexVertexMaterialArray.h"
+//#include "BulletCollision/CollisionShapes/btOptimizedBvh.h"
+
+
+///Obtains the material for a specific triangle
+const btMaterial * btMultimaterialTriangleMeshShape::getMaterialProperties(int partID, int triIndex)
+{
+    const unsigned char * materialBase = 0;
+    int numMaterials;
+    PHY_ScalarType materialType;
+    int materialStride;
+    const unsigned char * triangleMaterialBase = 0;
+    int numTriangles;
+    int triangleMaterialStride;
+    PHY_ScalarType triangleType;
+
+    ((btTriangleIndexVertexMaterialArray*)m_meshInterface)->getLockedReadOnlyMaterialBase(&materialBase, numMaterials, materialType, materialStride,
+        &triangleMaterialBase, numTriangles, triangleMaterialStride, triangleType, partID);
+
+    // return the pointer to the place with the friction for the triangle
+    // TODO: This depends on whether it's a moving mesh or not
+    // BUG IN GIMPACT
+    //return (btScalar*)(&materialBase[triangleMaterialBase[(triIndex-1) * triangleMaterialStride] * materialStride]);
+    int * matInd = (int *)(&(triangleMaterialBase[(triIndex * triangleMaterialStride)]));
+    btMaterial *matVal = (btMaterial *)(&(materialBase[*matInd * materialStride]));
+    return (matVal);
+}

src/BulletCollision/CollisionShapes/btMultimaterialTriangleMeshShape.h

@@ -0,0 +1,125 @@
+/*
+Bullet Continuous Collision Detection and Physics Library
+Copyright (c) 2003-2008 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.
+*/
+
+/// This file was created by Alex Silverman
+
+#ifndef BVH_TRIANGLE_MATERIAL_MESH_SHAPE_H
+#define BVH_TRIANGLE_MATERIAL_MESH_SHAPE_H
+
+#include "btBvhTriangleMeshShape.h"
+#include "btMaterial.h"
+
+///BvhTriangleMaterialMeshShape extends BvhTriangleMeshShape.
+///Its main contribution is the interface into a material array.
+ATTRIBUTE_ALIGNED16(class) btMultimaterialTriangleMeshShape : public btBvhTriangleMeshShape
+{
+    btAlignedObjectArray <btMaterial*> m_materialList;
+    int ** m_triangleMaterials;
+
+public:
+
+	BT_DECLARE_ALIGNED_ALLOCATOR();
+
+    btMultimaterialTriangleMeshShape(): btBvhTriangleMeshShape() {}
+    btMultimaterialTriangleMeshShape(btStridingMeshInterface* meshInterface, bool useQuantizedAabbCompression, bool buildBvh = true):
+        btBvhTriangleMeshShape(meshInterface, useQuantizedAabbCompression, buildBvh)
+        {
+            btVector3 m_triangle[3];
+            const unsigned char *vertexbase;
+            int numverts;
+            PHY_ScalarType type;
+            int stride;
+            const unsigned char *indexbase;
+            int indexstride;
+            int numfaces;
+            PHY_ScalarType indicestype;
+
+            //m_materialLookup = (int**)(btAlignedAlloc(sizeof(int*) * meshInterface->getNumSubParts(), 16));
+
+            for(int i = 0; i < meshInterface->getNumSubParts(); i++)
+            {
+                m_meshInterface->getLockedReadOnlyVertexIndexBase(
+                    &vertexbase,
+                    numverts,
+                    type,
+                    stride,
+                    &indexbase,
+                    indexstride,
+                    numfaces,
+                    indicestype,
+                    i);
+                //m_materialLookup[i] = (int*)(btAlignedAlloc(sizeof(int) * numfaces, 16));
+            }
+        }
+
+	///optionally pass in a larger bvh aabb, used for quantization. This allows for deformations within this aabb
+	btMultimaterialTriangleMeshShape(btStridingMeshInterface* meshInterface, bool useQuantizedAabbCompression,const btVector3& bvhAabbMin,const btVector3& bvhAabbMax, bool buildBvh = true):
+        btBvhTriangleMeshShape(meshInterface, useQuantizedAabbCompression, bvhAabbMin, bvhAabbMax, buildBvh)
+        {
+            btVector3 m_triangle[3];
+            const unsigned char *vertexbase;
+            int numverts;
+            PHY_ScalarType type;
+            int stride;
+            const unsigned char *indexbase;
+            int indexstride;
+            int numfaces;
+            PHY_ScalarType indicestype;
+
+            //m_materialLookup = (int**)(btAlignedAlloc(sizeof(int*) * meshInterface->getNumSubParts(), 16));
+
+            for(int i = 0; i < meshInterface->getNumSubParts(); i++)
+            {
+                m_meshInterface->getLockedReadOnlyVertexIndexBase(
+                    &vertexbase,
+                    numverts,
+                    type,
+                    stride,
+                    &indexbase,
+                    indexstride,
+                    numfaces,
+                    indicestype,
+                    i);
+                //m_materialLookup[i] = (int*)(btAlignedAlloc(sizeof(int) * numfaces * 2, 16));
+            }
+        }
+	
+    virtual ~btMultimaterialTriangleMeshShape()
+    {
+/*
+        for(int i = 0; i < m_meshInterface->getNumSubParts(); i++)
+        {
+            btAlignedFree(m_materialValues[i]);
+            m_materialLookup[i] = NULL;
+        }
+        btAlignedFree(m_materialValues);
+        m_materialLookup = NULL;
+*/
+    }
+	virtual int	getShapeType() const
+	{
+		return MULTIMATERIAL_TRIANGLE_MESH_PROXYTYPE;
+	}
+	
+	//debugging
+	virtual const char*	getName()const {return "MULTIMATERIALTRIANGLEMESH";}
+
+    ///Obtains the material for a specific triangle
+    const btMaterial * getMaterialProperties(int partID, int triIndex);
+
+}
+;
+
+#endif //BVH_TRIANGLE_MATERIAL_MESH_SHAPE_H

src/BulletCollision/CollisionShapes/btTriangleIndexVertexMaterialArray.cpp

@@ -0,0 +1,86 @@
+/*
+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.
+*/
+
+///This file was created by Alex Silverman
+
+#include "btTriangleIndexVertexMaterialArray.h"
+
+btTriangleIndexVertexMaterialArray::btTriangleIndexVertexMaterialArray(int numTriangles,int* triangleIndexBase,int triangleIndexStride,
+                                   int numVertices,btScalar* vertexBase,int vertexStride,
+                                   int numMaterials, unsigned char* materialBase, int materialStride,
+                                   int* triangleMaterialsBase, int materialIndexStride) :
+btTriangleIndexVertexArray(numTriangles, triangleIndexBase, triangleIndexStride, numVertices, vertexBase, vertexStride)
+{
+    btMaterialProperties mat;
+
+    mat.m_numMaterials = numMaterials;
+    mat.m_materialBase = materialBase;
+    mat.m_materialStride = materialStride;
+#ifdef BT_USE_DOUBLE_PRECISION
+    mat.m_materialType = PHY_DOUBLE;
+#else
+    mat.m_materialType = PHY_FLOAT;
+#endif
+
+    mat.m_numTriangles = numTriangles;
+    mat.m_triangleMaterialsBase = (unsigned char *)triangleMaterialsBase;
+    mat.m_triangleMaterialStride = materialIndexStride;
+    mat.m_triangleType = PHY_INTEGER;
+
+    addMaterialProperties(mat);
+}
+
+
+void btTriangleIndexVertexMaterialArray::getLockedMaterialBase(unsigned char **materialBase, int& numMaterials, PHY_ScalarType& materialType, int& materialStride,
+                                   unsigned char ** triangleMaterialBase, int& numTriangles, int& triangleMaterialStride, PHY_ScalarType& triangleType, int subpart)
+{
+    btAssert(subpart< getNumSubParts() );
+
+    btMaterialProperties& mats = m_materials[subpart];
+
+    numMaterials = mats.m_numMaterials;
+    (*materialBase) = (unsigned char *) mats.m_materialBase;
+#ifdef BT_USE_DOUBLE_PRECISION
+    materialType = PHY_DOUBLE;
+#else
+    materialType = PHY_FLOAT;
+#endif
+    materialStride = mats.m_materialStride;
+
+    numTriangles = mats.m_numTriangles;
+    (*triangleMaterialBase) = (unsigned char *)mats.m_triangleMaterialsBase;
+    triangleMaterialStride = mats.m_triangleMaterialStride;
+    triangleType = mats.m_triangleType;
+}
+
+void btTriangleIndexVertexMaterialArray::getLockedReadOnlyMaterialBase(const unsigned char **materialBase, int& numMaterials, PHY_ScalarType& materialType, int& materialStride,
+                                           const unsigned char ** triangleMaterialBase, int& numTriangles, int& triangleMaterialStride, PHY_ScalarType& triangleType, int subpart)
+{
+    btMaterialProperties& mats = m_materials[subpart];
+
+    numMaterials = mats.m_numMaterials;
+    (*materialBase) = (const unsigned char *) mats.m_materialBase;
+#ifdef BT_USE_DOUBLE_PRECISION
+    materialType = PHY_DOUBLE;
+#else
+    materialType = PHY_FLOAT;
+#endif
+    materialStride = mats.m_materialStride;
+
+    numTriangles = mats.m_numTriangles;
+    (*triangleMaterialBase) = (const unsigned char *)mats.m_triangleMaterialsBase;
+    triangleMaterialStride = mats.m_triangleMaterialStride;
+    triangleType = mats.m_triangleType;
+}

src/BulletCollision/CollisionShapes/btTriangleIndexVertexMaterialArray.h

@@ -0,0 +1,84 @@
+/*
+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.
+*/
+
+///This file was created by Alex Silverman
+
+#ifndef BT_MULTIMATERIAL_TRIANGLE_INDEX_VERTEX_ARRAY_H
+#define BT_MULTIMATERIAL_TRIANGLE_INDEX_VERTEX_ARRAY_H
+
+#include "btTriangleIndexVertexArray.h"
+
+
+ATTRIBUTE_ALIGNED16( struct)	btMaterialProperties
+{
+    ///m_materialBase ==========> 2 btScalar values make up one material, friction then restitution
+    int m_numMaterials;
+    const unsigned char * m_materialBase;
+    int m_materialStride;
+    PHY_ScalarType m_materialType;
+    ///m_numTriangles <=========== This exists in the btIndexedMesh object for the same subpart, but since we're
+    ///                           padding the structure, it can be reproduced at no real cost
+    ///m_triangleMaterials =====> 1 integer value makes up one entry
+    ///                           eg: m_triangleMaterials[1] = 5; // This will set triangle 2 to use material 5
+    int m_numTriangles; 
+    const unsigned char * m_triangleMaterialsBase;
+    int m_triangleMaterialStride;
+    ///m_triangleType <========== Automatically set in addMaterialProperties
+    PHY_ScalarType m_triangleType;
+};
+
+typedef btAlignedObjectArray<btMaterialProperties>	MaterialArray;
+
+///TriangleIndexVertexMaterialArray is built on TriangleIndexVertexArray
+///The addition of a material array allows for the utilization of the partID and
+///triangleIndex that are returned in the ContactAddedCallback.  As with
+///TriangleIndexVertexArray, no duplicate is made of the material data, so it
+///is the users responsibility to maintain the array during the lifetime of the
+///TriangleIndexVertexMaterialArray.
+ATTRIBUTE_ALIGNED16(class) btTriangleIndexVertexMaterialArray : public btTriangleIndexVertexArray
+{
+protected:
+    MaterialArray       m_materials;
+		
+public:
+	BT_DECLARE_ALIGNED_ALLOCATOR();
+
+    btTriangleIndexVertexMaterialArray()
+	{
+	}
+
+    btTriangleIndexVertexMaterialArray(int numTriangles,int* triangleIndexBase,int triangleIndexStride,
+        int numVertices,btScalar* vertexBase,int vertexStride,
+        int numMaterials, unsigned char* materialBase, int materialStride,
+        int* triangleMaterialsBase, int materialIndexStride);
+
+    virtual ~btTriangleIndexVertexMaterialArray() {}
+
+    void	addMaterialProperties(const btMaterialProperties& mat, PHY_ScalarType triangleType = PHY_INTEGER)
+    {
+        m_materials.push_back(mat);
+        m_materials[m_materials.size()-1].m_triangleType = triangleType;
+    }
+
+    virtual void getLockedMaterialBase(unsigned char **materialBase, int& numMaterials, PHY_ScalarType& materialType, int& materialStride,
+        unsigned char ** triangleMaterialBase, int& numTriangles, int& triangleMaterialStride, PHY_ScalarType& triangleType ,int subpart = 0);
+
+    virtual void getLockedReadOnlyMaterialBase(const unsigned char **materialBase, int& numMaterials, PHY_ScalarType& materialType, int& materialStride,
+        const unsigned char ** triangleMaterialBase, int& numTriangles, int& triangleMaterialStride, PHY_ScalarType& triangleType, int subpart = 0);
+
+}
+;
+
+#endif //BT_MULTIMATERIAL_TRIANGLE_INDEX_VERTEX_ARRAY_H

src/BulletCollision/CollisionShapes/btTriangleShape.h

@@ -27,7 +27,6 @@ public:
 
 	btVector3	m_vertices1[3];
 
-
 	virtual int getNumVertices() const
 	{
 		return 3;
@@ -84,13 +83,12 @@ public:
 
 
 
-	btTriangleShape(const btVector3& p0,const btVector3& p1,const btVector3& p2)
+    btTriangleShape(const btVector3& p0,const btVector3& p1,const btVector3& p2)
-	{
+    {
-		m_vertices1[0] = p0;
+        m_vertices1[0] = p0;
-		m_vertices1[1] = p1;
+        m_vertices1[1] = p1;
-		m_vertices1[2] = p2;
+        m_vertices1[2] = p2;
-	}
+    }
-
 
 
 	virtual void getPlane(btVector3& planeNormal,btPoint3& planeSupport,int i) const

src/BulletDynamics/Dynamics/btRigidBody.cpp

@@ -77,7 +77,7 @@ void	btRigidBody::setupRigidBody(const btRigidBody::btRigidBodyConstructionInfo&
 	m_friction = constructionInfo.m_friction;
 	m_restitution = constructionInfo.m_restitution;
 
-	m_collisionShape = constructionInfo.m_collisionShape;
+	setCollisionShape( constructionInfo.m_collisionShape );
 	m_debugBodyId = uniqueId++;
 	
 	setMassProps(constructionInfo.m_mass, constructionInfo.m_localInertia);