applied patch contributed by Tim Johansson: adds support for multiple mesh parts in combination with bvh, add short index support for meshes.

src/BulletCollision/CollisionShapes/btBvhTriangleMeshShape.cpp

@@ -141,12 +141,13 @@ void	btBvhTriangleMeshShape::processAllTriangles(btTriangleCallback* callback,co
 				nodeSubPart);
 
 			int* gfxbase = (int*)(indexbase+nodeTriangleIndex*indexstride);
+			btAssert(indicestype==PHY_INTEGER||indicestype==PHY_SHORT);
 	
 			const btVector3& meshScaling = m_meshInterface->getScaling();
 			for (int j=2;j>=0;j--)
 			{
 				
-				int graphicsindex = gfxbase[j];
+				int graphicsindex = indicestype==PHY_SHORT?((short*)gfxbase)[j]:gfxbase[j];
 
 
 #ifdef DEBUG_TRIANGLE_MESH

src/BulletCollision/CollisionShapes/btOptimizedBvh.cpp

@@ -95,7 +95,9 @@ void btOptimizedBvh::build(btStridingMeshInterface* triangles, bool useQuantized
 
 		virtual void internalProcessTriangleIndex(btVector3* triangle,int partId,int  triangleIndex)
 		{
-			btAssert(partId==0);
+			// The partId and triangle index must fit in the same (positive) integer
+			btAssert(partId < (1<<MAX_NUM_PARTS_IN_BITS));
+			btAssert(triangleIndex < (1<<(31-MAX_NUM_PARTS_IN_BITS)));
 			//negative indices are reserved for escapeIndex
 			btAssert(triangleIndex>=0);
 
@@ -132,7 +134,7 @@ void btOptimizedBvh::build(btStridingMeshInterface* triangles, bool useQuantized
 			m_optimizedTree->quantizeWithClamp(&node.m_quantizedAabbMin[0],aabbMin);
 			m_optimizedTree->quantizeWithClamp(&node.m_quantizedAabbMax[0],aabbMax);
 
-			node.m_escapeIndexOrTriangleIndex = triangleIndex;
+			node.m_escapeIndexOrTriangleIndex = (partId<<(31-MAX_NUM_PARTS_IN_BITS)) | triangleIndex;
 
 			m_triangleNodes.push_back(node);
 		}
@@ -256,7 +258,7 @@ void	btOptimizedBvh::updateBvhNodes(btStridingMeshInterface* meshInterface,int f
 
 	btAssert(m_useQuantization);
 
-	int nodeSubPart=0;
+	int curNodeSubPart=-1;
 
 	//get access info to trianglemesh data
 		const unsigned char *vertexbase;
@@ -267,7 +269,6 @@ void	btOptimizedBvh::updateBvhNodes(btStridingMeshInterface* meshInterface,int f
 		int indexstride;
 		int numfaces;
 		PHY_ScalarType indicestype;
-		meshInterface->getLockedReadOnlyVertexIndexBase(&vertexbase,numverts,	type,stride,&indexbase,indexstride,numfaces,indicestype,nodeSubPart);
 
 		btVector3	triangleVerts[3];
 		btVector3	aabbMin,aabbMax;
@@ -282,7 +283,15 @@ void	btOptimizedBvh::updateBvhNodes(btStridingMeshInterface* meshInterface,int f
 			if (curNode.isLeafNode())
 			{
 				//recalc aabb from triangle data
+				int nodeSubPart = curNode.getPartId();
 				int nodeTriangleIndex = curNode.getTriangleIndex();
+				if (nodeSubPart != curNodeSubPart)
+				{
+					if (curNodeSubPart >= 0)
+						meshInterface->unLockReadOnlyVertexBase(curNodeSubPart);
+					meshInterface->getLockedReadOnlyVertexIndexBase(&vertexbase,numverts,	type,stride,&indexbase,indexstride,numfaces,indicestype,nodeSubPart);
+					btAssert(indicestype==PHY_INTEGER||indicestype==PHY_SHORT);
+				}
 				//triangles->getLockedReadOnlyVertexIndexBase(vertexBase,numVerts,
 
 				int* gfxbase = (int*)(indexbase+nodeTriangleIndex*indexstride);
@@ -291,7 +300,7 @@ void	btOptimizedBvh::updateBvhNodes(btStridingMeshInterface* meshInterface,int f
 				for (int j=2;j>=0;j--)
 				{
 					
-					int graphicsindex = gfxbase[j];
+					int graphicsindex = indicestype==PHY_SHORT?((short*)gfxbase)[j]:gfxbase[j];
 					btScalar* graphicsbase = (btScalar*)(vertexbase+graphicsindex*stride);
 #ifdef DEBUG_PATCH_COLORS
 					btVector3 mycolor = color[index&3];
@@ -347,7 +356,8 @@ void	btOptimizedBvh::updateBvhNodes(btStridingMeshInterface* meshInterface,int f
 
 		}
 
-		meshInterface->unLockReadOnlyVertexBase(nodeSubPart);
+		if (curNodeSubPart >= 0)
+			meshInterface->unLockReadOnlyVertexBase(curNodeSubPart);
 
 		
 }
@@ -713,7 +723,7 @@ void btOptimizedBvh::walkRecursiveQuantizedTreeAgainstQueryAabb(const btQuantize
 	{
 		if (isLeafNode)
 		{
-			nodeCallback->processNode(0,currentNode->getTriangleIndex());
+			nodeCallback->processNode(currentNode->getPartId(),currentNode->getTriangleIndex());
 		} else
 		{
 			//process left and right children
@@ -776,7 +786,7 @@ void	btOptimizedBvh::walkStacklessQuantizedTree(btNodeOverlapCallback* nodeCallb
 		
 		if (isLeafNode && aabbOverlap)
 		{
-			nodeCallback->processNode(0,rootNode->getTriangleIndex());
+			nodeCallback->processNode(rootNode->getPartId(),rootNode->getTriangleIndex());
 		} 
 		
 		//PCK: unsigned instead of bool

src/BulletCollision/CollisionShapes/btOptimizedBvh.h

@@ -31,6 +31,9 @@ class btStridingMeshInterface;
 //Note: currently we have 16 bytes per quantized node
 #define MAX_SUBTREE_SIZE_IN_BYTES  2048
 
+// 10 gives the potential for 1024 parts, with at most 2^21 (2097152) (minus one
+// actually) triangles each (since the sign bit is reserved
+#define MAX_NUM_PARTS_IN_BITS 10
 
 ///btQuantizedBvhNode is a compressed aabb node, 16 bytes.
 ///Node can be used for leafnode or internal node. Leafnodes can point to 32-bit triangle index (non-negative range).
@@ -57,7 +60,14 @@ ATTRIBUTE_ALIGNED16	(struct) btQuantizedBvhNode
 	int	getTriangleIndex() const
 	{
 		btAssert(isLeafNode());
-		return m_escapeIndexOrTriangleIndex;
+		// Get only the lower bits where the triangle index is stored
+		return (m_escapeIndexOrTriangleIndex&~((~0)<<(31-MAX_NUM_PARTS_IN_BITS)));
+	}
+	int	getPartId() const
+	{
+		btAssert(isLeafNode());
+		// Get only the highest bits where the part index is stored
+		return (m_escapeIndexOrTriangleIndex>>(31-MAX_NUM_PARTS_IN_BITS));
 	}
 }
 ;

src/BulletCollision/CollisionShapes/btTriangleIndexVertexArray.cpp

@@ -54,7 +54,7 @@ void	btTriangleIndexVertexArray::getLockedVertexIndexBase(unsigned char **vertex
 
 	(*indexbase) = (unsigned char *)mesh.m_triangleIndexBase;
 	indexstride = mesh.m_triangleIndexStride;
-	indicestype = PHY_INTEGER;
+	indicestype = mesh.m_indexType;
 }
 
 void	btTriangleIndexVertexArray::getLockedReadOnlyVertexIndexBase(const unsigned char **vertexbase, int& numverts,PHY_ScalarType& type, int& vertexStride,const unsigned char **indexbase,int & indexstride,int& numfaces,PHY_ScalarType& indicestype,int subpart) const
@@ -73,6 +73,6 @@ void	btTriangleIndexVertexArray::getLockedReadOnlyVertexIndexBase(const unsigned
 	numfaces = mesh.m_numTriangles;
 	(*indexbase) = (const unsigned char *)mesh.m_triangleIndexBase;
 	indexstride = mesh.m_triangleIndexStride;
-	indicestype = PHY_INTEGER;
+	indicestype = mesh.m_indexType;
 }
 

src/BulletCollision/CollisionShapes/btTriangleIndexVertexArray.h

@@ -34,7 +34,10 @@ ATTRIBUTE_ALIGNED16( struct)	btIndexedMesh
 	int			m_numVertices;
 	const unsigned char *		m_vertexBase;
 	int			m_vertexStride;
-	int			pad[2];
+	// The index type is set when adding an indexed mesh to the
+	// btTriangleIndexVertexArray, do not set it manually
+	PHY_ScalarType		m_indexType;
+	int			pad;
 }
 ;
 
@@ -64,9 +67,10 @@ public:
 	//just to be backwards compatible
 	btTriangleIndexVertexArray(int numTriangleIndices,int* triangleIndexBase,int triangleIndexStride,int numVertices,btScalar* vertexBase,int vertexStride);
 	
-	void	addIndexedMesh(const btIndexedMesh& mesh)
+	void	addIndexedMesh(const btIndexedMesh& mesh, PHY_ScalarType indexType = PHY_INTEGER)
 	{
 		m_indexedMeshes.push_back(mesh);
+		m_indexedMeshes[m_indexedMeshes.size()-1].m_indexType = indexType;
 	}