support concave soft bodies, preliminary. could be used for cloth too. need vertex pinning/constraint attach to other objects.

2 files changed, 59 insertions, 35 deletions

diff --git a/extern/bullet2/src/BulletCollision/CollisionShapes/btTriangleMesh.cpp b/extern/bullet2/src/BulletCollision/CollisionShapes/btTriangleMesh.cpp
index bcea97052d6..29d26316316 100644
--- a/extern/bullet2/src/BulletCollision/CollisionShapes/btTriangleMesh.cpp
+++ b/extern/bullet2/src/BulletCollision/CollisionShapes/btTriangleMesh.cpp
@@ -19,7 +19,8 @@ subject to the following restrictions:
 
 btTriangleMesh::btTriangleMesh (bool use32bitIndices,bool use4componentVertices)
 :m_use32bitIndices(use32bitIndices),
-m_use4componentVertices(use4componentVertices)
+m_use4componentVertices(use4componentVertices),
+m_weldingThreshold(0.0)
 {
 	btIndexedMesh meshIndex;
 	meshIndex.m_numTriangles = 0;
@@ -60,49 +61,66 @@ m_use4componentVertices(use4componentVertices)
 
 }
 
-		
-void	btTriangleMesh::addTriangle(const btVector3& vertex0,const btVector3& vertex1,const btVector3& vertex2)
+void	btTriangleMesh::addIndex(int index)
 {
-	m_indexedMeshes[0].m_numTriangles++;
-	m_indexedMeshes[0].m_numVertices+=3;
-
-	if (m_use4componentVertices)
+	if (m_use32bitIndices)
 	{
-		m_4componentVertices.push_back(vertex0);
-		m_4componentVertices.push_back(vertex1);
-		m_4componentVertices.push_back(vertex2);
-		m_indexedMeshes[0].m_vertexBase = (unsigned char*)&m_4componentVertices[0];
+		m_32bitIndices.push_back(index);
+		m_indexedMeshes[0].m_triangleIndexBase = (unsigned char*) &m_32bitIndices[0];
 	} else
 	{
-		m_3componentVertices.push_back(vertex0.getX());
-		m_3componentVertices.push_back(vertex0.getY());
-		m_3componentVertices.push_back(vertex0.getZ());
-
-		m_3componentVertices.push_back(vertex1.getX());
-		m_3componentVertices.push_back(vertex1.getY());
-		m_3componentVertices.push_back(vertex1.getZ());
-
-		m_3componentVertices.push_back(vertex2.getX());
-		m_3componentVertices.push_back(vertex2.getY());
-		m_3componentVertices.push_back(vertex2.getZ());
-		m_indexedMeshes[0].m_vertexBase = (unsigned char*)&m_3componentVertices[0];
+		m_16bitIndices.push_back(index);
+		m_indexedMeshes[0].m_triangleIndexBase = (unsigned char*) &m_16bitIndices[0];
 	}
+}
 
-	if (m_use32bitIndices)
+int	btTriangleMesh::findOrAddVertex(const btVector3& vertex)
+{
+	//return index of new/existing vertex
+	//todo: could use acceleration structure for this
+	if (m_use4componentVertices)
 	{
-		int curIndex = m_32bitIndices.size();
-		m_32bitIndices.push_back(curIndex++);
-		m_32bitIndices.push_back(curIndex++);
-		m_32bitIndices.push_back(curIndex++);
-		m_indexedMeshes[0].m_triangleIndexBase = (unsigned char*) &m_32bitIndices[0];
+		for (int i=0;i< m_4componentVertices.size();i++)
+		{
+			if ((m_4componentVertices[i]-vertex).length2() <= m_weldingThreshold)
+			{
+				return i;
+			}
+		}
+		m_indexedMeshes[0].m_numVertices++;
+		m_4componentVertices.push_back(vertex);
+		m_indexedMeshes[0].m_vertexBase = (unsigned char*)&m_4componentVertices[0];
+
+		return m_4componentVertices.size()-1;
+		
 	} else
 	{
-		short curIndex = static_cast<short>(m_16bitIndices.size());
-		m_16bitIndices.push_back(curIndex++);
-		m_16bitIndices.push_back(curIndex++);
-		m_16bitIndices.push_back(curIndex++);
-		m_indexedMeshes[0].m_triangleIndexBase = (unsigned char*) &m_16bitIndices[0];
+		
+		for (int i=0;i< m_3componentVertices.size();i+=3)
+		{
+			btVector3 vtx(m_3componentVertices[i],m_3componentVertices[i+1],m_3componentVertices[i+2]);
+			if ((vtx-vertex).length2() <= m_weldingThreshold)
+			{
+				return i/3;
+			}
+		}
+		m_3componentVertices.push_back(vertex.getX());
+		m_3componentVertices.push_back(vertex.getY());
+		m_3componentVertices.push_back(vertex.getZ());
+		m_indexedMeshes[0].m_numVertices++;
+		m_indexedMeshes[0].m_vertexBase = (unsigned char*)&m_3componentVertices[0];
+		return (m_3componentVertices.size()/3)-1;
 	}
+
+}
+		
+void	btTriangleMesh::addTriangle(const btVector3& vertex0,const btVector3& vertex1,const btVector3& vertex2)
+{
+	m_indexedMeshes[0].m_numTriangles++;
+		
+	addIndex(findOrAddVertex(vertex0));
+	addIndex(findOrAddVertex(vertex1));
+	addIndex(findOrAddVertex(vertex2));
 }
 
 int btTriangleMesh::getNumTriangles() const
diff --git a/extern/bullet2/src/BulletCollision/CollisionShapes/btTriangleMesh.h b/extern/bullet2/src/BulletCollision/CollisionShapes/btTriangleMesh.h
index e4d41d5ede0..1f51b2f2c87 100644
--- a/extern/bullet2/src/BulletCollision/CollisionShapes/btTriangleMesh.h
+++ b/extern/bullet2/src/BulletCollision/CollisionShapes/btTriangleMesh.h
@@ -25,6 +25,7 @@ subject to the following restrictions:
 ///It allows either 32bit or 16bit indices, and 4 (x-y-z-w) or 3 (x-y-z) component vertices.
 ///If you want to share triangle/index data between graphics mesh and collision mesh (btBvhTriangleMeshShape), you can directly use btTriangleIndexVertexArray or derive your own class from btStridingMeshInterface.
 ///Performance of btTriangleMesh and btTriangleIndexVertexArray used in a btBvhTriangleMeshShape is the same.
+///It has a brute-force option to weld together closeby vertices.
 class btTriangleMesh : public btTriangleIndexVertexArray
 {
 	btAlignedObjectArray<btVector3>	m_4componentVertices;
@@ -34,11 +35,16 @@ class btTriangleMesh : public btTriangleIndexVertexArray
 	btAlignedObjectArray<unsigned short int>		m_16bitIndices;
 	bool	m_use32bitIndices;
 	bool	m_use4componentVertices;
-
+	
 
 	public:
+		btScalar	m_weldingThreshold;
+
 		btTriangleMesh (bool use32bitIndices=true,bool use4componentVertices=true);
 
+		int		findOrAddVertex(const btVector3& vertex);
+		void	addIndex(int index);
+
 		bool	getUse32bitIndices() const
 		{
 			return m_use32bitIndices;