public bool OnBulletCreate()
    {
        if( collisionShapePtr != null ) // can't be created multi-times
            return true;

        if( ShapeType == CollisionShapeType.BoxShape)
        {
            btVector3 vec = new btVector3(BoxShapeVec.x*transform.localScale.x,BoxShapeVec.y*transform.localScale.y,BoxShapeVec.z*transform.localScale.z);
            boxShape = new btBoxShape(vec.GetSwigPtr());
            collisionShapePtr = boxShape.GetSwigPtr();
        }
        else if( ShapeType == CollisionShapeType.SphereShape)
        {
            float maxFactor = Mathf.Max(transform.localScale.x,transform.localScale.y);
            maxFactor = Mathf.Max(transform.localScale.z,maxFactor);
            sphereShape = new btSphereShape(SphereShapeRadius*maxFactor);
            collisionShapePtr = sphereShape.GetSwigPtr();
        }
        else if( ShapeType == CollisionShapeType.CapsuleShape)
        {
            float maxFactor = Mathf.Max(transform.localScale.x,transform.localScale.z);

            capsuleShape = new btCapsuleShape(CapsuleRadius*maxFactor,CapsuleHeight*transform.localScale.y);
            collisionShapePtr = capsuleShape.GetSwigPtr();
        }
        else if( ShapeType == CollisionShapeType.CylinderShape)
        {
            float maxFactor = Mathf.Max(transform.localScale.x,transform.localScale.z);
            btVector3 vec = new btVector3(CylinderRadius*maxFactor,CylinderHeight*transform.localScale.y,CylinderRadius*maxFactor);
            cylinderShape = new btCylinderShape(vec.GetSwigPtr());
            collisionShapePtr = cylinderShape.GetSwigPtr();
        }
        else if( ShapeType == CollisionShapeType.ConeShape)
        {
            float maxFactor = Mathf.Max(transform.localScale.x,transform.localScale.z);
            coneShape = new btConeShape(ConeRadius*maxFactor,ConeHeight*transform.localScale.y);
            collisionShapePtr = coneShape.GetSwigPtr();
        }
        else if( ShapeType == CollisionShapeType.ConvexHull )
        {
            if(CheckUnityMesh() == false)
                return false;

            List<float> vertexposList = new List<float>();

            for(int index=0;index<meshFilter.mesh.vertexCount;index++)
            {
                Vector3 vec = meshFilter.mesh.vertices[index];
                vertexposList.Add(vec.x);
                vertexposList.Add(vec.y);
                vertexposList.Add(vec.z);
            }

            convexHull = new btConvexHullShape(vertexposList.ToArray(),meshFilter.mesh.vertexCount,3*sizeof(float));
            convexPolyhedral = convexHull.GetPolihedralConvexShape();
            //convexPolyhedral.initializePolyhedralFeatures();
            collisionShapePtr = convexHull.GetSwigPtr();

        }
        else if( ShapeType == CollisionShapeType.CompoundShape )
        {
            // use all its children's collision shapes to create itself...
            if( CollisionShapeArray == null || CollisionShapeArray.Length == 0 )
            {
                Debug.Log("There is no child collision shapes to use CompoundShape!");
                return false;
            }

            compoundShape = new btCompoundShape();

            for( int i=0;i<CollisionShapeArray.Length;i++)
            {
                if( CollisionShapeArray[i] == null )
                    continue;

                if( CollisionShapeArray[i].gameObject == gameObject )
                    continue;

                bool result = CollisionShapeArray[i].OnBulletCreate();
                if( result == false )
                {
                    Debug.Log(" Bullet Collision Create Error!");
                    return false;
                }

                Transform t = CollisionShapeArray[i].transform;
                Matrix4x4 objMatrix = Matrix4x4.TRS(t.localPosition,t.localRotation,t.localScale);

                btVector3 pos = new btVector3(t.localPosition.x,t.localPosition.y,t.localPosition.z);
                btQuaternion rot = new btQuaternion(t.localRotation.x,t.localRotation.y,t.localRotation.z,t.localRotation.w);

                btTransform trans = new btTransform(rot,pos);

                compoundShape.addChildShape(trans.GetSwigPtr(),CollisionShapeArray[i].GetCollisionShapePtr());
            }

            collisionShapePtr = compoundShape.GetSwigPtr();

        }
        else if( ShapeType == CollisionShapeType.BvhTriangleMeshShape )
        {
            if(CheckUnityMesh() == false)
                return false;
            List<float> verList = new List<float>();
            for(int index=0;index<meshFilter.mesh.vertexCount;index++)
            {
                Vector3 vec = meshFilter.mesh.vertices[index];
                //vec = transform.TransformPoint(vec);
                verList.Add(vec.x);
                verList.Add(vec.y);
                verList.Add(vec.z);
            }

            meshVertexArray = verList.ToArray();

            List<int> indexList = new List<int>();
            // Unity3D counter clock-wise to Bullet's clock wise.
            for( int i=0;i< meshFilter.mesh.triangles.Length;i+=3)
            {
                indexList.Add(meshFilter.mesh.triangles[i]);
                indexList.Add(meshFilter.mesh.triangles[i+2]);
                indexList.Add(meshFilter.mesh.triangles[i+1]);
            }

            meshIndexArray = indexList.ToArray();

            triangleArray = new btTriangleIndexVertexArray(indexList.Count/3,meshIndexArray,3*sizeof(int),
                                                                                      meshFilter.mesh.vertexCount,meshVertexArray,3*sizeof(float));
            bvhTriangleMeshShape = new btBvhTriangleMeshShape(triangleArray.GetSwigPtr(),true);
            collisionShapePtr = bvhTriangleMeshShape.GetSwigPtr();
        }
        else if( ShapeType == CollisionShapeType.StaticPlaneShape)
        {
            btVector3 vec = new btVector3(StaticPlaneNormal.x,StaticPlaneNormal.y,StaticPlaneNormal.z);
            staticPlaneShape = new btStaticPlaneShape(vec.GetSwigPtr(),StaticPlaneConstant);
            collisionShapePtr = staticPlaneShape.GetSwigPtr();
        }

        return true;
    }
 internal static HandleRef getCPtr(btConvexHullShape obj)
 {
     return((obj == null) ? new HandleRef(null, IntPtr.Zero) : obj.swigCPtr);
 }
 internal static HandleRef getCPtr(btConvexHullShape obj) {
   return (obj == null) ? new HandleRef(null, IntPtr.Zero) : obj.swigCPtr;
 }