public void GImpactVsCompoundshape(CollisionObject body0,
                                           CollisionObject body1,
                                           GImpactShapeInterface shape0,
                                           CompoundShape shape1, bool swapped)
        {
            IndexedMatrix orgtrans1 = body1.GetWorldTransform();

            if (BulletGlobals.g_streamWriter != null && BulletGlobals.debugGimpactAlgo)
            {
                BulletGlobals.g_streamWriter.WriteLine("GImpactAglo::GImpactVsCompoundshape");
            }


            int i = shape1.GetNumChildShapes();

            while (i-- != 0)
            {
                CollisionShape colshape1   = shape1.GetChildShape(i);
                IndexedMatrix  childtrans1 = orgtrans1 * shape1.GetChildTransform(i);

                body1.SetWorldTransform(ref childtrans1);

                //collide child shape
                GImpactVsShape(body0, body1,
                               shape0, colshape1, swapped);


                //restore transforms
                body1.SetWorldTransform(ref orgtrans1);
            }
        }
        public void GImpactVsConcave(
            CollisionObject body0,
            CollisionObject body1,
            GImpactShapeInterface shape0,
            ConcaveShape shape1, bool swapped)
        {
            GImpactTriangleCallback tricallback = new GImpactTriangleCallback();

            tricallback.algorithm     = this;
            tricallback.body0         = body0;
            tricallback.body1         = body1;
            tricallback.gimpactshape0 = shape0;
            tricallback.swapped       = swapped;
            tricallback.margin        = shape1.GetMargin();

            //getting the trimesh AABB
            IndexedMatrix gimpactInConcaveSpace;

            gimpactInConcaveSpace = body1.GetWorldTransform().Inverse() * body0.GetWorldTransform();

            IndexedVector3 minAABB, maxAABB;

            shape0.GetAabb(gimpactInConcaveSpace, out minAABB, out maxAABB);

            shape1.ProcessAllTriangles(tricallback, ref minAABB, ref maxAABB);
        }
        protected void GImpactVsShapeFindPairs(
            ref IndexedMatrix trans0,
            ref IndexedMatrix trans1,
            GImpactShapeInterface shape0,
            CollisionShape shape1,
            ObjectArray <int> collided_primitives)
        {
            AABB boxshape = new AABB();


            if (shape0.HasBoxSet())
            {
                IndexedMatrix trans1to0 = trans0.Inverse();
                //trans1to0 *= trans1;
                trans1to0 = trans1to0 * trans1;
                //trans1to0 = MathUtil.BulletMatrixMultiply(trans1,trans1to0);
                shape1.GetAabb(ref trans1to0, out boxshape.m_min, out boxshape.m_max);
#if DEBUG
                if (BulletGlobals.g_streamWriter != null && BulletGlobals.debugGimpactAlgo)
                {
                    MathUtil.PrintMatrix(BulletGlobals.g_streamWriter, "GImpactAglo::GImpactVsShapeFindPairs trans1to0", trans1to0);
                    MathUtil.PrintVector3(BulletGlobals.g_streamWriter, "box min", boxshape.m_min);
                    MathUtil.PrintVector3(BulletGlobals.g_streamWriter, "box max", boxshape.m_max);
                }
#endif
                shape0.GetBoxSet().BoxQuery(ref boxshape, collided_primitives);
            }
            else
            {
                shape1.GetAabb(ref trans1, out boxshape.m_min, out boxshape.m_max);

                AABB boxshape0 = new AABB();
                int  i         = shape0.GetNumChildShapes();

                while (i-- != 0)
                {
                    shape0.GetChildAabb(i, ref trans0, out boxshape0.m_min, out boxshape0.m_max);

                    if (boxshape.HasCollision(ref boxshape0))
                    {
                        collided_primitives.Add(i);
                    }
                }
            }
        }
        public void Initialize(GImpactShapeInterface gim_shape)
        {
            m_gim_shape = gim_shape;
            //select retriever
            if (m_gim_shape.NeedsRetrieveTriangles())
            {
                m_current_retriever = m_tri_retriever;
            }
            else if (m_gim_shape.NeedsRetrieveTetrahedrons())
            {
                m_current_retriever = m_tetra_retriever;
            }
            else
            {
                m_current_retriever = m_child_retriever;
            }

            m_current_retriever.m_parent = this;
        }
        protected void GImpactVsGImpactFindPairs(
            ref IndexedMatrix trans0,
            ref IndexedMatrix trans1,
            GImpactShapeInterface shape0,
            GImpactShapeInterface shape1, PairSet pairset)
        {
            if (shape0.HasBoxSet() && shape1.HasBoxSet())
            {
                GImpactQuantizedBvh.FindCollision(shape0.GetBoxSet(), ref trans0, shape1.GetBoxSet(), ref trans1, pairset);
            }
            else
            {
                AABB boxshape0 = new AABB();
                AABB boxshape1 = new AABB();
                int  i         = shape0.GetNumChildShapes();

                while (i-- != 0)
                {
                    shape0.GetChildAabb(i, ref trans0, out boxshape0.m_min, out boxshape0.m_max);

                    int j = shape1.GetNumChildShapes();
                    while (j-- != 0)
                    {
                        shape1.GetChildAabb(i, ref trans1, out boxshape1.m_min, out boxshape1.m_max);

                        if (boxshape1.HasCollision(ref boxshape0))
                        {
                            pairset.PushPair(i, j);
                        }
                    }
                }
            }
#if DEBUG
            if (BulletGlobals.g_streamWriter != null && BulletGlobals.debugGimpactAlgo)
            {
                BulletGlobals.g_streamWriter.WriteLine("GImpactAglo::GImpactVsGImpactFindPairs [{0}]", pairset.Count);
            }
#endif
        }
        public void GImpactVsConcave(
                          CollisionObject body0,
                          CollisionObject body1,
                          GImpactShapeInterface shape0,
                          ConcaveShape shape1, bool swapped)
        {
            GImpactTriangleCallback tricallback = new GImpactTriangleCallback();
            tricallback.algorithm = this;
            tricallback.body0 = body0;
            tricallback.body1 = body1;
            tricallback.gimpactshape0 = shape0;
            tricallback.swapped = swapped;
            tricallback.margin = shape1.GetMargin();

            //getting the trimesh AABB
            IndexedMatrix gimpactInConcaveSpace;

            gimpactInConcaveSpace = body1.GetWorldTransform().Inverse() * body0.GetWorldTransform();

            IndexedVector3 minAABB, maxAABB;
            shape0.GetAabb(gimpactInConcaveSpace, out minAABB, out maxAABB);

            shape1.ProcessAllTriangles(tricallback, ref minAABB, ref maxAABB);

        }
        public void GImpactVsCompoundshape(CollisionObject body0,
                          CollisionObject body1,
                          GImpactShapeInterface shape0,
                          CompoundShape shape1, bool swapped)
        {
            IndexedMatrix orgtrans1 = body1.GetWorldTransform();

            if (BulletGlobals.g_streamWriter != null && BulletGlobals.debugGimpactAlgo)
            {
                BulletGlobals.g_streamWriter.WriteLine("GImpactAglo::GImpactVsCompoundshape");
            }


            int i = shape1.GetNumChildShapes();
            while (i-- != 0)
            {

                CollisionShape colshape1 = shape1.GetChildShape(i);
                IndexedMatrix childtrans1 = orgtrans1 * shape1.GetChildTransform(i);

                body1.SetWorldTransform(ref childtrans1);

                //collide child shape
                GImpactVsShape(body0, body1,
                              shape0, colshape1, swapped);


                //restore transforms
                body1.SetWorldTransform(ref orgtrans1);
            }

        }
        public void GImpactVsShape(CollisionObject body0,
                          CollisionObject body1,
                          GImpactShapeInterface shape0,
                          CollisionShape shape1, bool swapped)
        {
            if (BulletGlobals.g_streamWriter != null && BulletGlobals.debugGimpactAlgo)
	        {
		        BulletGlobals.g_streamWriter.WriteLine("GImpactAglo::GImpactVsShape");
	        }


            if (shape0.GetGImpactShapeType() == GIMPACT_SHAPE_TYPE.CONST_GIMPACT_TRIMESH_SHAPE)
            {
                GImpactMeshShape meshshape0 = shape0 as GImpactMeshShape;

                // check this...
                //int& part = swapped ? m_part1 : m_part0;
                //part = meshshape0.GetMeshPartCount();
                int part = meshshape0.GetMeshPartCount();

                while (part-- != 0)
                {

                    GImpactVsShape(body0,
                          body1,
                          meshshape0.GetMeshPart(part),
                          shape1, swapped);

                }
                if (swapped)
                {
                    m_part1 = part;
                }
                else
                {
                    m_part0 = part;
                }
                return;
            }

#if GIMPACT_VS_PLANE_COLLISION
	if(shape0.GetGImpactShapeType() == GIMPACT_SHAPE_TYPE.CONST_GIMPACT_TRIMESH_SHAPE_PART &&
		shape1.GetShapeType() == BroadphaseNativeTypes.STATIC_PLANE_PROXYTYPE)
	{
		GImpactMeshShapePart shapepart = shape0 as GImpactMeshShapePart;
		StaticPlaneShape planeshape = shape1 as StaticPlaneShape;
        GImpactTrimeshpartVsPlaneCollision(body0, body1, shapepart, planeshape, swapped);
		return;
	}

#endif



            if (shape1.IsCompound())
            {
                CompoundShape compoundshape = shape1 as CompoundShape;
                GImpactVsCompoundshape(body0, body1, shape0, compoundshape, swapped);
                return;
            }
            else if (shape1.IsConcave())
            {
                ConcaveShape concaveshape = shape1 as ConcaveShape;
                GImpactVsConcave(body0, body1, shape0, concaveshape, swapped);
                return;
            }


            IndexedMatrix orgtrans0 = body0.GetWorldTransform();

            IndexedMatrix orgtrans1 = body1.GetWorldTransform();

            ObjectArray<int> collided_results = new ObjectArray<int>(64);

            GImpactVsShapeFindPairs(ref orgtrans0, ref orgtrans1, shape0, shape1, collided_results);

            if (collided_results.Count == 0) return;


            shape0.LockChildShapes();

            using (GIM_ShapeRetriever retriever0 = BulletGlobals.GIM_ShapeRetrieverPool.Get())
            {
                retriever0.Initialize(shape0);
                bool child_has_transform0 = shape0.ChildrenHasTransform();


                int i = collided_results.Count;

                if (BulletGlobals.g_streamWriter != null && BulletGlobals.debugGimpactAlgo)
                {
                    BulletGlobals.g_streamWriter.WriteLine("GImpactAglo::GImpactVsShape [{0}]", collided_results.Count);
                }


                while (i-- != 0)
                {
                    int child_index = collided_results[i];
                    if (swapped)
                        m_triface1 = child_index;
                    else
                        m_triface0 = child_index;

                    CollisionShape colshape0 = retriever0.GetChildShape(child_index);

                    if (child_has_transform0)
                    {
                        body0.SetWorldTransform(orgtrans0 * shape0.GetChildTransform(child_index));
                    }

                    //collide two shapes
                    if (swapped)
                    {
                        ShapeVsShapeCollision(body1, body0, shape1, colshape0);
                    }
                    else
                    {
                        ShapeVsShapeCollision(body0, body1, colshape0, shape1);
                    }

                    //restore transforms
                    if (child_has_transform0)
                    {
                        body0.SetWorldTransform(ref orgtrans0);
                    }

                }

                shape0.UnlockChildShapes();
            }
        }
        //! Collides two gimpact shapes
        /*!
        \pre shape0 and shape1 couldn't be btGImpactMeshShape objects
        */


        public void GImpactVsGImpact(CollisionObject body0,
                          CollisionObject body1,
                          GImpactShapeInterface shape0,
                          GImpactShapeInterface shape1)
        {
            if (shape0.GetGImpactShapeType() == GIMPACT_SHAPE_TYPE.CONST_GIMPACT_TRIMESH_SHAPE)
            {
                GImpactMeshShape meshshape0 = shape0 as GImpactMeshShape;
                m_part0 = meshshape0.GetMeshPartCount();

                while (m_part0-- != 0)
                {
                    GImpactVsGImpact(body0, body1, meshshape0.GetMeshPart(m_part0), shape1);
                }

                return;
            }

            if (shape1.GetGImpactShapeType() == GIMPACT_SHAPE_TYPE.CONST_GIMPACT_TRIMESH_SHAPE)
            {
                GImpactMeshShape meshshape1 = shape1 as GImpactMeshShape;
                m_part1 = meshshape1.GetMeshPartCount();

                while (m_part1-- != 0)
                {

                    GImpactVsGImpact(body0, body1, shape0, meshshape1.GetMeshPart(m_part1));

                }

                return;
            }


            IndexedMatrix orgtrans0 = body0.GetWorldTransform();
            IndexedMatrix orgtrans1 = body1.GetWorldTransform();

            PairSet pairset = new PairSet();

            GImpactVsGImpactFindPairs(ref orgtrans0, ref orgtrans1, shape0, shape1, pairset);

            if (pairset.Count == 0) return;


            if (BulletGlobals.g_streamWriter != null && BulletGlobals.debugGimpactAlgo)
            {
                BulletGlobals.g_streamWriter.WriteLine("GImpactAglo::GImpactVsGImpact [{0}]",pairset.Count);
            }

            if (shape0.GetGImpactShapeType() == GIMPACT_SHAPE_TYPE.CONST_GIMPACT_TRIMESH_SHAPE_PART &&
                shape1.GetGImpactShapeType() == GIMPACT_SHAPE_TYPE.CONST_GIMPACT_TRIMESH_SHAPE_PART)
            {
                GImpactMeshShapePart shapepart0 = shape0 as GImpactMeshShapePart;
                GImpactMeshShapePart shapepart1 = shape1 as GImpactMeshShapePart;
                //specialized function
#if BULLET_TRIANGLE_COLLISION
    CollideGjkTriangles(body0,body1,shapepart0,shapepart1,&pairset[0].m_index1,pairset.size());
#else
                CollideSatTriangles(body0, body1, shapepart0, shapepart1, pairset, pairset.Count);
#endif

                return;
            }

            //general function

            shape0.LockChildShapes();
            shape1.LockChildShapes();

            using(GIM_ShapeRetriever retriever0 = BulletGlobals.GIM_ShapeRetrieverPool.Get())
            using (GIM_ShapeRetriever retriever1 = BulletGlobals.GIM_ShapeRetrieverPool.Get())
            {
                retriever0.Initialize(shape0);
                retriever1.Initialize(shape1);

                bool child_has_transform0 = shape0.ChildrenHasTransform();
                bool child_has_transform1 = shape1.ChildrenHasTransform();

                int i = pairset.Count;
                while (i-- != 0)
                {
                    GIM_PAIR pair = pairset[i];
                    m_triface0 = pair.m_index1;
                    m_triface1 = pair.m_index2;
                    CollisionShape colshape0 = retriever0.GetChildShape(m_triface0);
                    CollisionShape colshape1 = retriever1.GetChildShape(m_triface1);

                    if (child_has_transform0)
                    {
                        body0.SetWorldTransform(orgtrans0 * shape0.GetChildTransform(m_triface0));
                    }

                    if (child_has_transform1)
                    {
                        body1.SetWorldTransform(orgtrans1 * shape1.GetChildTransform(m_triface1));
                    }

                    //collide two convex shapes
                    ConvexVsConvexCollision(body0, body1, colshape0, colshape1);


                    if (child_has_transform0)
                    {
                        body0.SetWorldTransform(ref orgtrans0);
                    }

                    if (child_has_transform1)
                    {
                        body1.SetWorldTransform(ref orgtrans1);
                    }

                }

                shape0.UnlockChildShapes();
                shape1.UnlockChildShapes();
            }
        }
        protected void GImpactVsShapeFindPairs(
                          ref IndexedMatrix trans0,
                          ref IndexedMatrix trans1,
                          GImpactShapeInterface shape0,
                          CollisionShape shape1,
                          ObjectArray<int> collided_primitives)
        {
            AABB boxshape = new AABB();


            if (shape0.HasBoxSet())
            {
                IndexedMatrix trans1to0 = trans0.Inverse();
                //trans1to0 *= trans1;
                trans1to0 = trans1to0 * trans1;
                //trans1to0 = MathUtil.BulletMatrixMultiply(trans1,trans1to0);
                shape1.GetAabb(ref trans1to0, out boxshape.m_min, out boxshape.m_max);
                if (BulletGlobals.g_streamWriter != null && BulletGlobals.debugGimpactAlgo)
                {
                    MathUtil.PrintMatrix(BulletGlobals.g_streamWriter, "GImpactAglo::GImpactVsShapeFindPairs trans1to0", trans1to0);
                    MathUtil.PrintVector3(BulletGlobals.g_streamWriter, "box min", boxshape.m_min);
                    MathUtil.PrintVector3(BulletGlobals.g_streamWriter, "box max", boxshape.m_max);
                }
                shape0.GetBoxSet().BoxQuery(ref boxshape, collided_primitives);
            }
            else
            {
                shape1.GetAabb(ref trans1, out boxshape.m_min, out boxshape.m_max);

                AABB boxshape0 = new AABB();
                int i = shape0.GetNumChildShapes();

                while (i-- != 0)
                {
                    shape0.GetChildAabb(i, ref trans0, out boxshape0.m_min, out boxshape0.m_max);

                    if (boxshape.HasCollision(ref boxshape0))
                    {
                        collided_primitives.Add(i);
                    }
                }

            }


        }
        protected void GImpactVsGImpactFindPairs(
                          ref IndexedMatrix trans0,
                          ref IndexedMatrix trans1,
                          GImpactShapeInterface shape0,
                          GImpactShapeInterface shape1, PairSet pairset)
        {
            if (shape0.HasBoxSet() && shape1.HasBoxSet())
            {
                GImpactQuantizedBvh.FindCollision(shape0.GetBoxSet(), ref trans0, shape1.GetBoxSet(), ref trans1, pairset);
            }
            else
            {
                AABB boxshape0 = new AABB();
                AABB boxshape1 = new AABB();
                int i = shape0.GetNumChildShapes();

                while (i-- != 0)
                {
                    shape0.GetChildAabb(i, ref trans0, out boxshape0.m_min, out boxshape0.m_max);

                    int j = shape1.GetNumChildShapes();
                    while (j-- != 0)
                    {
                        shape1.GetChildAabb(i, ref trans1, out boxshape1.m_min, out boxshape1.m_max);

                        if (boxshape1.HasCollision(ref boxshape0))
                        {
                            pairset.PushPair(i, j);
                        }
                    }
                }
            }
            if (BulletGlobals.g_streamWriter != null && BulletGlobals.debugGimpactAlgo)
            {
                BulletGlobals.g_streamWriter.WriteLine("GImpactAglo::GImpactVsGImpactFindPairs [{0}]", pairset.Count);
            }
        }
        public void Initialize(GImpactShapeInterface gim_shape)
        {
            m_gim_shape = gim_shape;
            //select retriever
            if (m_gim_shape.NeedsRetrieveTriangles())
            {
                m_current_retriever = m_tri_retriever;
            }
            else if (m_gim_shape.NeedsRetrieveTetrahedrons())
            {
                m_current_retriever = m_tetra_retriever;
            }
            else
            {
                m_current_retriever = m_child_retriever;
            }

            m_current_retriever.m_parent = this;
        }
        public void GImpactVsShape(CollisionObject body0,
                                   CollisionObject body1,
                                   GImpactShapeInterface shape0,
                                   CollisionShape shape1, bool swapped)
        {
            if (BulletGlobals.g_streamWriter != null && BulletGlobals.debugGimpactAlgo)
            {
                BulletGlobals.g_streamWriter.WriteLine("GImpactAglo::GImpactVsShape");
            }


            if (shape0.GetGImpactShapeType() == GIMPACT_SHAPE_TYPE.CONST_GIMPACT_TRIMESH_SHAPE)
            {
                GImpactMeshShape meshshape0 = shape0 as GImpactMeshShape;

                // check this...
                //int& part = swapped ? m_part1 : m_part0;
                //part = meshshape0.GetMeshPartCount();
                int part = meshshape0.GetMeshPartCount();

                while (part-- != 0)
                {
                    GImpactVsShape(body0,
                                   body1,
                                   meshshape0.GetMeshPart(part),
                                   shape1, swapped);
                }
                if (swapped)
                {
                    m_part1 = part;
                }
                else
                {
                    m_part0 = part;
                }
                return;
            }

#if GIMPACT_VS_PLANE_COLLISION
            if (shape0.GetGImpactShapeType() == GIMPACT_SHAPE_TYPE.CONST_GIMPACT_TRIMESH_SHAPE_PART &&
                shape1.GetShapeType() == BroadphaseNativeTypes.STATIC_PLANE_PROXYTYPE)
            {
                GImpactMeshShapePart shapepart  = shape0 as GImpactMeshShapePart;
                StaticPlaneShape     planeshape = shape1 as StaticPlaneShape;
                GImpactTrimeshpartVsPlaneCollision(body0, body1, shapepart, planeshape, swapped);
                return;
            }
#endif



            if (shape1.IsCompound())
            {
                CompoundShape compoundshape = shape1 as CompoundShape;
                GImpactVsCompoundshape(body0, body1, shape0, compoundshape, swapped);
                return;
            }
            else if (shape1.IsConcave())
            {
                ConcaveShape concaveshape = shape1 as ConcaveShape;
                GImpactVsConcave(body0, body1, shape0, concaveshape, swapped);
                return;
            }


            IndexedMatrix orgtrans0 = body0.GetWorldTransform();

            IndexedMatrix orgtrans1 = body1.GetWorldTransform();

            ObjectArray <int> collided_results = new ObjectArray <int>(64);

            GImpactVsShapeFindPairs(ref orgtrans0, ref orgtrans1, shape0, shape1, collided_results);

            if (collided_results.Count == 0)
            {
                return;
            }


            shape0.LockChildShapes();

            using (GIM_ShapeRetriever retriever0 = BulletGlobals.GIM_ShapeRetrieverPool.Get())
            {
                retriever0.Initialize(shape0);
                bool child_has_transform0 = shape0.ChildrenHasTransform();


                int i = collided_results.Count;

                if (BulletGlobals.g_streamWriter != null && BulletGlobals.debugGimpactAlgo)
                {
                    BulletGlobals.g_streamWriter.WriteLine("GImpactAglo::GImpactVsShape [{0}]", collided_results.Count);
                }


                while (i-- != 0)
                {
                    int child_index = collided_results[i];
                    if (swapped)
                    {
                        m_triface1 = child_index;
                    }
                    else
                    {
                        m_triface0 = child_index;
                    }

                    CollisionShape colshape0 = retriever0.GetChildShape(child_index);

                    if (child_has_transform0)
                    {
                        body0.SetWorldTransform(orgtrans0 * shape0.GetChildTransform(child_index));
                    }

                    //collide two shapes
                    if (swapped)
                    {
                        ShapeVsShapeCollision(body1, body0, shape1, colshape0);
                    }
                    else
                    {
                        ShapeVsShapeCollision(body0, body1, colshape0, shape1);
                    }

                    //restore transforms
                    if (child_has_transform0)
                    {
                        body0.SetWorldTransform(ref orgtrans0);
                    }
                }

                shape0.UnlockChildShapes();
            }
        }
        //! Collides two gimpact shapes

        /*!
         * \pre shape0 and shape1 couldn't be btGImpactMeshShape objects
         */


        public void GImpactVsGImpact(CollisionObject body0,
                                     CollisionObject body1,
                                     GImpactShapeInterface shape0,
                                     GImpactShapeInterface shape1)
        {
            if (shape0.GetGImpactShapeType() == GIMPACT_SHAPE_TYPE.CONST_GIMPACT_TRIMESH_SHAPE)
            {
                GImpactMeshShape meshshape0 = shape0 as GImpactMeshShape;
                m_part0 = meshshape0.GetMeshPartCount();

                while (m_part0-- != 0)
                {
                    GImpactVsGImpact(body0, body1, meshshape0.GetMeshPart(m_part0), shape1);
                }

                return;
            }

            if (shape1.GetGImpactShapeType() == GIMPACT_SHAPE_TYPE.CONST_GIMPACT_TRIMESH_SHAPE)
            {
                GImpactMeshShape meshshape1 = shape1 as GImpactMeshShape;
                m_part1 = meshshape1.GetMeshPartCount();

                while (m_part1-- != 0)
                {
                    GImpactVsGImpact(body0, body1, shape0, meshshape1.GetMeshPart(m_part1));
                }

                return;
            }


            IndexedMatrix orgtrans0 = body0.GetWorldTransform();
            IndexedMatrix orgtrans1 = body1.GetWorldTransform();

            PairSet pairset = new PairSet();

            GImpactVsGImpactFindPairs(ref orgtrans0, ref orgtrans1, shape0, shape1, pairset);

            if (pairset.Count == 0)
            {
                return;
            }


            if (BulletGlobals.g_streamWriter != null && BulletGlobals.debugGimpactAlgo)
            {
                BulletGlobals.g_streamWriter.WriteLine("GImpactAglo::GImpactVsGImpact [{0}]", pairset.Count);
            }

            if (shape0.GetGImpactShapeType() == GIMPACT_SHAPE_TYPE.CONST_GIMPACT_TRIMESH_SHAPE_PART &&
                shape1.GetGImpactShapeType() == GIMPACT_SHAPE_TYPE.CONST_GIMPACT_TRIMESH_SHAPE_PART)
            {
                GImpactMeshShapePart shapepart0 = shape0 as GImpactMeshShapePart;
                GImpactMeshShapePart shapepart1 = shape1 as GImpactMeshShapePart;
                //specialized function
#if BULLET_TRIANGLE_COLLISION
                CollideGjkTriangles(body0, body1, shapepart0, shapepart1, &pairset[0].m_index1, pairset.size());
#else
                CollideSatTriangles(body0, body1, shapepart0, shapepart1, pairset, pairset.Count);
#endif

                return;
            }

            //general function

            shape0.LockChildShapes();
            shape1.LockChildShapes();

            using (GIM_ShapeRetriever retriever0 = BulletGlobals.GIM_ShapeRetrieverPool.Get())
                using (GIM_ShapeRetriever retriever1 = BulletGlobals.GIM_ShapeRetrieverPool.Get())
                {
                    retriever0.Initialize(shape0);
                    retriever1.Initialize(shape1);

                    bool child_has_transform0 = shape0.ChildrenHasTransform();
                    bool child_has_transform1 = shape1.ChildrenHasTransform();

                    int i = pairset.Count;
                    while (i-- != 0)
                    {
                        GIM_PAIR pair = pairset[i];
                        m_triface0 = pair.m_index1;
                        m_triface1 = pair.m_index2;
                        CollisionShape colshape0 = retriever0.GetChildShape(m_triface0);
                        CollisionShape colshape1 = retriever1.GetChildShape(m_triface1);

                        if (child_has_transform0)
                        {
                            body0.SetWorldTransform(orgtrans0 * shape0.GetChildTransform(m_triface0));
                        }

                        if (child_has_transform1)
                        {
                            body1.SetWorldTransform(orgtrans1 * shape1.GetChildTransform(m_triface1));
                        }

                        //collide two convex shapes
                        ConvexVsConvexCollision(body0, body1, colshape0, colshape1);


                        if (child_has_transform0)
                        {
                            body0.SetWorldTransform(ref orgtrans0);
                        }

                        if (child_has_transform1)
                        {
                            body1.SetWorldTransform(ref orgtrans1);
                        }
                    }

                    shape0.UnlockChildShapes();
                    shape1.UnlockChildShapes();
                }
        }