added OpenCL cloth demo, contributed by AMD.

updated GpuSoftBodySolvers
updated DirectCompute cloth demo

src/BulletMultiThreaded/GpuSoftBodySolvers/OpenCL/OpenCLC10/UpdateNodes.cl

@@ -0,0 +1,39 @@
+MSTRINGIFY(
+
+
+__kernel void 
+updateVelocitiesFromPositionsWithVelocitiesKernel( 
+	int numNodes,
+	float isolverdt,
+	__global float4 * g_vertexPositions,
+	__global float4 * g_vertexPreviousPositions,
+	__global int * g_vertexClothIndices,
+	__global float *g_clothVelocityCorrectionCoefficients,
+	__global float * g_clothDampingFactor,
+	__global float4 * g_vertexVelocities,
+	__global float4 * g_vertexForces GUID_ARG)
+{
+	int nodeID = get_global_id(0);
+	if( nodeID < numNodes )
+	{	
+		float4 position = g_vertexPositions[nodeID];
+		float4 previousPosition = g_vertexPreviousPositions[nodeID];
+		float4 velocity = g_vertexVelocities[nodeID];
+		int clothIndex = g_vertexClothIndices[nodeID];
+		float velocityCorrectionCoefficient = g_clothVelocityCorrectionCoefficients[clothIndex];
+		float dampingFactor = g_clothDampingFactor[clothIndex];
+		float velocityCoefficient = (1.f - dampingFactor);
+		
+		float4 difference = position - previousPosition;
+				
+		velocity += difference*velocityCorrectionCoefficient*isolverdt;
+		
+		// Damp the velocity
+		velocity *= velocityCoefficient;
+		
+		g_vertexVelocities[nodeID] = velocity;
+		g_vertexForces[nodeID] = (float4)(0.f, 0.f, 0.f, 0.f);								
+	}
+}
+
+);