//compute screen-space position
    float4 position;
    position.x = input.TexCoord.x * 2.0f - 1.0f;
    position.y = -(input.TexCoord.y * 2.0f - 1.0f);
    position.z = depthVal;
    position.w = 1.0f;
	       
    //transform to world space
    position = mul(position, InvertViewProjection);
    position /= position.w;
	
	float4 projection = mul(position, LightWVP);
	projection /= projection.w;
	
	float2 projectedTexCoords;
	
    projectedTexCoords[0] = projection.x / projection.w / 2.0f + 0.5f;
    projectedTexCoords[1] = -projection.y / projection.w / 2.0f + 0.5f;
    
    float4 moments = tex2D(shadowSampler, projectedTexCoords);