private void SetupShadowShader(DrawState state)
{
ICamera shadowCamera = this.shadowMapTarget.Camera;
//compute the view*projection matrix for the shadow map camera...
Matrix view, projection, viewProjection;
shadowCamera.GetViewMatrix(out view);
shadowCamera.GetProjectionMatrix(out projection, this.shadowMapTarget.Size);
Matrix.Multiply(ref view, ref projection, out viewProjection);
//and the view direction
Vector3 viewDirection;
shadowCamera.GetCameraViewDirection(out viewDirection);
//set the matrix and other constants in the shadow mapping shader instances
Shader.ShadowShader shader = state.GetShader <Shader.ShadowShader>();
Shader.ShadowShaderBlend shaderBlend = state.GetShader <Shader.ShadowShaderBlend>();
//non-blending shader
shader.ShadowMap = this.shadowMapTarget.GetTexture();
shader.SetShadowMapProjection(ref viewProjection);
shader.SetShadowViewDirection(ref viewDirection);
//setup the same constants for the blending shader
shaderBlend.ShadowMap = this.shadowMapTarget.GetTexture();
shaderBlend.SetShadowMapProjection(ref viewProjection);
shaderBlend.SetShadowViewDirection(ref viewDirection);
}