float SchlickGGXGeometricShadowingFunction (float NdotL, float NdotV, float roughness)
{
    float k = roughness / 2;

    float SmithL = (NdotL)/ (NdotL * (1- k) + k);
    float SmithV = (NdotV)/ (NdotV * (1- k) + k);

	float Gs =  (SmithL * SmithV);
	return Gs;
}

GeometricShadow *= SchlickGGXGeometricShadowingFunction (NdotL, NdotV, roughness);