// Importance sampling: compute an importance sample {phi, theta} and generate a local (z-up) microsurface normal, as well as an according normal distribution
@@ -37,6 +49,7 @@ vec2 ggxImportanceSample(const in vec2 random_sample, const in float roughness)
returnvec2(phi,theta);
}
// With a given random sample, this function will generate an importance sample (output via the importance parameter), as well as an accordingly sampled z-up local microsurface normal