message: Principled_getTransparency optimization
diff: @@ -339,15 +339,15 @@ vec3f Principled_getTransparency(const uniform PathTraceMaterial* uniform materi
  return T;
  // cut-out opacity
  - if (opacity > EPS)
  + if (self->thin && opacity > EPS)
  {
  - // refractive dielectric base
  + // glass base
  const float specular = clamp(self->specular * get1f(self->specularMap, dg.st, 1.f));
  const float metallic = clamp(self->metallic * get1f(self->metallicMap, dg.st, 1.f));
  const float dielectric = (1.f - metallic);
  - const float refractive = dielectric * transmission * specular;
  + const float glass = dielectric * transmission * specular;
  - if (refractive > EPS)
  + if (glass > EPS)
  {
  const float roughness = clamp(self->roughness * get1f(self->roughnessMap, dg.st, 1.f));
  const float anisotropy = clamp(self->anisotropy * get1f(self->anisotropyMap, dg.st, 1.f));
  @@ -355,8 +355,6 @@ vec3f Principled_getTransparency(const uniform PathTraceMaterial* uniform materi
  const float cosThetaO = max(-dot(ray.dir, dg.Ns), 0.f);
  - if (self->thin)
  - {
  // thin
  float ior = self->ior * get1f(self->iorMap, dg.st, 1.f);
  if (ior < 1.f) ior = rcp(ior);
  @@ -371,7 +369,6 @@ vec3f Principled_getTransparency(const uniform PathTraceMaterial* uniform materi
  T = ThinDielectric_getTransparency(cosThetaO, eta, attenuation);
  else
  T = ThinMicrofacetDielectric_getTransparency(cosThetaO, eta, roughness, anisotropy, attenuation);
  - }
  // clear coat
  const float coat = clamp(self->coat * get1f(self->coatMap, dg.st, 1.f));
  