Function MetalMaterial__eval

tutorials/pathtracer/pathtracer_device.cpp:643–659

}

Vec3fa MetalMaterial__eval(ISPCMetalMaterial* This, const BRDF& brdf, const Vec3fa& wo, const DifferentialGeometry& dg, const Vec3fa& wi)
{
  const FresnelConductor fresnel = make_FresnelConductor(Vec3fa(This->eta),Vec3fa(This->k));
  const PowerCosineDistribution distribution = make_PowerCosineDistribution(rcp(This->roughness));

  const float cosThetaO = dot(wo,dg.Ns);
  const float cosThetaI = dot(wi,dg.Ns);
  if (cosThetaI <= 0.0f || cosThetaO <= 0.0f) return Vec3fa(0.f);
  const Vec3fa wh = normalize(wi+wo);
  const float cosThetaH = dot(wh, dg.Ns);
  const float cosTheta = dot(wi, wh); // = dot(wo, wh);
  const Vec3fa F = eval(fresnel,cosTheta);
  const float D = eval(distribution,cosThetaH);
  const float G = min(1.0f, min(2.0f * cosThetaH * cosThetaO / cosTheta,
                                2.0f * cosThetaH * cosThetaI / cosTheta));
  return (Vec3fa(This->reflectance)*F) * D * G * rcp(4.0f*cosThetaO);
}

Vec3fa MetalMaterial__sample(ISPCMetalMaterial* This, const BRDF& brdf, const Vec3fa& Lw, const Vec3fa& wo, const DifferentialGeometry& dg, Sample3f& wi_o, Medium& medium, const Vec2f& s)
{