eval transmitted should do 1-F

Author: keptsecret

include/nbl/builtin/hlsl/bxdf/base/cook_torrance_base.hlsl

@@ -184,7 +184,14 @@ struct SCookTorrance
         scalar_type clampedVdotH = cache.getVdotH();
         NBL_IF_CONSTEXPR(IsBSDF)
             clampedVdotH = hlsl::abs(clampedVdotH);
-        return impl::__implicit_promote<spectral_type, typename fresnel_type::vector_type>::__call(_f(clampedVdotH)) * DG;
+        
+        NBL_IF_CONSTEXPR(IsBSDF)
+        {
+            const scalar_type reflectance = _f(clampedVdotH)[0];
+            return hlsl::promote<spectral_type>(hlsl::mix(reflectance, scalar_type(1.0) - reflectance, cache.isTransmission())) * DG;
+        }
+        else
+            return impl::__implicit_promote<spectral_type, typename fresnel_type::vector_type>::__call(_f(clampedVdotH)) * DG;
     }
 
     template<typename C=bool_constant<!IsBSDF> >
@@ -267,7 +274,7 @@ struct SCookTorrance
             return sample_type::createInvalid();    // should check if sample direction is invalid
 
         cache = anisocache_type::createPartial(VdotH, LdotH, localH.z, transmitted, rcpEta);
-        // assert(cache.isValid(fresnel.getRefractionOrientedEta())); TODO get clarification on case NdotV<0, transmitted=false (technically not TIR?)
+        // assert(cache.isValid(fresnel.getRefractionOrientedEta()));
 
         struct reflect_refract_wrapper  // so we don't recalculate LdotH
         {
@@ -347,7 +354,7 @@ struct SCookTorrance
         fresnel_type _f = impl::getOrientedFresnel<fresnel_type, IsBSDF>::__call(fresnel, interaction.getNdotV());
 
         const bool valid = impl::checkValid<fresnel_type, IsBSDF>::template __call<sample_type, Interaction, MicrofacetCache>(_f, _sample, interaction, cache);
-        assert(valid);
+        // assert(valid);
 
         scalar_type G2_over_G1 = scalar_type(1.0);
         if (_pdf < bit_cast<scalar_type>(numeric_limits<scalar_type>::infinity))

include/nbl/builtin/hlsl/bxdf/fresnel.hlsl

@@ -438,7 +438,7 @@ struct Dielectric
 
     static T __call(NBL_CONST_REF_ARG(T) orientedEta2, const scalar_type clampedCosTheta)
     {
-        const scalar_type sinTheta2 = 1.0 - clampedCosTheta * clampedCosTheta;
+        const scalar_type sinTheta2 = scalar_type(1.0) - clampedCosTheta * clampedCosTheta;
 
         // the max() clamping can handle TIR when orientedEta2<1.0
         const T t0 = hlsl::sqrt<T>(hlsl::max<T>(orientedEta2 - sinTheta2, hlsl::promote<T>(0.0)));
@@ -447,7 +447,7 @@ struct Dielectric
         const T t2 = orientedEta2 * clampedCosTheta;
         const T rp = (t0 - t2) / (t0 + t2);
 
-        return (rs * rs + rp * rp) * 0.5f;
+        return (rs * rs + rp * rp) * scalar_type(0.5);
     }
 
     T operator()(const scalar_type clampedCosTheta)