don't handle microfacet cache in path tracer, let mat sys do it; also eval and pdf don't need to take in cache

Author: keptsecret

include/nbl/builtin/hlsl/path_tracing/concepts.hlsl

@@ -161,7 +161,7 @@ NBL_CONCEPT_END(
 #define NBL_CONCEPT_PARAM_2 (matid, typename T::material_id_type)
 #define NBL_CONCEPT_PARAM_3 (aniso_inter, typename T::anisotropic_interaction_type)
 #define NBL_CONCEPT_PARAM_4 (iso_inter, typename T::isotropic_interaction_type)
-#define NBL_CONCEPT_PARAM_5 (aniso_cache, typename T::anisocache_type)
+#define NBL_CONCEPT_PARAM_5 (cache_, typename T::cache_type)
 #define NBL_CONCEPT_PARAM_6 (iso_cache, typename T::isocache_type)
 #define NBL_CONCEPT_PARAM_7 (u, typename T::vector3_type)
 #define NBL_CONCEPT_PARAM_8 (cie_y, typename T::measure_type)
@@ -171,7 +171,7 @@ NBL_CONCEPT_BEGIN(9)
 #define matid NBL_CONCEPT_PARAM_T NBL_CONCEPT_PARAM_2
 #define aniso_inter NBL_CONCEPT_PARAM_T NBL_CONCEPT_PARAM_3
 #define iso_inter NBL_CONCEPT_PARAM_T NBL_CONCEPT_PARAM_4
-#define aniso_cache NBL_CONCEPT_PARAM_T NBL_CONCEPT_PARAM_5
+#define cache_ NBL_CONCEPT_PARAM_T NBL_CONCEPT_PARAM_5
 #define iso_cache NBL_CONCEPT_PARAM_T NBL_CONCEPT_PARAM_6
 #define u NBL_CONCEPT_PARAM_T NBL_CONCEPT_PARAM_7
 #define cie_y NBL_CONCEPT_PARAM_T NBL_CONCEPT_PARAM_8
@@ -182,15 +182,14 @@ NBL_CONCEPT_END(
     ((NBL_CONCEPT_REQ_TYPE)(T::quotient_pdf_type))
     ((NBL_CONCEPT_REQ_TYPE)(T::measure_type))
     ((NBL_CONCEPT_REQ_TYPE)(T::anisotropic_interaction_type))
-    ((NBL_CONCEPT_REQ_TYPE)(T::isotropic_interaction_type))
-    ((NBL_CONCEPT_REQ_TYPE)(T::anisocache_type))
-    ((NBL_CONCEPT_REQ_TYPE)(T::isocache_type))
+    ((NBL_CONCEPT_REQ_TYPE)(T::cache_type))
     ((NBL_CONCEPT_REQ_TYPE)(T::bxdfnode_type))
     ((NBL_CONCEPT_REQ_TYPE)(T::create_params_t))
     ((NBL_CONCEPT_REQ_TYPE_ALIAS_CONCEPT)(BxdfNode, typename T::bxdfnode_type))
-    ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((matsys.eval(matid, _sample, aniso_inter, aniso_cache)), ::nbl::hlsl::is_same_v, typename T::measure_type))
-    ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((matsys.generate(matid, aniso_inter, u, aniso_cache)), ::nbl::hlsl::is_same_v, typename T::sample_type))
-    ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((matsys.quotient_and_pdf(matid, _sample, aniso_inter, aniso_cache)), ::nbl::hlsl::is_same_v, typename T::quotient_pdf_type))
+    ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((matsys.eval(matid, _sample, aniso_inter)), ::nbl::hlsl::is_same_v, typename T::measure_type))
+    ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((matsys.generate(matid, aniso_inter, u, cache_)), ::nbl::hlsl::is_same_v, typename T::sample_type))
+    ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((matsys.pdf(matid, _sample, aniso_inter)), ::nbl::hlsl::is_same_v, typename T::scalar_type))
+    ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((matsys.quotient_and_pdf(matid, _sample, aniso_inter, cache_)), ::nbl::hlsl::is_same_v, typename T::quotient_pdf_type))
     ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((matsys.getBxDFNode(matid, aniso_inter)), ::nbl::hlsl::is_same_v, typename T::bxdfnode_type))
     ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((matsys.hasEmission(matid)), ::nbl::hlsl::is_same_v, bool))
     ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((matsys.setMonochromeEta(matid, cie_y)), ::nbl::hlsl::is_same_v, typename T::scalar_type))
@@ -199,7 +198,7 @@ NBL_CONCEPT_END(
 #undef cie_y
 #undef u
 #undef iso_cache
-#undef aniso_cache
+#undef cache_
 #undef iso_inter
 #undef aniso_inter
 #undef matid

include/nbl/builtin/hlsl/path_tracing/unidirectional.hlsl

@@ -44,8 +44,7 @@ struct Unidirectional
     using closest_hit_type = typename Intersector::closest_hit_type;
     using bxdfnode_type = typename MaterialSystem::bxdfnode_type;
     using anisotropic_interaction_type = typename MaterialSystem::anisotropic_interaction_type;
-    using isotropic_interaction_type = typename anisotropic_interaction_type::isotropic_interaction_type;
-    using anisocache_type = typename MaterialSystem::anisocache_type;
+    using cache_type = typename MaterialSystem::cache_type;
     using quotient_pdf_type = typename NextEventEstimator::quotient_pdf_type;
     using tolerance_method_type = typename NextEventEstimator::tolerance_method_type;
 
@@ -102,21 +101,17 @@ struct Unidirectional
             sample_type nee_sample = ret.getSample();
             quotient_pdf_type neeContrib = ret.getQuotientPdf();
 
-            // We don't allow non watertight transmitters in this renderer
-            // but if we allowed non-watertight transmitters (single water surface), it would make sense just to apply this line by itself
-            const scalar_type monochromeEta = materialSystem.setMonochromeEta(matID, throughputCIE_Y);
-            bxdf::fresnel::OrientedEtas<monochrome_type> orientedEta = bxdf::fresnel::OrientedEtas<monochrome_type>::create(interaction.getNdotV(), hlsl::promote<monochrome_type>(monochromeEta));
-            anisocache_type _cache = anisocache_type::template create<anisotropic_interaction_type, sample_type>(interaction, nee_sample, orientedEta);
+            // We don't allow non watertight transmitters in this renderer, one cannot reach a light from the backface (optimization)
 
             // While NEE or other generators are not supposed to pick up Delta lobes by accident, we need the MIS weights to add up to 1 for the non-delta lobes.
             // So we need to weigh the Delta lobes as if the MIS weight is always 1, but other areas regularly.
             // Meaning that eval's pdf should equal quotient's pdf , this way even the diffuse contributions coming from within a specular lobe get a MIS weight near 0 for NEE.
             // This stops a discrepancy in MIS weights and NEE mistakenly trying to add non-delta lobe contributions with a MIS weight > 0 and creating energy from thin air.
             if (neeContrib.pdf > scalar_type(0.0))
             {
-                // we'll need an `eval_and_mis_weight` and `quotient_and_mis_weight`
-                const scalar_type bsdf_pdf = materialSystem.pdf(matID, nee_sample, interaction, _cache);
-                neeContrib.quotient *= materialSystem.eval(matID, nee_sample, interaction, _cache) * rcpChoiceProb;
+                // TODO: we'll need an `eval_and_mis_weight` and `quotient_and_mis_weight`
+                const scalar_type bsdf_pdf = materialSystem.pdf(matID, nee_sample, interaction);
+                neeContrib.quotient *= materialSystem.eval(matID, nee_sample, interaction) * rcpChoiceProb;
                 const scalar_type otherGenOverLightAndChoice = bsdf_pdf * rcpChoiceProb / neeContrib.pdf;
                 neeContrib.quotient /= 1.f + otherGenOverLightAndChoice * otherGenOverLightAndChoice;   // balance heuristic
 
@@ -137,7 +132,7 @@ struct Unidirectional
         vector3_type bxdfSample;
         vector3_type throughput = ray.getPayloadThroughput();
         {
-            anisocache_type _cache;
+            cache_type _cache;
             sample_type bsdf_sample = materialSystem.generate(matID, interaction, eps1, _cache);
 
             if (!bsdf_sample.isValid())