nee method to get env light id, added minor checks for pdf=0 and stuff

Author: keptsecret

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

@@ -5,6 +5,7 @@
 #define _NBL_BUILTIN_HLSL_PATH_TRACING_CONCEPTS_INCLUDED_
 
 #include <nbl/builtin/hlsl/concepts.hlsl>
+#include <nbl/builtin/hlsl/bxdf/common.hlsl>
 
 namespace nbl
 {
@@ -32,17 +33,12 @@ NBL_CONCEPT_END(
 #undef rand
 #include <nbl/builtin/hlsl/concepts/__end.hlsl>
 
-namespace impl
-{
-struct DummyInteraction {};
-}
-
 #define NBL_CONCEPT_NAME Ray
 #define NBL_CONCEPT_TPLT_PRM_KINDS (typename)
 #define NBL_CONCEPT_TPLT_PRM_NAMES (T)
 #define NBL_CONCEPT_PARAM_0 (ray, T)
 #define NBL_CONCEPT_PARAM_1 (v, typename T::vector3_type)
-#define NBL_CONCEPT_PARAM_2 (interaction, impl::DummyInteraction)
+#define NBL_CONCEPT_PARAM_2 (interaction, bxdf::surface_interactions::SIsotropic<bxdf::ray_dir_info::SBasic<float>, typename T::spectral_type>)
 #define NBL_CONCEPT_PARAM_3 (scalar, typename T::scalar_type)
 #define NBL_CONCEPT_PARAM_4 (color, typename T::spectral_type)
 NBL_CONCEPT_BEGIN(5)
@@ -56,7 +52,7 @@ NBL_CONCEPT_END(
     ((NBL_CONCEPT_REQ_TYPE)(T::vector3_type))
     ((NBL_CONCEPT_REQ_TYPE)(T::spectral_type))
     ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((ray.init(v/*origin*/, v/*direction*/)), ::nbl::hlsl::is_same_v, void))
-    ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((ray.template setInteraction<impl::DummyInteraction>(interaction)), ::nbl::hlsl::is_same_v, void))
+    ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((ray.template setInteraction<bxdf::surface_interactions::SIsotropic<bxdf::ray_dir_info::SBasic<float>, typename T::spectral_type> >(interaction)), ::nbl::hlsl::is_same_v, void))
     ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((ray.initPayload()), ::nbl::hlsl::is_same_v, void))
     ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((ray.shouldDoMIS()), ::nbl::hlsl::is_same_v, bool))
     ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((ray.foundEmissiveMIS(scalar)), ::nbl::hlsl::is_same_v, typename T::spectral_type))
@@ -267,6 +263,7 @@ NBL_CONCEPT_END(
     ((NBL_CONCEPT_REQ_TYPE_ALIAS_CONCEPT)(Ray, typename T::ray_type))
     ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((nee.deferred_pdf(scene, id, ray)), ::nbl::hlsl::is_same_v, typename T::scalar_type))
     ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((nee.template generate_and_quotient_and_pdf<impl::DummyMaterialSystem>(scene, matSys, v/*origin*/, interaction, v/*xi*/, depth)), ::nbl::hlsl::is_same_v, typename T::sample_quotient_return_type))
+    ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((nee.get_env_light_id()), ::nbl::hlsl::is_same_v, typename T::light_id_type))
     ((NBL_CONCEPT_REQ_EXPR_RET_TYPE)((nee.get_environment_radiance(ray)), ::nbl::hlsl::is_same_v, typename T::spectral_type))
 );
 #undef scene

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

@@ -84,7 +84,6 @@ struct Unidirectional
         vector3_type eps1 = randGen(depth * 2u + 1u, _sample);
 
         const vector3_type intersectP = intersectData.getPosition();
-        measure_type throughputCIE_Y = interaction.getLuminosityContributionHint();
 
         // sample lights
         const scalar_type neeProbability = bxdf.getNEEProb();
@@ -102,8 +101,6 @@ struct Unidirectional
             sample_type nee_sample = ret.getSample();
             quotient_pdf_type neeContrib = ret.getQuotientPdf();
 
-            // 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.
@@ -113,8 +110,11 @@ struct Unidirectional
                 // 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
+                if (!hlsl::isinf(neeContrib.pdf))
+                {
+                    const scalar_type otherGenOverLightAndChoice = bsdf_pdf * rcpChoiceProb / neeContrib.pdf;
+                    neeContrib.quotient /= 1.f + otherGenOverLightAndChoice * otherGenOverLightAndChoice;   // balance heuristic
+                }
 
                 const vector3_type origin = intersectP;
                 const vector3_type direction = nee_sample.getL().getDirection();
@@ -169,9 +169,8 @@ struct Unidirectional
 
     void missProgram(NBL_REF_ARG(ray_type) ray)
     {
-        vector3_type finalContribution = nee.get_environment_radiance(ray);
-        typename nee_type::light_id_type env_light_id;
-        env_light_id.id = 0u;
+        measure_type finalContribution = nee.get_environment_radiance(ray);
+        typename nee_type::light_id_type env_light_id = nee.get_env_light_id();
         const scalar_type pdf = nee.deferred_pdf(scene, env_light_id, ray);
         finalContribution *= ray.foundEmissiveMIS(pdf * pdf);
         ray.addPayloadContribution(finalContribution);
@@ -198,8 +197,6 @@ struct Unidirectional
         const uint32_t sampleCount = sampleIndex + 1;
         accumulator.addSample(sampleCount, ray.getPayloadAccumulatiion());
 
-        // TODO: visualize high variance
-
         // TODO: russian roulette early exit?
     }