Bxdf fixes cook torrance #930

devshgraphicsprogramming · 2025-09-16T14:03:10Z

Description

Continues #899 , #916 and #919

Testing

TODO list:

…eturn quants

include/nbl/builtin/hlsl/bxdf/common.hlsl

include/nbl/builtin/hlsl/math/functions.hlsl

devshgraphicsprogramming · 2025-09-16T14:11:56Z

include/nbl/builtin/hlsl/cpp_compat/vector.hlsl

+#ifndef __HLSL_VERSION
+namespace std
+{
+template<typename T, uint16_t N>
+struct hash<nbl::hlsl::vector<T,N> >
+{
+    size_t operator()(const nbl::hlsl::vector<T,N>& v) const noexcept
+    {
+        size_t seed = 0;
+        NBL_UNROLL for (uint16_t i = 0; i < N; i++)
+            nbl::core::hash_combine(seed, v[i]);
+        return seed;
+    }
+};
+
+template<typename T>
+struct hash<nbl::hlsl::vector<T,1> >
+{
+    size_t operator()(const nbl::hlsl::vector<T,1>& v) const noexcept
+    {
+        std::hash<T> hasher;
+        return hasher(v.x);
+    }
+};
+}
+#endif


are you sure having this specialization globally is a good idea ?

What do you use it for ?

Also used in the bucket bxdf test, for hash map buckets

then define it in that example, nowhere else

I moved this over from the test due to this comment
Devsh-Graphics-Programming/Nabla-Examples-and-Tests#165 (comment)

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

devshgraphicsprogramming · 2025-09-17T17:20:56Z

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

+    N ndf;
+    F fresnel;
+};
+
+template<class Config, class N, class F>
+NBL_PARTIAL_REQ_TOP(config_concepts::MicrofacetConfiguration<Config> && ndf::NDF<N> && fresnel::Fresnel<F>)
+struct SCookTorrance<Config, N, F, true NBL_PARTIAL_REQ_BOT(config_concepts::MicrofacetConfiguration<Config> && ndf::NDF<N> && fresnel::Fresnel<F>) >
+{


any chance at inheriting from a common base for both BRDF and BSDF, so that we don't have so much duplicate code (BRDF and BSDF only differ in how they factor the reflectance into the generation and pdf)

devshgraphicsprogramming · 2025-09-23T07:47:52Z

include/nbl/builtin/hlsl/bxdf/reflection/beckmann.hlsl

+    static this_t create(scalar_type A, NBL_CONST_REF_ARG(spectral_type) eta, NBL_CONST_REF_ARG(spectral_type) etak)
    {
        this_t retval;
        retval.__base.ndf.__base.A = vector2_type(A, A);
        retval.__base.ndf.__base.a2 = A*A;
-        retval.__base.fresnel.ior = ior0;
-        retval.__base.fresnel.iork = ior1;
-        retval.__base.fresnel.iork2 = ior1*ior1;
+        retval.__base.fresnel.eta = eta;
+        retval.__base.fresnel.etak2 = etak * etak;
+        retval.__base.fresnel.etaLen2 = eta * eta + retval.__base.fresnel.etak2;
        return retval;
    }


why are you assuming the fresnel used ?

devshgraphicsprogramming · 2025-09-23T07:48:07Z

include/nbl/builtin/hlsl/bxdf/reflection/beckmann.hlsl

-        spectral_type ior0;
-        spectral_type ior1;


you need to pass the fresnel already set up

devshgraphicsprogramming · 2025-09-23T07:48:44Z

include/nbl/builtin/hlsl/bxdf/reflection/ggx.hlsl

-        return create(params.A, params.ior0, params.ior1);
+        return create(params.A, params.eta, params.etak);
    }



why do all these still exist and aren't just typedefs for Cook Torrance ?

devshgraphicsprogramming · 2025-09-23T07:49:18Z

include/nbl/builtin/hlsl/bxdf/reflection/lambertian.hlsl

    sample_type generate(NBL_CONST_REF_ARG(isotropic_interaction_type) interaction, const vector2_type u)
    {
-        return __base.generate(anisotropic_interaction_type::create(interaction), u);
+        return __base.template generate<vector2_type>(anisotropic_interaction_type::create(interaction), u);
    }
    sample_type generate(NBL_CONST_REF_ARG(anisotropic_interaction_type) interaction, const vector2_type u)
    {
-        return __base.generate(interaction, u);
+        return __base.template generate<vector2_type>(interaction, u);
    }


why not just typedef instead of writing pointless passthrough class ?

devshgraphicsprogramming · 2025-09-23T07:52:13Z

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

        {
-            quant_type G2 = ndf.template correlated<sample_type, isotropic_interaction_type>(gq, qq, _sample, interaction);
-            DG *= G2.microfacetMeasure;
+            DG *= ndf.template correlated<sample_type, isotropic_interaction_type>(gq, _sample, interaction);


lower the gq creation as well

devshgraphicsprogramming · 2025-09-23T07:52:17Z

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

        {
-            quant_type G2 = ndf.template correlated<sample_type, anisotropic_interaction_type>(gq, qq, _sample, interaction);
-            DG *= G2.microfacetMeasure;
+            DG *= ndf.template correlated<sample_type, anisotropic_interaction_type>(gq, _sample, interaction);


lower the gq creation as well

… for now

…ction/cache versions

…ook torrance template

…y moved into base

…xdfs

…nctionality moved into base

keptsecret added 23 commits September 4, 2025 10:46

changes to dual measure quant, old stuff commented out for now

5218545

create query structs in beckmann ndf, removed query concepts, funcs r…

f7525af

…eturn quants

did the same for ggx ndf, some fixes to beckmann

c50db68

Merge branch 'master' into bxdf_fixes_cook_torrance

c49bedb

fixes to ndf concept

319c954

moved eval, quotient/pdf into cook torrance base

4eeacf1

moved generate H into ndfs, generate impl in cook torrance base

e7bc784

use new cook torrance base in microfacet bxdfs

72226bb

Merge branch 'master' into bxdf_fixes_cook_torrance

f34b348

numerous typo bug fixes

ad13044

fixes to ggx ndf

d8d2116

fixed conductor fresnel naming ior as eta

238b08e

minor fixes to beckmann ndf, removed obsolete comments

8bc707f

added luminosity contribution hint to cook torrance bsdfs

9fb28cf

added aniso overloads to isotropic bxdf methods

4cb8a0a

checks for invalid generate sample

392dc31

removed obsolete commented out stuff

02de86e

added cartesian-polar conversions from unit tests

4a7f532

Merge branch 'fix_rotation_mat' into bxdf_fixes_cook_torrance

80c4f67

Merge branch 'master' into bxdf_fixes_cook_torrance

6233bd1

vector hashes

ce5fbac

Merge branch 'fix_rotation_mat' into bxdf_fixes_cook_torrance

47e814b

Merge branch 'master' into bxdf_fixes_cook_torrance

c983975

devshgraphicsprogramming commented Sep 16, 2025

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devshgraphicsprogramming commented Sep 16, 2025

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include/nbl/builtin/hlsl/math/functions.hlsl Outdated Show resolved Hide resolved

devshgraphicsprogramming commented Sep 16, 2025

View reviewed changes

keptsecret added 2 commits September 17, 2025 15:26

fix fresnel usage in bxdf pdf

0f2ee0b

fix F calc in generate

b5f02e6

devshgraphicsprogramming commented Sep 17, 2025

View reviewed changes

include/nbl/builtin/hlsl/bxdf/fresnel.hlsl Outdated Show resolved Hide resolved

devshgraphicsprogramming commented Sep 17, 2025

View reviewed changes

keptsecret added 3 commits September 22, 2025 16:38

made smith functions return measureless

3e3589b

use type alias macro from config

4bdf199

adjust ndf concept, change fresnel conductor ior to eta

4faecc3

devshgraphicsprogramming commented Sep 23, 2025

View reviewed changes

keptsecret added 21 commits September 23, 2025 16:01

combine brdf/bsdf cook torrance into same struct, old stuff commented…

407da2f

… for now

moved duplicate code in eval, pdf, quotient_pdf into templated intera…

638b8b5

…ction/cache versions

some changes to fresnel, cook torrance base

c587820

reverted ggx ndf to use optimizations

d438360

pdf function checks for backfacing V

5f49f11

reduced beckmann, ggx ndfs to single struct with enable_ifs

627074b

put concepts back in for ndf impl

3896231

ggx ndf determine clamp with template bool

91b39d5

moved A out of ndf base into generate base

2a3cda3

added create methods to ndfs, cook torrance base; slight changes to c…

c9f9366

…ook torrance template

make beckmann + ggx bxdfs typedefs of cooktorrance base, functionalit…

fd128e6

…y moved into base

added flipSign func that copies sign of rhs

882375e

remove unused var

b22d570

moved cook torrance base into base folder, removed commented out in b…

c0586f5

…xdfs

make lambertian + oren nayar bxdfs typedefs of corresponding base, fu…

9eeb248

…nctionality moved into base

fix microfacet bxdf concept

26c76e4

fixes to cook torrance generate

58e2a0b

templated ray_dir_info reflect/refract funcs

2a08728

pdf should return inf when smooth cook torrance bxdf

b993e47

set pdf=0 in specific cases

f3cb6ff

added checking for TIR in bsdfs

7389c9a

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Bxdf fixes cook torrance #930

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devshgraphicsprogramming commented Sep 16, 2025 •

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devshgraphicsprogramming commented Sep 16, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Description

Testing

TODO list:

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devshgraphicsprogramming commented Sep 16, 2025 •

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