New tgmath #165

Przemog1 · 2024-12-30T12:54:39Z

No description provided.

…Examples-and-Tests into bxdf_unit_tests

…ng/Nabla-Examples-and-Tests into bxdf_unit_tests

devshgraphicsprogramming · 2025-01-06T08:51:06Z

why do you have random things from sorakrit here instead of your own branch against his or master ?

I literally can't see whats yours and what's @keptsecret's.

66_HLSLBxDFTests/app_resources/tests.hlsl

devshgraphicsprogramming · 2025-01-08T08:48:07Z

66_HLSLBxDFTests/app_resources/tests.hlsl

+        retval.T = nbl::hlsl::normalize<float32_t3>(rngFloat301(retval.rng));
+
+        retval.T = nbl::hlsl::normalize<float32_t3>(retval.T - nbl::hlsl::dot<float32_t3>(retval.T, retval.N) * retval.N); // gram schmidt


you can still generate T almost colinear to N and end up with numerical issues, personally I'd use the frisvad basis function + random rotation around N (only one random number needed)

devshgraphicsprogramming · 2025-01-08T08:51:51Z

66_HLSLBxDFTests/app_resources/tests.hlsl

+        retval.eta = 1.3;// rngFloat01(retval.rng) + 1.0;
+        retval.ior = float32_t3x2(1.02, 1.0,      // randomize at some point?
+                                1.3, 2.0,
+                                1.02, 1.0);


you can only have one:

eta for BSDFs (things that refract) because refraction can only be done monochrome (each wavelength refracts at different angle)

ior for BRDFs (things that reflect) because reflection is alawys the same

Also eta is just a ratio of two refractive indices, and using matrix<float32_T,3,2> is very bad semantically because it assumes we'll have 3 spectral buckets.

Ideally we should do tests in monochrome, so just a float eta should be enough or vector<float,2> ior

Do we want to keep ior as a matrix in the BxDF?
For the BRDFs https://github.com/Devsh-Graphics-Programming/Nabla/blob/6fc78a46f466d176f1b3a4c84f18f7448d3cd894/include/nbl/builtin/hlsl/bxdf/reflection.hlsl#L361

no dont keep it was a super bad idea, I also want to make everything templated so that vector<T,3> isn't implied for the colours and we could do other number of spectral buckets (1, 2 or 4 for spectral rendering)

devshgraphicsprogramming · 2025-01-08T09:19:52Z

66_HLSLBxDFTests/app_resources/tests.hlsl

+        SBxDFTestResources retval;
+
+        retval.rng = nbl::hlsl::Xoroshiro64Star::construct(seed);
+        retval.u = float32_t3(rngFloat01(retval.rng), rngFloat01(retval.rng), 0.0);


the third random number is sometimes necessary to discern discrete BxDF branches:

reflection vs refraction in e.g. glass

diffuse vs specular in e.g. plastic

choosing a leaf BxDF in a mixture/tree of BxDFs

devshgraphicsprogramming · 2025-01-08T09:21:03Z

66_HLSLBxDFTests/app_resources/tests.hlsl

+    ray_dir_info_t dV(int axis)
+    {
+        float32_t3 d = (float32_t3)0.0;
+        d[axis] += h;
+        ray_dir_info_t retval;
+        retval.direction = V.direction + d;
+        return retval;
+    }
+
+    float h = 0.001;


what do you need dV for?

this is not the way to vary V parameter

devshgraphicsprogramming · 2025-01-08T09:40:00Z

66_HLSLBxDFTests/app_resources/tests.hlsl

@@ -78,6 +80,9 @@ struct SBxDFTestResources
    float32_t2 alpha;
    float eta;
    float32_t3x2 ior;
+
+    float32_t3 eta2;    // what is this?


eta squared, compute on the fly, don't leave stuff like this here

devshgraphicsprogramming · 2025-01-08T09:50:43Z

66_HLSLBxDFTests/app_resources/tests.hlsl

+        t.meta.result = t.test();
+        t.meta.testName = "u offset";
+        return t.meta;
+    }


setting those thousands of times will be expensive, function should be void and not return anything, callback instead of meta

devshgraphicsprogramming · 2025-01-08T09:54:35Z

66_HLSLBxDFTests/app_resources/tests.hlsl

+    static STestMeta run(uint32_t2 seed)
+    {
+        this_t t;
+        t.init(seed);


I'd make the function take uint32_t as an argument, then run a hash function (wide not deep)
https://rene.ruhr/gfx/gpuhash/

This will make it easy to invoke multiple run(uint32_t invocationID) in parallel independently, be it on CPU with for loop or GPU with gl_GlobalInvocationID.x

devshgraphicsprogramming · 2025-01-08T10:07:43Z

66_HLSLBxDFTests/app_resources/tests.hlsl

+template<class BxDF, bool aniso = false>
+struct TestVOffset : TestBxDF<BxDF>
+{
+    using base_t = TestBase<BxDF>;
+    using this_t = TestVOffset<BxDF, aniso>;
+
+    float32_t4 test()
+    {
+        sample_t s, sx, sy, sz;
+        quotient_pdf_t pdf;
+        float32_t3 brdf;
+        aniso_cache cache, dummy;
+
+        iso_interaction isointerx = iso_interaction::create(base_t::rc.dV(0), base_t::rc.N);
+        aniso_interaction anisointerx = aniso_interaction::create(isointerx, base_t::rc.T, base_t::rc.B);
+        iso_interaction isointery = iso_interaction::create(base_t::rc.dV(1), base_t::rc.N);
+        aniso_interaction anisointery = aniso_interaction::create(isointery, base_t::rc.T, base_t::rc.B);
+        iso_interaction isointerz = iso_interaction::create(base_t::rc.dV(2), base_t::rc.N);
+        aniso_interaction anisointerz = aniso_interaction::create(isointerz, base_t::rc.T, base_t::rc.B);


there's no point to this test existing, the test I've outlined ONLY makes sense for varying (differentiating) the 2D random number xi, because thats the uniform distribution that must be stretched and squeezed to form the PDF of the importance sampler

devshgraphicsprogramming · 2025-01-08T10:08:37Z

66_HLSLBxDFTests/main.cpp

+
+#include "app_resources/tests.hlsl"
+
+#define ASSERT_ZERO(x) (assert(all<bool32_t4>((x.result) < float32_t4(1e-3))));


use a nice callback

devshgraphicsprogramming · 2025-01-08T10:10:14Z

66_HLSLBxDFTests/main.cpp

+    const uint32_t2 state = uint32_t2(12u, 69u);    // (12u, 69u)
+
+    // test u offset, 2 axis
+    ASSERT_ZERO((TestUOffset<bxdf::reflection::SLambertianBxDF<sample_t, iso_interaction, aniso_interaction>>::run(state)));
+    ASSERT_ZERO((TestUOffset<bxdf::reflection::SOrenNayarBxDF<sample_t, iso_interaction, aniso_interaction>>::run(state)));
+    printResult(TestUOffset<bxdf::reflection::SBeckmannBxDF<sample_t, iso_cache, aniso_cache>,false>::run(state));
+    ASSERT_ZERO((TestUOffset<bxdf::reflection::SBeckmannBxDF<sample_t, iso_cache, aniso_cache>,true>::run(state)));
+    printResult(TestUOffset<bxdf::reflection::SGGXBxDF<sample_t, iso_cache, aniso_cache>,false>::run(state));
+    ASSERT_ZERO((TestUOffset<bxdf::reflection::SGGXBxDF<sample_t, iso_cache, aniso_cache>,true>::run(state)));
+
+    ASSERT_ZERO((TestUOffset<bxdf::transmission::SLambertianBxDF<sample_t, iso_interaction, aniso_interaction>>::run(state)));
+    printResult(TestUOffset<bxdf::transmission::SBeckmannDielectricBxDF<sample_t, iso_cache, aniso_cache>,false>::run(state));
+    ASSERT_ZERO((TestUOffset<bxdf::transmission::SBeckmannDielectricBxDF<sample_t, iso_cache, aniso_cache>,true>::run(state)));
+    printResult(TestUOffset<bxdf::transmission::SGGXDielectricBxDF<sample_t, iso_cache, aniso_cache>,false>::run(state));
+    printResult(TestUOffset<bxdf::transmission::SGGXDielectricBxDF<sample_t, iso_cache, aniso_cache>,true>::run(state));


you need to run the tests thousands of times with different seeds, I'd use for_each over a ranges::iota_view with par_unseq policy to perform these tests on all CPU cores at once.
https://godbolt.org/z/xvxE7jzE3

this connects with https://github.com/Devsh-Graphics-Programming/Nabla-Examples-and-Tests/pull/165/files#r1906914911

devshgraphicsprogramming · 2025-01-08T10:21:49Z

66_HLSLBxDFTests/app_resources/tests.hlsl

+        if NBL_CONSTEXPR_FUNC (is_basic_brdf_v<BxDF>)
+        {
+            s = base_t::bxdf.generate(base_t::anisointer, base_t::rc.u.xy);
+            sx = base_t::bxdf.generate(base_t::anisointer, base_t::rc.u.xy + float32_t2(base_t::rc.h,0));
+            sy = base_t::bxdf.generate(base_t::anisointer, base_t::rc.u.xy + float32_t2(0,base_t::rc.h));
+        }
+        if NBL_CONSTEXPR_FUNC (is_microfacet_brdf_v<BxDF>)
+        {
+            s = base_t::bxdf.generate(base_t::anisointer, base_t::rc.u.xy, cache);
+            sx = base_t::bxdf.generate(base_t::anisointer, base_t::rc.u.xy + float32_t2(base_t::rc.h,0), dummy);
+            sy = base_t::bxdf.generate(base_t::anisointer, base_t::rc.u.xy + float32_t2(0,base_t::rc.h), dummy);
+        }
+        if NBL_CONSTEXPR_FUNC (is_basic_bsdf_v<BxDF>)
+        {
+            s = base_t::bxdf.generate(base_t::anisointer, base_t::rc.u);
+            sx = base_t::bxdf.generate(base_t::anisointer, base_t::rc.u + float32_t3(base_t::rc.h,0,0));
+            sy = base_t::bxdf.generate(base_t::anisointer, base_t::rc.u + float32_t3(0,base_t::rc.h,0));
+        }
+        if NBL_CONSTEXPR_FUNC (is_microfacet_bsdf_v<BxDF>)
+        {
+            s = base_t::bxdf.generate(base_t::anisointer, base_t::rc.u, cache);
+            float32_t3 ux = base_t::rc.u + float32_t3(base_t::rc.h,0,0);
+            sx = base_t::bxdf.generate(base_t::anisointer, ux, dummy);
+            float32_t3 uy = base_t::rc.u + float32_t3(0,base_t::rc.h,0);
+            sy = base_t::bxdf.generate(base_t::anisointer, uy, dummy);
+        }


h should be a parameter of each individual specialized BxDF test, because its specific to the differential test and also may need to change depending on the BxDF getting tested

also maybe compute the perturbed u above for readability

devshgraphicsprogramming · 2025-01-08T10:25:42Z

66_HLSLBxDFTests/app_resources/tests.hlsl

+        float32_t2x2 m = float32_t2x2(sx.TdotL - s.TdotL, sy.TdotL - s.TdotL, sx.BdotL - s.BdotL, sy.BdotL - s.BdotL);
+        float det = nbl::hlsl::determinant<float32_t2x2>(m);
+
+        return float32_t4(nbl::hlsl::abs<float32_t3>(pdf.value() - brdf), nbl::hlsl::abs<float>(det*pdf.pdf/s.NdotL) * 0.5);


this needs to be done better semantically with a callback, one thing for each individually.

Alos pdf.value() does not equal brdf in general!!!!!

P.s. the *0.5 thing on the PDF to Jacobian ratio was a thing for visualization, you should really have a callback which gets triggered if the value is too far from 1.0

devshgraphicsprogramming · 2025-01-08T10:38:52Z

66_HLSLBxDFTests/app_resources/tests.hlsl

+        }
+


you need to skip checking anything that produces an "impossible" s, so if eval or quotient is 0, you can skip the rest of the function (but not before you check pdf and quotient for 0 and INF respectively - the checks also check for NaN)

add more simple tests for:

pdf>0 because something you generated cannot have 0 probability of getting generated

quotient<INF always because our importance sampler's job is to prevent that!

positivity, all pdf, quotient, and eval need to be >=0

recprocity (eval must be equal if we swap L and V around, make a method/function to swap L and V around in s, the interaction, the bxdf itself and the cache)

Leave lots of comments.

Also when pdf is close to INF (above some super high threshold) you need to back off the last test you have here

devshgraphicsprogramming · 2025-01-09T15:46:41Z

66_HLSLBxDFTests/app_resources/tests.hlsl

+        retval.V.direction = nbl::hlsl::normalize<float32_t3>(projected_hemisphere_generate<float>(rngUniformDist<float32_t2>(retval.rng)));
+        retval.N = nbl::hlsl::normalize<float32_t3>(projected_hemisphere_generate<float>(rngUniformDist<float32_t2>(retval.rng)));


not projected hemisphere, just hemisphere.

Also not hemisphere but full sphere, because its good to test that BRDFs handle invalid (below hemisphere) correctly

devshgraphicsprogramming · 2025-01-10T10:28:01Z

66_HLSLBxDFTests/app_resources/tests.hlsl

+uint32_t pcg_hash(uint32_t v)
+{
+    uint32_t state = v * 747796405u + 2891336453u;
+	uint32_t word = ((state >> ((state >> 28u) + 4u)) ^ state) * 277803737u;
+	return (word >> 22u) ^ word;
+}


this is useful in its own header like xoroshiro is

…ng/Nabla-Examples-and-Tests into bxdf_unit_tests

keptsecret and others added 18 commits December 17, 2024 10:35

hlsl bxdf test dir

ba9fde5

test bxdf compiles

4f9dc9f

minor namespace changes

2091701

added bsdf test

385bcec

Merge branch 'master' into bxdf_unit_tests

5ba4dfd

fix namespace

9212b65

Example 62 fix

32f959d

Merge branch 'master' into bxdf_unit_tests

8128422

working? test

70b28d8

rng test util struct

f177090

beckmann dielectric test

382c862

Updated examples

e0bde55

Merge branch 'master' of github.com:Devsh-Graphics-Programming/Nabla-…

46c80dc

…Examples-and-Tests into bxdf_unit_tests

Fixes

677323b

Merge branch 'bxdf_unit_tests' of github.com:Devsh-Graphics-Programmi…

1bc825d

…ng/Nabla-Examples-and-Tests into bxdf_unit_tests

Merge branch 'master' into bxdf_unit_tests

76db120

fix syntax

9de6ae8

more tests (all brdfs) and utils

6dbc89a

keptsecret added 5 commits January 7, 2025 14:55

template tests

9c379eb

all existing tests into templates

5140f85

simplify test template and usage

fb7b31b

diff v test

3c415fd

test metadata struct for more info

3524449

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keptsecret added 2 commits January 9, 2025 14:59

improve rng function

17b253c

fix bugs in rng

59d14c3

devshgraphicsprogramming reviewed Jan 9, 2025

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keptsecret added 4 commits January 10, 2025 11:47

fix tests, use uniform sampling

fac1ed1

use new sampling

1ecd0c0

hash to uint2 seed

c983141

use glm quaternions instead

c02c9f0

devshgraphicsprogramming reviewed Jan 10, 2025

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keptsecret and others added 13 commits January 13, 2025 12:03

callbacks on detect error

0c3d657

fix callback usage bugs

01d4799

changed ior, spectral_type usage in bxdf

887c3a0

use new pcg hlsl

9ab4e8e

callback reruns bxdf compute

c8859c0

added bxdf names for debugging

414f961

Saving work

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Merge branch 'bxdf_unit_tests' of github.com:Devsh-Graphics-Programmi…

cdff4c6

…ng/Nabla-Examples-and-Tests into bxdf_unit_tests

check util functions

3668d99

reciprocity test

a66dc44

negative value checks

b5d9778

Saving work

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Merge branch 'bxdf_unit_tests' of github.com:Devsh-Graphics-Programmi…

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…ng/Nabla-Examples-and-Tests into bxdf_unit_tests

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New tgmath #165

New tgmath #165

Przemog1 commented Dec 30, 2024

devshgraphicsprogramming commented Jan 6, 2025 •

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		retval.T = nbl::hlsl::normalize<float32_t3>(rngFloat301(retval.rng));

		retval.T = nbl::hlsl::normalize<float32_t3>(retval.T - nbl::hlsl::dot<float32_t3>(retval.T, retval.N) * retval.N); // gram schmidt


		#include "app_resources/tests.hlsl"

		#define ASSERT_ZERO(x) (assert(all<bool32_t4>((x.result) < float32_t4(1e-3))));

		retval.V.direction = nbl::hlsl::normalize<float32_t3>(projected_hemisphere_generate<float>(rngUniformDist<float32_t2>(retval.rng)));
		retval.N = nbl::hlsl::normalize<float32_t3>(projected_hemisphere_generate<float>(rngUniformDist<float32_t2>(retval.rng)));

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devshgraphicsprogramming commented Jan 6, 2025 •

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