Hlsl path tracer #224

devshgraphicsprogramming · 2025-11-03T16:17:03Z

@keptsecret after you merge master again, you'll probably have the UI mess up and show changed from the merge commit, so close and reopen again

devshgraphicsprogramming · 2025-11-13T10:47:09Z

31_HLSLPathTracer/app_resources/hlsl/scene.hlsl

+    static this_t create(
+        NBL_CONST_REF_ARG(Shape<PST_SPHERE>) spheres[SCENE_SPHERE_COUNT],
+        NBL_CONST_REF_ARG(Shape<PST_TRIANGLE>) triangles[SCENE_TRIANGLE_COUNT],
+        NBL_CONST_REF_ARG(Shape<PST_RECTANGLE>) rectangles[SCENE_RECTANGLE_COUNT],
+        uint32_t sphereCount, uint32_t triangleCount, uint32_t rectangleCount,
+        NBL_CONST_REF_ARG(light_type) lights[LIGHT_COUNT], uint32_t lightCount,
+        NBL_CONST_REF_ARG(bxdfnode_type) bxdfs[BXDF_COUNT], uint32_t bxdfCount)
+    {
+        this_t retval;
+        retval.spheres = spheres;
+        retval.triangles = triangles;
+        retval.rectangles = rectangles;
+        retval.sphereCount = sphereCount;
+        retval.triangleCount = triangleCount;
+        retval.rectangleCount = rectangleCount;
+
+        retval.lights = lights;
+        retval.lightCount = lightCount;
+
+        retval.bxdfs = bxdfs;
+        retval.bxdfCount = bxdfCount;
+        return retval;
+    }


we wont be needing this

devshgraphicsprogramming · 2025-11-13T10:49:33Z

CMakeLists.txt

 	# Showcase compute pathtracing
 	add_subdirectory(30_ComputeShaderPathTracer)

+	add_subdirectory(31_HLSLPathTracer EXCLUDE_FROM_ALL)


remove EXCLUDE_FROM_ALL I want CI running on this before we merge

devshgraphicsprogramming · 2025-11-13T10:51:18Z

31_HLSLPathTracer/app_resources/hlsl/render_common.hlsl

+[[vk::binding(1, 2)]] Buffer<uint3> sampleSequence;
+
+[[vk::combinedImageSampler]][[vk::binding(2, 2)]] Texture2D<uint2> scramblebuf; // unused
+[[vk::combinedImageSampler]][[vk::binding(2, 2)]] SamplerState scrambleSampler;


sampleSequence should just be a BDA provided via push constant of QuantizedSequence (3 21bit unorms packed into a struct of size 8 and alignment 4)

devshgraphicsprogramming · 2025-11-13T10:52:14Z

31_HLSLPathTracer/app_resources/hlsl/render_common.hlsl

+    int sampleCount;
+    int depth;


if you add the BDA for sample sequence then you'll have just enough Push Constants left to add a float32_t3x4 for the light transform

devshgraphicsprogramming · 2025-11-13T10:52:46Z

31_HLSLPathTracer/app_resources/hlsl/render_common.hlsl

+
+[[vk::binding(1, 2)]] Buffer<uint3> sampleSequence;
+
+[[vk::combinedImageSampler]][[vk::binding(2, 2)]] Texture2D<uint2> scramblebuf; // unused


please use the scramble buffer, it will allow us to do stuff like key-exchanges to attempt to get Blue Noise (as per some Heitz papers)

devshgraphicsprogramming · 2025-11-13T10:53:08Z

31_HLSLPathTracer/main.cpp

+struct PTPushConstant {
+	matrix4SIMD invMVP;
+	int sampleCount;
+	int depth;
+};


use the same struct as in your render_common.hlsl

devshgraphicsprogramming · 2025-11-13T10:56:12Z

31_HLSLPathTracer/app_resources/hlsl/render.comp.hlsl

+using namespace nbl;
+using namespace hlsl;
+
+NBL_CONSTEXPR uint32_t WorkgroupSize = 512;


optimal is 64 due to not holding up everything with divergence (lots of small WGs in the same SM co-reisdent)

btw this needs to be in shared header

devshgraphicsprogramming · 2025-11-13T10:56:22Z

31_HLSLPathTracer/app_resources/hlsl/render.comp.hlsl

+NBL_CONSTEXPR uint32_t MAX_DEPTH_LOG2 = 4;
+NBL_CONSTEXPR uint32_t MAX_SAMPLES_LOG2 = 10;


shared header!

devshgraphicsprogramming · 2025-11-13T10:56:41Z

31_HLSLPathTracer/app_resources/hlsl/render.comp.hlsl

+#ifdef SPHERE_LIGHT
+#define SPHERE_COUNT 9
+#define TRIANGLE_COUNT 0
+#define RECTANGLE_COUNT 0
+#endif
+
+#ifdef TRIANGLE_LIGHT
+#define TRIANGLE_COUNT 1
+#define SPHERE_COUNT 8
+#define RECTANGLE_COUNT 0
+#endif
+
+#ifdef RECTANGLE_LIGHT
+#define RECTANGLE_COUNT 1
+#define SPHERE_COUNT 8
+#define TRIANGLE_COUNT 0
+#endif
+
+#define LIGHT_COUNT 1
+#define BXDF_COUNT 7


want this baked in STATIC_INLINE_CONSTEXPR in 3 different scenes

devshgraphicsprogramming · 2025-11-13T10:57:34Z

31_HLSLPathTracer/main.cpp

+		constexpr static inline uint32_t2 WindowDimensions = { 1280, 720 };
+		constexpr static inline uint32_t MaxFramesInFlight = 5;
+		constexpr static inline clock_t::duration DisplayImageDuration = std::chrono::milliseconds(900);
+		constexpr static inline uint32_t DefaultWorkGroupSize = 512u;
+		constexpr static inline uint32_t MaxDescriptorCount = 256u;
+		constexpr static inline uint32_t MaxDepthLog2 = 4u; // 5
+		constexpr static inline uint32_t MaxSamplesLog2 = 10u; // 18
+		constexpr static inline uint32_t MaxBufferDimensions = 3u << MaxDepthLog2;
+		constexpr static inline uint32_t MaxBufferSamples = 1u << MaxSamplesLog2;
+		constexpr static inline uint8_t MaxUITextureCount = 1u;


lot of this stuff should be in shared header between HLSL and C++

…htracer doesn't need create params

…actor

…params into render_common

keptsecret added 30 commits February 3, 2025 14:52

copied ex 30 to new ex 31

eab0f70

ignore events on imgui focus

8521123

initial files for pathtracer

b171724

intersection logic

af35393

changes to intersection logic

5a5fbfe

completed material system?

85e67ad

sphere nee stuff

2c500b1

triangle sampling

e6a9916

rectangle sampling

6dc25eb

nee stuff

22bd6f9

scene representation, getmeasure for pt

3bb858b

moved scene rep out, some closest hit stuff

f5adbf6

sample light part of closest hit

159d153

fix bugs, reorganize traceRay

a7350db

sample bsdf in closest hit

8a4e0a9

set up path tracer render shader

72104b8

finish render shader

202c645

hlsl path tracer initial, bug fixes

2f77555

fix shader bugs

99aed47

Merge branch 'master' into hlsl_path_tracer

a1a8ec0

bug fixes #3

a802a97

fix include when embed resources off

eed47e7

fixed more bugs #4

6e26dae

Merge branch 'master' into hlsl_path_tracer

3827fd3

fix compile hlsl shader bug

da661c0

more bug fixes #5

f97757b

more bug fixes #6

8e759f2

Merge branch 'master' into hlsl_path_tracer

2dfadfe

refactor to use new frisvad

b1831d9

fix bugs again

cb5662a

devshgraphicsprogramming commented Nov 13, 2025

View reviewed changes

Przemog1 and others added 20 commits November 13, 2025 21:56

Refactored resolve.comp.hlsl

badb4a6

refactor bxdf usage

05226bf

fix missing hash problem, working path tracer

aced36c

added checks to invalid samples

8b8fab0

merged rwmc, fix conflicts

d4e5754

fix errors from merge

16c8d42

fixes to rectangle light sampling nans (that regressed somehow)

310263e

minor changes to used workgroup size

c123d17

refactor partitionRandVar usage

b7eb8a3

refactor box muller usage

6688843

moved light, ray, objectID structs into userspace example_common; pat…

f2e79ec

…htracer doesn't need create params

reduce nee duplicate code, added template scalar_type to shapes + ref…

6c9dc30

…actor

moved bxdfs array into mat system, lights array into nee

52c654b

partial spec Scene by light shape, ProceduralShapeType in namespace

dc91a9e

moved a lot of defines into static const in Scene, moved some render …

c342c4c

…params into render_common

changed sampleSequence to bda

d0cc24e

fixes compacting QuantizedSequence

90631e6

moved everything into the correct namespaces/user space

39c686f

path tracer uses concepts on component types

1508702

check for storagePushConstant16, fix typos

08d8396

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Hlsl path tracer #224

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devshgraphicsprogramming commented Nov 3, 2025

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		[[vk::binding(1, 2)]] Buffer<uint3> sampleSequence;

		[[vk::combinedImageSampler]][[vk::binding(2, 2)]] Texture2D<uint2> scramblebuf; // unused

		NBL_CONSTEXPR uint32_t MAX_DEPTH_LOG2 = 4;
		NBL_CONSTEXPR uint32_t MAX_SAMPLES_LOG2 = 10;

Hlsl path tracer #224

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Hlsl path tracer #224

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devshgraphicsprogramming commented Nov 3, 2025

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