Diffuse Roughness support #16253

MiiBond · 2025-03-05T22:03:04Z

This PR replaces #16183

This PR implements the base_diffuse_roughness parameter from the OpenPBR specification.

The diffuse roughness is implemented for analytic lights, realtime-filtered IBL, prefiltered IBL and spherical harmonics.
I've added a flag to a material to choose between Lambert, Burley and the new Energy Conserving Oren-Nayar (EON) model used by OpenPBR. The default is OpenPBR's EON model.

The previous behaviour was to use Burley diffuse for analytical lights and Lambert for IBL. Also, previously, specular roughness was applied to diffuse roughness for analytical lights while IBL didn't use it at all (because it was simply Lambertian). So, the new default slightly changes existing projects that used analytical lights but I question how noticeable that will be.

Analytical Light:
https://playground.babylonjs.com/?snapshot=refs/pull/16253/merge#MXACV7#3

Realtime IBL:
https://playground.babylonjs.com/?snapshot=refs/pull/16253/merge#MXACV7#5

The diffuse roughness models are heavily dependent on the light direction and view direction and are therefore difficult to handle with a prefiltered IBL. I came up with two methods for approximating roughness with prefiltered IBL's. The first, if we prefiltered using CDF, we generate a dominant light direction to use in the BRDF calculations. It works reasonably well.

Prefiltered IBL with CDF:
https://playground.babylonjs.com/?snapshot=refs/pull/16253/merge#MXACV7#9

The second approach, if you don't use CDF, is by approximating roughness by bending the surface normal towards the camera to add some of the retro-reflective behaviour that you get with EON. Because of this, you'll notice that Burley and EON are identical and the shadow terminator appears to move as diffuse roughness increases. In practice, however, this example uses an extreme IBL with a bright sunlight. With other IBL's, the effect tends to be more convincing.

Prefiltered IBL without CDF
https://playground.babylonjs.com/?snapshot=refs/pull/16253/merge#MXACV7#10

The default IBL lighting in Sandbox uses spherical harmonics so we need to approximate diffuse roughness with this as well. I'm using the same bent normal technique as with prefiltered IBL without CDF.

Spherical Harmonics IBL
https://playground.babylonjs.com/?snapshot=refs/pull/16253/merge#MXACV7#11

bjsplat · 2025-03-05T22:04:28Z

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bjsplat · 2025-03-05T22:15:54Z

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packages/dev/core/src/Materials/PBR/pbrBaseMaterial.ts

bjsplat · 2025-03-05T23:16:24Z

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bjsplat · 2025-03-05T23:16:27Z

Visualization tests for WebGPU

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bjsplat · 2025-03-06T02:23:23Z

Visualization tests for WebGPU

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bjsplat · 2025-03-06T02:23:25Z

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bjsplat · 2025-03-06T22:37:17Z

Visualization tests for WebGPU

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bjsplat · 2025-03-06T22:37:18Z

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bjsplat · 2025-03-07T05:45:56Z

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bjsplat · 2025-03-07T05:45:59Z

Visualization tests for WebGPU

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bjsplat · 2025-03-07T07:18:52Z

Visualization tests for WebGPU

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bjsplat · 2025-03-07T07:18:52Z

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virtualzavie

This is only a partial review with a couple of comments.

packages/tools/tests/test/visualization/ReferenceImages/openpbr-base-diffuse-roughness.png

...ols/tests/test/visualization/ReferenceImages/openpbr-base-diffuse-roughness-realtime-ibl.png

packages/tools/tests/test/visualization/config.json

virtualzavie

Continued review.

packages/dev/core/src/Shaders/ShadersInclude/hdrFilteringFunctions.fx

packages/dev/core/src/Shaders/ShadersInclude/pbrBlockReflection.fx

packages/dev/core/src/Shaders/ShadersInclude/pbrDirectLightingFunctions.fx

packages/dev/core/src/ShadersWGSL/ShadersInclude/pbrDirectLightingFunctions.fx

bjsplat · 2025-03-10T18:31:47Z

Visualization tests for WebGPU

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bjsplat · 2025-03-10T18:59:43Z

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bjsplat · 2025-03-10T21:35:08Z

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bjsplat · 2025-03-10T21:47:31Z

Visualization tests for WebGPU

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bjsplat · 2025-03-12T00:28:31Z

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bjsplat · 2025-03-12T00:42:06Z

Visualization tests for WebGPU

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bjsplat · 2025-03-12T01:45:08Z

WebGL2 visualization test reporter:

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bjsplat · 2025-03-12T02:26:03Z

Visualization tests for WebGPU

https://snapshots-cvgtc2eugrd3cgfd.z01.azurefd.net/refs/pull/16253/merge/testResults/webgpuplaywright/index.html

bjsplat · 2025-03-12T19:14:55Z

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bjsplat · 2025-03-12T19:26:27Z

Visualization tests for WebGPU

https://snapshots-cvgtc2eugrd3cgfd.z01.azurefd.net/refs/pull/16253/merge/testResults/webgpuplaywright/index.html

Co-authored-by: Popov72 <[email protected]>

bjsplat · 2025-05-05T16:12:26Z

Please make sure to label your PR with "bug", "new feature" or "breaking change" label(s).
To prevent this PR from going to the changelog marked it with the "skip changelog" label.

MiiBond · 2025-05-05T16:21:20Z

@Popov72 @sebavan
The linter in the CI is giving me this error but I don't get it locally:

error @typescript-eslint/naming-convention: Interface name `GLTFLoaderExtensionOptions` must have one of the following prefixes: I

I'll make this change but I wanted to call this out.

bjsplat · 2025-05-05T16:24:10Z

Please make sure to label your PR with "bug", "new feature" or "breaking change" label(s).
To prevent this PR from going to the changelog marked it with the "skip changelog" label.

bjsplat · 2025-05-05T16:42:47Z

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bjsplat · 2025-05-05T16:56:09Z

Visualization tests for WebGPU

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bjsplat · 2025-05-05T16:57:47Z

WebGL2 visualization test reporter:

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sebavan · 2025-05-05T17:51:43Z

@Popov72 @sebavan The linter in the CI is giving me this error but I don't get it locally:
error @typescript-eslint/naming-convention: Interface name `GLTFLoaderExtensionOptions` must have one of the following prefixes: I
I'll make this change but I wanted to call this out.

I do not think we should change it

cc @RaananW

RaananW · 2025-05-05T18:16:05Z

@Popov72 @sebavan The linter in the CI is giving me this error but I don't get it locally:
error @typescript-eslint/naming-convention: Interface name `GLTFLoaderExtensionOptions` must have one of the following prefixes: I
I'll make this change but I wanted to call this out.

No need to replace the entire interface, you will need to add eslint-disable-next-line @typescript-eslint/naming-convention before the line using it (where you used it).

Fetch from master and run npm install to be sure you are up to date with the newest eslint rules

This reverts commit ad419a4.

bjsplat · 2025-05-05T18:50:03Z

Visualization tests for WebGPU

https://snapshots-cvgtc2eugrd3cgfd.z01.azurefd.net/refs/pull/16253/merge/testResults/webgpuplaywright/index.html

bjsplat · 2025-05-05T18:54:03Z

WebGL2 visualization test reporter:

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bjsplat · 2025-05-05T21:02:04Z

WebGL2 visualization test reporter:

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bjsplat · 2025-05-05T21:13:57Z

Visualization tests for WebGPU

https://snapshots-cvgtc2eugrd3cgfd.z01.azurefd.net/refs/pull/16253/merge/testResults/webgpuplaywright/index.html

bjsplat · 2025-05-05T22:00:45Z

Visualization tests for WebGPU

https://snapshots-cvgtc2eugrd3cgfd.z01.azurefd.net/refs/pull/16253/merge/testResults/webgpuplaywright/index.html

bjsplat · 2025-05-05T22:03:27Z

WebGL2 visualization test reporter:

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MiiBond marked this pull request as draft March 5, 2025 22:03

MiiBond commented Mar 5, 2025

View reviewed changes

packages/dev/core/src/Materials/PBR/pbrBaseMaterial.ts Outdated Show resolved Hide resolved

MiiBond force-pushed the openpbr/diffuse_roughness branch from 3580a82 to 55f34a0 Compare March 7, 2025 04:29

virtualzavie reviewed Mar 7, 2025

View reviewed changes

MiiBond force-pushed the openpbr/diffuse_roughness branch from 203a6cf to 5ee9410 Compare March 11, 2025 23:57

MiiBond marked this pull request as ready for review March 12, 2025 18:25

MiiBond force-pushed the openpbr/diffuse_roughness branch from 6b0f7a4 to 2f1cf0e Compare March 12, 2025 18:37

MiiBond and others added 6 commits May 5, 2025 09:07

Update packages/dev/core/src/Materials/PBR/pbrBaseMaterial.ts

a9d9965

Co-authored-by: Popov72 <[email protected]>

Add defines for diffuse roughness models

1ec22e7

Rename diffuse roughness model to diffuse model

3ce5fa8

Move diffuse model param to pbrMaterial

9e914d6

Add default diffuse model to PBRMaterial

f3b936a

Simplify dominantDirection setting

d4278a2

MiiBond force-pushed the openpbr/diffuse_roughness branch from 1acd8bf to d4278a2 Compare May 5, 2025 16:10

Rename GLTFLoaderExtensionOptions

ad419a4

Revert "Rename GLTFLoaderExtensionOptions"

a5f0dbf

This reverts commit ad419a4.

Popov72 approved these changes May 5, 2025

View reviewed changes

deltakosh enabled auto-merge (squash) May 5, 2025 18:21

Add eslint-disable line in rough diffuse glTF loader

4250924

auto-merge was automatically disabled May 5, 2025 18:23
Head branch was pushed to by a user without write access

sebavan approved these changes May 5, 2025

View reviewed changes

Update voxel shadow tests to make them faster

264d811

Add new reference image for voxel shadows test

64a669e

Diffuse Roughness support #16253

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Diffuse Roughness support #16253

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