Babylon Editor - export texture scaling

Questions
21

Hey @Drigax, it the playground working and enough for you? :slight_smile:

22

Hey @julien-moreau, thanks for the playground! I took a look, but Iā€™m not quite seeing what youā€™re seeingā€¦

My first test is to use one of my testing rigs that exports the scene, disposes the old scene, and imports fom glTF into the new scene:

Here is the starting scene with some modifications to see the texture orientation clearer using a UV checkerboard:
https://playground.babylonjs.com/#DHZKGW#2

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when we enable the scene export then import with identical camera settings we get:
https://playground.babylonjs.com/#DHZKGW#3

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Ignoring the change in lighting intensity, it looks like weā€™re properly applying the texture transform to the output texture hereā€¦

we can even inspect the output glb:

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to see that we are actually preserving the original orientation of the texture, and just exporting with KHR_texture_transform to handle the vscaling

1 Like
23

Hey @Drigax, I think it has been fixed while you were looking for the bug because I donā€™t reproduce the bug anymore using my own playground :slight_smile:

Iā€™m testing with the scene of @sguerrero right now to confirm, but Iā€™m pretty sure it is.

24

Confirmed!

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3 Likes
25

This is awesome news! Thank you @julien-moreau and @Drigax for all your time spent looking into the issue.

2 Likes
26

Hi, I think the bug still exists with PBRMaterials (Specular/Glossiness). If I export a .glb using GLTF2Export.GLBAsync, the KHR_texture_transform is missing for Specular Glossiness PBRMaterials. Metallic Roughness PBRMaterials are working fine on the other hand. I am on 4.2.0-beta.

1 Like
27

@Drigax might be able to shade some lights on this one

1 Like
28

*rimshot*

29

@thegabman Do you have a repro in a PG we can debug?

30

Hi,
sorry for being that late with my reply.
I just modified @Drigax playground to reproduce my problem.

https://playground.babylonjs.com/#DHZKGW#7

If ā€œuseMetallicWorkflowā€ is true, than everything is working fine. Otherwise the scaling is not applied.

1 Like
31

Ah, that appears to happen because when converting the textures from specGloss to metalRough, weā€™re dropping the extension and transform information when creating the new baseColor textureā€¦

The fix is not too straightforward, as weā€™ll have to bake texture transform information before combining baseColor + glossiness textures, so any texture transform will be applied to the output texture (I donā€™t think its too straightforward to preserve texture transform data of two combined texturesā€¦)

Iā€™ll create an issue to track this, but Iā€™m not too sure this will be done before 4.2 release. Texture transform is lost when exporting SpecGloss textures Ā· Issue #8968 Ā· BabylonJS/Babylon.js Ā· GitHub

32

Okay, sound plausible. I got around this issue by implementing a custom postprocess to convert my diffuse/spec/gloss textures to baseColor/metal/rough textures following the math of the GLTFMaterialExporter. I apply this postprocess right before exporting my scene to a gltf/glb. For now that does the job.

For the future it would be great to keep the spec/gloss textures in the export using the KHR_materials_pbrSpecularGlossiness instead of converting them to metal/rough.

1 Like
33

Maybe a year ago KHR_materials_specularGlossiness might have been the best solution, but at this point is probably most pragmatic to support KHR_materials_specular, since itā€™s finally proposed for ratification. Iā€™m re-titling this issue to represent this work, As Iā€™d rather not move forward with the texture transform baking approach either, it feels like a half measure as well :slight_smile: