[Feature request] glTF KHR_materials_variants extension

[cx20]

Is your feature request related to a problem? Please describe.
Recently, some models using the KHR_materials_variants extension have been added to the Khronos glTF Sample models repository.
However, Filament does not support this extension, so I am unable to try it.

The following is an example of a model from the KHR_materials_variants extension.

Model	Screenshot
Glam Velvet Sofa
Materials Variants Shoe
Sheen Chair

Describe the solution you'd like
It is expected that support and sample code for the KHR_materials_variants extension will be provided.

Describe alternatives you've considered
I am testing some samples with gltf-test, but until this extension is supported, the test will be marked as Fail.

[romainguy]

It's something we'd like to support as well. It should be fairly easy since the concept of variants should map very well to our concept of MaterialInstance.

[issacclee]

Sorry to piggy back on this question.
For complex gltf model with multiple heavily textured material variants, it normally would make sense to also employ extensions such as KHR_texture_basisu to reduce the packaged assets transmission size.
Currently it seems filament doesn't support KHR_texture_basisu extension. I was wondering if the filament team would consider support it?

[cx20]

@issacclee I think the following are issues related to KHR_texture_basisu.

#1378

[issacclee]

@issacclee I think the following are issues related to KHR_texture_basisu.

#1378

Ah, thanks!

[ThomasGorisse]

Describe alternatives you've considered
I am testing some samples with gltf-test, but until this extension is supported, the test will be marked as Fail.

@cx20 Your repo rocks!
Thanks for your crazy work. It's very helpful.

[cx20]

@prideout Thank you for supporting this extension. I have confirmed that this extension works with gltf-test.
https://github.com/cx20/gltf-test

[cx20]

#5361