Loading a glTF scene doesn't use the correct UV map for ambient occlusion about bevy

[bugsweeper]

This also has problems with UV-map, but may be different kind

[geckoxx]

It is a similar issue. The material in the file is using a specific texCoord for its occlusionTexture but this is ignored by the gltf loader:

bevy/crates/bevy_gltf/src/loader.rs

Line 856 in ade70b3

// TODO: handle occlusion_texture.tex_coord() (the *set* index for the right texcoords)

But the main issue is that bevy_pbr uses only one texcoord attribute for all textures. So it does not support multiple UV maps at the moment.

[jf908]

I thought with the lightmap update in 0.13, bevy pbr supported 2 UV maps? three.js is hardcoded to use the 2nd UV map for ambient occlusion and lightmap textures and the 1st UV map for everything else. Perhaps bevy could follow the same convention until multiple UV maps become more flexible?

[bugsweeper]

It is a similar issue. The material in the file is using a specific texCoord for its occlusionTexture but this is ignored by the gltf loader

Problem is that baseColorTexture uses TEXCOORD_0, but (!!!) occlusionTexture uses TEXCOORD_1, bevy_pbr does use same ATTRIBUTE_UV_0 for both of them, that's why loader can't load this glb in mesh+StandardMaterial with correct bevy_pbr interpretation