bevyengine
Add support for KHR_texture_transform
Objective
Support the KHR_texture_transform extension for the glTF loader.
- Fixes #6335
Solution
As is, this only supports a single transform. Looking at Godot's source, they support one transform with an optional second one for detail, AO, and emission. glTF specifies one per texture. The public domain materials I looked at seem to share the same transform. So maybe having just one is acceptable for now. I tried to include a warning if multiple different transforms exist for the same material.
Note the gltf crate doesn't expose the texture transform for the normal and occlusion textures, which it should, so I just ignored those for now.
Via cargo run --release --example scene_viewer ~/src/clone/glTF-Sample-Models/2.0/TextureTransformTest/glTF/TextureTransformTest.gltf:
Changelog
Support for the KHR_texture_transform extension added.
Your PR increases Bevy Minimum Supported Rust Version. Please update the rust-version field in the root Cargo.toml file.
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Your screenshot doesn't look exactly like the expected (https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/TextureTransformTest), it seems the background for out of texture quads are not the same. Do you know why?
How would it work with https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/TextureTransformMultiTest?
Your screenshot doesn't look exactly like the expected (https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/TextureTransformTest), it seems the background for out of texture quads are not the same. Do you know why?
The default camera and lighting in the scene viewer make it hard to see. The background in the arrow texture is there, just very faint, if that's what you mean.
How would it work with https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/TextureTransformMultiTest?
This looks far from complete because the loader doesn't support texture coord sets. I see there's some TODOs in the source code. The renderer doesn't do clearcoat, and the gltf crate doesn't expose a texture transform for occlusion.
A Affine2 seems better (smaller and faster) for the transform than a Mat3?
Adopted; I'm currently updating this PR to main and addressing the comments on my fork :)
