Compressing texture with uastc logs KTX error that might be misleading

[hybridherbst]

Describe the bug
The same file as for #502 logs an error "Zstd deflation failed; KTX error: Out of memory" when attempting to compress with uastc.
This seems to be incorrect or misleading, as the file is tiny (or it's a bug in toktx maybe?).

To Reproduce
Steps to reproduce the behavior:

1. Download https://github.com/donmccurdy/glTF-Transform/files/8090577/TexturedCube.zip
2. Run gltf-transform uastc TexturedCube.glb TexturedCube.uastc.glb
3. Observe exception with (I think) misleading error message

Expected behavior
Either better error message or the file should pass and compress properly.

Additional context

[donmccurdy]

Verbose output:

gltf-transform uastc ~/Desktop/TexturedCube.glb ~/Desktop/TexturedCube.uastc.glb --verbose
debug: Found KTX-Software v4.0.0.
debug: Texture 1/1 (baseColorTexture)
debug: • toktx --genmipmap --uastc 2 --zcmp 18 /var/folders/n5/m5lw96654zn9mpq7lk351jbh0000gn/T/tmp-38216-8yePbD4FogiF-.ktx2 /var/folders/n5/m5lw96654zn9mpq7lk351jbh0000gn/T/tmp-38216-uuOJFUdUVzRj-.jpg

error: • Texture compression failed:

       toktx: Zstd deflation failed; KTX error: Out of memory.



error: Texture compression failed

I have a hunch the image needs to be resized 8x1 → 8x4 for UASTC compression, but not sure whether toktx should handle that automatically or if it requires glTF Transform to provide the --resize flag. Will investigate, thanks!

[donmccurdy]

The OOM error for UASTC will be fixed in KTX Software by KhronosGroup/KTX-Software#527. The error reported with ETC1S appears to have a different cause. In the meantime, resizing the texture to 12x12 or larger works around the problem, but that value may be specific to this texture.