TextureAtlas region not working in Albeto StandardMaterial3D, and pixel values of texture are broken

[djkato]

Tested versions

v4.2.2.stable.fedora [15073af]

System information

Godot v4.2.2.stable (15073af) - Fedora Linux 40 (Workstation Edition) - Wayland - GLES3 (Compatibility) - AMD Radeon Graphics (radeonsi, renoir, LLVM 18.1.6, DRM 3.57, 6.10.4-200.fc40.x86_64) () - AMD Ryzen 5 7530U with Radeon Graphics (12 Threads)

Issue description

The texture atlas doesn't work as albeto texture map neither set programatically through script nor through gui. Also, the pixels of my pixel art are completely mis-colored. I got my pixel art sprite sheet from https://piskelapp.com, exported as atlas png.

Steps to reproduce

1. export from piskelapp random pixel art atlas
2. create characterBody3d > MeshInstance3D
3. atlas texture in mesh material albeto
4. try to set region of mesh

Minimal reproduction project (MRP)

MRP-atlastexture.zip

[AThousandShips]

This is a limitation that is undocumented, AtlasTexture only works in specific contexts, see also:

• Can I use part of a sprite as the light texture? #95507

[AThousandShips]

Thank you for reporting, this is a missing feature and the proposal is tracked here:

• Make AtlasTextures work with SpatialMaterial/3D meshes godot-proposals#1708

Consolidating there

[Calinou]

Also, the pixels of my pixel art are completely mis-colored.

Set the compression mode for the source image to Lossless in the Import dock.