I am modeling a house in Blender (specifically I have modeled wall, roof, and floor pieces that I am assembling in Godot). In Blender I modeled, unwrapped, and then moved the UV mapping onto a solid color according to a palette image (which I will try to include here). In Blender everything looks okay, but in Godot these slightly dark spots appear on the red walls. I am not sure what caused this, or if this is a problem with something I did in Blender or in importing to Godot.
The texture is probably being VRAM compressed. Select the texture in Godot and, in the Import tab, change the compress mode to Loseless and click on Reimport
What is the resolution of your atlas texture when it’s in godot?
I would always recommend against using Lossless textures, though if you have a very limited set of texture assets loaded, or if they are super small it is ok.
It just looks like you are inheriting some of the filtering type blending with the neighboring atlas chunks of those colors, and the compression could be causing that to be more visible, but I think there are other solutions.
I would try making your shader read that atlas texture as the filter type nearest and see if that helps. If that works, you’ll just want to sample that texture with the base filtering as I see you have some gradients for when you do want some mapping that accepts the gradients across the surface.
Another thing to do is change your UV’s so they can potentially not inherit any filtering bleed from atlas color chunk to another, if you are truly just wanting to grab a flat color, you can shrink those UV’s down a lot per chunk so they are much further away from the borders of the atlas chunk, if that’s possible you can keep the filtering on to get good gradients on those other atlas tiles.