Describe the compatibility issue

Shading on Create contraptions is odd as one of the two triangles that make up some face will be darker than the other.

Screenshots

Super Duper Vanilla:

Complimentary Shaders reimagined:

Desktop (please complete the following information):

• GPU: RX 6800 XT
• Shader loader: Iris 1.6.10
• Shader version: 1.3.5
• Mod/modpack: mods.json

Additional context

I'm also using Iris & Oculus Flywheel Compat which mixes Flywheel shaders with Iris shaders. Just wanted to note that these graphical artifacts are appearing with and without that mod installed.

I tried inspecting the differences in the shader code between the two packs but I wasn't able to resolve as I'm not very proficient with these more advanced shaders.

Hello, I myself noticed this same issue but this is not limited to Create contraptions. This is also apparent in moving blocks (block entities). This is because Create contraptions and moving blocks (block entities) share the same gbuffer shader program.

While I do have a temporary fix for this, this is mostly due to the shader loader's fault on how they handle vanilla ambient occlusion. For now we just need to bully make an issue on Iris' Github repository about fixing separate vanilla AO on moving blocks (block entities).