Fog breaks rendering of unshaded materials.

[EzraT]

Godot version

4.0.beta6

System information

Windows 10, Vulkan/OpenGL3, NVIDIA GTX1060

Issue description

Demonstration Videos:

1.mp4

2.mp4

3.mp4

As the title says, unshaded material rendering breaks when any form of fog is enabled, this issue is especially noticeable if the material also uses the add blend mode. Fog does not affect unshaded materials in Godot 3, so unless I'm missing something this should not be happening in Godot 4 either.
Happens in forward_plus, mobile and opengl3 renderers.

Steps to reproduce

1. Download and open the reproduction project below.
2. Select the WorldEnvironment node and toggle fog on and off.

Minimal reproduction project

srp_fogbug.zip

[Calinou]

Duplicate of #56374.

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@EzraT Remember that for GitHub video previews to work, you need to have a blank line before and after the video URL. I edited your post accordingly, but remember to do this in the future 🙂