OpenGL: Clearcoat has no effect if BaseMaterial3D roughness is exactly 0 - Githubissues

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OpenGL: Clearcoat has no effect if BaseMaterial3D roughness is exactly 0 #83223

Open Calinou opened 1 year ago

Calinou commented 1 year ago

Related to https://github.com/godotengine/godot/issues/95207.

Godot version

4.2.beta1

System information

Fedora 38, GeForce RTX 4090 (NVIDIA 535.104.05)

Issue description

When using the Compatibility rendering method, Clearcoat has no effect if BaseMaterial3D roughness is exactly 0:

Screenshot_20231013_012642 webp

However, it works if roughness is set to 0.01 or 1.0:

Roughness 0.01	Roughness 1.0

This issue only occurs in Compatibility, not Forward+ or Mobile. I noticed it while working on a solution for https://github.com/godotengine/godot/issues/69327.

Steps to reproduce

Add a MeshInstance3D and DirectionalLight3D (so that clearcoat can be seen).
Assign a BaseMaterial3D to the MeshInstance3D, with Roughness set to exactly 0.0 and enable Clearcoat.

Minimal reproduction project

Clearcoat_Test_2.zip

clayjohn commented 1 year ago

See: https://github.com/godotengine/godot/blob/51f81e1c88499f04d2ebdcc0be0b34e73f5e90eb/servers/rendering/renderer_rd/shaders/scene_forward_lights_inc.glsl#L187