Clearcoat effect on materials is too subtle

[Calinou]

Operating system or device, Godot version, GPU Model and driver (if graphics related): Windows 10, Godot Git 5614902, NVIDIA GeForce GTX 1080

Issue description: The clearcoat effect on materials is too subtle, and isn't noticeable at all on most materials of the Material Testers demo; it's only very slightly noticeable on the "mirror" material. This may hint at a bug in the PBR shader.

Steps to reproduce: Create a SpatialMaterial, enable its Clearcoat property, then play around with the Clearcoat and Gloss values.

[adriansnetlis]

Yes, I agree that clearcoat doesn't work right.

To me it looks like clearcoat only uses data from light sources and doesn't use reflection map. Clearcoat should also sample reflection map to produce correct results.

[alukreis]

Could this be closed given the referenced ticket is closed as fixed?

[Calinou]

@alukreis I'm not sure if this was fixed, but I noticed it seems to be closer to the intended effect when using a material with roughness set to 0.5. Here's a specular highlight on a material with Clearcoat disabled:

And this is the same material with Clearcoat intensity and gloss set to 1:

Unlike the highlights created by increasing the Specular intensity, the clearcoat dot is much less "diffuse" over the material.

@reduz I'd like your input on this 🙂 Have any changes been made to Clearcoat in the Vulkan renderer, or is the current approach considered correct?

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Edit: reduz told me the Clearcoat property probably doesn't act as intended, but he's not sure if he can fix it right away. He'll put this issue as a "task for grabs" for those looking to improve the Vulkan renderer.

[KoBeWi]

Looks still valid in 2ba96f0

[toddwong]

Seems it's been a while. How is it going?

[Calinou]

Seems fine as of 4.0.2 (left = no clearcoat, right = with clearcoat, using default properties):

And in 3.6.beta1 too (this was likely fixed earlier, but I wanted to test with TorusMesh):

(The effect appears stronger in 4.0, but the light parameters are different in my test projects.)

Testing projects:

• 4.x: test_clearcoat_4.x.zip
• 3.x: test_clearcoat_3.x.zip

[Calinou]

@toddwong Please don't ask support questions here, as this issue tracker is meant to be used for bug reports only. Use one of the other community channels instead.