[3.x] Built-in toon diffuse mode too bright

[atirut-w]

Godot version

v3.4.4.stable.fedora [419e713]

System information

Fedora Linux 36 (Workstation Edition), GLES 3

Issue description

When you set a material's diffuse mode to toon and have a light source(only tested with directional light), the lit part of the material becomes significantly brighter than normal materials of the same albedo with Burly(ddefault) diffuse mode.

This is more noticeable with the Glow effect enabled(screen mode) and shadow disabled(a separate issue of toon shader being dependent on shadowmap instead of dot product?).

Testing condition:

• Directional light energy at 1
• default skybox

With shadows

Without glow

With glow

Without shadows

Without glow

With glow

Steps to reproduce

1. New scene
2. Add directional light
3. Add mesh with toon material
4. Burn your retinas

Minimal reproduction project

No response

[fire]

@lyuma mentioned to me about dividing by a pi constant. Do you remember?

[Calinou]

Note that changing this in 3.x will break compatibility with existing projects, unless it's made opt-in via a project setting (which could be automatically enabled in projects created with 3.6).

[atirut-w]

@Calinou can a fix for this get into 4.0? It seems to kind of also be happening in alpha 13 and I'd like this fixed before the freeze.

[Calinou]

@Calinou can a fix for this get into 4.0? It seems to kind of also be happening in alpha 13 and I'd like this fixed before the freeze.

Bug fixes are not affected by the feature freeze – they can be contributed at any time 🙂

I'd recommend looking into opening a pull request yourself.

[Calinou]

@atirut-w Can you test this in 4.2.beta 6? This may be fixed as evidenced by #65544 (comment).

This wasn't backported to 3.x yet though (see my above comment about compatibility).

[atirut-w]

I'll try it out this afternoon-evening, thanks. 👍

[atirut-w]

@Calinou it is indeed fixed, in the latest master branch. The "receding shadows" issue is still present, but I think this is easily fixable by changing the order of lighting calculations. It's probably a similar issue to the ones I've encountered when making custom lightings.