Vulkan: SDFGI does not take custom ambient light settings into account when Read Sky Light is enabled (unlike VoxelGI)

[Calinou]

Godot version

4.0.dev (84f59c6)

System information

Fedora 34, GeForce GTX 1080 (NVIDIA 470.74)

Issue description

SDFGI does not take custom ambient light settings into account when Read Sky Light is enabled (unlike VoxelGI). On the other hand, sky color changes are taken into account by SDFGI.

This was confirmed by @FilipLundby in #39965 (comment).

No GI

no-gi.mp4

VoxelGI

voxel-gi.mp4

SDFGI

The editor is forced to redraw continuously to make sure #54892 doesn't get in the way.

sdfgi.mp4

Steps to reproduce

• Enable SDFGI and its Read Sky Light property in WorldEnvironment.
• Set a non-black ambient light color in WorldEnvironment, and reduce Sky Contribution so it begins to appear.
• Notice how it has no effect unless you disable SDFGI.

Minimal reproduction project

test_sdfgi_custom_ambient_light.zip