Vulkan: VoxelGI is much brighter at 512 subdivisions compared to 64, 128 or 256 subdivisions

[Calinou]

Godot version

4.0.dev (2a9dd65)

System information

Fedora 34, GeForce GTX 1080 (NVIDIA 470.74)

Issue description

Indirect lighting and reflections from VoxelGI appear to be much brighter at 512 subdivisions compared to 64, 128 or 256 subdivisions. It's possible to (partially) compensate for this by decreasing VoxelGIData's Energy property to 0.25, but this requires manual work that could be avoided.

Use Two Bounces disabled

64 subdivisions	128 subdivisions	256 subdivisions	512 subdivisions

Use Two Bounces enabled

64 subdivisions	128 subdivisions	256 subdivisions	512 subdivisions

Steps to reproduce

• Add a VoxelGI node. Set Subdiv to 256.
• Add some MeshInstances with their global illumination mode set to Baked.
• Select the VoxelGI node and click Bake in the toolbar at the top of the 3D editor viewport.
• Set Subdiv to 512 and click Bake again.

Minimal reproduction project

test_voxelgi_large.zip