Vulkan: Full-size GI rendering still results in slightly blurry edges

[Calinou]

Related to #54978.

Godot version

4.0.dev (d13c3c9)

System information

Fedora 34, GeForce GTX 1080 (NVIDIA 495.46)

Issue description

Full-size GI rendering still results in slightly blurry edges, despite it being full resolution. This may hint at a misconfiguration of the rendering size or the sampler (should it use nearest-neighbor at full resolution?).

This occurs with both SDFGI and VoxelGI, since they both rely on deferred rendering in master.

Fixing this issue may also improve half-resolution GI appearance slightly, since it will be perfectly aligned on the pixel grid.

Click to view at full size.

SDFGI edge (blurry)

Most lighting is contributed by SDFGI here, so the edge becomes blurry.
Cropped portion of the above screenshot with 400% nearest-neighbor scaling.

Bright edge (sharp)

Most lighting is not contributed by SDFGI here, so the edge remains sharp.
Cropped portion of the above screenshot with 400% nearest-neighbor scaling.

Steps to reproduce

• Add a MeshInstance3D with its global illumination mode set to Baked. The mesh should be a scene where significant large areas are shaded by solid surfaces.
• Add a DirectionalLight3D node with shadows enabled.
• Add a WorldEnvironment node with a new Environment resource.
• Enable SDFGI in the Environment resource.

Minimal reproduction project

test_sdfgi_num_cascades.zip

[akien-mga]

Fixed by #61070.