Godot version

4.0.dev (2a9dd65)

System information

Fedora 34, GeForce GTX 1080 (NVIDIA 470.74)

Issue description

Despite lightmap rendering not working correctly when using the Vulkan Mobile backend, LightmapGI baking does work. However, it ignores environment lighting from the sky when it's enabled in the node properties.

Note: You need to switch back to the Vulkan Clustered backend and restart the editor to see the lightmap baked in the Vulkan Mobile backend in the editor/project.

Lightmap baked in Vulkan Clustered

Lightmap baked in Vulkan Mobile (then displayed in Vulkan Clustered)

Steps to reproduce

• Import a glTF scene. Set the light bake mode to Static Lightmaps in the Import dock and click Reimport.
• Add a LightmapGI node.
• Bake lightmaps. Open the resulting EXR file in an image editor.
• Switch to Vulkan Mobile backend in the project settings (search for back end).
  • Note: The MRP linked below already uses the Vulkan Mobile backend by default.
• Restart the editor and bake lightmaps again. Open the resulting EXR file in an image editor for comparison. Notice the environment lighting is missing.

Minimal reproduction project

test_vulkan_clustered_vs_mobile_lightmap_sampling.zip

With .godot/ included to workaround importing issue: https://0x0.st/orQD.zip _{(link expires in September 2022)}