Vulkan: Error when baking LightmapGI if Bounces is set to 0 and there are no lights with Static bake mode

Calinou commented 1 year ago

Godot version

4.0.beta6

System information

Fedora 36, Vulkan Forward Plus, AMD Radeon RX 6900 XT

Issue description

If Bounces on a LightmapGI node is set to 0 and there are no lights with Static bake mode, baking lightmaps will fail at the end. The lightmapper will write an OpenEXR file that Godot can't import: exr.zip

  Transient parent has another exclusive child.
  core/io/file_access.cpp:758 - Condition "f.is_null()" is true. Continuing.
  Unable to open file: res://.godot/imported/Scene.exr-f8a9d171130ce3b526802f87761ad0fc.ctexarray.
  Failed loading resource: res://.godot/imported/Scene.exr-f8a9d171130ce3b526802f87761ad0fc.ctexarray. Make sure resources have been imported by opening the project in the editor at least once.
  Failed loading resource: res://Scene.exr. Make sure resources have been imported by opening the project in the editor at least once.
  scene/3d/lightmap_gi.cpp:179 - Condition "t.is_null()" is true. Returning: ret
  core/io/file_access.cpp:758 - Condition "f.is_null()" is true. Continuing.
  Unable to open file: res://.godot/imported/Scene.exr-f8a9d171130ce3b526802f87761ad0fc.ctexarray.
  Failed loading resource: res://.godot/imported/Scene.exr-f8a9d171130ce3b526802f87761ad0fc.ctexarray. Make sure resources have been imported by opening the project in the editor at least once.
  Failed loading resource: res://Scene.exr. Make sure resources have been imported by opening the project in the editor at least once.
  scene/3d/lightmap_gi.cpp:179 - Condition "t.is_null()" is true. Returning: ret
Done baking lightmaps in 00:00:02.

A "Load Errors" dialog will also appear, as the resulting texture file is not valid:

The bake should complete successfully instead, even if setting Bounces to 0 with no lights that have their bake mode set to Static will result in a fully black lightmap.

Steps to reproduce

Ensure there are no other lights with the bake mode set to Static in the scene.
Set the LightmapGI's Bounces property to 0.
Set the DirectionalLight3D's bake mode to Dynamic (the default).
Select the LightmapGI node and click Bake Lightmaps at the top of the 3D editor viewport.