Improve display for lightmap probes in the editor

[Calinou]

• Use the default Back cull mode to improve performance slightly and prevent obstructing the camera.
• Fade probes when the camera gets close as to be less intrusive.

Unfortunately, I didn't manage to make direct light display on probes. Removing unshaded draw mode doesn't make them receive any light, likely because of the general light mask used by 3D editor gizmos.

• See Improve LightmapProbe placement workflow godot-proposals#7938 (comment).

Testing project: test_lightmap_preview_bake_4.x.zip

Preview

simplescreenrecorder-2023-10-23_23.28.22.mp4

[jcostello]

Can the distance be adjusted?

[Calinou]

Can the distance be adjusted?

It should be feasible to add an editor setting to change the distance, or make it fade out in the distance (instead of fading out when the camera gets close). Due to BaseMaterial3D limitations, you have to choose between fading out the material when the camera gets close, or when the camera gets far – you can't do both.

[jcostello]

It should be feasible to add an editor setting to change the distance, or make it fade out in the distance (instead of fading out when the camera gets close). Due to BaseMaterial3D limitations, you have to choose between fading out the material when the camera gets close, or when the camera gets far – you can't do both.

Right. To me fading out when the material gets closer is enough since having probes in front of the camera is annoying. Changing that distance will be helpfull

[Geometror]

Nice! I think we should also consider this for the SDFGI Probes debug view.
Honestly, I don't know whether we really need an editor setting for this - we can add one later if people need it.

[clayjohn]

Thank you!