Add option to export Geometry Nodes Instances in Blender importer

[ywmaa]

Should close: godotengine/godot-proposals#8991

[fire]

I approve of Export Geometry Nodes Instances in blend importer as as a Godot Engine proposal. I haven't done the technical review yet.

[ywmaa]

Hey, I just gave this PR a test, it works great if this is solved:
https://projects.blender.org/blender/blender/issues/122237

which is already solved, I think it will land with a new blender 4.1 minor release and/or with 4.2 release.

I think we can safely merge this PR if the issue on blender side is included with their distrubted blender version.

edit:
the blender issue above is fixed here:
https://projects.blender.org/blender/blender-addons/commit/6b8b29648c3bb05f20d99f6eca775bffd05d490a

got the link from the issue discussion.

[ywmaa]

I kindly suggest merging this PR as it adds only 9 lines of code, that hopefully won't break anything, and the feature will be there once blender includes the fix on their end.

also the geometry nodes feature will only work if blender's major is 4 and minor is 1 or more, meaning it shouldn't do anything to users who still use blender 3.x as the importer.

[ywmaa]

Ok, I will apply this patch, but also I found out that with blender 4.1.1 the importing fails if export_lights is true, only one export_lights or export_geometry_nodes_instances must be true and the other is false, see the discussion here about this issue:
https://projects.blender.org/blender/blender/issues/122237

Now should I:
1- bump the blender version for this feature to 4.2, though I am still reporting the issue to blender team, so not 100% sure it will land in 4.2 (but then we won't be able to use export_geometry_nodes_instances in 4.1)
2- leave it at 4.1, but add a workaround for 4.1 only: disabling export_lights if export_geometry_nodes_instances is enabled.

what is the best solution ?

[fire]

I think 2 is better for wider compatibility. Blender 4.2 doesn't work fully yet due to the vertex color error.

[ywmaa]

Great news, Blender 4.2 (Development) now has the issue solved:
https://projects.blender.org/blender/blender/issues/122379#issuecomment-1200660

so this PR will work with 4.2 without the 4.1 workaround.

This PR as it is now should work with 4.1 (with the workaround), and 4.2 and up (without any workaround).

[warcaninos]

Could this be merged for 4.3 or is it planned for 4.4 ?

[AThousandShips]

For 4.4 at the earliest, we're not accepting new features for 4.3 at this time

[ywmaa]

I just rebased and tested it with the new released Blender 4.2 LTS, and it works!

this PR should be ready when the door opens for Godot 4.4.

[ywmaa]

is it possible for this to get merged since 4.4 is now WIP ?

[akien-mga]

Thanks! And congrats for your first merged Godot contribution 🎉