Godot GLTF Export Fails to Export Pure Skeleton Animations with No Meshes

[fire]

Godot version

e188d61

System information

Mac Mini, Apple Silicon on Firefox

Issue description

The Godot GLTF export feature is unable to export pure skeleton animations without any associated meshes. This issue occurs when attempting to export a scene containing only a skeleton and its animations, without any mesh instances.

See also godotengine/FBX2glTF#19 for the import like this.

A potential solution could involve updating the GLTF export code to handle cases where there are no mesh instances present in the scene, ensuring that the skeleton and its animations are still exported correctly.

Steps to reproduce

Steps to Reproduce:

1. Create a new Godot project.
2. Import a gltf animation with meshes
3. Delete the meshes
4. Go to Project > Export As > GLTF Scene.
5. Choose a destination folder and click "Export".

Expected Result:

The GLTF file should be exported successfully, containing the skeleton and its animations without any mesh data.

Actual Result:

The export process fails, and the resulting GLTF file does not contain the skeleton. It contains a lot of nodes. Without the skeleton, the animation cannot be used for the godot engine humanoid for example.

Minimal reproduction project

tscn_animation_without_mesh_export.zip