Blender imports will always start within `.godot/imported` folder because we first convert the .blend file to .gltf, store it in `.godot/imported` and run the import from there, so on-disk resources linked from .blend files end up with duplicate textures.
Add get_scene_node_path and has_additional_data to GLTFNode, remove center of mass ignore warning in physics (it's supported now), rename `d` to `mesh_dict` in mesh import code.
Individual bones are not represented as `Node`s in Godot, in order to support meta functionality for them the skeleton has to carry the information similarly to how other per-bone properties are handled.
- Also adds support for GLTF import/export
This is useful for custom tagging of objects with properties (for example in Blender) and having this available in the editor for scripting.
- Adds import logic to propagate the parsed GLTF extras all the way to the resulting Node->meta
- Adds export logic to save Godot Object meta into GLTF extras
- Supports `nodes`, `meshes` and `materials` (in GLTF sense of the words)
- GLBs produced by godot don't pass validation when there's no data in the buffer segment. The segment is dropped but the size of the chunk_header is still reported in total length (incorrectly)
- Remove empty "extensions" JSON object being appended to all nodes (if it's still empty). This is just cutting down on unnecessary bloat and consistent with the rest of the file's attempts to not emit any keys that are equal to their default value.
- Allow the case where root_nodes is empty. This is permitted by the GLTF spec. Moreover it can happen fairly naturally when using the ROOT_NODE_MODE_MULTI_ROOT root node mode on a scene with only a root node (which is valid in godot).
- Don't create an initial buffer until we're ready to write data into it (buffers of byteLength=0 don't pass validation).
* Replaces `find(...) != -1` with `contains` for `String`
* Replaces `find(...) == -1` with `!contains` for `String`
* Replaces `find(...) != -1` with `has` for containers
* Replaces `find(...) == -1` with `!has` for containers
