glTF exporter: allow user extension in asset

io_scene_gltf2/__init__.py

@@ -15,7 +15,7 @@
 bl_info = {
     'name': 'glTF 2.0 format',
     'author': 'Julien Duroure, Scurest, Norbert Nopper, Urs Hanselmann, Moritz Becher, Benjamin Schmithüsen, Jim Eckerlein, and many external contributors',
-    "version": (1, 4, 14),
+    "version": (1, 4, 15),
     'blender': (2, 90, 0),
     'location': 'File > Import-Export',
     'description': 'Import-Export as glTF 2.0',

io_scene_gltf2/blender/exp/gltf2_blender_gltf2_exporter.py

@@ -23,6 +23,7 @@ from io_scene_gltf2.io.exp import gltf2_io_binary_data
 from io_scene_gltf2.io.exp import gltf2_io_buffer
 from io_scene_gltf2.io.exp import gltf2_io_image_data
 from io_scene_gltf2.blender.exp import gltf2_blender_export_keys
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 class GlTF2Exporter:
@@ -44,6 +45,8 @@ class GlTF2Exporter:
             generator='Khronos glTF Blender I/O v' + get_version_string(),
             min_version=None,
             version='2.0')
+        
+        export_user_extensions('gather_asset_hook', export_settings, asset)
 
         self.__gltf = gltf2_io.Gltf(
             accessors=[],
@@ -103,6 +106,8 @@ class GlTF2Exporter:
             gltf2_io.MaterialNormalTextureInfoClass,
             gltf2_io.MaterialOcclusionTextureInfoClass
         ]
+        
+        self.__traverse(asset)
 
     @property
     def glTF(self):