glTF exporter: define a user extension API

16 files changed, 108 insertions, 7 deletions

diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channel_target.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channel_target.py
index fa0f9976..5fcd4ede 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channel_target.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channel_target.py
@@ -20,6 +20,7 @@ from io_scene_gltf2.blender.exp.gltf2_blender_gather_cache import cached
 from io_scene_gltf2.blender.exp import gltf2_blender_gather_nodes
 from io_scene_gltf2.blender.exp import gltf2_blender_gather_joints
 from io_scene_gltf2.blender.exp import gltf2_blender_gather_skins
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 @cached
 def gather_animation_channel_target(channels: typing.Tuple[bpy.types.FCurve],
@@ -29,13 +30,23 @@ def gather_animation_channel_target(channels: typing.Tuple[bpy.types.FCurve],
                                     export_settings
                                     ) -> gltf2_io.AnimationChannelTarget:
 
-        return gltf2_io.AnimationChannelTarget(
+        animation_channel_target = gltf2_io.AnimationChannelTarget(
             extensions=__gather_extensions(channels, blender_object, export_settings, bake_bone),
             extras=__gather_extras(channels, blender_object, export_settings, bake_bone),
             node=__gather_node(channels, blender_object, export_settings, bake_bone),
             path=__gather_path(channels, blender_object, export_settings, bake_bone, bake_channel)
         )
 
+        export_user_extensions('gather_animation_channel_target_hook',
+                               export_settings,
+                               animation_channel_target,
+                               channels,
+                               blender_object,
+                               bake_bone,
+                               bake_channel)
+
+        return animation_channel_target
+
 def __gather_extensions(channels: typing.Tuple[bpy.types.FCurve],
                         blender_object: bpy.types.Object,
                         export_settings,
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channels.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channels.py
index d217b217..50918b68 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channels.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channels.py
@@ -23,6 +23,7 @@ from io_scene_gltf2.blender.exp import gltf2_blender_gather_animation_samplers
 from io_scene_gltf2.blender.exp import gltf2_blender_gather_animation_channel_target
 from io_scene_gltf2.blender.exp import gltf2_blender_get
 from io_scene_gltf2.blender.exp import gltf2_blender_gather_skins
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 @cached
@@ -149,13 +150,26 @@ def __gather_animation_channel(channels: typing.Tuple[bpy.types.FCurve],
     if not __filter_animation_channel(channels, blender_object, export_settings):
         return None
 
-    return gltf2_io.AnimationChannel(
+    animation_channel = gltf2_io.AnimationChannel(
         extensions=__gather_extensions(channels, blender_object, export_settings, bake_bone),
         extras=__gather_extras(channels, blender_object, export_settings, bake_bone),
         sampler=__gather_sampler(channels, blender_object, export_settings, bake_bone, bake_channel, bake_range_start, bake_range_end, action_name),
         target=__gather_target(channels, blender_object, export_settings, bake_bone, bake_channel)
     )
 
+    export_user_extensions('gather_animation_channel_hook',
+                           export_settings,
+                           animation_channel,
+                           channels,
+                           blender_object,
+                           bake_bone,
+                           bake_channel,
+                           bake_range_start,
+                           bake_range_end,
+                           action_name)
+
+    return animation_channel
+
 
 def __filter_animation_channel(channels: typing.Tuple[bpy.types.FCurve],
                                blender_object: bpy.types.Object,
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_samplers.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_samplers.py
index 5d5d310c..cd237f35 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_samplers.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_samplers.py
@@ -27,6 +27,7 @@ from io_scene_gltf2.io.com import gltf2_io
 from io_scene_gltf2.io.com import gltf2_io_constants
 from io_scene_gltf2.io.exp import gltf2_io_binary_data
 from . import gltf2_blender_export_keys
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 @cached
@@ -55,7 +56,7 @@ def gather_animation_sampler(channels: typing.Tuple[bpy.types.FCurve],
                                                  export_settings)
 
 
-    return gltf2_io.AnimationSampler(
+    sampler = gltf2_io.AnimationSampler(
         extensions=__gather_extensions(channels, blender_object_if_armature, export_settings, bake_bone, bake_channel),
         extras=__gather_extras(channels, blender_object_if_armature, export_settings, bake_bone, bake_channel),
         input=__gather_input(channels, blender_object_if_armature, non_keyed_values,
@@ -72,6 +73,19 @@ def gather_animation_sampler(channels: typing.Tuple[bpy.types.FCurve],
                                export_settings)
     )
 
+    export_user_extensions('gather_animation_sampler_hook',
+                            export_settings,
+                            sampler,
+                            channels,
+                            blender_object,
+                            bake_bone,
+                            bake_channel,
+                            bake_range_start,
+                            bake_range_end,
+                            action_name)
+
+    return sampler
+
 def __gather_non_keyed_values(channels: typing.Tuple[bpy.types.FCurve],
                               blender_object: bpy.types.Object,
                               blender_object_if_armature: typing.Optional[bpy.types.Object],
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animations.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animations.py
index a2e903e5..bf78dabd 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_animations.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_animations.py
@@ -19,6 +19,7 @@ from io_scene_gltf2.io.com import gltf2_io
 from io_scene_gltf2.blender.exp import gltf2_blender_gather_animation_channels
 from io_scene_gltf2.io.com.gltf2_io_debug import print_console
 from ..com.gltf2_blender_extras import generate_extras
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 def gather_animations(blender_object: bpy.types.Object,
@@ -108,6 +109,8 @@ def __gather_animation(blender_action: bpy.types.Action,
     if not animation.channels:
         return None
 
+    export_user_extensions('gather_animation_hook', export_settings, animation, blender_action, blender_object)
+
     return animation
 
 
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_cameras.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_cameras.py
index 3cde0fcb..6075440c 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_cameras.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_cameras.py
@@ -16,6 +16,7 @@ from . import gltf2_blender_export_keys
 from io_scene_gltf2.blender.exp.gltf2_blender_gather_cache import cached
 from ..com.gltf2_blender_extras import generate_extras
 from io_scene_gltf2.io.com import gltf2_io
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 import bpy
 import math
@@ -26,7 +27,7 @@ def gather_camera(blender_camera, export_settings):
     if not __filter_camera(blender_camera, export_settings):
         return None
 
-    return gltf2_io.Camera(
+    camera = gltf2_io.Camera(
         extensions=__gather_extensions(blender_camera, export_settings),
         extras=__gather_extras(blender_camera, export_settings),
         name=__gather_name(blender_camera, export_settings),
@@ -35,6 +36,10 @@ def gather_camera(blender_camera, export_settings):
         type=__gather_type(blender_camera, export_settings)
     )
 
+    export_user_extensions('gather_camera_hook', export_settings, camera, blender_camera)
+
+    return camera
+
 
 def __filter_camera(blender_camera, export_settings):
     return bool(__gather_type(blender_camera, export_settings))
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_image.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_image.py
index 9309eb64..183da33e 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_image.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_image.py
@@ -26,6 +26,7 @@ from io_scene_gltf2.io.exp import gltf2_io_image_data
 from io_scene_gltf2.io.com import gltf2_io_debug
 from io_scene_gltf2.blender.exp import gltf2_blender_image
 from io_scene_gltf2.blender.exp.gltf2_blender_gather_cache import cached
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 @cached
@@ -47,7 +48,7 @@ def gather_image(
     uri = __gather_uri(image_data, mime_type, name, export_settings)
     buffer_view = __gather_buffer_view(image_data, mime_type, name, export_settings)
 
-    return __make_image(
+    image = __make_image(
         buffer_view,
         __gather_extensions(blender_shader_sockets_or_texture_slots, export_settings),
         __gather_extras(blender_shader_sockets_or_texture_slots, export_settings),
@@ -57,6 +58,10 @@ def gather_image(
         export_settings
     )
 
+    export_user_extensions('gather_image_hook', export_settings, image, blender_shader_sockets_or_texture_slots)
+
+    return image
+
 @cached
 def __make_image(buffer_view, extensions, extras, mime_type, name, uri, export_settings):
     return gltf2_io.Image(
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_material_normal_texture_info_class.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_material_normal_texture_info_class.py
index ee948ff2..4a46814c 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_material_normal_texture_info_class.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_material_normal_texture_info_class.py
@@ -21,6 +21,7 @@ from io_scene_gltf2.blender.exp import gltf2_blender_search_node_tree
 from io_scene_gltf2.blender.exp import gltf2_blender_export_keys
 from io_scene_gltf2.blender.exp import gltf2_blender_get
 from io_scene_gltf2.io.com.gltf2_io_extensions import Extension
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 @cached
@@ -41,6 +42,11 @@ def gather_material_normal_texture_info_class(blender_shader_sockets_or_texture_
     if texture_info.index is None:
         return None
 
+    export_user_extensions('gather_material_normal_texture_info_class_hook',
+                           export_settings,
+                           texture_info,
+                           blender_shader_sockets_or_texture_slots)
+
     return texture_info
 
 
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_material_occlusion_texture_info_class.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_material_occlusion_texture_info_class.py
index 4c4297ce..da603bdf 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_material_occlusion_texture_info_class.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_material_occlusion_texture_info_class.py
@@ -20,6 +20,7 @@ from io_scene_gltf2.blender.exp import gltf2_blender_gather_texture
 from io_scene_gltf2.blender.exp import gltf2_blender_search_node_tree
 from io_scene_gltf2.blender.exp import gltf2_blender_get
 from io_scene_gltf2.io.com.gltf2_io_extensions import Extension
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 @cached
@@ -40,6 +41,11 @@ def gather_material_occlusion_texture_info_class(blender_shader_sockets_or_textu
     if texture_info.index is None:
         return None
 
+    export_user_extensions('gather_material_occlusion_texture_info_class_hook',
+                           export_settings,
+                           texture_info,
+                           blender_shader_sockets_or_texture_slots)
+
     return texture_info
 
 
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials.py
index 9b9a9abe..fceb46f1 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials.py
@@ -25,6 +25,7 @@ from io_scene_gltf2.blender.exp import gltf2_blender_search_node_tree
 from io_scene_gltf2.blender.exp import gltf2_blender_gather_materials_pbr_metallic_roughness
 from ..com.gltf2_blender_extras import generate_extras
 from io_scene_gltf2.blender.exp import gltf2_blender_get
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 @cached
@@ -55,6 +56,8 @@ def gather_material(blender_material, mesh_double_sided, export_settings):
         pbr_metallic_roughness=__gather_pbr_metallic_roughness(blender_material, orm_texture, export_settings)
     )
 
+    export_user_extensions('gather_material_hook', export_settings, material, blender_material)
+
     return material
     # material = blender_primitive['material']
     #
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials_pbr_metallic_roughness.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials_pbr_metallic_roughness.py
index 04a0fcd1..77c7fe55 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials_pbr_metallic_roughness.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials_pbr_metallic_roughness.py
@@ -20,6 +20,7 @@ from io_scene_gltf2.blender.exp import gltf2_blender_gather_texture_info, gltf2_
 from io_scene_gltf2.blender.exp import gltf2_blender_get
 from io_scene_gltf2.blender.exp.gltf2_blender_gather_cache import cached
 from io_scene_gltf2.io.com.gltf2_io_debug import print_console
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 @cached
@@ -37,6 +38,8 @@ def gather_material_pbr_metallic_roughness(blender_material, orm_texture, export
         roughness_factor=__gather_roughness_factor(blender_material, export_settings)
     )
 
+    export_user_extensions('gather_material_pbr_metallic_roughness_hook', export_settings, material, blender_material, orm_texture)
+
     return material
 
 
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_mesh.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_mesh.py
index 3af26ced..50df1395 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_mesh.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_mesh.py
@@ -20,6 +20,7 @@ from io_scene_gltf2.io.com import gltf2_io
 from io_scene_gltf2.blender.exp import gltf2_blender_gather_primitives
 from ..com.gltf2_blender_extras import generate_extras
 from io_scene_gltf2.io.com.gltf2_io_debug import print_console
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 @cached
@@ -45,6 +46,17 @@ def gather_mesh(blender_mesh: bpy.types.Mesh,
     if len(mesh.primitives) == 0:
         print_console("WARNING", "Mesh '{}' has no primitives and will be omitted.".format(mesh.name))
         return None
+
+    export_user_extensions('gather_mesh_hook',
+                           export_settings,
+                           mesh,
+                           blender_mesh,
+                           blender_object,
+                           vertex_groups,
+                           modifiers,
+                           skip_filter,
+                           material_names)
+
     return mesh
 
 
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_nodes.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_nodes.py
index f1901180..b30f6a0e 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_nodes.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_nodes.py
@@ -28,6 +28,7 @@ from io_scene_gltf2.blender.exp import gltf2_blender_gather_lights
 from ..com.gltf2_blender_extras import generate_extras
 from io_scene_gltf2.io.com import gltf2_io
 from io_scene_gltf2.io.com import gltf2_io_extensions
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 def gather_node(blender_object, blender_scene, export_settings):
@@ -86,6 +87,8 @@ def __gather_node(blender_object, blender_scene, export_settings):
             node.children.append(correction_node)
         node.camera = None
 
+    export_user_extensions('gather_node_hook', export_settings, node, blender_object)
+
     return node
 
 
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_sampler.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_sampler.py
index 78fbc282..80b74e9c 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_sampler.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_sampler.py
@@ -15,6 +15,7 @@
 import bpy
 from io_scene_gltf2.io.com import gltf2_io
 from io_scene_gltf2.blender.exp.gltf2_blender_gather_cache import cached
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 @cached
@@ -22,7 +23,7 @@ def gather_sampler(blender_shader_node: bpy.types.Node, export_settings):
     if not __filter_sampler(blender_shader_node, export_settings):
         return None
 
-    return gltf2_io.Sampler(
+    sampler = gltf2_io.Sampler(
         extensions=__gather_extensions(blender_shader_node, export_settings),
         extras=__gather_extras(blender_shader_node, export_settings),
         mag_filter=__gather_mag_filter(blender_shader_node, export_settings),
@@ -32,6 +33,10 @@ def gather_sampler(blender_shader_node: bpy.types.Node, export_settings):
         wrap_t=__gather_wrap_t(blender_shader_node, export_settings)
     )
 
+    export_user_extensions('gather_sampler_hook', export_settings, sampler, blender_shader_node)
+
+    return sampler
+
 
 def __filter_sampler(blender_shader_node, export_settings):
     if not blender_shader_node.interpolation == 'Closest' and not blender_shader_node.extension == 'CLIP':
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_skins.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_skins.py
index 18503fdd..1ee54b89 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_skins.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_skins.py
@@ -21,6 +21,7 @@ from io_scene_gltf2.io.com import gltf2_io_constants
 from io_scene_gltf2.blender.exp import gltf2_blender_gather_accessors
 from io_scene_gltf2.blender.exp import gltf2_blender_gather_joints
 from io_scene_gltf2.blender.com import gltf2_blender_math
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 @cached
@@ -35,7 +36,7 @@ def gather_skin(blender_object, export_settings):
     if not __filter_skin(blender_object, export_settings):
         return None
 
-    return gltf2_io.Skin(
+    skin = gltf2_io.Skin(
         extensions=__gather_extensions(blender_object, export_settings),
         extras=__gather_extras(blender_object, export_settings),
         inverse_bind_matrices=__gather_inverse_bind_matrices(blender_object, export_settings),
@@ -44,6 +45,10 @@ def gather_skin(blender_object, export_settings):
         skeleton=__gather_skeleton(blender_object, export_settings)
     )
 
+    export_user_extensions('gather_skin_hook', export_settings, skin, blender_object)
+
+    return skin
+
 
 def __filter_skin(blender_object, export_settings):
     if not export_settings[gltf2_blender_export_keys.SKINS]:
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_texture.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_texture.py
index fbf8483a..b906413f 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_texture.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_texture.py
@@ -21,6 +21,7 @@ from io_scene_gltf2.blender.exp import gltf2_blender_gather_sampler
 from io_scene_gltf2.blender.exp import gltf2_blender_search_node_tree
 from io_scene_gltf2.blender.exp import gltf2_blender_gather_image
 from io_scene_gltf2.io.com import gltf2_io_debug
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 @cached
@@ -51,6 +52,8 @@ def gather_texture(
     if texture.source is None:
         return None
 
+    export_user_extensions('gather_texture_hook', export_settings, texture, blender_shader_sockets_or_texture_slots)
+
     return texture
 
 
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_texture_info.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_texture_info.py
index 124c8ba0..66b9b4eb 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_texture_info.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_texture_info.py
@@ -21,6 +21,7 @@ from io_scene_gltf2.blender.exp import gltf2_blender_search_node_tree
 from io_scene_gltf2.blender.exp import gltf2_blender_get
 from io_scene_gltf2.io.com.gltf2_io_debug import print_console
 from io_scene_gltf2.io.com.gltf2_io_extensions import Extension
+from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
 
 
 @cached
@@ -40,6 +41,8 @@ def gather_texture_info(blender_shader_sockets_or_texture_slots: typing.Union[
     if texture_info.index is None:
         return None
 
+    export_user_extensions('gather_texture_info_hook', export_settings, texture_info, blender_shader_sockets_or_texture_slots)
+
     return texture_info