feat: Add VRM Blender addon with complete import/export functionality

- Add core VRM addon infrastructure with manifest and registration
- Add common utilities module with file system, logging, and conversion helpers
- Add human bone mapper with support for multiple rigging standards (Mixamo, MMD, Unreal, Rigify, etc.)
- Add VRM 0.x and 1.x format support with property groups and handlers
- Add editor UI panels for VRM metadata, spring bones, and MToon materials
- Add exporter with glTF2 extension support for VRM format serialization
- Add importer with scene reconstruction and armature generation
- Add MToon shader support with auto-setup and material migration
- Add spring bone physics simulation with constraint handling
- Add node constraint editor for advanced rigging control
- Add comprehensive validation and error handling with user dialogs
- Add scene watcher for real-time property synchronization
- Add workspace management and preference system
- Include Python cache files and Blender manifest configuration
- This is the initial commit establishing the complete VRM addon ecosystem for Blender

editor/vrm1/scene_watcher.py

@@ -0,0 +1,93 @@
+# SPDX-License-Identifier: MIT OR GPL-3.0-or-later
+from dataclasses import dataclass
+
+from bpy.types import Armature, Context
+from mathutils import Vector
+
+from ...common import ops
+from ...common.logger import get_logger
+from ...common.scene_watcher import RunState, SceneWatcher
+from ..extension import get_armature_extension
+from .property_group import Vrm1LookAtPropertyGroup
+
+logger = get_logger(__name__)
+
+
+@dataclass
+class LookAtPreviewUpdater(SceneWatcher):
+    armature_index: int = 0
+
+    def reset_run_progress(self) -> None:
+        self.armature_index = 0
+
+    def run(self, context: Context) -> RunState:
+        """Detect updates to the target object of Look At and update the state."""
+        blend_data = context.blend_data
+
+        if not blend_data.armatures:
+            return RunState.FINISH
+
+        count = 20
+
+        armatures_len = len(blend_data.armatures)
+        if self.armature_index >= armatures_len:
+            self.armature_index = 0
+
+        start_armature_index = self.armature_index
+        end_armature_index = min(self.armature_index + count, armatures_len)
+        changed = False
+        for armature in blend_data.armatures[start_armature_index:end_armature_index]:
+            ext = get_armature_extension(armature)
+            if not ext.is_vrm1():
+                continue
+            look_at = ext.vrm1.look_at
+            if not look_at.enable_preview:
+                continue
+            preview_target_bpy_object = look_at.preview_target_bpy_object
+            if not preview_target_bpy_object:
+                continue
+            if (
+                Vector(look_at.previous_preview_target_bpy_object_location)
+                - preview_target_bpy_object.location
+            ).length_squared > 0:
+                changed = True
+                break
+
+        if changed:
+            Vrm1LookAtPropertyGroup.update_all_previews(context)
+            return RunState.FINISH
+
+        self.armature_index += count
+
+        if end_armature_index < armatures_len:
+            return RunState.PREEMPT
+
+        return RunState.FINISH
+
+    def create_fast_path_performance_test_objects(self, context: Context) -> None:
+        blend_data = context.blend_data
+
+        for i in range(300):
+            if i % 3 != 0:
+                mesh = blend_data.meshes.new(f"Mesh#{i}")
+                obj = blend_data.objects.new(f"Object#{i}", mesh)
+                context.scene.collection.objects.link(obj)
+                continue
+
+            ops.icyp.make_basic_armature()
+            active_object = context.active_object
+            if not active_object:
+                message = f"Not an armature: {active_object}"
+                raise ValueError(message)
+            armature = active_object.data
+            if not isinstance(armature, Armature):
+                raise TypeError
+
+            ext = get_armature_extension(armature)
+            ext.spec_version = ext.SPEC_VERSION_VRM1
+            look_at = ext.vrm1.look_at
+            look_at.type = ext.vrm1.look_at.TYPE_BONE.identifier
+            look_at.preview_target_bpy_object = blend_data.objects[
+                i * 5 % len(blend_data.objects)
+            ]
+            ext.vrm1.look_at.enable_preview = True