feat: apply modifiers for VRM1 in Blender 4.2

src/io_scene_vrm/exporter/abstract_base_vrm_exporter.py

@@ -5,20 +5,24 @@
 from contextlib import contextmanager
 from typing import Optional, Union
 
+import bmesh
 import bpy
 from bpy.types import Armature, Context, Mesh, NodesModifier, Object
 from mathutils import Quaternion
 
 from ..common import ops, shader
 from ..common.convert import Json
 from ..common.deep import make_json
+from ..common.logging import get_logger
 from ..common.workspace import save_workspace
 from ..editor.extension import get_armature_extension, get_material_extension
 from ..editor.search import MESH_CONVERTIBLE_OBJECT_TYPES
 from ..editor.vrm0.property_group import Vrm0HumanoidPropertyGroup
 from ..editor.vrm1.property_group import Vrm1HumanoidPropertyGroup
 from ..external import io_scene_gltf2_support
 
+logger = get_logger(__name__)
+
 
 class AbstractBaseVrmExporter(ABC):
     def __init__(
@@ -311,18 +315,43 @@ def assign_dict(
     return True
 
 
-def force_apply_modifiers(context: Context, obj: Object) -> Optional[Mesh]:
+def force_apply_modifiers(
+    context: Context, obj: Object, *, persistent: bool
+) -> Optional[Mesh]:
     if obj.type not in MESH_CONVERTIBLE_OBJECT_TYPES:
         return None
+    obj_data = obj.data
+    if obj_data is None:
+        return None
 
     # https://docs.blender.org/api/2.80/Depsgraph.html
     # TODO: シェイプキーが壊れることがあるらしい
     depsgraph = context.evaluated_depsgraph_get()
-    mesh_owner = obj.evaluated_get(depsgraph)
-    mesh_from_mesh_owner = mesh_owner.to_mesh(
+    evaluated_obj = obj.evaluated_get(depsgraph)
+    evaluated_temporary_mesh = evaluated_obj.to_mesh(
         preserve_all_data_layers=True, depsgraph=depsgraph
     )
-    if not mesh_from_mesh_owner:
+    if not evaluated_temporary_mesh:
         return None
 
-    return mesh_from_mesh_owner.copy()
+    if not persistent:
+        return evaluated_temporary_mesh.copy()
+
+    # ドキュメントにはBlendDataMeshes.new_from_object()を使うべきと書いてあるが、
+    # それだとシェイプキーが保持されない。
+    if isinstance(obj_data, Mesh):
+        evaluated_mesh = obj_data.copy()
+    else:
+        logger.error(
+            "Unexpected object type: %s name=%s",
+            type(obj_data),
+            obj_data.name,
+        )
+        evaluated_mesh = context.blend_data.meshes.new(name=obj_data.name)
+    bm = bmesh.new()
+    try:
+        bm.from_mesh(evaluated_temporary_mesh)
+        bm.to_mesh(evaluated_mesh)
+    finally:
+        bm.free()
+    return evaluated_mesh

src/io_scene_vrm/exporter/vrm0_exporter.py

@@ -2316,7 +2316,9 @@ def mesh_to_bin_and_dict(
 
             shape_key_names: Sequence[str] = []
             with save_workspace(self.context):
-                main_mesh_data = force_apply_modifiers(self.context, mesh)
+                main_mesh_data = force_apply_modifiers(
+                    self.context, mesh, persistent=False
+                )
                 if not main_mesh_data:
                     continue
                 shape_key_name_to_mesh_data: dict[str, Mesh] = {}
@@ -2334,7 +2336,9 @@ def mesh_to_bin_and_dict(
 
                         shape_key.value = 1.0
                         self.context.view_layer.update()
-                        shape_mesh = force_apply_modifiers(self.context, mesh)
+                        shape_mesh = force_apply_modifiers(
+                            self.context, mesh, persistent=False
+                        )
                         shape_key.value = 0.0
                         self.context.view_layer.update()
 

src/io_scene_vrm/exporter/vrm1_exporter.py

@@ -20,6 +20,7 @@
     DampedTrackConstraint,
     Image,
     Material,
+    Mesh,
     Node,
     Object,
 )
@@ -2755,7 +2756,7 @@ def force_apply_modifiers_to_object(
         return
 
     original_mesh_data = mesh_object.data
-    if not original_mesh_data:
+    if not isinstance(original_mesh_data, Mesh):
         return
 
     armature_modifier_name_to_show_render_and_show_viewport: dict[
@@ -2775,14 +2776,15 @@ def force_apply_modifiers_to_object(
         mesh_data_name = original_mesh_data.name
         original_mesh_data.name = "Backup-Apply-Data-" + uuid4().hex
 
-        mesh_data: Optional[ID] = force_apply_modifiers(context, mesh_object)
+        mesh_data: Optional[ID] = force_apply_modifiers(
+            context, mesh_object, persistent=True
+        )
         if not mesh_data:
             return
 
-        mesh_data.user_remap(original_mesh_data)
-        mesh_data = mesh_object.data
-        if not mesh_data:
-            return
+        original_mesh_data.user_remap(mesh_data)
+        if original_mesh_data.users <= 1:
+            context.blend_data.meshes.remove(original_mesh_data)
 
         mesh_data.name = mesh_data_name
     finally: