blenderings/mesh_baking/tool.py

import bpy
from bpy.types import Context, Object, Scene, Collection, ViewLayer, LayerCollection

def get_first_collection_sharing_scene(scene: Scene, obj: Object):
    def collection_in_scene(collection: Collection, tree: Collection):
        if collection == tree:
            return True
        return any(collection_in_scene(collection, child) for child in tree.children)
    return next(candidate for candidate in obj.users_collection if collection_in_scene(candidate, scene.collection))

def collection_to_layer_collection(view_layer: ViewLayer, collection: Collection) -> LayerCollection:
    wl = [view_layer.layer_collection]
    while len(wl):
        lc = wl.pop()
        if lc.collection == collection:
            return lc
        wl.extend(lc.children)

def is_pc2_enabled():
    return hasattr(bpy.ops, "export_shape") and hasattr(bpy.ops.export_shape, "pc2")

def export_pc2_filepath(obj: Object, absolute=False):
    path = f"//{obj.name}.pc2"
    return bpy.path.abspath(path) if absolute else path

def export_pc2(scene: Scene, obj: Object):
    path = export_pc2_filepath(obj, absolute=True)
    frame_start = scene.frame_start
    scene.frame_set(frame_start)
    frame_end = scene.frame_end
    bpy.context.view_layer.objects.active = obj
    bpy.context.view_layer.update()
    bpy.ops.export_shape.pc2(filepath=path, check_existing=False, rot_x90=False, world_space=False, apply_modifiers=True, range_start=frame_start, range_end=frame_end, sampling='1')
    bpy.context.view_layer.update()
    frame_end = scene.frame_end
    scene.frame_set(frame_start)
    bpy.context.view_layer.update()
    for modifier in obj.modifiers:
        bpy.ops.object.modifier_apply(modifier=modifier.name)
        bpy.context.view_layer.update()

def create_proxy(view_layer: ViewLayer, scene: Scene, obj: Object):
    copy = obj.copy()
    copy.name = f"{obj.name}Bake"
    copy.data = copy.data.copy()
    copy.constraints.clear()
    c = get_first_collection_sharing_scene(scene, obj)
    c.objects.link(copy)
    export_pc2(scene, copy)
    mod = copy.modifiers.new("Mesh Bake", "MESH_CACHE")
    mod.cache_format = "PC2"
    mod.filepath = export_pc2_filepath(copy)

    c.objects.unlink(obj)
    cc = bpy.data.collections.new(f"{obj.name}-unbaked")
    cc.objects.link(obj)
    c.children.link(cc)
    lcc = collection_to_layer_collection(view_layer, cc)
    lcc.exclude = True

class BakeMeshOperator(bpy.types.Operator):
    bl_idname = "object.bakemesh"
    bl_label = "Bake Mesh to PC2"

    @classmethod
    def poll(Cls, context: Context):
        return context.active_object is not None

    def execute(self, context: Context):
        if not is_pc2_enabled():
            self.report({"ERROR"}, "PC2 export addon must be enabled")
            return {'FINISHED'}
        scene = context.scene
        obj = context.active_object
        create_proxy(context.view_layer, scene, obj)
        return {'FINISHED'}

def BakeMeshOperator_menu_func(self, context: Context):
    return self.layout.operator(BakeMeshOperator.bl_idname)

def register():
    bpy.types.VIEW3D_MT_object.append(BakeMeshOperator_menu_func)

def unregister():
    bpy.types.VIEW3D_MT_object.remove(BakeMeshOperator_menu_func)