kitbash3d-create-assets.py

import bpy
import glob
import os
import os.path as path
import time
import uuid
from datetime import date
from math import radians

"""
Sources : 
https://gist.github.com/Psyda/7b795a392d0f7ec8ff1a4345b08e17a3
https://projects.blender.org/blender/blender/issues/93893
https://github.com/Gorgious56/asset_browser_utilities/blob/master/core/library/tool.py#L12

Launch : 
/blender/app/blender --background --python /blender/assets/Kitbash3D/kitbash3d-create-assets.py
"""

# --------------------------------------------------------------------------------------------

library_dirname = path.dirname(path.abspath(__file__))
kit_catalog = {}

def main():
    today = str(date.today())
    blendcats_filepath = path.join(library_dirname, "blender_assets.cats.txt")

    # clean previous assets catalogs
    if path.exists(blendcats_filepath):
        os.remove(blendcats_filepath)

    if path.exists(blendcats_filepath + "~"):
        os.remove(blendcats_filepath + "~")

    # loop on subfolder only, not root files
    for entry in os.scandir(library_dirname):
        if not entry.name.startswith(".") and entry.is_dir():
            for file in glob.glob(path.join(library_dirname, entry.name, "**/*.blend"), recursive=True):
                process_blender_file(file)

    with open(blendcats_filepath, "a") as file:
        file.write(f"# Generation date: {today}\n")

        file.write("VERSION 1\n")

        for catalog_name, catalog_uid in kit_catalog.items():
            catalog_hyphen = catalog_name.replace("/", "-")
            file.write(f"{catalog_uid}:{catalog_name}:{catalog_hyphen}\n")

    print("finish! quitting...")
    bpy.ops.wm.quit_blender()


def process_blender_file(blend_filepath):
    blend_dirname = path.dirname(blend_filepath)

    # simulate open file from directory
    os.chdir(blend_dirname)
    bpy.ops.wm.open_mainfile(filepath=blend_filepath)

    # create catalogs mappings
    catalog_name = path.basename(blend_dirname)

    if catalog_name not in kit_catalog:
        kit_catalog[catalog_name] = str(uuid.uuid4())

    catalog_uid = kit_catalog[catalog_name]

    # remove all others scenes
    for scene in bpy.data.scenes:
        if not scene.name.startswith("KB3D_"):
            bpy.data.scenes.remove(scene, do_unlink=True)

    # checks for missings files
    missing_images = list_missing_blend_images()

    if len(missing_images) > 0:
        print("########## MISSING IMAGES: ##########")

        for missing_img in missing_images:
            print(f"# {missing_img}")

        print("####################################")

    # get current scene
    scene = bpy.context.scene

    # remove all cameras
    for obj in scene.objects:
        if obj.type == "CAMERA":
            bpy.data.objects.remove(obj)

    # remove all empties empty
    for obj in scene.objects:
        if obj.type == "EMPTY" and len(obj.children) == 0:
            bpy.data.objects.remove(obj)

    # current collections assets already done
    collections_assets_names = [col.name for col in scene.collection.children]

    # convert all empty to collection
    for obj in scene.objects:
        if obj.type == "EMPTY" and obj.name.startswith("KB3D_"):
            obj.location = (0, 0, 0)

            # wrap object to collection if not already
            if obj.name not in collections_assets_names:
                create_collection_from_object(scene, obj)
    
    # add default camera/world for rendering
    scene.camera = create_scene_camera(scene)
    scene.world = create_scene_world(scene)
    scene_apply_rendering_settings(scene)

    # create assets from the new collections
    for col in scene.collection.children:

        if col.asset_data is None:
            col.asset_mark()

        col.asset_data.catalog_id = catalog_uid

        if col.preview is None:
            generate_asset_preview_from_collection(scene, col)

    # cleanup preview datas and render
    bpy.data.objects.remove(scene.camera)
    bpy.data.worlds.remove(scene.world)
    bpy.data.orphans_purge(do_recursive=True)

    # if bpy.data.is_dirty:
    time.sleep(1)

    bpy.context.preferences.filepaths.save_version = 0  # No backup blends needed
    bpy.ops.wm.save_as_mainfile(filepath=blend_filepath)


def scene_apply_rendering_settings(scene):
    scene.render.engine = "CYCLES"
    scene.cycles.device = "GPU"
    scene.cycles.feature_set = "SUPPORTED"

    scene.cycles.samples = 10
    scene.cycles.use_denoising = False

    scene.cycles.use_auto_tile = False
    scene.render.use_persistent_data = True

    scene.render.resolution_x = 200
    scene.render.resolution_y = 200

    scene.render.image_settings.file_format = "PNG"
    scene.render.image_settings.color_mode = "RGBA"
    scene.render.image_settings.compression = 15
    scene.render.image_settings.color_management = "FOLLOW_SCENE"
    scene.render.film_transparent = True

    scene.display_settings.display_device = "sRGB"
    scene.view_settings.view_transform = "Standard"
    scene.view_settings.look = "Medium Contrast"
    scene.view_settings.exposure = 0.00
    scene.view_settings.gamma = 1


def create_scene_camera(scene):
    camera = bpy.data.cameras.new("Camera")
    camera_obj = bpy.data.objects.new("Camera Render", camera)

    camera_obj.location = (0, 0, 0)
    camera_obj.rotation_euler = (radians(75), radians(0), radians(45))

    scene.collection.objects.link(camera_obj)

    return camera_obj


def create_scene_world(scene):
    world = bpy.data.worlds.new("World Render")
    world.use_nodes = True

    node_tree = world.node_tree
    node_tree.nodes.clear()

    node_background = node_tree.nodes.new(type="ShaderNodeBackground")
    node_background.inputs.get("Color").default_value = (1, 1, 1, 1) # white
    node_background.inputs.get("Strength").default_value = 1

    node_output = node_tree.nodes.new(type="ShaderNodeOutputWorld")

    node_tree.links.new(input=node_background.outputs.get("Background"), output=node_output.inputs.get("Surface"))

    return world


def create_collection_from_object(scene, obj):
    print("create_collection:", obj.name)

    # create a collection and add it to scene main collection
    new_collection = bpy.data.collections.new(obj.name)
    scene.collection.children.link(new_collection)

    # move all objects to collection
    new_collection.objects.link(obj)
    for child in obj.children:
        new_collection.objects.link(child)

    # unlink all children from previous parent
    scene.collection.objects.unlink(obj)
    for child in obj.children:
        scene.collection.objects.unlink(child)


def generate_asset_preview_from_collection(scene, col):
    print("generate_preview:", col.name)

    # mark other collections as non-visible
    for col2 in scene.collection.children:
        col2.hide_render = (col2.name != col.name)

    # center the camera acording to objects in collection
    visible_objects = [obj.name for obj in col.all_objects.values()]

    for obj in scene.objects:
        obj.select_set(obj.name in visible_objects)

    bpy.ops.view3d.camera_to_view_selected()

    # finally, render
    preview_filename = str(uuid.uuid4()) + ".png"
    scene.render.filepath = path.join(bpy.app.tempdir, preview_filename)

    bpy.ops.render.render(write_still=True)

    while bpy.app.is_job_running("RENDER"):
        print("Waiting for render...")
        time.sleep(1)

    with bpy.context.temp_override(id=col):
        bpy.ops.ed.lib_id_load_custom_preview(filepath=str(scene.render.filepath))

    # re-set default visility values
    for col2 in scene.collection.children:
        col2.hide_render = False


def list_missing_blend_libs():
    return [bpy.path.abspath(lib.filepath) for lib in bpy.data.libraries
        if not path.exists(bpy.path.abspath(lib.filepath))]

def list_missing_blend_images():
    return [bpy.path.abspath(img.filepath) for img in bpy.data.images
        if img.source == "FILE" and img.packed_file is None and not path.exists(bpy.path.abspath(img.filepath))]


if __name__ == "__main__":
    main()