loading screen

func load_scene(current_scene, next_scene):
    # add loading scene to the root
    var loading_scene_instance = loading_scene.instantiate()
    get_tree().get_root().call_deferred("add_child",loading_scene_instance)

    # find the targeted scene
    var loader = ResourceLoader.load_threaded_request(next_scene)

    #check for errors
    if loader == null:
        # handle your error
        print("error occured while getting the scene")
        return

    current_scene.queue_free()
    # creating a little delay, that lets the loading screen to appear.
    await get_tree().create_timer(0.5).timeout

    # loading the next_scene using poll() function
    # since poll() function loads data in chunks thus we need to put that in loop
    while true:
        var error = loader.poll()
        # when we get a chunk of data
        if error == OK:
            # update the progress bar according to amount of data loaded
            var progress_bar = loading_scene_instance.get_node("ProgressBar")
            progress_bar.value = float(loader.get_stage())/loader.get_stage_count() * 100
        # when all the data have been loaded
        elif error == ERR_FILE_EOF:
            # creating scene instance from loaded data
            var scene = loader.get_resource().instantiate()
            # adding scene to the root
            get_tree().get_root().call_deferred("add_child",scene)
            # removing loading scene
            loading_scene_instance.queue_free()
            return
        else:
            # handle your error
            print('error occurred while loading chunks of data')
            return