Add change_scene_to_node() method

[sky94520]

Describe the project you are working on

A 2D survivor game at mobile platform using c#

Describe the problem or limitation you are having in your project

Godot has change_scene_to_file and change_scene_to_packed methods, change_scene_to_packed. Whyt not add method change_scene_to_node(const Ref &p_node).
Now I use sub thread load and instance scene, and add_child, set_current_scene. but the replacement is raised error at Android Platform which too many

Condition 'p_elem->_root != this' is true

I guess the godot source code has another logic while change scene.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

I can use the new method to change_scene

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

No

If this enhancement will not be used often, can it be worked around with a few lines of script?

No

Is there a reason why this should be core and not an add-on in the asset library?

No

[AThousandShips]

Are you adding the node to the scene on the thread as well? That's not supported, you also can't load the same file in multiple threads

[sky94520]

Thank your reply. I don't change scene at thread.
Firstly, I load and instance scene at thread, and call_deffered to change_scene.
Because Godot doesn't method like change_scene_to_node, so I do use set current_scene like this

	var tree : SceneTree = self.get_tree()
	# Remove the old scene
	var old_scene = tree.current_scene
	
	tree.root.remove_child(old_scene)
	old_scene.queue_free()

	# Add the new scene
	tree.root.add_child(new_scene)

The above code run normally at first, and will raise error and the game will crashed at Android.
The Godot console raise many same error:

Condition 'p_elem->_root != this' is true

[Mickeon]

If this enhancement will not be used often, can it be worked around with a few lines of script?

No

To be pedantic, I believe yes?

get_tree().current_node.free()
get_tree().current_node = new_node

[dalexeev]

To be pedantic, I believe yes?

get_tree().current_node.free()
get_tree().current_node = new_node

Condition 'p_elem->_root != this' is true

func change_scene_to_node(node: Node) -> void:
    await get_tree().process_frame
    get_tree().current_scene.free()
    get_tree().root.add_child(node)
    get_tree().current_scene = node

[AThousandShips]

Does this happen on 4.3.dev4? Are you using TileMap?

[sky94520]

I am sorry, My Godot Version is Godot 4.2.1 stable C#.
Besides, you are right, I do use TileMap. The error is raised because TileMap? I want to use 4.3dev4, but now official doesn't Android C# export template.

[AThousandShips]

That's the issue then, the issue you're facing is a bug, solved by:

• Prevent threading problems in TileMap godot#87478

It will be in a future 4.2 version as well, done in:

• [4.2] Prevent threading problems in TileMap godot#88916

[sky94520]

Looking forward to the arrival of the new version.
Thank you very much!!!

[AThousandShips]

If you experience any other problems after those fixes have been added to a release you use, please report it as a bug :)

[Calinou]

Moving to discussion, as there is no concrete technical implementation provided.