Export scene by attached script Type

[codevogel]

Describe the project you are working on

A little 2d top-down strategy game.

Describe the problem or limitation you are having in your project

Coming from a Unity background, I am used to being able to assign a Prefab of a certain Type

e.g. I could export a Player on my PlayerSpawner and it would only accept prefabs that have the Player component attached.

As Godot's 'replacement' for Prefabs is Scenes, I would like to see something similar possible with scenes.

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

Right now, if I have a PlayerSpawner, and expose a Player with export, I can only select already existing instances of Player in the inspector.

I would like to also be able to select scenes that have the class_name Player script attached to their root node.

Right now, I can either:

• refer to the player 'prefab' scene by path: This is pretty bad given now it relies on a hardcoded path.
• @export var player_scene: PackedScene: With this, we can select ANY scene, even things that are not a Player, like a Door. So, we end up having to do a cast on instantiating the node, to verify that we are indeed spawning a Player.

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

Since Node only allows one gdscript to be attached, and a Scene always has a Root node, I would imagine it would be possible to restrict the Inspector to only select scenes that have the Player script attached to their root node.

e.g. return a list of scenes for the inspector that are filtered by something like this (pseudocode):

func is_scene_selectable(scene: PackedScene):
    return true if scene.attached_script? is player else false

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

Yes, for example, each time you instantiate a scene, you check it's type, but since this is something that happens often, it results into more and more lines of code.

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

Since it would also assume that you don't need to cast the player scene node to a Player.

[BlackShift]

Related to:

• Allow us to strongly type packed scenes #782
• Allow type specification of root node for exported PackedScenes #5255
• Add a generic parameter to PackedScene (like Array) to allow for easier type safety #6694

[codevogel]

Related to:

* [Allow us to strongly type packed scenes #782](https://github.com/godotengine/godot-proposals/issues/782)

* [Allow type specification of root node for exported PackedScenes #5255](https://github.com/godotengine/godot-proposals/issues/5255)

* [Add a generic parameter to PackedScene (like Array) to allow for easier type safety #6694](https://github.com/godotengine/godot-proposals/issues/6694)

Thanks, I did some digging but I couldn't find these issues at the time of posting