SubViewport rendered as ViewportTexture doesn't receive InputEvents

[ascripter]

Godot version

v4.1.stable.official [9704596]

System information

Godot v4.1.stable - Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce 940MX (NVIDIA; 31.0.15.1654) - Intel(R) Core(TM) i7-7820HQ CPU @ 2.90GHz (8 Threads)

Issue description

When projecting a SubViewport as a texture (i.e. tested with ViewportTexture for Sprite2D and Sprite3D), and the scene inside the SubViewport contains any Control elements, they are not accessible / don't receive any InputEvents.

Explicitly forcing them to get the focus via Control.grab_focus() seems to work, but then any input is just ignored. Tried it with and without SubViewport.handle_input_locally, as well with callback-scripts that reside in nodes inside and outside the SubViewport.

Steps to reproduce

The attached project has two buttons, the "outer" is a child of the main node, while the "inner" is projected as a Sprite2D's texture. The inner button can't be pressed, no matter how I try it.

Minimal reproduction project

viewport_test.zip

[AThousandShips]

I'm not sure this is supposed to work, they should be in a SubViewportContainer to have access to this functionality AFAIK

I think you need to pass the input forward to the viewport in this case, see here

[Sauermann]

You can find a rationale for the current behavior in #9950 (comment)

So you have two options:

1. Use a SubViewportContainer, which automatically sends events to its child SubViewports.
2. Implement InputEvent-propagation based on your individual requirements from Sprite2D. (In the post above you find a link for how to do this in a 3D-application)

I would like to close this issue, since the current behavior is expected and also documented in https://docs.godotengine.org/en/latest/tutorials/inputs/inputevent.html

[Sauermann]

If you need the functionality for 2D/3D in an automated way, you could give a thumbs-up to the proposal godotengine/godot-proposals#6524