The Clip Children option in Sprite2D does not work correctly

[Aidaxo]

Godot version

4.1.1.stable

System information

Godot v4.1.1.stable - Windows 10.0.20348 - Vulkan (Forward+) - dedicated NVIDIA RTX A2000 12GB (NVIDIA; 31.0.15.3625) - Intel(R) Xeon(R) Gold 6342 CPU @ 2.80GHz (48 Threads)

Issue description

The 2D Masking / Clipping feature was introduced in version 4.0.
https://godotengine.org/article/godots-2d-engine-gets-several-improvements-upcoming-40/

It was a really handy feature, but when updating 4.0->4.1.1 it suddenly stopped working.

The test project opened in Godot 4.0 is displayed correctly.

The same project opened in 4.1.1 looks bad.

Experimentally, we were able to establish that the changes in the behaviour of the function occurred in 4.0.1.

Steps to reproduce

When Clip Children=Clip Only is enabled in the properties of the masking Sprite2D, its texture continues to be displayed and no masking occurs.

Minimal reproduction project

N/A

[Calinou]

@Aidaxo Please upload a minimal reproduction project to make this easier to troubleshoot.

[Aidaxo]

Minimal reproduction project is attached
test_project.zip

[Swarkin]

Most likely related:
Having a parent with clip_children enabled will make all children's clip_children behave as if they were set to Clip + Draw.
Trying to show it here:

unknown_2023.08.06-03.01.mp4

This does not seem like intended behaviour.

[klaritan]

Can confirm this is an issue. Sprite2D parent simply cannot clip children (also Sprite2D) at all. Still an issue for latest Godot 4.2

[clayjohn]

The problem here is that you are trying to enable clip_children on a node that is a child of a CanvasGroup.

The docs explicitly say that you cannot do that:

Note: Since CanvasGroup and CanvasItem.clip_children both utilize the backbuffer, children of a CanvasGroup who have their CanvasItem.clip_children set to anything other than CanvasItem.CLIP_CHILDREN_DISABLED will not function correctly.

That being said, there is already a PR to change the behaviour of clip_children so that it will support nesting. See #74859