get_global_mouse_position() is shifted in the viewport's transform

[JohnEmhoff]

Godot version

4.0rc1

System information

Linux

Issue description

This is a copy of #30215, as it seems it was incorrectly closed (or there's a regression).

When I use the get_global_mouse_position() in a normal scene, the coordinates are right, but when I use in a scene that uses a viewport container to render pixelated the scene, the coordinates are incorrect.

Steps to reproduce

Add a viewport node with a non-1:1 scale. Note that get_global_mouse_position returns the wrong coordinates.

Minimal reproduction project

scale-bug-4rc1.zip

[Sauermann]

# mouse = to_local(mouse) # no effect?

In your MRP, it is correct, that to_local has no effect in this case, because TileMap has a default transform.
to_local is not affected by the viewport.

The SubViewport-setup in your MRP looks complicated. Doesn't look like a trivial issue to investigate.

[Sauermann]

Somehow you managed to bring the SubViewport into an inconsistent state in the editor.

SubViewportConteiner.stretch == true implies that SubViewport.size is set automatically by the SubViewportContainer.
However in your MRP you have

• SubViewportConteiner.size == (2560x1440)
• SubViewportConteiner.stretch == true
• SubViewport.size == (640x360)

This will cause problems, as described in #66906, which fixed a different way to create an inconsistent state.

The following topics might also be interesting for you.

related to #61301
related to godotengine/godot-proposals#6221
related to godotengine/godot-proposals#1666

Currently the method that brings you as close as possible to your wanted functionality is to set in your MRP SubViewportContainer.stretch_shrink = 4

This will automatically scale the SubViewport to the size of 1/4 of the SubViewportContainer.

If this doesn't satisfy your requirements, I would like to suggest, that you describe your needed functionality in the form of a proposal in https://github.com/godotengine/godot-proposals

[JohnEmhoff]

Thanks, I'll mess around and see if that fixes the mouse coordinates. This particular project was created in version 3.something then migrated to 4 which might explain how it got into such a weird state.