OpenXR fix character centric recenter code

[BastiaanOlij]

This fixes the recenter code to work with different reference spaces.

While these changes also apply to Godot 4.3, not all XR runtimes properly trigger the recenter signal. For this to consistently work godotengine/godot#99159 is required.

[BastiaanOlij]

Note, this else if is purely here for documentation purposes so that anyone reading this code knows, the headset already applies the required logic.

[dsnopek]

Seems like a good idea to me!

[BastiaanOlij]

One thing we may wish to add to this demo is setting the project settings to LOCAL_FLOOR space as the default recommended reference space.

cc @dsnopek

[dsnopek]

I tested on Quest 3 with Godot master (which includes godotengine/godot#99159) and it worked great for me!

One thing we may wish to add to this demo is setting the project settings to LOCAL_FLOOR space as the default recommended reference space.

I would be in favor of this! I think LOCAL_FLOOR is a good default for most projects.

[BastiaanOlij]

Note to production team. While this PR does require a fix to fully work, we should contemplate merging it already as it does improve the demo and it ensure people don't copy code into their project that will not work correctly once the Godot releases with the fix.
However fully understand if we hold off until 4.4 is release and/or the fix is cherry picked for 4.3

[aaronfranke]

If it's not completely broken in 4.3 then we can merge this, as long as the code samples are updated to follow the GDScript style guide.

[dsnopek]

Note to production team. While this PR does require a fix to fully work, we should contemplate merging it already as it does improve the demo and it ensure people don't copy code into their project that will not work correctly once the Godot releases with the fix.

I personally think this is fine to merge now. I don't think the code in this PR is really broken in 4.3; it's just that there's an additional bug in 4.3 that prevents it from fully working. I think the code from before the PR also suffers from the same issue.

Tying this back to something else discussed above: if we also updated this demo to use the "Local Floor" reference space, then re-centering would work out-of-the-box - it'd only be the example code showing how to recent when using the "Stage" reference space that wouldn't work.