expose XRInterface::get_transform_for_view to gdscript

[cheece]

Hello again

By exposing XRInterface::get_transform_for_view, it's possible to implement true stereoscopic mirrors and portals in VR previously impossible in godot.

Previously i made a PR for 3.x only since viewport textures seemed to be not working on godot 4 but I found the workaround was to set the viewport size to something different than the default 512, it's now working.

I made a demo for godot 4 using the method to render stereoscopic mirrors in VR, it can be found here:
https://github.com/cheece/godot-vr-mirror-test-g4

[dsnopek]

Personally, I think exposing this is fine! Should we also expose get_projection_for_view()?

As far as PR review, it'd be nice to have a description for the API docs!

@BastiaanOlij Do you see any issues with exposing this?

[BastiaanOlij]

@dsnopek in Godot 4 I have no problems in exposing this and agree that we should also expose get_projection_for_view now that Projection (was CameraMatrix) is supported in GDScript.

[cheece]

@dsnopek in Godot 4 I have no problems in exposing this and agree that we should also expose get_projection_for_view now that Projection (was CameraMatrix) is supported in GDScript.

thanks, should I edit the PR to include get_projection_for_view then?

[dsnopek]

thanks, should I edit the PR to include get_projection_for_view then?

Yes, please!

[dsnopek]

Other than the minor parameter naming thing I pointed out above, (UPDATE: I was wrong about the parameter names) the code changes here are looking good to me!

However, you're also going to need to squash your changes down into a single commit (per Godot's PR workflow):

https://docs.godotengine.org/en/stable/community/contributing/pr_workflow.html#the-interactive-rebase

[cheece]

Ok 👍 , I think it should be fixed now

[dsnopek]

Thanks! Looks good to me!

[clayjohn]

Looks great, thanks!