feat: implement XR API

[okwasniewski]

Summary:

This PR introduces the XR API.

Example:

const{XR}=require('@callstack/react-native-visionos');//...constOpenXRSession=()=>{const[isOpen,setIsOpen]=React.useState(false);constopenXRSession=async()=>{try{if(!XR.supportsMultipleScenes){Alert.alert('Error','Multiple scenes are not supported');return;}awaitXR.requestSession('TestImmersiveSpace');setIsOpen(true);}catch(e){Alert.alert('Error',e.message);setIsOpen(false);}};constcloseXRSession=async()=>{if(isOpen){awaitXR.endSession();}};return(<Viewstyle={styles.container}><Textstyle={styles.title}>Is XR session open: {isOpen}</Text><Buttontitle="Open XR Session"onPress={openXRSession}/><Buttontitle="Close XR Session"onPress={closeXRSession}/></View>);};

To-Do

• Rename the API
• Polish error handling
• Return info if immersive space is open
• Test out Old Architecture
• Write docs

Opening immersive space might fail in two scenarios: 1. App doesn't support multi window, user cancels the operation.

Demo

CleanShot.2024-01-26.at.11.01.58.mp4

[matthargett]

Try to cross-reference the WebXR/OpenXR API to see if we can find a middle ground between them and visionOS specifics. It would be nice to be able to use this API across XR devices.

[okwasniewski]

@matthargett Looks like equivalent for WebXR is navigator.xr.requestSession() we can rename the API to XR and methods to:

• Spatial.openImmersiveSpace(ID) -> XR.requestSession(ID)
• Spatial.dismissImersiveSpace() -> XR.endSession()

WebXR returns session object and it ends the session by calling .end() on this object. I think the closest we can get is XR.endSession()

[okwasniewski]

I needed to generate separate set of Codegen specs for visionOS because the built-in one was overwritten when I used Yarn 4 (with Yarn v1 it was working fine) I'm guessing the issue comes from the order of how node_modules are discoevered by codegen.

If codegen finds react-native-visionos first, then react-native generated spec overwrites it later, but if it finds it second then everything is working fine.

cc: @Saadnajmi - you mentioned that rn-macos overwrites some Codegen specs of Alert module - maybe you will also run into this or maybe it's only related to adding new modules

[matthargett]

is there a way to fix this in yarn or RN codegen so it resolved in a human-observable order, rather than inode creation order(UNIX-based) or something else random on Windows? This is a class of support issue that can devolve into "works fine on my machine" :/

[Saadnajmi]

Are you using yarn 4 with the node_modules linker? curious

[okwasniewski]

Yes! With node_modules linker, I'm not sure why there is a discrepancy between those versions but it kind of makes sense as @callstack/react-native-visionos is higher in the node_modules folder than react-native (therefore the overwrite). I think creating a separate spec for OOT platform-specific modules is a safer bet

[okwasniewski]

Todo: check how this affects rest of the app

[Saadnajmi]

on RNM, turning this on meant going through a different code path for intializing the window / scene, so the window set by RCTAppDelegate stopped showing. I guess on this fork, y'all have already gone full custom SwiftUI entry point though.