WebXR: request common reference spaces as features

WebXR's requestReferenceSpace only works if the corresponding feature
was requested at session creation time. For simplicity, just ask for
the interesting ones as optional features, but be aware that the
requestReferenceSpace call will fail if it turns out to be unavailable.
('local' is always available for immersive sessions and doesn't need to
be requested separately.)

examples/js/vr/WebVR.js

@@ -99,7 +99,15 @@ THREE.WEBVR = {
 
 				if ( currentSession === null ) {
 
-					navigator.xr.requestSession( 'immersive-vr' ).then( onSessionStarted );
+					// WebXR's requestReferenceSpace only works if the corresponding feature
+					// was requested at session creation time. For simplicity, just ask for
+					// the interesting ones as optional features, but be aware that the
+					// requestReferenceSpace call will fail if it turns out to be unavailable.
+					// ('local' is always available for immersive sessions and doesn't need to
+					// be requested separately.)
+
+					var sessionInit = { optionalFeatures: [ 'local-floor', 'bounded-floor' ] };
+					navigator.xr.requestSession( 'immersive-vr', sessionInit ).then( onSessionStarted );
 
 				} else {
 

examples/jsm/vr/WebVR.js

@@ -14,7 +14,6 @@ var WEBVR = {
 		if ( options && options.referenceSpaceType ) {
 
 			renderer.vr.setReferenceSpaceType( options.referenceSpaceType );
-
 		}
 
 		function showEnterVR( device ) {
@@ -101,7 +100,15 @@ var WEBVR = {
 
 				if ( currentSession === null ) {
 
-					navigator.xr.requestSession( 'immersive-vr' ).then( onSessionStarted );
+					// WebXR's requestReferenceSpace only works if the corresponding feature
+					// was requested at session creation time. For simplicity, just ask for
+					// the interesting ones as optional features, but be aware that the
+					// requestReferenceSpace call will fail if it turns out to be unavailable.
+					// ('local' is always available for immersive sessions and doesn't need to
+					// be requested separately.)
+
+					var sessionInit = { optionalFeatures: [ 'local-floor', 'bounded-floor' ] };
+					navigator.xr.requestSession( 'immersive-vr', sessionInit ).then( onSessionStarted );
 
 				} else {