Detect XR usage

src/DOM.js

@@ -2221,6 +2221,13 @@ class HTMLIFrameElement extends HTMLSrcableElement {
                   onrequest(req) {
                     parentPort.postMessage(req);
                   },
+                  onxrmode(event) {
+                    this.dispatchEvent(new CustomEvent('xrmode', {
+                      detail: {
+                        xr: event.xr,
+                      },
+                    }));
+                  },
                   onhapticpulse(event) {
                     parentPort.postMessage({
                       method: 'emit',

src/Document.js

@@ -162,6 +162,14 @@ function initDocument (document, window) {
   }
 
   process.nextTick(async () => {
+    const _tryDispatchEvent = (target, event) => {
+      try {
+        target.dispatchEvent(event);
+      } catch(err) {
+        console.warn(err);
+      }
+    };
+
     if (body) {
       const bodyChildNodes = body.childNodes;
       body.childNodes = new window.NodeList();
@@ -173,7 +181,11 @@ function initDocument (document, window) {
       }
 
       body.childNodes = bodyChildNodes;
-      body._emit('children', Array.from(bodyChildNodes), [], null, null);
+      try {
+        body._emit('children', Array.from(bodyChildNodes), [], null, null);
+      } catch(err) {
+        console.warn(err);
+      }
 
       try {
         await GlobalContext._runHtml(document.body, window);
@@ -182,9 +194,9 @@ function initDocument (document, window) {
       }
 
       document.readyState = 'interactive';
-      document.dispatchEvent(new Event('readystatechange', {target: document}));
+      _tryDispatchEvent(document, new Event('readystatechange', {target: document}));
 
-      document.dispatchEvent(new Event('DOMContentLoaded', {
+      _tryDispatchEvent(document, new Event('DOMContentLoaded', {
         target: document,
         bubbles: true,
       }));
@@ -196,19 +208,24 @@ function initDocument (document, window) {
       }
 
       document.readyState = 'interactive';
-      document.dispatchEvent(new Event('readystatechange', {target: document}));
+      _tryDispatchEvent(document, new Event('readystatechange', {target: document}));
 
-      document.dispatchEvent(new Event('DOMContentLoaded', {
+      _tryDispatchEvent(document, new Event('DOMContentLoaded', {
         target: document,
         bubbles: true,
       }));
     }
 
     document.readyState = 'complete';
-    document.dispatchEvent(new Event('readystatechange', {target: document}));
+    _tryDispatchEvent(document, new Event('readystatechange', {target: document}));
 
     document.dispatchEvent(new Event('load', {target: document}));
-    window.dispatchEvent(new Event('load', {target: window}));
+    _tryDispatchEvent(window, new Event('load', {target: window}));
+
+    parentPort.postMessage({
+      method: 'xrMode',
+      xr: GlobalContext.requestedXr,
+    });
   });
 
   return document;

src/Window.js

@@ -103,6 +103,7 @@ GlobalContext.id = id;
 GlobalContext.args = args;
 GlobalContext.version = version;
 GlobalContext.baseUrl = options.baseUrl;
+GlobalContext.requestedXr = false;
 
 const {_parseDocument, _parseDocumentAst, getBoundDocumentElements, DocumentType, DOMImplementation, initDocument} = require('./Document');
 const {
@@ -824,7 +825,12 @@ const _makeRequestAnimationFrame = window => (fn, priority = 0) => {
       return _parseDocumentAst(htmlAst, window, false);
     }
   };
-  window.addEventListener = EventTarget.prototype.addEventListener.bind(window);
+  window.addEventListener = function(e, fn, opts) {
+    if (e === 'vrdisplayactivate') {
+      GlobalContext.requestedXr = true;
+    }
+    return EventTarget.prototype.addEventListener.apply(window, arguments);
+  };
   window.removeEventListener = EventTarget.prototype.removeEventListener.bind(window);
   window.dispatchEvent = EventTarget.prototype.dispatchEvent.bind(window);
   window.Image = HTMLImageElement;
@@ -1193,6 +1199,8 @@ const _makeRequestAnimationFrame = window => (fn, priority = 0) => {
 
   const _makeMrDisplays = () => {
     const _onrequestpresent = async () => {
+      GlobalContext.requestedXr = true;
+
       // if (!GlobalContext.xrState.isPresenting[0]) {
         await new Promise((accept, reject) => {
           vrPresentState.responseAccepts.push(accept);

src/WindowVm.js

@@ -194,6 +194,9 @@ const _makeWindow = (options = {}, handlers = {}) => {
   window.on('framebuffer', e => {
     window.framebuffer = e;
   });
+  window.on('xrMode', e => {
+    options.onxrmode && options.onxrmode(e);
+  });
   window.on('hapticPulse', e => {
     options.onhapticpulse && options.onhapticpulse(e);
   });