initial VR support for the viewer

A new VR helper will be created when the viewer was done initializing.
For now there is no UI element to enable this.
The function toggleVR() will toggle between the two modes.
In VR mode the object AND environment will be scaled to fit the VR perspective.
In VR the object will float in front of the user's eyes.
For now there is no option to move or scale the object in VR.
Position tracking is turned on and also teleportation on the ground.

Initial commit for https://github.com/BabylonJS/Babylon.js/issues/4413

Viewer/src/managers/sceneManager.ts

@@ -813,9 +813,10 @@ export class SceneManager {
             return !this.environmentHelper || (mesh !== this.environmentHelper.ground && mesh !== this.environmentHelper.rootMesh && mesh !== this.environmentHelper.skybox);
         });
         const sceneDiagonal = sceneExtends.max.subtract(sceneExtends.min);
-        const sceneDiagonalLenght = sceneDiagonal.length();
-        if (isFinite(sceneDiagonalLenght))
-            this.camera.upperRadiusLimit = sceneDiagonalLenght * 4;
+        const sceneDiagonalLength = sceneDiagonal.length();
+        if (isFinite(sceneDiagonalLength)) {
+            this.camera.upperRadiusLimit = sceneDiagonalLength * 4;
+        }
 
         // sanity check!
         if (this.scene.imageProcessingConfiguration) {

dist/preview release/what's new.md

@@ -66,6 +66,7 @@
 - New lab feature - global light rotation [#4347](https://github.com/BabylonJS/Babylon.js/issues/4347) ([RaananW](https://github.com/RaananW))
 - New NPM package - babylonjs-viewer-assets, to separate the binary assets and the code of the viewer ([RaananW](https://github.com/RaananW))
 - A new HD-Toggler button allows setting a better hardware scaling rate ([RaananW](https://github.com/RaananW))
+- An initial support for WebVR is implemented ([RaananW](https://github.com/RaananW))
 
 ### Documentation