Do not resize the canvas while presenting or on mobile

src/core/scene/a-scene.js

@@ -456,11 +456,13 @@ module.exports.AScene = registerElement('a-scene', {
         var canvas = this.canvas;
         var embedded = this.getAttribute('embedded') && !this.is('vr-mode');
         var size;
+        var isEffectPresenting = this.effect && this.effect.isPresenting;
         // Do not update renderer, if a camera or a canvas have not been injected.
         // In VR mode, VREffect handles canvas resize based on the dimensions returned by
         // the getEyeParameters function of the WebVR API. These dimensions are independent of
-        // the window size, therefore should not be overwritten with the window's width and height.
-        if (!camera || !canvas || this.is('vr-mode')) { return; }
+        // the window size, therefore should not be overwritten with the window's width and height,
+        // except when in fullscreen mode.
+        if (!camera || !canvas || (this.is('vr-mode') && (this.isMobile || isEffectPresenting))) { return; }
         // Update camera.
         size = getCanvasSize(canvas, embedded);
         camera.aspect = size.width / size.height;

tests/core/scene/a-scene.test.js

@@ -388,6 +388,58 @@ suite('a-scene (without renderer)', function () {
     });
   });
 
+  suite.only('resize', function () {
+    var sceneEl;
+    var setSizeSpy;
+
+    setup(function () {
+      sceneEl = this.el;
+      AScene.prototype.resize.restore();
+      sceneEl.camera = { updateProjectionMatrix: function () {} };
+      sceneEl.canvas = document.createElement('canvas');
+      sceneEl.renderer = { setSize: function () {} };
+
+      setSizeSpy = this.sinon.spy(sceneEl.renderer, 'setSize');
+    });
+
+    test('resize renderer when not in vr mode', function () {
+      sceneEl.resize();
+
+      assert.ok(setSizeSpy.called);
+    });
+
+    test('resize renderer when in vr mode in fullscreen presentation (desktop, no headset)', function () {
+      sceneEl.effect = {
+        isPresenting: false
+      };
+      sceneEl.addState('vr-mode');
+
+      sceneEl.resize();
+
+      assert.ok(setSizeSpy.called);
+    });
+
+    test('does not resize renderer when in vr mode on mobile', function () {
+      sceneEl.isMobile = true;
+      sceneEl.addState('vr-mode');
+
+      sceneEl.resize();
+
+      assert.notOk(setSizeSpy.called);
+    });
+
+    test('does not resize renderer when in vr mode and presenting in a headset', function () {
+      sceneEl.effect = {
+        isPresenting: true
+      };
+      sceneEl.addState('vr-mode');
+
+      sceneEl.resize();
+
+      assert.notOk(setSizeSpy.called);
+    });
+  });
+
   suite('pointerRestricted', function () {
     setup(function () {
       var sceneEl = this.el;