e best
          // results post-distortion.
          var leftEye = vrDisplay.getEyeParameters("left");
          var rightEye = vrDisplay.getEyeParameters("right");

          // For simplicity we're going to render both eyes at the same size,
          // even if one eye needs less resolution. You can render each eye at
          // the exact size it needs, but you'll need to adjust the viewports to
          // account for that.
          webglCanvas.width = Math.max(leftEye.renderWidth, rightEye.render