Width) * 2;
          webglCanvas.height = Math.max(leftEye.renderHeight, rightEye.renderHeight);
        } else {
          // We only want to change the size of the canvas drawing buffer to
          // match the window dimensions when we're not presenting.
          webglCanvas.width = window.innerWidth * window.devicePixelRatio * 2;
          webglCanvas.height = window.innerHeight * window.devicePixelRatio * 2;
        }
      }

      function onAnimationFrame (t) {
        stats.begin();

        gl.