在移動設備中使用js調用陀螺儀api

此爲開發vr全景，所用到的：

window.addEventListener('deviceorientation', function(event) {
  var alpha = event.alpha;
  // var beta = event.beta;
  var gamma = event.gamma;
  var newH = event.alpha / 2 * (-1);
  var newV = event.gamma * 1;
  if (gamma <= 0) {
    newV = 90 + gamma;
    newH = -alpha;
  } else {
    newV = gamma - 90;
    alpha = (alpha + 180) % 360;
    newH = -alpha;
  }

  // 處理邏輯
  pano1.call('lookat(' + newH + ',' + newV + ',20)');
  pano2.call('lookat(' + newH + ',' + newV + ',20)');
}, false);