two

sensor.js

var degtorad = Math.PI / 180;

function makeRotationMatrix(alpha, beta, gamma) {
  var _x = beta  ? beta  * degtorad : 0;
  var _y = gamma ? gamma * degtorad : 0;
  var _z = alpha ? alpha * degtorad : 0;

  var cX = Math.cos( _x );
  var cY = Math.cos( _y );
  var cZ = Math.cos( _z );
  var sX = Math.sin( _x );
  var sY = Math.sin( _y );
  var sZ = Math.sin( _z );

  //
  // ZXY-ordered rotation matrix construction.
  //

  var m11 = cZ * cY - sZ * sX * sY;
  var m12 = - cX * sZ;
  var m13 = cY * sZ * sX + cZ * sY;

  var m21 = cY * sZ + cZ * sX * sY;
  var m22 = cZ * cX;
  var m23 = sZ * sY - cZ * cY * sX;

  var m31 = - cX * sY;
  var m32 = sX;
  var m33 = cX * cY;

  return [
    m11, m12, m13, 0,
    m21, m22, m23, 0,
    m31, m32, m33, 0,
    0, 0, 0, 1
  ];
};

function handleOrientation(e) {
  let matrix = makeRotationMatrix(e.alpha, e.beta, e.gamma);
  if (matrix) {

  }
}

function getPermission() {
  if (typeof DeviceOrientationEvent.requestPermission === "function") {
    DeviceOrientationEvent.requestPermission()
      .then(permissionState => {
        if (permissionState === "granted") {
          window.addEventListener("deviceorientation", handleOrientation);
        }
      }).catch(console.error);
  }
}