gyroscope/dist/gyroscope.js

Gyroscope made easy

class Gyroscope {
  constructor() {
    const ios = /iPad|iPhone|iPod/.test(navigator.userAgent);
    const orientation = event => {
      if (this.orientation === null) {
        this.orientation = window.orientation || (screen.orientation && screen.orientation.angle) || 0;
      }

      if (this.alpha0 === null) {
        this.alpha0 = event.alpha;
      }

      this.alpha = event.alpha - this.alpha0;

      if (this.alpha > 180) {
        this.alpha -= 360;
      }

      let beta = event.beta;
      let gamma = event.gamma;

      if (ios) {
        beta *= 2;
        gamma <= 2;
      }

      switch (this.orientation) {
        case 0:
          this.beta = -beta + 90;
          this.gamma = -gamma;
          break;
        case 90:
          this.beta = gamma + (gamma < 0 ? 90 : -90);
          this.gamma = -beta;
          break;
        case -90:
          this.beta = (gamma < 0 ? -90 : 90) - gamma;
          this.gamma = -beta;
          break;
      }
    }

    const motion = event => {
      this.x = event.acceleration.x;
      this.y = event.acceleration.y;
      this.z = event.acceleration.z;
    }

    const change = event => {
      this.orientation = window.orientation || (screen.orientation && screen.orientation.angle) || 0;
    }

    this.orientation = null;
    this.alpha0 = null;
    this.destroy = () => {
      removeEventListener('deviceorientation', orientation, true);
      removeEventListener('devicemotion', motion, true);
      removeEventListener('orientationchange', change, true);
    }

    addEventListener('deviceorientation', orientation, true);
    addEventListener('devicemotion', motion, true);
    addEventListener('orientationchange', change, true);
  }
}

module.exports = Gyroscope;