Babylon.js/Babylon/Cameras/VR/babylon.vrDeviceOrientationCamera.ts

module BABYLON {
    export class VRDeviceOrientationFreeCamera extends BABYLON.FreeCamera {
		public _alpha = 0;
		public _beta = 0;
		public _gamma = 0;
	
        private _offsetOrientation: { yaw: number; pitch: number; roll: number };
        private _deviceOrientationHandler;

        constructor(name: string, position: Vector3, scene: Scene) {
            super(name, position, scene);

            this.setSubCameraMode(Camera.SUB_CAMERA_MODE_VR);

            this._deviceOrientationHandler = this._onOrientationEvent.bind(this);
        }

        public _onOrientationEvent(evt: DeviceOrientationEvent): void {
            this._alpha = +evt.alpha|0;
            this._beta = +evt.beta|0;
            this._gamma = +evt.gamma|0;

            if (this._gamma < 0) {
            	this._gamma = 90 + this._gamma;
            }
            else {
				// Incline it in the correct angle.
            	this._gamma = 270 - this._gamma;
            }

            this.rotation.x = this._gamma / 180.0 * Math.PI;   
			this.rotation.y = -this._alpha / 180.0 * Math.PI;	
			this.rotation.z	= this._beta / 180.0 * Math.PI;		
        }

        public attachControl(element: HTMLElement, noPreventDefault?: boolean): void {
            super.attachControl(element, noPreventDefault);

            window.addEventListener("deviceorientation", this._deviceOrientationHandler);
        }

        public detachControl(element: HTMLElement): void {
            super.detachControl(element);

            window.removeEventListener("deviceorientation", this._deviceOrientationHandler);
        }
	}
}