Source: device-orientation-controls.js

/** 
 Class to handle device orientation.
 * IMPORTANT - this code is a modified version the former official three.js 
 * DeviceOrientationControls class, which was formerly provided with the
 * three.js repo
 *
 * Changes:
 * 
 * - use "deviceorientationabsolute" rather than "deviceorientation"
 *   where available
 *
 * @author richt / http://richt.me
 * @author WestLangley / http://github.com/WestLangley
 *
 * W3C Device Orientation control (http://w3c.github.io/deviceorientation/spec-source-orientation.html)
 */

/*
import {
    Euler,
    EventDispatcher,
    MathUtils,
    Quaternion,
    Vector3
} from 'three';
*/

import * as THREE from 'three';

const _zee = new THREE.Vector3( 0, 0, 1 );
const _euler = new THREE.Euler();
const _q0 = new THREE.Quaternion();
const _q1 = new THREE.Quaternion( - Math.sqrt( 0.5 ), 0, 0, Math.sqrt( 0.5 ) ); // - PI/2 around the x-axis

const _changeEvent = { type: 'change' };

class DeviceOrientationControls extends THREE.EventDispatcher {

    /**
     * Create an instance of DeviceOrientationControls.
     * @param {Object} object - the object to attach the controls to
     * (usually your Three.js camera)
     */
    constructor( object ) {

        super();

        if ( window.isSecureContext === false ) {

            console.error( 'THREE.DeviceOrientationControls: DeviceOrientationEvent is only available in secure contexts (https)' );

        }

        const scope = this;

        const EPS = 0.000001;
        const lastQuaternion = new THREE.Quaternion();

        this.object = object;
        this.object.rotation.reorder( 'YXZ' );

        this.enabled = true;

        this.deviceOrientation = {};
        this.screenOrientation = 0;

        this.alphaOffset = 0; // radians

        this.deviceOrientationEventName =
              "ondeviceorientationabsolute" in window
            ? "deviceorientationabsolute"
            : "deviceorientation";

        const onDeviceOrientationChangeEvent = function ( event ) {

            scope.deviceOrientation = event;

        };

        const onScreenOrientationChangeEvent = function () {

            scope.screenOrientation = window.orientation || 0;

        };

        // The angles alpha, beta and gamma form a set of intrinsic Tait-Bryan angles of type Z-X'-Y''

        const setObjectQuaternion = function ( quaternion, alpha, beta, gamma, orient ) {

            _euler.set( beta, alpha, - gamma, 'YXZ' ); // 'ZXY' for the device, but 'YXZ' for us

            quaternion.setFromEuler( _euler ); // orient the device

            quaternion.multiply( _q1 ); // camera looks out the back of the device, not the top

            quaternion.multiply( _q0.setFromAxisAngle( _zee, - orient ) ); // adjust for screen orientation

        };

        this.connect = function () {

            onScreenOrientationChangeEvent(); // run once on load

            // iOS 13+

            if ( window.DeviceOrientationEvent !== undefined && typeof window.DeviceOrientationEvent.requestPermission === 'function' ) {

                window.DeviceOrientationEvent.requestPermission().then( function ( response ) {

                    if ( response == 'granted' ) {

                        window.addEventListener( 'orientationchange', onScreenOrientationChangeEvent );
                        window.addEventListener( scope.deviceOrientationEventName, onDeviceOrientationChangeEvent );

                    }

                } ).catch( function ( error ) {

                    console.error( 'THREE.DeviceOrientationControls: Unable to use DeviceOrientation API:', error );

                } );

            } else {

                window.addEventListener( 'orientationchange', onScreenOrientationChangeEvent );
                window.addEventListener( scope.deviceOrientationEventName, onDeviceOrientationChangeEvent );

            }

            scope.enabled = true;

        };

        this.disconnect = function () {

            window.removeEventListener( 'orientationchange', onScreenOrientationChangeEvent );
            window.removeEventListener( scope.deviceOrientationEventName, onDeviceOrientationChangeEvent );

            scope.enabled = false;

        };

        /**
         * Update the device orientation controls.
         * Should be called from your three.js rendering/animation function.
         */
        this.update = function () {

            if ( scope.enabled === false ) return;

            const device = scope.deviceOrientation;

            if ( device ) {

                const alpha = device.alpha ? THREE.MathUtils.degToRad( device.alpha ) + scope.alphaOffset : 0; // Z

                const beta = device.beta ? THREE.MathUtils.degToRad( device.beta ) : 0; // X'

                const gamma = device.gamma ? THREE.MathUtils.degToRad( device.gamma ) : 0; // Y''

                const orient = scope.screenOrientation ? THREE.MathUtils.degToRad( scope.screenOrientation ) : 0; // O

                setObjectQuaternion( scope.object.quaternion, alpha, beta, gamma, orient );

                if ( 8 * ( 1 - lastQuaternion.dot( scope.object.quaternion ) ) > EPS ) {

                    lastQuaternion.copy( scope.object.quaternion );
                    scope.dispatchEvent( _changeEvent );

                }

            }

        };

        this.dispose = function () {

            scope.disconnect();

        };

        this.connect();

    }

}

export { DeviceOrientationControls };