Babylon.js/src/Cameras/deviceOrientationCamera.ts

import { FreeCamera } from "./freeCamera";
import { Scene } from "../scene";
import { Quaternion, Vector3, Axis } from "../Maths/math";
import { Node } from "../node";

    Node.AddNodeConstructor("DeviceOrientationCamera", (name, scene) => {
        return () => new DeviceOrientationCamera(name, Vector3.Zero(), scene);
    });

    // We're mainly based on the logic defined into the FreeCamera code
    /**
     * This is a camera specifically designed to react to device orientation events such as a modern mobile device
     * being tilted forward or back and left or right.
     */
    export class DeviceOrientationCamera extends FreeCamera {

        private _initialQuaternion: Quaternion;
        private _quaternionCache: Quaternion;

        /**
         * Creates a new device orientation camera
         * @param name The name of the camera
         * @param position The start position camera
         * @param scene The scene the camera belongs to
         */
        constructor(name: string, position: Vector3, scene: Scene) {
            super(name, position, scene);
            this._quaternionCache = new Quaternion();
            this.inputs.addDeviceOrientation();
        }

        /**
         * Gets the current instance class name ("DeviceOrientationCamera").
         * This helps avoiding instanceof at run time.
         * @returns the class name
         */
        public getClassName(): string {
            return "DeviceOrientationCamera";
        }

        /**
         * @hidden
         * Checks and applies the current values of the inputs to the camera. (Internal use only)
         */
        public _checkInputs(): void {
            super._checkInputs();
            this._quaternionCache.copyFrom(this.rotationQuaternion);
            if (this._initialQuaternion) {
                this._initialQuaternion.multiplyToRef(this.rotationQuaternion, this.rotationQuaternion);
            }
        }

        /**
         * Reset the camera to its default orientation on the specified axis only.
         * @param axis The axis to reset
         */
        public resetToCurrentRotation(axis: Axis = Axis.Y): void {

            //can only work if this camera has a rotation quaternion already.
            if (!this.rotationQuaternion) { return; }

            if (!this._initialQuaternion) {
                this._initialQuaternion = new Quaternion();
            }

            this._initialQuaternion.copyFrom(this._quaternionCache || this.rotationQuaternion);

            ['x', 'y', 'z'].forEach((axisName) => {
                if (!(<any>axis)[axisName]) {
                    (<any>this._initialQuaternion)[axisName] = 0;
                } else {
                    (<any>this._initialQuaternion)[axisName] *= -1;
                }
            });
            this._initialQuaternion.normalize();
            //force rotation update
            this._initialQuaternion.multiplyToRef(this.rotationQuaternion, this.rotationQuaternion);
        }
    }