/**
     * Google Daydream controller
     */
    export class DaydreamController extends WebVRController {
        /**
         * Base Url for the controller model.
         */
        public static MODEL_BASE_URL: string = 'https://controllers.babylonjs.com/generic/';

        /**
         * File name for the controller model.
         */
        public static MODEL_FILENAME: string = 'generic.babylon';

        /**
         * Gamepad Id prefix used to identify Daydream Controller.
         */
        public static readonly GAMEPAD_ID_PREFIX: string = 'Daydream'; // id is 'Daydream Controller'

        /**
         * Creates a new DaydreamController from a gamepad
         * @param vrGamepad the gamepad that the controller should be created from
         */
        constructor(vrGamepad: any) {
            super(vrGamepad);
            this.controllerType = PoseEnabledControllerType.DAYDREAM;
        }

        /**
         * Implements abstract method on WebVRController class, loading controller meshes and calling this.attachToMesh if successful.
         * @param scene scene in which to add meshes
         * @param meshLoaded optional callback function that will be called if the mesh loads successfully.
         */
        public initControllerMesh(scene: Scene, meshLoaded?: (mesh: AbstractMesh) => void) {
            SceneLoader.ImportMesh("", DaydreamController.MODEL_BASE_URL, DaydreamController.MODEL_FILENAME, scene, (newMeshes) => {
                this._defaultModel = newMeshes[1];
                this.attachToMesh(this._defaultModel);

                if (meshLoaded) {
                    meshLoaded(this._defaultModel);
                }
            });
        }

        /**
         * Called once for each button that changed state since the last frame
         * @param buttonIdx Which button index changed
         * @param state New state of the button
         * @param changes Which properties on the state changed since last frame
         */
        protected _handleButtonChange(buttonIdx: number, state: ExtendedGamepadButton, changes: GamepadButtonChanges) {
            // Daydream controller only has 1 GamepadButton (on the trackpad).
            if (buttonIdx === 0) {
                let observable = this.onTriggerStateChangedObservable;
                if (observable) {
                    observable.notifyObservers(state);
                }
            } else {
                // If the app or home buttons are ever made available
                Tools.Warn(`Unrecognized Daydream button index: ${buttonIdx}`);
            }
        }
    }