/**
 * Gamepad helper class used by HUD and VRHelper, NOT used by 3rd person camera.
 * Implementes UI control with gamepad: selecting and activating HUD buttons in and out of XR,
 * and XR teleportation and interaction with scene. As gamepad is not standard XR controller,
 * and mobiles don't come with XR controller, this is the only option to interact with scene in mobile VR.
 * Traverse through hud menus with gamepad buttons, left/right/up/down, either left or right hand.
 * Activate current option with either trigger or up.
 * To teleport and rotate in (mobile) XR, use thumbstick, and to interact, use trigger.
 */
export class GamepadHelper {
    /**
     * @type {GamepadHelper}
     */
    static instance: GamepadHelper;
    static getInstance(scene: any): GamepadHelper;
    constructor(scene: any);
    scene: any;
    gamepadState: {};
    connectListeners: any[];
    axisListeners: any[];
    triggerListeners: any[];
    hudLeft: number[];
    hudRight: number[];
    hudUp: number[];
    hudDown: number[];
    /**
     * Main point of gamepad support, called from the constructor.
     * Once the browser emits gamepadconnected event,
     * installs tracker function into main rendering loop, to track states that
     * rotate the camera, teleport, and fire gamepad button events.
     */
    trackGamepad(): void;
    gamepad: Gamepad;
    /**
     * Gamepad button event handler. Buttons left/right/up/down are forwarded to the HUD.
     * Trigger button and select button events are forwarded either to HUD, or to the scene, as appropriate.
     * @param index button index, see https://github.com/alvaromontoro/gamecontroller.js/blob/master/public/gamepad.svg
     * @param state true/false for pressed/released
     */
    gamepadButton(index: any, state: any): void;
    /** Returns true if HUD can process gamepad event, i.e. a button or form is currently active.*/
    forwardToHud(index: any): boolean;
    notifyListeners(listeners: any, event: any): void;
    addAxisListener(callback: any): void;
    removeAxisListener(callback: any): void;
    addConnectListener(callback: any): void;
    removeConnectListener(callback: any): void;
    addTriggerListener(callback: any): void;
    removeTriggerListener(callback: any): void;
}