import { IXRTrackablePlatformFeature } from "@galacean/engine-design";
import { XRTrackingState } from "../../input/XRTrackingState";
import { XRFeature } from "../XRFeature";
import { XRRequestTracking } from "./XRRequestTracking";
import { XRTracked } from "./XRTracked";
/**
 * The base class of XR trackable manager.
 */
export declare abstract class XRTrackableFeature<T extends XRTracked = XRTracked, K extends XRRequestTracking<T> = XRRequestTracking<T>> extends XRFeature<IXRTrackablePlatformFeature<T, K>> {
    protected static _uuid: number;
    protected _requestTrackings: K[];
    protected _tracked: T[];
    protected _added: T[];
    protected _updated: T[];
    protected _removed: T[];
    protected _statusSnapshot: Record<number, XRTrackingState>;
    private _listeners;
    /**
     * Add a listening function for tracked object changes.
     * @param listener - The listening function
     */
    addChangedListener(listener: (added: readonly T[], updated: readonly T[], removed: readonly T[]) => void): void;
    /**
     * Remove a listening function of tracked object changes.
     * @param listener - The listening function
     */
    removeChangedListener(listener: (added: readonly T[], updated: readonly T[], removed: readonly T[]) => void): void;
    _onUpdate(): void;
    _onSessionStop(): void;
    _onSessionExit(): void;
    protected _addRequestTracking(requestTracking: K): void;
    protected _removeRequestTracking(requestTracking: K): void;
    protected _removeAllRequestTrackings(): void;
    protected abstract _generateTracked(): T;
}