import { AssetReference } from "../../engine/engine_addressables.js";
import { type NeedleXREventArgs } from "../../engine/engine_xr.js";
import { Behaviour } from "../Component.js";
/**
 * The WebARSessionRoot is the root object for a WebAR session and used to place the scene in AR.
 * It is also responsible for scaling the user in AR and to define the center of the AR scene.
 * If not present in the scene it will be created automatically by the WebXR component when entering an AR session.
 *
 * **Note**: If the WebXR component {@link WebXR.autoCenter} option is enabled the scene will be automatically centered based on the content in the scene.
 *
 * @example Callback when the scene has been placed in AR:
 * ```ts
 * WebARSessionRoot.onPlaced((args) => {
 *    console.log("Scene has been placed in AR");
 * });
 * ```
 *
 * @summary Root object for WebAR sessions, managing scene placement and user scaling in AR.
 * @category XR
 * @group Components
 */
export declare class WebARSessionRoot extends Behaviour {
    private static _eventListeners;
    /**
     * Event that is called when the scene has been placed in AR.
     * @param cb the callback that is called when the scene has been placed
     * @returns a function to remove the event listener
     */
    static onPlaced(cb: (args: {
        instance: WebARSessionRoot;
    }) => void): () => void;
    private static _hasPlaced;
    /**
     * @returns true if the scene has been placed in AR by the user or automatic placement
     */
    static get hasPlaced(): boolean;
    /** The scale of the user in AR.
     * **NOTE**: a large value makes the scene appear smaller
     * @default 1
     */
    get arScale(): number;
    set arScale(val: number);
    private _arScale;
    /** When enabled the placed scene forward direction will towards the XRRig
     * @deprecated
     * @default false
    */
    invertForward: boolean;
    /** When assigned this asset will be loaded and visualize the placement while in AR
     * @default null
     */
    customReticle?: AssetReference;
    /** Enable touch transform to translate, rotate and scale the scene in AR with multitouch
     * @default true
     */
    arTouchTransform: boolean;
    /** When enabled the scene will be placed automatically when a point in the real world is found
     * @default false
     */
    autoPlace: boolean;
    /** When enabled the scene center will be automatically calculated from the content in the scene */
    autoCenter: boolean;
    /** When enabled a XR anchor is created at the scene placement position and the scene
     * stays at that anchored point while tracking refines during the XR session.
     * On platforms without WebXR anchor support this gracefully falls back to plain placement.
     * @default true
     **/
    useXRAnchor: boolean;
    /** true if we're currently placing the scene */
    private _isPlacing;
    /** This is the world matrix of the ar session root when entering webxr
     * it is applied when the scene has been placed (e.g. if the session root is x:10, z:10 we want this position to be the center of the scene)
     */
    private readonly _startOffset;
    private _createdPlacementObject;
    private readonly _reparentedComponents;
    private readonly _placementScene;
    /** the reticles used for placement */
    private readonly _reticle;
    /** reference-space hit poses, in sync with the reticles — captured while placing when {@link useXRAnchor}
     * is enabled, because hit test results can not be used outside the animation frame that produced them */
    private readonly _hitRefPoses;
    private _placementStartTime;
    private _rigPlacementMatrix?;
    /** if useAnchor is enabled this is the anchor we have created on placing the scene using the placement hit */
    private _anchor;
    /** the placement pose (reference space) waiting for anchor creation on the next animation frame */
    private _pendingAnchorPose;
    /** the last anchor pose (in rig space) that has been applied to the rig */
    private readonly _anchorLastLocalPose;
    /** user input is used for ar touch transform */
    private userInput?;
    onEnable(): void;
    supportsXR(mode: XRSessionMode): boolean;
    onEnterXR(_args: NeedleXREventArgs): void;
    onLeaveXR(): void;
    onUpdateXR(args: NeedleXREventArgs): void;
    private updateReticleAndHits;
    private onPlaceScene;
    private onSetScale;
    private onRevertSceneChanges;
    /**
     * Deferred anchor creation and per-frame anchor tracking. Called from {@link onUpdateXR} after the scene has been placed.
     *
     * Creation can not happen during placement: `XRHitTestResult.createAnchor` only works while the animation
     * frame that produced the hit is active, and placement runs from an input event where that frame is already
     * over (`XRFrame.createAnchor` equally requires an active animation frame). So {@link onPlaceScene} only
     * records the reference-space pose and the anchor is created here, on the next animation frame.
     *
     * Once the anchor exists, its pose *changes* (delta in rig space) are applied to the XR rig: the world pose
     * of the anchored point stays constant while tracking refines, without discarding other rig modifications
     * ({@link arTouchTransform} user adjustments, {@link arScale}).
     */
    private updateXRAnchor;
    private upVec;
    private lookPoint;
    private worldUpVec;
    private applyViewBasedTransform;
    private onApplyPose;
}