import * as THREE from 'three';
import type { Disposable, FrameContext } from '../types.js';
/** Tuning for {@link createPathCamera}: look-around ranges (radians), look smoothing, and travel speed. */
export interface PathCameraOptions {
    /** Max look-around yaw in radians. Default 0.25 (~14°). */
    yawRange?: number;
    /** Max look-around pitch in radians. Default 0.18. */
    pitchRange?: number;
    /** Look smoothing rate (higher = snappier). Default 6. */
    smoothing?: number;
    /** Units per second along the curve. Default 2. */
    speed?: number;
}
/** What a path camera rides: a curve plus its total length. `SegmentStream` satisfies it. */
export interface PathCameraSource {
    /** Current path curve. May be swapped/rebuilt between frames. */
    curve: THREE.Curve<THREE.Vector3> & {
        points?: THREE.Vector3[];
    };
    /** Total path length in world units. */
    total: number;
}
/** Handle returned by {@link createPathCamera}. `distance` is writable for seeking; `dispose()` removes the pointer listeners. */
export interface PathCamera extends Disposable {
    /** Distance travelled along the curve (writable for seeking). */
    distance: number;
    /** Advance and orient the camera. Call once per frame. */
    update(ctx: FrameContext, speedOverride?: number): void;
}
/**
 * Rail-riding camera: advances `distance` along the source curve at `speed`,
 * orients along the tangent, and layers smoothed pointer look-around within
 * the yaw/pitch ranges.
 *
 * @param camera - Perspective camera to drive.
 * @param source - Curve + total length; may be swapped between frames
 * (segment streams rebuild it as segments append).
 * @param element - Element whose pointer movement drives look-around.
 * @param options - Ranges, smoothing, and speed.
 * @returns A {@link PathCamera}; call `update(ctx)` once per frame.
 */
export declare function createPathCamera(camera: THREE.PerspectiveCamera, path: PathCameraSource, element: HTMLElement, { yawRange, pitchRange, smoothing, speed }?: PathCameraOptions): PathCamera;
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