import type { App, AppOptions } from '../core/app.js';
import type { PathCamera, PathCameraOptions } from '../camera/path-camera.js';
import type { SegmentStream, SegmentStreamOptions, StreamSegmentInput } from '../procedural/segment-stream.js';
import type { StateSource } from '../state/controller.js';
import type { SeededRng, Disposable } from '../types.js';
/** Options for {@link createRailsScaffold}: `AppOptions` minus orbit/state, plus segment-stream and path-camera tuning and the `segment` factory. */
export interface RailsScaffoldOptions<S extends object> extends Omit<AppOptions<S>, 'orbit' | 'state'>, SegmentStreamOptions, PathCameraOptions {
    state?: StateSource<S>;
    /** Build segment #index. Runs ahead of the camera; keep it deterministic via rng. */
    segment: (index: number, rng: SeededRng) => StreamSegmentInput;
    /** Append the next segment when less than this path length remains. Default 40. */
    prefetchDistance?: number;
}
/** Handle returned by {@link createRailsScaffold}. `dispose()` detaches state, then disposes the camera rig, the stream, and the app. */
export interface RailsScaffold<S extends object> extends Disposable {
    app: App<S>;
    stream: SegmentStream;
    rig: PathCamera;
}
/**
 * On-rails scaffold: an endless segment stream stitched into one curve and a
 * path camera travelling it with pointer look-around. You supply a `segment`
 * factory (seeded rng in hand); the scaffold appends segments ahead of the
 * camera and evicts them behind it — constant memory, infinite ride.
 *
 * @param options - State source, the deterministic `segment` builder,
 * `prefetchDistance`, plus segment-stream and path-camera tuning.
 * @returns A {@link RailsScaffold} with the app, the segment `stream`, and
 * the path-camera `rig`.
 * @remarks Per frame this costs two curve samples and a length check; segment
 * builds amortize over the ride and evicted segments dispose their own GPU
 * memory. A degenerate zero-length segment is guarded against (16 appends max
 * per prefetch pass).
 * @example
 * const ride = createRailsScaffold({ canvas, segment: (i, rng) => tunnelSegment(rng) })
 * ride.app.start()
 */
export declare function createRailsScaffold<S extends object = Record<string, unknown>>({ state, segment, prefetchDistance, maxActive, lift, tension, yawRange, pitchRange, smoothing, speed, ...appOptions }: RailsScaffoldOptions<S>): RailsScaffold<S>;
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