/** Stable identifier for a visibility-tracked object or camera. */
export type VisibilityId = string | number;
/** World-space point; `z` is optional for 2D adapters. */
export interface VisibilityPoint {
    x: number;
    y: number;
    z?: number;
}
/** Sphere bounds used for visibility/streaming distance checks. */
export interface VisibilityBounds {
    center: VisibilityPoint;
    radius: number;
}
/** A camera's position and reach, as seen by the visibility system. */
export interface CameraVisibilityContext {
    id: VisibilityId;
    position: VisibilityPoint;
    /** Approximate visible radius in world units. Adapters may derive this from a frustum. */
    visibleRadius: number;
    /** Extra distance used to request assets before an object becomes visible. */
    preloadMargin?: number;
    /** Cameras such as editor thumbnails can opt out of influencing streaming. */
    influencesStreaming?: boolean;
}
/** Per-object escape hatches that bypass or tune the default visibility policy. */
export interface VisibilityOverrides {
    alwaysVisible?: boolean;
    neverUnload?: boolean;
    cullingDisabled?: boolean;
    streamingDisabled?: boolean;
    minRenderDistance?: number;
    maxRenderDistance?: number;
    preloadMargin?: number;
}
/** An entity/asset tracked by `VisibilitySystem.evaluate`. */
export interface VisibilityObject {
    id: VisibilityId;
    bounds: VisibilityBounds;
    overrides?: VisibilityOverrides;
}
/** Baseline policy settings a `VisibilitySystem` is constructed with. */
export interface VisibilityDefaults {
    enabled: boolean;
    streamingEnabled: boolean;
    minRenderDistance: number;
    maxRenderDistance: number;
    preloadMargin: number;
    unloadGraceMs: number;
    hysteresis: number;
}
/** Default `VisibilityDefaults` a `VisibilitySystem` falls back to when unspecified. */
export declare const DEFAULT_VISIBILITY_SETTINGS: Readonly<VisibilityDefaults>;
/** Result of evaluating one object against the active cameras this tick. */
export interface VisibilityDecision {
    render: boolean;
    load: boolean;
    unload: boolean;
    reason: "always-visible" | "culling-disabled" | "visible" | "preload" | "distance-culled" | "outside-view" | "grace-period" | "streaming-disabled";
}
/**
 * Engine-level visibility and asset-residency policy.
 *
 * Render culling and asset streaming are intentionally separate. This class never
 * destroys entities or throttles simulation; adapters decide how to apply results.
  * @internal
  */
export declare class VisibilitySystem {
    #private;
    readonly settings: VisibilityDefaults;
    constructor(settings?: Partial<VisibilityDefaults>);
    evaluate(object: VisibilityObject, cameras: readonly CameraVisibilityContext[], now?: number): VisibilityDecision;
    setLoaded(id: VisibilityId, loaded: boolean, now?: number): void;
    forget(id: VisibilityId): void;
    clear(): void;
}