import type { WorldBounds } from "./features.js";
import { type TerrainField } from "./terrain.js";
export type Rgb = readonly [number, number, number];
export type ColorInput = string | Rgb;
export interface RegionHeight {
    baseHeight: number;
    amplitude: number;
    frequency: number;
    octaves?: number;
    lacunarity?: number;
    persistence?: number;
    ridged?: boolean;
}
/**
 * A content-agnostic region. The engine blends `height` and the visual/physical
 * knobs (`tint`, `water`, `fog`, `speedMultiplier`, …) across region borders and
 * selects the dominant region by nearest center in `selector` space. `data` is an
 * opaque payload the engine never inspects — games hang their own content off it
 * (spawn tables, prop palettes, structure ids, names, …).
 */
export interface RegionDef<T = unknown> {
    id: string;
    selector: readonly number[];
    height: RegionHeight;
    tint?: ColorInput;
    steepTint?: ColorInput;
    water?: ColorInput;
    fog?: ColorInput;
    fogDensity?: number;
    speedMultiplier?: number;
    data?: T;
}
export interface RegionSample<T = unknown> {
    region: RegionDef<T>;
    weight: number;
    selector: readonly number[];
    tint: Rgb;
    steepTint: Rgb;
    water: Rgb | null;
    fog: Rgb | null;
    fogDensity: number;
    speedMultiplier: number;
    data: T | undefined;
}
export interface RegionField<T = unknown> extends TerrainField {
    sampleRegion(x: number, z: number): RegionSample<T>;
    readonly regions: readonly RegionDef<T>[];
    readonly seaLevel: number;
    readonly seed: number;
}
export interface RegionFieldConfig<T = unknown> {
    regions: readonly RegionDef<T>[];
    seed?: number;
    bounds?: WorldBounds;
    seaLevel?: number;
    /** Noise frequency per selector axis (defaults to 0.004 for every axis). */
    selectorFrequencies?: readonly number[];
    /** Per-axis distance weight when picking the nearest region (defaults to 1). */
    axisWeights?: readonly number[];
    /** Border sharpness; higher = tighter blends. */
    sharpness?: number;
    /** Domain-warp distance applied to selector sampling (0 disables). */
    warp?: number;
}
export declare function createRegionField<T = unknown>(config: RegionFieldConfig<T>): RegionField<T>;
export declare function isRegionField(field: TerrainField): field is RegionField;