import type { Aabb } from "./geometry.js";
import type { RegionField, RegionSample } from "./regions.js";
/** One placeable class. `item` is an opaque id the caller maps to a mesh/entity. */
export interface ScatterLayer {
    item: string;
    density: number;
    minScale?: number;
    maxScale?: number;
    maxSlope?: number;
    aboveWaterOnly?: boolean;
}
export interface ScatterInstance {
    id: string;
    item: string;
    x: number;
    z: number;
    y: number;
    scale: number;
    rotation: number;
    regionId: string;
}
/**
 * Deterministically place opaque items across `area`, grounded on a region field.
 * For each grid cell it asks `layersFor` which items may appear in that region and
 * rolls one against their densities. The engine never interprets `item` — a game
 * maps it to a mesh or entity. Content scatter (region-driven density) as opposed to
 * `scatter` in `./scatter`, which is renderer-free geometric point distribution.
 */
export declare function scatterItems<T>(field: RegionField<T>, area: Aabb, layersFor: (sample: RegionSample<T>) => readonly ScatterLayer[], options?: {
    cell?: number;
    max?: number;
    saltKey?: number;
}): ScatterInstance[];
/** Weighted pick from opaque entries; `roll` in [0, 1). Returns null when empty. */
export declare function pickWeighted<T>(entries: readonly {
    value: T;
    weight: number;
}[], roll: number): T | null;