/**
 * Per-tile paint pipeline for the atmosphere shell.
 *
 * The shell carries a vertex `color` attribute that the shader masks on
 * `max(r, g, b)` to decide between procedural tint and caller-supplied
 * tile paint. The painter pre-computes the K nearest tiles (and their
 * normalised blend weights) for every shell vertex once at build time,
 * so the runtime paint loop is a single allocation-free pass over the
 * vertex buffer.
 *
 * Smooth dégradés between adjacent painted tiles come from K=3: the
 * weighted average of the three nearest tiles produces a soft edge that
 * the procedural FBm pattern then breaks up — no visible polygon
 * boundaries on the icosphere even at low subdivisions.
 */
import * as THREE from 'three';
import type { Tile } from '../../geometry/hexasphere.types';
/** Per-tile RGB triple consumed by `AtmoShellPainter.paintFromTiles`. */
export interface AtmoShellRGB {
    r: number;
    g: number;
    b: number;
}
/**
 * Maximum number of tiles blended into each shell vertex. K=3 gives smooth
 * edges between adjacent hex centres; raising it would only smear the
 * paint further at no visible benefit on the ~2.5k shell vertices.
 */
export declare const SHELL_PAINT_K = 3;
/** Painter handle returned by {@link createAtmoShellPainter}. */
export interface AtmoShellPainter {
    /**
     * Stamps per-tile RGB into the shell's vertex colour buffer using a
     * K-nearest blend. Tiles missing from `colors` simply don't contribute;
     * vertices whose K-nearest neighbourhood is fully unpainted are reset
     * to `(0, 0, 0)` so the shader falls back to the procedural tint.
     *
     * No-op when the painter was built without `tiles` (decorative shell
     * with no gameplay link).
     */
    paintFromTiles: (colors: Map<number, AtmoShellRGB>) => void;
}
/**
 * Builds the painter for an atmosphere shell. When `tiles` is empty or
 * undefined, the returned `paintFromTiles` is a no-op — the shell stays
 * purely procedural.
 *
 * The colour attribute is mutated in place; the painter flips
 * `needsUpdate` on the attribute so Three.js re-uploads it on the next
 * frame.
 */
export declare function createAtmoShellPainter(input: {
    pos: THREE.BufferAttribute;
    colorAttr: THREE.BufferAttribute;
    tiles: readonly Tile[] | undefined;
}): AtmoShellPainter;
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