/**
 * Pure shell-dimension math for the sol interactive mesh.
 *
 * No Three.js allocation, no state — just geometry calculations derived
 * from `BodyConfig`. The radial partition `[core | sol | atmo]` stays
 * the conceptual model:
 *
 *   - core     : `[0, coreRadius]`              length `coreRadiusRatio × radius`
 *   - sol      : `[coreRadius, solOuterRadius]` length `(1 − coreRadiusRatio − atmosphereThickness) × radius`
 *   - atmo     : `[solOuterRadius, radius]`     length `atmosphereThickness × radius`
 *
 * The sol mesh built from these metrics covers the **sol band only**. The
 * atmosphere lives on its own dedicated board mesh ({@link buildAtmoBoardMesh})
 * — the radial atmo span surfaces here as `atmoFraction` for the board
 * mesh's caller (`assemblePlanetSceneGraph`) to size its prisms, but no
 * geometry produced from this module ever sits above `solOuterRadius`.
 */
import type { Tile } from '../../geometry/hexasphere.types';
import type { BodySimulation } from '../../sim/BodySimulation';
import type { TerrainLevel } from '../types/terrain.types';
/**
 * Resolves the per-tile sol height for the unified shell. Pure look-up
 * into the palette — the band-indexed elevation model already stamps a
 * monotonically increasing height on every band, so the resolver only
 * has to clamp to `maxHeight`.
 */
export declare function resolveSolHeight(tile: Tile, sim: BodySimulation, levels: TerrainLevel[], maxHeight: number): number;
/**
 * Aggregate of every geometric dimension the sol mesh and the atmo board
 * builder need at build time. Everything here is a deterministic function
 * of `sim.config`.
 */
export interface LayeredShellMetrics {
    /** Visual silhouette radius (= `config.radius`). */
    solSurfaceRadius: number;
    /** World radius of the opaque inner core sphere. */
    coreRadius: number;
    /** Outer radius of the sol band — where the sol caps top out. */
    solOuterRadius: number;
    /** Sol band thickness (`solOuterRadius - coreRadius`). */
    shellThickness: number;
    /** Ceiling for tile sol heights; equals {@link shellThickness}. */
    maxTerrainHeight: number;
    /** Atmosphere band fraction of the radius (`atmosphereThickness ∈ [0, 1]`). */
    atmoFraction: number;
    /** Atmosphere band thickness in world units (`solSurfaceRadius - solOuterRadius`). */
    atmoHeadroom: number;
    /** Integer band count `N` for the staircase elevation model. */
    bandCount: number;
    /** Per-band world-unit step. */
    bandUnit: number;
    /**
     * Band-space → world-radius converter. Fractional bands (e.g. sea
     * level sliding between two integer bands) slide linearly along the
     * same axis, keeping the waterline in lockstep with the hex caps.
     */
    bandToRadius: (band: number) => number;
}
/**
 * Derives every shell + atmo + band dimension used by the sol mesh and
 * the atmo board from a simulation's config.
 *
 * The visible planet silhouette is exactly `config.radius` — the sol mesh
 * caps at `solOuterRadius`, the atmo board spans
 * `[solOuterRadius, config.radius]`, and a tile's elevation is clamped to
 * the sol band so peaks never poke into the atmo region.
 */
export declare function computeLayeredShellMetrics(sim: BodySimulation): LayeredShellMetrics;
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