/**
 * Spatial Hash Grid 3D
 *
 * Uniform-grid spatial hash for broadphase collision detection and
 * proximity queries in 3D. Pure data structure, no ECS dependencies.
 */
export interface SpatialEntry3D {
    entityId: number;
    x: number;
    y: number;
    z: number;
    halfW: number;
    halfH: number;
    halfD: number;
    /** Generation stamp used by query functions to dedup multi-cell hits without a Set. Internal. */
    _lastSeenGen: number;
    /** Rebuild generation when this entry was last inserted. Internal. */
    _aliveGen: number;
}
/**
 * A cell bucket — entries plus the alive-gen at which the bucket was last
 * filled. Buckets are reset lazily on the next insert in a new generation
 * (see `insertEntity3D`); queries skip buckets whose `_gen` is stale.
 *
 * Internal — exposed only through `SpatialHashGrid3D.cells`.
 */
interface CellBucket3D extends Array<SpatialEntry3D> {
    _gen: number;
}
export interface SpatialHashGrid3D {
    cellSize: number;
    invCellSize: number;
    cells: Map<number, CellBucket3D>;
    /**
     * Dense, indexed by entityId. Holes are `undefined`. Entries from previous
     * rebuilds remain in place for in-place reuse (zero allocation in steady
     * state); liveness is determined by `entry._aliveGen === grid._aliveGen`.
     * Internal — read live entries via `getLiveEntry3D` / `liveEntryCount3D` helpers.
     *
     * High-water-mark grows with max entityId ever inserted; despawned ids
     * leave their slot occupied by a stale entry. Acceptable when the entity
     * manager recycles ids or peak count is bounded.
     */
    entries: (SpatialEntry3D | undefined)[];
    /** Monotonic counter bumped by each `clearGrid3D` call. Internal. */
    _aliveGen: number;
    /** Monotonic counter bumped on each query; entries record their last-seen gen for O(1) dedup. Internal. */
    _queryGen: number;
}
/**
 * Hash a cell coordinate triple to a single integer key.
 * Uses large-prime XOR to distribute values.
 */
export declare function hashCell3D(cx: number, cy: number, cz: number): number;
/**
 * Create a new empty 3D spatial hash grid.
 */
export declare function createGrid3D(cellSize: number): SpatialHashGrid3D;
/**
 * Prepare the grid for a rebuild.
 *
 * O(1): bumps the alive-generation counter so entries inserted prior to this
 * call are implicitly stale. `getLiveEntry3D` / `liveEntryCount3D` filter
 * entries by the current gen; queries skip buckets whose own `_gen` lags
 * behind the alive gen; `insertEntity3D` resets a bucket's `length` lazily
 * the first time it is touched in a new generation.
 *
 * Existing `SpatialEntry3D` objects and `CellBucket3D` arrays remain in
 * place for reuse, so steady-state rebuilds allocate zero entries and zero
 * buckets, regardless of how many cells have ever been touched.
 */
export declare function clearGrid3D(grid: SpatialHashGrid3D): void;
/**
 * Insert an entity into all overlapping cells of the grid.
 */
export declare function insertEntity3D(grid: SpatialHashGrid3D, entityId: number, x: number, y: number, z: number, halfW: number, halfH: number, halfD: number): void;
/**
 * Collect entity IDs from all cells overlapping the given 3D box.
 *
 * Appends to `result` (caller clears/truncates first if reusing). Multi-cell
 * entries are deduplicated via a per-grid generation stamp on each
 * `SpatialEntry3D`.
 *
 * When `minId` is provided, only entries with `entityId > minId` are added —
 * used for symmetric broadphase pair generation.
 */
export declare function gridQueryBox3D(grid: SpatialHashGrid3D, minX: number, minY: number, minZ: number, maxX: number, maxY: number, maxZ: number, result: number[], minId?: number): void;
/**
 * Collect entity IDs within a sphere. AABB-to-point distance filter against
 * the cells overlapping the sphere's bounding box. Appends to `result`.
 */
export declare function gridQueryRadius3D(grid: SpatialHashGrid3D, cx: number, cy: number, cz: number, radius: number, result: number[]): void;
/**
 * Get the current-generation entry for an entityId, or `undefined` if the
 * entity isn't in the index for this rebuild. Stale entries from previous
 * rebuilds remain in `entries` for in-place reuse but are filtered here.
 */
export declare function getLiveEntry3D(grid: SpatialHashGrid3D, entityId: number): SpatialEntry3D | undefined;
/**
 * Count entries inserted in the current rebuild generation. Linear scan —
 * intended for tests and diagnostics, not hot paths.
 */
export declare function liveEntryCount3D(grid: SpatialHashGrid3D): number;
/**
 * High-level spatial index API for 3D broadphase queries.
 *
 * Defined here (the utility layer) so that narrowphase3D can accept it
 * without importing the ECS plugin. The spatial-index3D plugin creates
 * an object that implements this interface and registers it as a resource.
 */
export interface SpatialIndex3D {
    readonly grid: SpatialHashGrid3D;
    queryBox(minX: number, minY: number, minZ: number, maxX: number, maxY: number, maxZ: number): number[];
    queryBoxInto(minX: number, minY: number, minZ: number, maxX: number, maxY: number, maxZ: number, result: number[], minId?: number): void;
    queryRadius(cx: number, cy: number, cz: number, radius: number): number[];
    queryRadiusInto(cx: number, cy: number, cz: number, radius: number, result: number[]): void;
    getEntry(entityId: number): SpatialEntry3D | undefined;
}
export {};