Class GridSpatialIndex

packages/spatial/src/GridSpatialIndex.ts:60–384

 * @en Uses uniform grid for spatial partitioning, suitable for evenly distributed objects
 */
export class GridSpatialIndex<T> implements ISpatialIndex<T> {
    private readonly _cellSize: number;
    private readonly _cells: Map<string, Set<GridItem<T>>> = new Map();
    private readonly _itemMap: Map<T, GridItem<T>> = new Map();

    constructor(config: GridSpatialIndexConfig) {
        this._cellSize = config.cellSize;
    }

    // =========================================================================
    // ISpatialIndex 实现 | ISpatialIndex Implementation
    // =========================================================================

    get count(): number {
        return this._itemMap.size;
    }

    /**
     * @zh 插入对象
     * @en Insert object
     */
    insert(item: T, position: IVector2): void {
        if (this._itemMap.has(item)) {
            this.update(item, position);
            return;
        }

        const cellKey = this._getCellKey(position);
        const gridItem: GridItem<T> = { item, position: { x: position.x, y: position.y }, cellKey };

        this._itemMap.set(item, gridItem);
        this._addToCell(cellKey, gridItem);
    }

    /**
     * @zh 移除对象
     * @en Remove object
     */
    remove(item: T): boolean {
        const gridItem = this._itemMap.get(item);
        if (!gridItem) {
            return false;
        }

        this._removeFromCell(gridItem.cellKey, gridItem);
        this._itemMap.delete(item);
        return true;
    }

    /**
     * @zh 更新对象位置
     * @en Update object position
     */
    update(item: T, newPosition: IVector2): boolean {
        const gridItem = this._itemMap.get(item);
        if (!gridItem) {
            return false;
        }