Floor3D.tsx

import { useMemo } from 'react';
import * as THREE from 'three';
import type { ThreeEvent } from '@react-three/fiber';
import type { Room } from '../../scene/schema';
import { describeRoom, SELECTED_COLOR, type Selected3D } from '../../scene/describe';
import type { UnitSystem } from '../../scene/units';

type Props = {
  room: Room;
  /** Vertical position of the floor surface (default 0). */
  y?: number;
  color?: string;
  units: UnitSystem;
  selectedId: string | null;
  onSelect: (sel: Selected3D | null) => void;
};

export function Floor3D({ room, y = 0, color, units, selectedId, onSelect }: Props) {
  const geom = useMemo(() => {
    const shape = new THREE.Shape();