问从旋转网格中投射多条射线

EN

import {  RefObject } from "react";
import * as THREE from "three";
import React from "react";
import { useFrame, useThree } from "@react-three/fiber";

export type RayCastResult = {
  hit: boolean;
  angle: number;
  direction: THREE.Vector3;
  distance: number;
};

export const useRaycasts = ({
  count = 4,
  near = 1,
  far = 10,
  obj
}: {
  count?: number;
  near?: number;
  far?: number;
  obj: RefObject<THREE.Mesh>;
}): { rays: RayCastResult[] } => {
  const rays = React.useMemo(() => {
    const rays: RayCastResult[] = [];
    let angle = 0;
    const step = (2 * Math.PI) / count;

    for (let i = 0; i < count; i++) {
      rays.push({
        hit: false,
        angle: angle,
        direction: new THREE.Vector3(
          Math.cos(angle),
          0,
          Math.sin(angle)
        ).normalize(),
        distance: 10
      });
      angle += step;
    }

    return rays;
  }, [count]);

  const pos = React.useMemo(() => new THREE.Vector3(), []);
  const dir = React.useMemo(() => new THREE.Vector3(), []);

  const { scene, raycaster } = useThree();

  useFrame(() => {
    if (!obj.current) return;

    obj.current.getWorldDirection(dir);
    obj.current.getWorldPosition(pos);

    rays.forEach((direction, i) => {
      if (!obj.current) return;
      raycaster.set(
        pos,
        dir
          .applyAxisAngle(rays[0].direction, obj.current?.rotation.y)
          .normalize()
        //dir.applyAxisAngle(rays[i].direction, rays[i].angle),
        //dir.applyAxisAngle(rays[i].direction, Math.PI / 2)
        //dir.applyQuaternion(obj.current.quaternion).add(rays[i].direction)
      );

      raycaster.near = near;
      raycaster.far = far;

      const intersects = raycaster.intersectObjects(scene.children);

      // ONLY check first object
      if (intersects.length) {
        rays[i].hit = true;
        rays[i].distance = intersects[0].distance;
      } else {
        rays[i].hit = false;
        rays[i].distance = raycaster.far;
      }
    });
  });

  return { rays };
};