1 点光源不能单独作用域几何体。需要有其他光源的辅助

2 如果你添加了点光源，同时设置的是默认值，那么界面上很可能展示的几何体没有任何光源效

3对于点光源特别注意它的属性光照距的衰退量也就是decay。其默认值为2.，如果我们设置一个较小的值就能在界面中看见效果：

4 注意几何体的材质：必须设置为对光照有反应的材质，比如MeshStandardMaterial，MeshLambertMaterial等

设置默认值时的效果：

而设置decay：0以后的效果：

可以看到已经出现了光晕的效果。正常点光源的展示效果出来了。

我们最后看代码：

<template>
  <div>
  </div>
</template>
<script  setup>
import { ref } from "vue";
import * as THREE from "three";
import { OrbitControls } from "three/examples/jsm/controls/OrbitControls";
import * as Dat from "dat.gui";
const scene = new THREE.Scene();
const camara = new THREE.PerspectiveCamera(
  45,
  window.innerWidth / window.innerHeight,
  0.01,
  1000
);
camara.position.set(50, 50, 50);
const gui = new Dat.GUI();

//创建平面
const planeGeometry = new THREE.PlaneGeometry(80, 80);
const planeMaterial = new THREE.MeshStandardMaterial({ color: "#ccc" });
const plane = new THREE.Mesh(planeGeometry, planeMaterial);
scene.add(plane);
plane.position.set(0, -2, 0);
plane.rotation.x = -Math.PI / 2;
plane.receiveShadow = true;

//创建几何体
const SphereGeometry = new THREE.SphereGeometry(4);
const sphMaterial = new THREE.MeshLambertMaterial();
const sep = new THREE.Mesh(SphereGeometry, sphMaterial);
sep.castShadow = true;
scene.add(sep);

const renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.shadowMap.enabled = true;
document.body.appendChild(renderer.domElement);

//加入环境光
const ambLight = new THREE.AmbientLight("#fff", 0.5);
ambLight.position.set(0, 0, 0);
scene.add(ambLight);

//点光源
const pointLighControl = {
  color: "#f00",
  intensity: 1,
  decay: 4, //沿着光照距离的衰退量。默认值为 2
  distance: 2 //光源照射的最大距离。默认值为 0（无限远）
};

const pointLight = new THREE.PointLight(
  pointLighControl.color,
  pointLighControl.intensity
);
pointLight.position.set(10, 10, 10);
pointLight.castShadow = true;
pointLight.shadow.radius = 20;
pointLight.shadow.mapSize.set(2048, 2048);
scene.add(pointLight);

gui
  .add(pointLight.position, "x")
  .min(-5)
  .step(0.1);
gui
  .add(pointLight, "distance")
  .min(0)
  .max(10)
  .step(0.1);
gui
  .add(pointLight, "intensity")
  .min(0)
  .step(0.01)
  .max(10);
gui
  .add(pointLight, "decay")
  .min(0)
  .step(0.01)
  .max(5);
const pointHelper = new THREE.PointLightHelper(pointLight, 1);
scene.add(pointHelper);
//轨道控制器
const control = new OrbitControls(camara, renderer.domElement);

const render = () => {
  renderer.render(scene, camara);
  requestAnimationFrame(render);
  camara.updateMatrix();
  control.update();
};
render();
</script>
<style scoped>
</style>