使用阴影

1.给立方体添加castShadow，让立方体产生阴影

cube.castShadow = true;

2.创建一个地面用于接收阴影

 const planeGemetry = new THREE.PlaneGeometry(20, 30)
  const planeMaterial = new THREE.MeshPhongMaterial({ color: 0xffffff })
  const plane = new THREE.Mesh(planeGemetry, planeMaterial)
  plane.rotateZ(20);
  plane.position.z = -10;
  plane.position.x = 3;
  // 使用平面接收阴影
  plane.receiveShadow = true;
  scene.add(plane);

3.设置灯光开启阴影

spotLight.castShadow = true;

4.渲染器添加可以使用阴影的能力

 renderer.shadowMap.enabled = true;

完整代码

<template>
  <div>
    <canvas ref="container"
            height="700"
            width="1400"></canvas>
  </div>
</template>

<script setup>
import { onMounted, ref } from "vue";
import { THREE, CameraControls } from "@/global/three";

const container = ref(null);
// 创建渲染器
const createRenderer = () => new THREE.WebGLRenderer({ canvas: container.value, antialias: true });
// 创建相机
const createCamera = (options = {}) => {
  const { fov, aspect, near, far, positions, eyesP } = {
    fov: 40,
    aspect: 2,
    near: 0.1,
    far: 1000,
    positions: [0, 50, 0],
    eyesP: [0, 0, 0],
    ...options
  }
  const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
  camera.position.set(...positions);
  camera.lookAt(...eyesP)
  return camera
}

onMounted(() => {
  const clock = new THREE.Clock();
  const renderer = createRenderer();
  const camera = createCamera({
    positions: [0, 0, 20]
  });
  const controls = new CameraControls(camera, container.value)
  const scene = new THREE.Scene();

  // 创建一个立方体
  const cubeGemometry = new THREE.BoxGeometry(2, 2, 2)
  const cubeMaterial = new THREE.MeshLambertMaterial({ color: 0xff0000, wireframe: false, side: THREE.DoubleSide })
  const cube = new THREE.Mesh(cubeGemometry, cubeMaterial)
   // 让三维物体 产生阴影，使用平面接收阴影
  cube.castShadow = true;
  scene.add(cube)

  // 创建一个地面用于接收阴影
  const planeGemetry = new THREE.PlaneGeometry(20, 30)
  const planeMaterial = new THREE.MeshPhongMaterial({ color: 0xffffff })
  const plane = new THREE.Mesh(planeGemetry, planeMaterial)
  plane.rotateZ(20);
  plane.position.z = -10;
  plane.position.x = 3;
  // 使用平面接收阴影
  plane.receiveShadow = true;
  scene.add(plane);

  // 添加灯光
  const spotLight = new THREE.SpotLight(0xffffff);
  spotLight.position.set(-10, 10, 90);
   // 设置灯光开启阴影
  spotLight.castShadow = true;
  scene.add(spotLight);

  renderer.shadowMap.enabled = true;

  function render () {
    cube.rotation.x += 0.01;
    cube.rotation.y += 0.01;
    const delta = clock.getDelta();
    controls.update(delta);
    renderer.render(scene, camera)
    requestAnimationFrame(render)
  }
  requestAnimationFrame(render)
});
</script>

<style lang="scss" scoped></style>

效果图