dddd.gif

本文章介绍运用 threejs 操作3d物体实现鼠标跟随，核心思想就是控制相机跟随鼠标的反向移动，获取鼠标事件，计算方向；
核心代码：
camera.position.y = -(window.scrollY / window.innerHeight) * 30;

camera.position.x += (mouse.x * 5 - camera.position.x) * deltaTime * 5;

运用案例：
https://www.weedensenteret.no/
一个很漂亮的3d官网

还有腾讯云轮播的3d物体交互都是相通的原理
https://cloud.tencent.com/

截屏2023-04-10 17.06.51.png

import * as THREE from "three";
// 导入轨道控制器
import { OrbitControls } from "three/examples/jsm/controls/OrbitControls";
// 导入动画库
import gsap from "gsap";
// 导入dat.gui
import * as dat from "dat.gui";

// 目标：raycaster

// const gui = new dat.GUI();
// 1、创建场景
const scene = new THREE.Scene();

// 2、创建相机
const camera = new THREE.PerspectiveCamera(
  75,
  window.innerWidth / window.innerHeight,
  0.1,
  300
);

const textureLoader = new THREE.TextureLoader();
const particlesTexture = textureLoader.load("./textures/particles/1.png");
// 设置相机位置
camera.position.set(0, 0, 18);
scene.add(camera);

const cubeGeometry = new THREE.BoxBufferGeometry(2, 2, 2);
const material = new THREE.MeshBasicMaterial({
  wireframe: true,
});
const redMaterial = new THREE.MeshBasicMaterial({
  color: "#ff0000",
});

// 1000立方体
let cubeArr = [];
let cubeGroup = new THREE.Group();
for (let i = 0; i < 5; i++) {
  for (let j = 0; j < 5; j++) {
    for (let z = 0; z < 5; z++) {
      const cube = new THREE.Mesh(cubeGeometry, material);
      cube.position.set(i * 2 - 4, j * 2 - 4, z * 2 - 4);
      cubeGroup.add(cube);
      cubeArr.push(cube);
    }
  }
}

scene.add(cubeGroup);

const smallBall = new THREE.Mesh(
  new THREE.SphereBufferGeometry(0.1, 20, 20),
  new THREE.MeshBasicMaterial({ color: 0xff0000 })
);
smallBall.position.set(2, 2, 2);
//直线光源
const pointLight = new THREE.PointLight(0xff0000, 3);
// pointLight.position.set(2, 2, 2);
pointLight.castShadow = true;

// 设置阴影贴图模糊度
pointLight.shadow.radius = 20;
// 设置阴影贴图的分辨率
pointLight.shadow.mapSize.set(512, 512);

// 设置透视相机的属性
smallBall.add(pointLight);

// 创建投射光线对象
const raycaster = new THREE.Raycaster();

// 鼠标的位置对象
const mouse = new THREE.Vector2();

// 监听鼠标的位置
window.addEventListener("mousemove", (event) => {
  mouse.x = event.clientX / window.innerWidth - 0.5;
  mouse.y = event.clientY / window.innerHeight - 0.5;
});

// 监听鼠标的位置
window.addEventListener("click", (event) => {
  //   console.log(event);
  mouse.x = (event.clientX / window.innerWidth) * 2 - 1;
  mouse.y = -((event.clientY / window.innerHeight) * 2 - 1);
  raycaster.setFromCamera(mouse, camera);
  let result = raycaster.intersectObjects(cubeArr);
  //   console.log(result);
  //   result[0].object.material = redMaterial;
  result.forEach((item) => {
    item.object.material = redMaterial;
  });
});

// 初始化渲染器
// 渲染器透明
const renderer = new THREE.WebGLRenderer({ alpha: true });
// 设置渲染的尺寸大小
renderer.setSize(window.innerWidth, window.innerHeight);
// 开启场景中的阴影贴图
renderer.shadowMap.enabled = true;
renderer.physicallyCorrectLights = true;

// console.log(renderer);
// 将webgl渲染的canvas内容添加到body
document.body.appendChild(renderer.domElement);

// // 使用渲染器，通过相机将场景渲染进来
// renderer.render(scene, camera);

// 创建轨道控制器
// const controls = new OrbitControls(camera, renderer.domElement);
// // 设置控制器阻尼，让控制器更有真实效果,必须在动画循环里调用.update()。
// controls.enableDamping = true;

// 添加坐标轴辅助器
const axesHelper = new THREE.AxesHelper(5);
scene.add(axesHelper);
// 设置时钟
const clock = new THREE.Clock();

function render() {
  //   let time = clock.getElapsedTime();
  let deltaTime = clock.getDelta();
  //   根据当前滚动的scrolly，去设置相机移动的位置
  camera.position.y = -(window.scrollY / window.innerHeight) * 30;

  camera.position.x += (mouse.x * 5 - camera.position.x) * deltaTime * 5;
  //   controls.update();
  renderer.render(scene, camera);
  //   渲染下一帧的时候就会调用render函数
  requestAnimationFrame(render);
}

render();

// 监听画面变化，更新渲染画面
window.addEventListener("resize", () => {
  //   console.log("画面变化了");

  // 更新摄像头
  camera.aspect = window.innerWidth / window.innerHeight;
  //   更新摄像机的投影矩阵
  camera.updateProjectionMatrix();

  //   更新渲染器
  renderer.setSize(window.innerWidth, window.innerHeight);
  //   设置渲染器的像素比
  renderer.setPixelRatio(window.devicePixelRatio);
});