【Threejs】从零开始（十一）--3D交互事件

交互事件是通过光线投射进行实现的。接下来是一个相关案例。

1.首先准备基本环境

javascript 复制代码

// 导入three
import * as THREE from 'three'  // 导入threejs
//导入轨道控制器
import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls'


// 创建场景
const scene = new THREE.Scene()
scene.background = new THREE.Color(0x999999)

// 创建相机
const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000)
camera.position.z = 10

// 创建渲染器
const renderer = new THREE.WebGLRenderer()
renderer.setSize(window.innerWidth, window.innerHeight)
document.body.appendChild(renderer.domElement)

//辅助坐标系
const axesHelper = new THREE.AxesHelper(5)
scene.add(axesHelper)

// 创建控制器
const controls = new OrbitControls(camera, renderer.domElement)

//自适应窗口
window.addEventListener('resize', () => {
    camera.aspect = window.innerWidth / window.innerHeight
    camera.updateProjectionMatrix()
    renderer.setSize(window.innerWidth, window.innerHeight)
})

// 渲染循环
function animate() {
    requestAnimationFrame(animate)
    renderer.render(scene, camera)
}
animate()

2.创建三个球体

错开一点位置方便观察

javascript 复制代码

//创建3个球
const geometry = new THREE.SphereGeometry(1, 32, 32)//球体
const material1 = new THREE.MeshBasicMaterial({ color: 0x00ff00 })
const material2 = new THREE.MeshBasicMaterial({ color: 0xff0000 })
const material3 = new THREE.MeshBasicMaterial({ color: 0x0000ff })
const sphere1 = new THREE.Mesh(geometry, material1)
const sphere2 = new THREE.Mesh(geometry, material2)
const sphere3 = new THREE.Mesh(geometry, material3)
sphere1.position.x = -4
sphere2.position.x = 4
scene.add(sphere1, sphere2, sphere3)

3.实现交互

1.创建一个射线和二维的向量

javascript 复制代码

// 创建射线
const raycaster = new THREE.Raycaster()
const mouse = new THREE.Vector2()//创建二维向量

2.监听鼠标的点击事件

（1）先将鼠标的位置归一化到-1和1之间

（2）通过通过鼠标和摄像机位置确定射线位置

（3）计算物体和射线的交点

（4）改变交点物体的颜色

javascript 复制代码

// 监听鼠标移动
window.addEventListener('click', (event) => {
    // 将鼠标位置归一化到-1到1之间
    mouse.x = (event.clientX / window.innerWidth) * 2 - 1
    mouse.y = -(event.clientY / window.innerHeight) * 2 + 1
    //通过鼠标和摄像机位置设置射线
    raycaster.setFromCamera(mouse, camera)
    // 计算物体和射线的交点
    const intersects = raycaster.intersectObjects([sphere1, sphere2, sphere3])
     console.log(intersects)
    for (let i = 0; i < intersects.length; i++) {
        
        intersects[i].object.material.color.set(0xffff00)

    }

})

大功告成！！！