three.js加载PLY格式模型(vue中使用three.js56)

1.demo效果

如上图，该demo通过PLYLoader加载了PLY格式的模型，将汽车模型呈现在页面中

2.实现要点

2.1 PLY模型放置路径

vue中加载文件时默认的路径为public下，所以需要加载的文件放在该路径下，同时在vue的data属性中创建变量publicPath，此变量的值是vue中的环境变量process.env.BASE_URL

data() {
  return {
    publicPath: process.env.BASE_URL
  }
}

2.2 加载PLY模型

这我们通过PLYLoader导入模型，不过这里需要注意导入的路径，把我们创建的publicpath变量拼接到文件的路径上，在导入的回调函数中可以进行相关处理具体如下：

const loader = new PLYLoader()
loader.load(`${THIS.publicPath}models/test.ply`, model => {
	//对导入模型进行相关处理
	...
})

2.3 创建粒子材质纹理

//生成纹理
generateSprite() {
  const canvas = document.createElement('canvas')
  canvas.width = 16
  canvas.height = 16

  const context = canvas.getContext('2d')
  const gradient = context.createRadialGradient(
    canvas.width / 2,
    canvas.height / 2,
    0,
    canvas.width / 2,
    canvas.height / 2,
    canvas.width / 2
  )
  gradient.addColorStop(0, 'rgba(255,255,255,1)')
  gradient.addColorStop(0.2, 'rgba(0,255,255,1)')
  gradient.addColorStop(0.4, 'rgba(0,0,64,1)')
  gradient.addColorStop(1, 'rgba(0,0,0,1)')

  context.fillStyle = gradient
  context.fillRect(0, 0, canvas.width, canvas.height)

  const texture = new THREE.Texture(canvas)
  texture.needsUpdate = true
  return texture
}

2.4 格式化为粒子系统

// 创建粒子材质
const material = new THREE.PointsMaterial({
  color: 0xffffff,
  size: 0.4,
  opacity: 0.6,
  transparent: true,
  blending: THREE.AdditiveBlending,
  map: this.generateSprite()
})
// 创建粒子系统
this.mesh = new THREE.Points(geometry, material)
// 添加到场景
this.scene.add(this.mesh)

3.demo代码

<template>
  <div>
    <div id="container"></div>
  </div>
</template>

<script>
import * as THREE from 'three'
import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls.js'
import { PLYLoader } from 'three/examples/jsm/loaders/PLYLoader.js'

export default {
  data() {
    return {
      publicPath: process.env.BASE_URL,
      mesh: null,
      camera: null,
      scene: null,
      renderer: null,
      controls: null
    }
  },
  mounted() {
    this.init()
  },
  methods: {
    // 初始化
    init() {
      this.createScene() // 创建场景
      this.loadPLY() // 加载PLY模型
      this.createLight() // 创建光源
      this.createCamera() // 创建相机
      this.createRender() // 创建渲染器
      this.createControls() // 创建控件对象
      this.render() // 渲染
    },
    // 创建场景
    createScene() {
      this.scene = new THREE.Scene()
    },
    // 加载PLY模型
    loadPLY() {
      const THIS = this
      const loader = new PLYLoader()
      loader.load(`${THIS.publicPath}models/test.ply`, geometry => {
        // 创建粒子材质
        const material = new THREE.PointsMaterial({
          color: 0xffffff,
          size: 0.4,
          opacity: 0.6,
          transparent: true,
          blending: THREE.AdditiveBlending,
          map: this.generateSprite()
        })
        // 创建粒子系统
        this.mesh = new THREE.Points(geometry, material)
        // 添加到场景
        this.scene.add(this.mesh)
      })
    },
    //生成纹理
    generateSprite() {
      const canvas = document.createElement('canvas')
      canvas.width = 16
      canvas.height = 16

      const context = canvas.getContext('2d')
      const gradient = context.createRadialGradient(
        canvas.width / 2,
        canvas.height / 2,
        0,
        canvas.width / 2,
        canvas.height / 2,
        canvas.width / 2
      )
      gradient.addColorStop(0, 'rgba(255,255,255,1)')
      gradient.addColorStop(0.2, 'rgba(0,255,255,1)')
      gradient.addColorStop(0.4, 'rgba(0,0,64,1)')
      gradient.addColorStop(1, 'rgba(0,0,0,1)')

      context.fillStyle = gradient
      context.fillRect(0, 0, canvas.width, canvas.height)

      const texture = new THREE.Texture(canvas)
      texture.needsUpdate = true
      return texture
    },

    // 创建光源
    createLight() {
      // 环境光
      const ambientLight = new THREE.AmbientLight(0xffffff, 0.1) // 创建环境光
      this.scene.add(ambientLight) // 将环境光添加到场景

      const spotLight = new THREE.SpotLight(0xffffff) // 创建聚光灯
      spotLight.position.set(50, 50, 50)
      spotLight.castShadow = true
      this.scene.add(spotLight)
    },
    // 创建相机
    createCamera() {
      const element = document.getElementById('container')
      const width = element.clientWidth // 窗口宽度
      const height = element.clientHeight // 窗口高度
      const k = width / height // 窗口宽高比
      // PerspectiveCamera( fov, aspect, near, far )
      this.camera = new THREE.PerspectiveCamera(35, k, 0.1, 1000)
      this.camera.position.set(20, 20, 20) // 设置相机位置

      this.camera.lookAt(new THREE.Vector3(10, 40, 0)) // 设置相机方向
      this.scene.add(this.camera)
    },
    // 创建渲染器
    createRender() {
      const element = document.getElementById('container')
      this.renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true })
      this.renderer.setSize(element.clientWidth, element.clientHeight) // 设置渲染区域尺寸
      this.renderer.shadowMap.enabled = true // 显示阴影
      this.renderer.shadowMap.type = THREE.PCFSoftShadowMap
      this.renderer.setClearColor(0x3f3f3f, 1) // 设置背景颜色
      element.appendChild(this.renderer.domElement)
    },

    render() {
      if (this.mesh) {
        this.mesh.rotation.y += 0.006
      }
      this.renderer.render(this.scene, this.camera)
      requestAnimationFrame(this.render)
    },
    // 创建控件对象
    createControls() {
      this.controls = new OrbitControls(this.camera, this.renderer.domElement)
    }
  }
}
</script>
<style>
#container {
  position: absolute;
  width: 100%;
  height: 100%;
}
</style>