使用vue学习three.js之粒子和粒子系统-通过加载纹理贴图实现雨滴特效

1.VUE中纹理导入过程

1.1纹理图片存放路径

vue中导入时默认的public下，所以要使用的纹理图片需要放在该路径下，如下图images文件夹下的raindrop-3.png就是我们要使用的纹理图片

1.2获取环境变量中的BASE_URL

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

1.3通过THREE.TextureLoader加载纹理贴图

const THIS = this
const textureLoader = new THREE.TextureLoader()
const loadTexture = textureLoader.load(
  `${
      
      THIS.publicPath}images/raindrop-3.png`
)

2.创建雨滴特效

2.1用加载的纹理贴图创建雨滴

示例中将加载的雨滴纹理贴图，赋值给THREE.PointsMaterial材质的map属性，获得雨滴形状的粒子材质，然后随机创建雨滴并添加到Geometry对象的vertices属性中，最后使用THREE.Points创建粒子系统，并把该粒子系统添加到场景

// 创建粒子
createParticleSystem () {
    
    
  const THIS = this
  const textureLoader = new THREE.TextureLoader()
  const loadTexture = textureLoader.load(
    `${
      
      THIS.publicPath}images/raindrop-3.png`
  )
  // 创建几何体
  const geom = new THREE.Geometry()
  const material = new THREE.PointsMaterial({
    
    
    map: loadTexture,
    size: this.properties.size.value,
    transparent: this.properties.transparent,
    opacity: this.properties.opacity.value,
    sizeAttenuation: this.properties.sizeAttenuation,
    color: this.properties.color,
    blending: THREE.AdditiveBlending,
    depthTest: false // 解决透明度问题
  })
  const range = 160
  for (let i = 0; i < 3000; i++) {
    
    
    const particle = new THREE.Vector3(
      Math.random() * range - range / 2,
      Math.random() * range * 1.5,
      Math.random() * range - range / 2
    )
    particle.velocityY = 0.1 + Math.random() / 5
    particle.velocityX = (Math.random() - 0.5) / 3
    // 给几何体添加顶点坐标
    geom.vertices.push(particle)
  }
  // 创建粒子系统对象
  this.points = new THREE.Points(geom, material)
  this.points.sortParticles = true
  this.points.verticesNeedUpdate = true
  // 将粒子系统对象添加到场景
  this.scene.add(this.points)
}

2.2 实现下雨特效动画

在render() 函数中调用下面rainAnimation() 函数实现下雨特效动画

rainAnimation () {
    
    
  const vertices = this.points.geometry.vertices
  vertices.forEach(v => {
    
    
    v.y = v.y - v.velocityY * 3
    v.x = v.x - v.velocityX * 0.5
    if (v.y <= -60) v.y = 60
    if (v.x <= -20 || v.x >= 20) v.velocityX = v.velocityX * -1
  })
  // 实时更新网格的顶点信息
  this.points.geometry.verticesNeedUpdate = true
}

3.demo效果

4.demo代码

<template>
  <div>
    <div id="container"></div>
    <div class="controls-box">
      <section>
        <el-row>
          <el-checkbox v-model="properties.transparent" @change="redraw">transparent</el-checkbox>
        </el-row>
        <el-row>
          <div v-for="(item,key) in properties" :key="key">
            <div v-if="item&&item.name!=undefined">
              <el-col :span="8">
                <span class="vertice-span">{
    
    {
    
    item.name}}</span>
              </el-col>
              <el-col :span="13">
                <el-slider v-model="item.value" :min="item.min" :max="item.max" :step="item.step" :format-tooltip="formatTooltip" @change="redraw"></el-slider>
              </el-col>
              <el-col :span="3">
                <span class="vertice-span">{
    
    {
    
    item.value}}</span>
              </el-col>
            </div>
          </div>
        </el-row>
        <el-row>
          <el-col :span="8" class="label-col"><label> color</label></el-col>
          <el-col :span="16">
            <div @click="inputClick">
              <el-input :value="properties.color"></el-input>
            </div>
            <div v-show="isShowColors" class="color-select-layer">
              <sketch-picker v-model="properties.color" @input="colorChange"></sketch-picker>
            </div>
          </el-col>
        </el-row>
        <el-row>
          <el-checkbox v-model="properties.sizeAttenuation" @change="redraw">sizeAttenuation</el-checkbox>
        </el-row>
      </section>
    </div>
  </div>
</template>

<script>
import * as THREE from 'three'
import {
    
     OrbitControls } from 'three/examples/jsm/controls/OrbitControls.js'
import {
    
     Sketch } from 'vue-color'
export default {
    
    
  components: {
    
    
    'sketch-picker': Sketch
  },
  data () {
    
    
    return {
    
    
      publicPath: process.env.BASE_URL,
      properties: {
    
    
        size: {
    
    
          name: 'size',
          value: 4,
          min: 0,
          max: 20,
          step: 0.1
        },
        opacity: {
    
    
          name: 'opacity',
          value: 0.6,
          min: 0,
          max: 1,
          step: 0.1
        },
        transparent: true,
        sizeAttenuation: true,
        color: '#ccffcc'
      },
      isShowColors: false,
      points: null,
      camera: null,
      scene: null,
      renderer: null,
      controls: null
    }
  },
  mounted () {
    
    
    this.init()
  },
  methods: {
    
    
    formatTooltip (val) {
    
    
      return val
    },
    inputClick () {
    
    
      this.isShowColors = !this.isShowColors
    },
    colorChange (val) {
    
    
      this.properties.color = val.hex
      this.redraw()
    },
    // 初始化
    init () {
    
    
      this.createScene() // 创建场景
      this.createParticleSystem() // 创建粒子系统
      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()
    },
    // 创建粒子
    createParticleSystem () {
    
    
      const THIS = this
      const textureLoader = new THREE.TextureLoader()
      const loadTexture = textureLoader.load(
        `${
      
      THIS.publicPath}images/raindrop-3.png`
      )
      // 创建几何体
      const geom = new THREE.Geometry()
      const material = new THREE.PointsMaterial({
    
    
        map: loadTexture,
        size: this.properties.size.value,
        transparent: this.properties.transparent,
        opacity: this.properties.opacity.value,
        sizeAttenuation: this.properties.sizeAttenuation,
        color: this.properties.color,
        blending: THREE.AdditiveBlending,
        depthTest: false // 解决透明度问题
      })
      const range = 160
      for (let i = 0; i < 3000; i++) {
    
    
        const particle = new THREE.Vector3(
          Math.random() * range - range / 2,
          Math.random() * range * 1.5,
          Math.random() * range - range / 2
        )
        particle.velocityY = 0.1 + Math.random() / 5
        particle.velocityX = (Math.random() - 0.5) / 3
        // 给几何体添加顶点坐标
        geom.vertices.push(particle)
      }
      // 创建粒子系统对象
      this.points = new THREE.Points(geom, material)
      this.points.sortParticles = true
      this.points.verticesNeedUpdate = true
      // 将粒子系统对象添加到场景
      this.scene.add(this.points)
    },

    // 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(45, k, 0.1, 1000)
      this.camera.position.set(0, 0, 100) // 设置相机位置

      this.camera.lookAt(new THREE.Vector3(10, 0, 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.setClearColor(0x3f3f3f, 1) // 设置背景颜色
      element.appendChild(this.renderer.domElement)
    },
    redraw () {
    
    
      if (this.points) {
    
    
        this.scene.remove(this.points)
      }
      this.createParticleSystem()
    },
    rainAnimation () {
    
    
      const vertices = this.points.geometry.vertices
      vertices.forEach(v => {
    
    
        v.y = v.y - v.velocityY * 3
        v.x = v.x - v.velocityX * 0.5

        if (v.y <= -60) v.y = 60
        if (v.x <= -20 || v.x >= 20) v.velocityX = v.velocityX * -1
      })
      // 实时更新网格的顶点信息
      this.points.geometry.verticesNeedUpdate = true
    },
    render () {
    
    
      this.rainAnimation()
      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%;
}
.controls-box {
    
    
  position: absolute;
  right: 5px;
  top: 5px;
  width: 300px;
  padding: 10px;
  background-color: #fff;
  border: 1px solid #c3c3c3;
}
.label-col {
    
    
  padding: 8px 5px;
}
.color-select-layer {
    
    
  position: relative;
  left: -20px;
  padding: 15px 0;
}
.vertice-span {
    
    
  line-height: 38px;
  padding: 0 2px 0 10px;
}
</style>