使用vue学习three.js之加载和使用纹理- 通过设置纹理的wrapS、wrapT、repeat属性实现纹理的重复平铺，纹理的重复映射

1.demo效果

2. 纹理平铺的相关属性

在之前学习纹理对象Texture已经介绍过纹理的wrapS、wrapT、repeat属性，它们都是用来设置纹理重复的相关属性，在来简单说一下这几个属性

• wrapS
  纹理在水平方向上纹理包裹方式，在UV映射中对应于U，默认THREE.ClampToEdgeWrapping，表示纹理边缘与网格的边缘贴合。中间部分等比缩放。还可以设置为：THREE.RepeatWrapping(重复平铺) 和 THREE.MirroredRepeatWrapping（先镜像再重复平铺）
• wrapT
  纹理贴图在垂直方向上的包裹方式，在UV映射中对应于V，默认也是THREE.ClampToEdgeWrapping，与wrapS属性一样也可以设置为：THREE.RepeatWrapping(重复平铺) 和 THREE.MirroredRepeatWrapping（先镜像再重复平铺）
• repeat
  用来设置纹理将在表面上，分别在U、V方向重复多少次。
  repeat属性是Vector2类型，可以使用如下语句来为它赋值

this.cube.material.map.repeat.set(repeatX, repeatY)

repeatX 用来指定在x轴方向上多久重复一次，repeatY用来指定在y轴方向上多久重复一次
这两个变量取值范围与对应效果如下

如果设置等于1，则纹理不会重复
如果设置为 大于0小于1 的值，纹理会被放大
如果设置为 小于0 的值，那么会产生纹理的镜像
如果设置为 大于1 的值，纹理会重复平铺

3. 实现要点

属性改变时需要将新的值重新赋值给wrapS、wrapT、repeat属性，赋值过程和处理逻辑如下

//设置立方体的纹理重复数量
this.cube.material.map.repeat.set(
  this.properties.repeatX.value,
  this.properties.repeatY.value
)
//设置球体的纹理重复数量
this.sphere.material.map.repeat.set(
  this.properties.repeatX.value,
  this.properties.repeatY.value
)

//纹理不重复时，纹理包裹方式为重复平铺
if (this.properties.isRepeat) {
     
  this.cube.material.map.wrapS = THREE.RepeatWrapping
  this.cube.material.map.wrapT = THREE.RepeatWrapping
  this.sphere.material.map.wrapS = THREE.RepeatWrapping
  this.sphere.material.map.wrapT = THREE.RepeatWrapping
} else {
     
  //纹理不重复时，纹理包裹方式为纹理边缘与网格的边缘贴合
  this.cube.material.map.wrapS = THREE.ClampToEdgeWrapping
  this.cube.material.map.wrapT = THREE.ClampToEdgeWrapping
  this.sphere.material.map.wrapS = THREE.ClampToEdgeWrapping
  this.sphere.material.map.wrapT = THREE.ClampToEdgeWrapping
}

4. demo代码

<template>
  <div>
    <div id="container" />
    <div class="controls-box">
      <section>
        <el-row>
          <el-checkbox v-model="properties.isRepeat" @change="propertiesChange">
            isRepeat
          </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="propertiesChange" />
              </el-col>
              <el-col :span="3">
                <span class="vertice-span">{
     {
      item.value }}</span>
              </el-col>
            </div>
          </div>
        </el-row>
      </section>
    </div>
  </div>
</template>

<script>
import * as THREE from 'three'
import {
      OrbitControls } from 'three/examples/jsm/controls/OrbitControls.js'
export default {
     
  data() {
     
    return {
     
      properties: {
     
        repeatX: {
     
          name: 'repeatX',
          value: 1,
          min: -4,
          max: 4,
          step: 0.1
        },
        repeatY: {
     
          name: 'repeatY',
          value: 1,
          min: -4,
          max: 4,
          step: 0.1
        },
        isRepeat: true
      },
      cube: null,
      sphere: null,
      camera: null,
      scene: null,
      renderer: null,
      controls: null,
      step: 0
    }
  },
  mounted() {
     
    this.init()
  },
  methods: {
     
    formatTooltip(val) {
     
      return val
    },

    // 初始化
    init() {
     
      this.createScene() // 创建场景
      this.createModels() // 创建模型
      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()
    },
    // 创建模型
    createModels() {
     
      //创建砖块纹理的立方体
      this.cube = this.createMesh(
        new THREE.BoxGeometry(6, 6, 6),
        'brick-wall.jpg'
      )
      this.cube.position.x = -5
      this.scene.add(this.cube)

      //创建木条纹理的球体
      this.sphere = this.createMesh(
        new THREE.SphereGeometry(5, 20, 20),
        'floor-wood.jpg'
      )
      this.sphere.position.x = 5
      this.scene.add(this.sphere)
    },
    createMesh(geom, textureName) {
     
      //加载纹理
      const publicPath = process.env.BASE_URL
      const texture = new THREE.TextureLoader().load(
        `${
       publicPath}textures/general/` + textureName
      )

      //水平方向和垂直方向上纹理包裹方式为重复平铺
      texture.wrapS = THREE.RepeatWrapping
      texture.wrapT = THREE.RepeatWrapping

      const mat = new THREE.MeshPhongMaterial()
      mat.map = texture

      const mesh = new THREE.Mesh(geom, mat)
      return mesh
    },
    // 创建光源
    createLight() {
     
      // 环境光
      const ambientLight = new THREE.AmbientLight(0x242424, 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(0, 30, 30)
      spotLight.intensity = 1.2
      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(45, k, 0.1, 1000)
      this.camera.position.set(0, 12, 20) // 设置相机位置

      this.camera.lookAt(new THREE.Vector3(0, 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.shadowMap.enabled = true // 显示阴影
      // this.renderer.shadowMap.type = THREE.PCFSoftShadowMap
      this.renderer.setClearColor(0xeeeeee, 1) // 设置背景颜色
      element.appendChild(this.renderer.domElement)
    },

    propertiesChange() {
     
      //设置立方体的纹理重复数量
      this.cube.material.map.repeat.set(
        this.properties.repeatX.value,
        this.properties.repeatY.value
      )
      //设置球体的纹理重复数量
      this.sphere.material.map.repeat.set(
        this.properties.repeatX.value,
        this.properties.repeatY.value
      )

      //纹理不重复时，纹理包裹方式为重复平铺
      if (this.properties.isRepeat) {
     
        this.cube.material.map.wrapS = THREE.RepeatWrapping
        this.cube.material.map.wrapT = THREE.RepeatWrapping
        this.sphere.material.map.wrapS = THREE.RepeatWrapping
        this.sphere.material.map.wrapT = THREE.RepeatWrapping
      } else {
     
        //纹理不重复时，纹理包裹方式为纹理边缘与网格的边缘贴合
        this.cube.material.map.wrapS = THREE.ClampToEdgeWrapping
        this.cube.material.map.wrapT = THREE.ClampToEdgeWrapping
        this.sphere.material.map.wrapS = THREE.ClampToEdgeWrapping
        this.sphere.material.map.wrapT = THREE.ClampToEdgeWrapping
      }

      //更新材质中的纹理
      this.cube.material.map.needsUpdate = true
      this.sphere.material.map.needsUpdate = true
    },

    updateRotation() {
     
      this.step += 0.01
      this.cube.rotation.x = this.step
      this.cube.rotation.y = this.step
      this.sphere.rotation.x = this.step
      this.sphere.rotation.y = this.step
    },

    render() {
     
      this.updateRotation()
      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;
}

.vertice-span {
     
  line-height: 38px;
  padding: 0 2px 0 10px;
}
</style>