ThreeJS从创建场景到使用功能实例详解

export default class ThreeComponent extends React.Component<any, any> {
  private mount: any
  private camera: any
  private scene: any
  private renderer: any
  
  componentDidMount() {
    this.init()
    this.renders()
  }
  
  init = () => {
    // 相机
    this.camera = new THREE.PerspectiveCamera(30, this.mount.clientWidth / this.mount.clientHeight, 1, 2500)
    this.camera.position.set(500, 800, 1300)
    this.camera.lookAt(30, 0, 0)
    // 场景
    this.scene = new THREE.Scene()
    this.scene.background = new THREE.Color(0x000000)

    this.renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true })
    this.renderer.setClearColor(0xEEEEEE, 0.0)
    this.renderer.setPixelRatio(window.devicePixelRatio)
    this.renderer.setSize(this.mount.clientWidth, this.mount.clientHeight)
    this.mount.appendChild(this.renderer.domElement)
    window.addEventListener('resize', () => this.onWindowResize.bind(this))
  }

  onWindowResize = () => {
    this.camera.aspect = this.mount.clientWidth / this.mount.clientHeight
    this.camera.updateProjectionMatrix()

    this.renderer.setSize(this.mount.clientWidth, this.mount.clientHeight)

    this.renders()
  }
  
  renders = () => {
    this.renderer.render(this.scene, this.camera)
  }

  render() {
    return (
      <div id='canvas'
           style={{ width: '100%', height: '100%' }}
           ref={(mount) => {
             this.mount = mount
           }}/>
    )
  }
}

    const geometry = new THREE.PlaneGeometry(800, 400)
    // 设置透明以及颜色
    const material = new THREE.MeshBasicMaterial({ color: 0x091A20, transparent: true, opacity: 0.8 })
    const plane = new THREE.Mesh(geometry, material)
    // 这边操作的是旋转还是位置
    plane.rotation.x = 300.1
    plane.rotation.y = 0
    plane.rotation.z = 49.8
    plane.rotation.y = 0
    plane.position.x = 120
    plane.position.y = 200
    this.scene.add(plane)

    const image = require('../../assets/images/test.png').default
    // 因为添加图片加载是异步的，所以在load方法中操作，每次加载之后都要执行一遍renders方法，重新渲染场景
    new THREE.TextureLoader().load(image, (texture) => {
      // 设置透明度，以及基础材质的map
      const mat = new THREE.MeshBasicMaterial({ map: texture, transparent: true })
      const geom = new THREE.BoxGeometry(100, 100)
      const mesh = new THREE.Mesh(geom, mat)
      mesh.receiveShadow = true
      mesh.rotation.z = 19.7
      mesh.position.x = 0
      mesh.position.y = -30
      // 往plane平面中添加，这样就可以直接放到plane中，位置就是plane的位置
      plane.add(mesh)
      this.renders()
    })

// 这里引入MeshLine
import { MeshLine, MeshLineMaterial, MeshLineRaycast } from 'three.meshline'

      const mat = new THREE.MeshBasicMaterial({ map: texture1, transparent: true })
      const boxGeom = new THREE.BoxGeometry(60, 150)
      const mesh = new THREE.Mesh(boxGeom, mat)
      const mat1 = new THREE.MeshBasicMaterial({ map: texture2, transparent: true })
      const boxGeom1 = new THREE.BoxGeometry(60, 150)
      const mesh1 = new THREE.Mesh(boxGeom1, mat1)
      const point = []
      point.push(mesh.position) // mesh的位置
      point.push(mesh1.position)  // mesh1的位置
      // 点对点的线
      const line = new MeshLine()
      line.setPoints(point)
      const lineMaterial = new MeshLineMaterial({
        color: new THREE.Color(0xffffff),
        lineWidth: 10,
        transparent: true,
        opacity: 0.5
      })
      // 添加线
      const lineMesh = new THREE.Mesh(line.geometry, lineMaterial)
      plane.add(mesh)
      plane.add(mesh1)
      plane.add(lineMesh)
      // 更新完之后在执行一遍render，把东西渲染到画布中
      this.renders()

    const axesHelper = new THREE.AxesHelper(800)
    this.scene.add(axesHelper)

    // 缩放功能对应mesh进行缩放，每个mesh添加后都有固定的position， rotation， scale 属性
    mesh.position.set(x, y, z)
    mesh.rotation.set(x, y, z)
    mesh.scale.set(x, y, z)
    // 也可以这样, scale, rotation 都可以这么设置
    mesh.position.x = 0 
    mesh.position.y = 0
    mesh.position.z = 0

    //创建canvas
    const canvas = document.getElementById('text-canvas') as HTMLCanvasElement
    const ctx = canvas?.getContext('2d') as any
    canvas.width = 100
    canvas.height = 100
    ctx.fillStyle = 'transparent'
    ctx.fillRect(0, 0, 100, 100)
    ctx.fillStyle = '#FFFFFF'
    ctx.font = `normal ${attr.fontSize ?? 14}px "楷体"`
    ctx.fillText(text.length > 5 ? text.substr(0, 5) + '...' : text, 0, 40)
    // 导出图片路径
    const url = canvas.toDataURL('image/png')
    // 设置图片位置等信息
    new THREE.TextureLoader().load(url, (texture: any) => {
      const textGeom = new THREE.PlaneGeometry(200, 200)
      const mat1 = new THREE.MeshBasicMaterial({
        map: texture,
        transparent: true
      })
      const mesh1 = new THREE.Mesh(textGeom, mat1)
      mesh1.position.set(attr.x, attr.y, attr.z)
      if (attr.rotation !== undefined) {
        mesh1.rotation.set(attr.rotation.x, attr.rotation.y, attr.rotation.z)
      }
      mesh1.scale.set(0.8, 0.8, 0.8)
      if (attr.group !== undefined) {
        attr.group.add(mesh1)
        plane.add(attr.group)
      } else {
        plane.add(mesh1)
      }
      this.renders()
    })

    // 透视摄像机
    this.camera = new THREE.PerspectiveCamera(30, this.mount.clientWidth / this.mount.clientHeight, 1, 2500)

    // 正交摄像机
    this.camera = new THREE.OrthographicCamera(width / -4, width / 4, height / 4, height / -4, -100, 10000)

    this.camera.position.set(x, y, z)
    this.camera.lookAt(x, y, z)