使用 React 和 Threejs 創建一個VR全景項目的過程詳解

npx create-react-app parano	// 創建一個 React 項目
npm install -S typescript	// 安裝 typescript，這個是類型輔助插件，與全景項目關系不大
npm install -S @types/three	// 安裝 typescript 支持的 three.js 插件

import React from 'react'
import * as THREE from 'three'	// 引入 Three.js 插件
import banner from './img/playground.jpg'	// 引入全景圖
// props 類型聲明接口
interface MyProps {
}
// state 類型聲明接口
interface MyState {
}
class Pano extends React.Component<MyProps, MyState> {
  renderer: any = new THREE.WebGLRenderer()	// 創建一個渲染器
  scene: any = new THREE.Scene()	// 創建一個場景
  camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000)	// 創建一個攝像機
  geometry = new THREE.SphereBufferGeometry(100, 60, 40)	// 創建一個球形的容器，用於貼全景圖上去
  material: any	// 貼圖材質
  mesh: any
  constructor(props: any) {
    super (props)
    this.state = {}
  }
  componentDidMount () {
    this.geometry.scale(-1, 1, 1)
    let texture = new THREE.TextureLoader().load(banner)
    this.material = new THREE.MeshBasicMaterial({map: texture})
    this.mesh = new THREE.Mesh(this.geometry, this.material)
    this.renderer.setSize(window.innerWidth, window.innerHeight)
    document.body.appendChild(this.renderer.domElement)
    this.scene.add(this.mesh)
    this.camera.position.z = 0
    window.addEventListener('resize', this.onWindowResize, false)
    this.animate()
  }
	// 實現窗口大小改變的時候改變全景圖的顯示大小
  onWindowResize = () => {
    this.camera.aspect = window.innerWidth / window.innerHeight
    this.camera.updateProjectionMatrix()
    this.renderer.setSize(window.innerWidth, window.innerHeight)
  }
	// 逐幀渲染
  animate = () => {
    requestAnimationFrame(this.animate)
    this.mesh.rotation.y += 0.001
    this.renderer.render(this.scene, this.camera)
  }
  render () {
    return (
      <div></div>
    )
  }
}
export default Pano

import React from 'react';
import './App.css';
import Pano from './pano';

function App() {
 return (
  <div className="App">
   <Pano />
  </div>
 );
}

export default App;