sun() { //兩秒變化一次平行光
  let i=0
  setInterval(()=>{
    this.initSun(i)
    i++
  },2000)
}

Viewer.prototype.initSun = function (type) {
  let position = {}
  let color = '#ffffff'
  let intensity = 1
  switch (type) {
    case 0:
      position = {
        x: 270,
        y: 150,
        z: 0
      }
      intensity = 5
      break
    case 1:
      position = {
        x: 258,
        y: 170,
        z: 0
      }
      intensity = 7
      color = '#fcffc9'
      break
    case 2:
      position = {
        x: 245,
        y: 180,
        z: 0
      }
      intensity = 10
      color = '#ffe69f'
      break
    case 3:
      position = {
        x: 0,
        y: 100,
        z: 0
      }
      intensity = 15
      color = '#ffe69f'
      break
    case 4:
      position = {
        x: -245,
        y: 180,
        z: 0
      }
      intensity = 10
      color = '#e3894d'
      break
    case 5:
      position = {
        x: -258,
        y: 160,
        z: 0
      }
      intensity = 10
      color = '#ff8400'
      break
    default :
      position = {
        x: -270,
        y: 150,
        z: 0
      }
      intensity = 8
      color = '#ff8400'
      break
  }
  if (this.directionalLight) {
    this.directionalLight.setSun(position,color,intensity)
  } else {
    this.directionalLight = new zhdSun()
    this.directionalLight.renderFn(this.renderFunction)
    this.directionalLight.init({
      position,
      color,
      intensity,
      scene: this.scene,
      currentlayers: this.currentlayers
    })
  }
}

import TWEEN from '@tweenjs/tween.js'
import {zhdObject} from './zhdObject'
export class zhdSun extends zhdObject {
  constructor() {
    super()
    this.light = null
  }
}
//由于添加了TWEEN動畫庫，記得在animate中實時更新TWEEN
TWEEN.update()

init({position, color, intensity , currentlayers, scene}) {
  const directionalLight = new THREE.DirectionalLight(color, intensity) // 新建一個平行光源，顏色未白色，強度為1
  this.light = directionalLight
  directionalLight.position.set(position.x, position.y, position.z) // 將此平行光源調(diào)整到一個合適的位置
  directionalLight.castShadow = true // 將此平行光源產(chǎn)生陰影的屬性打開
  // 設(shè)置平行光的的陰影屬性，即一個長方體的長寬高，在設(shè)定值的范圍內(nèi)的物體才會產(chǎn)生陰影
  const d =100 //陰影范圍
  directionalLight.shadow.camera.left = -d
  directionalLight.shadow.camera.right = d
  directionalLight.shadow.camera.top = d
  directionalLight.shadow.camera.bottom = -d
  directionalLight.shadow.camera.near = 20
  directionalLight.shadow.camera.far = 8000
  directionalLight.shadow.mapSize.x = 2048 // 定義陰影貼圖的寬度和高度,必須為2的整數(shù)此冪
  directionalLight.shadow.mapSize.y = 2048 // 較高的值會以計算時間為代價提供更好的陰影質(zhì)量
  directionalLight.shadow.bias = -0.0005 //解決條紋陰影的出現(xiàn)
  this.setlayers(directionalLight, currentlayers)
  scene.add(directionalLight) // 將此平行光源加入場景中，我們才可以看到這個光源
  return directionalLight
}

setSun(position, color, intensity) {
  this.setTweens(this.light.position, position, 2000)
  this.light.color = new THREE.Color( color )
  this.light.intensity = intensity
}

setTweens(obj, newObj, duration = 1500) {
  var ro = new TWEEN.Tween(obj)
  ro.to(newObj, duration) // 變化后的位置以及動畫時間
  ro.easing(TWEEN.Easing.Sinusoidal.InOut)
  ro.onUpdate(function () {
  })
  ro.start()
}