text: // import * as mars3d from "mars3d"
  
  var map // mars3d.Map三维地图对象
  let dom
  
  // 需要覆盖config.json中地图属性参数（当前示例框架中自动处理合并）
  var mapOptions = {
    scene: {
      center: { lat: 36.873519, lng: 106.863496, alt: 19999205, heading: 354, pitch: -89 },
      orderIndependentTranslucency: false,
      contextOptions: { webgl: { alpha: true } }, // 允许透明
      showSun: false,
      showMoon: false,
      showSkyBox: false,
      showSkyAtmosphere: false,
      fog: false,
      globe: {
        baseColor: "rgba(0,0,0,0)",
        showGroundAtmosphere: false,
        enableLighting: false
      }
    }
  }
  
  /**
   * 初始化地图业务，生命周期钩子函数（必须）
   * 框架在地图初始化完成后自动调用该函数
   * @param {mars3d.Map} mapInstance 地图对象
   * @returns {void} 无
   */
  function onMounted(mapInstance) {
    map = mapInstance // 记录map
    dom = mars3d.DomUtil.get("mars3dContainer")
  }
  
  /**
   * 释放当前地图业务的生命周期函数
   * @returns {void} 无
   */
  function onUnmounted() {
    map = null
  }
  
  function show() {
    dom.style.backgroundImage = "none"
  }
  
  function show1() {
    dom.style.backgroundImage = "url(/img/tietu/backGroundImg.jpg)"
  }
  
  function show2() {
    dom.style.backgroundImage = "url(//data.mars3d.cn/file/img/world/world.jpg)"
  }
  
  function show3() {
    dom.style.backgroundImage = "url(/img/tietu/bg4.jpg)"
  }
  