Cesium的api之关于viewer(二)

1、构建一个viewer，如下创建；options的参数根据实际情况，进行设定

 var viewer = new Cesium.Viewer('cesiumContainer', {
      //Start in Columbus Viewer
      sceneMode : Cesium.SceneMode.COLUMBUS_VIEW,  // 设定3维地图的默认场景模式
      //Use standard Cesium terrain
      terrainProvider : new Cesium.CesiumTerrainProvider({    // 构建地形服务
      　　　　 url : '//cesiumjs.org/smallterrain',
      　　　　 credit : 'Terrain data courtesy Analytical Graphics, Inc.'
      }),
      *     //Hide the base layer picker
      *     baseLayerPicker : false,     // 设定基本图层提供不显示
      *     //Use OpenStreetMaps
      *     imageryProvider : new Cesium.OpenStreetMapImageryProvider({  // 调用openstreetmap瓦片服务
      *         url : '//a.tile.openstreetmap.org/'
      *     }),
      *     // Use high-res stars downloaded from https://github.com/AnalyticalGraphicsInc/cesium-assets
      *     skyBox : new Cesium.SkyBox({   // 设定近焦点和远焦点的x、y、z
      *         sources : {
      *           positiveX : 'stars/TychoSkymapII.t3_08192x04096_80_px.jpg',
      *           negativeX : 'stars/TychoSkymapII.t3_08192x04096_80_mx.jpg',
      *           positiveY : 'stars/TychoSkymapII.t3_08192x04096_80_py.jpg',
      *           negativeY : 'stars/TychoSkymapII.t3_08192x04096_80_my.jpg',
      *           positiveZ : 'stars/TychoSkymapII.t3_08192x04096_80_pz.jpg',
      *           negativeZ : 'stars/TychoSkymapII.t3_08192x04096_80_mz.jpg'
      *         }
      *     }),
      *     // Show Columbus View map with Web Mercator projection
      *     mapProjection : new Cesium.WebMercatorProjection()  // 设定投影坐标
      * });

var viewer = new