从零开始vue使用cesium开发3d地形terrainProvider（二）

var viewer = new Cesium.Viewer("cesiumContainer", {
  imageryProvider: Cesium.createWorldImagery({
    style: Cesium.IonWorldImageryStyle.AERIAL_WITH_LABELS,
  }),
  baseLayerPicker: false,
   terrainProvider : new Cesium.CesiumTerrainProvider({
        url : 'cesium',
        requestVertexNormals : true
    })
});
var layers = viewer.scene.imageryLayers;
var blackMarble = layers.addImageryProvider(
  new Cesium.IonImageryProvider({ assetId: 3812 })
);
blackMarble.alpha = 0.5;
blackMarble.brightness = 2.0;
layers.addImageryProvider(
  new Cesium.SingleTileImageryProvider({
    url: "../images/Cesium_Logo_overlay.png",
    rectangle: Cesium.Rectangle.fromDegrees(-75.0, 28.0, -67.0, 29.75),
  })
); 

   var viewer = new Cesium.Viewer('cesiumContainer', {
            terrainProvider: new Cesium.CesiumTerrainProvider({
                //     url: Cesium.IonResource.fromAssetId(1),
                url: "data/dem"
            }),
            })
        });