通過Entity添加形狀

先來看一個添加立方體的例子

var viewer = new Cesium.Viewer('cesiumContainer');
var redBox = **viewer.entities.add**({
  name : 'Red box with black outline',
  position: Cesium.Cartesian3.fromDegrees(-107.0, 40.0, 300000.0),
  box : {
    dimensions : new Cesium.Cartesian3(400000.0, 300000.0, 500000.0),
    material : Cesium.Color.RED.withAlpha(0.5),
    outline : true,
    outlineColor : Cesium.Color.BLACK
  }
});

viewer.zoomTo(viewer.entities);

效果如圖：

Jietu20180108-214130.jpg

通過CZML添加

通過CZML也可以添加幾何形狀，而且CZML還可以描述動畫(現在先有個印象，動畫以后介紹)

先來看看官網上的說明，CZML是一種JSON格式的字符串，用于描述與時間有關的動畫場景，CZML包含點、線、地標、模型、和其他的一些圖形元素，并指明了這些元素如何隨時間而變化。某種程度上說, Cesium 和 CZML的關系就像 Google Earth 和 KML。

var czml = [{
    "id" : "document",
    "name" : "box",
    "version" : "1.0"
},{
    "id" : "shape2",
    "name" : "Red box with black outline",
    "position" : {
        "cartographicDegrees" : [-107.0, 40.0, 300000.0]
    },
    "box" : {
        "dimensions" : {
            "cartesian": [400000.0, 300000.0, 500000.0]
        },
        "material" : {
            "solidColor" : {
                "color" : {
                    "rgba" : [255, 0, 0, 128]
                }
            }
        },
        "outline" : true,
        "outlineColor" : {
            "rgba" : [0, 0, 0, 255]
        }
    }
}];

var viewer = new Cesium.Viewer('cesiumContainer');
var dataSourcePromise = Cesium.CzmlDataSource.load(czml);
viewer.dataSources.add(dataSourcePromise);
viewer.zoomTo(dataSourcePromise);

可以看到單個的形狀和Entity的描述基本一致，只不過是使用JSON語法來描述，關于形狀描述可以參考官方API，下一節列出形狀的相關信息

形狀相關描述

下表來自于官方網站，但是連接改為本地鏈接了

?	?	?
Point	pointGeometry.png	entity.point - Reference Build/Documentation
Boxes	boxGeometry.png	entity.box - Code example - Reference Build/Documentation
Circles and Ellipses	ellipseGeometry.png	entity.ellipse - Code example - Reference Build/Documentation
Corridor	corridorGeometry.png	entity.corridor - Code example - Reference Build/Documentation
Cylinder and Cones	cylinderGeometry.png	entity.cylinder - Code example - Reference Build/Documentation
Polygons	polygonGeometry.png	entity.polygon - Code example - Reference Build/Documentation
Polylines	polylineGeometry.png	entity.polyline - Code example - Reference Build/Documentation
Polyline Volumes	polylineVolumeGeometry.png	entity.polylineVolume - Code example - Reference Build/Documentation
Rectangles	extentGeometry.png	entity.rectangle - Code example - Reference Build/Documentation
Spheres and Ellipsoids	ellipsoidGeometry.png	entity.ellipsoid - Code example - Reference Build/Documentation
Walls	wallGeometry.png	entity.wall - Code example - Reference Build/Documentation