#### # new RiverGeometry(options)

A description of a polygon on the ellipsoid. The polygon is Cesium.defined by a polygon hierarchy. Polygon geometry can be rendered with both `Primitive` and `GroundPrimitive`.

#### 参数:

名称 | 类型 | 默认值 | 描述
--- | --- | --- | ---
`options` | Object |  | Object with the following properties:
`polygonHierarchy` | PolygonHierarchy |  | A polygon hierarchy that can include holes.
`height` | Number | 0.0 | The distance in meters between the polygon and the ellipsoid surface.
`extrudedHeight` | Number |  | The distance in meters between the polygon's extruded face and the ellipsoid surface.
`vertexFormat` | Cesium.VertexFormat | Cesium.VertexFormat.DEFAULT | The vertex attributes to be computed.
`indices` | Array.<Number> |  | 自定义顶点索引
`st` | Float32Array |  | 自定义UV坐标
`stRotation` | Number | 0.0 | The rotation of the texture coordinates, in radians. A positive rotation is counter-clockwise.
`ellipsoid` | Cesium.Ellipsoid | Cesium.Ellipsoid.WGS84 | The ellipsoid to be used as a reference.
`granularity` | Number | Cesium.Math.RADIANS_PER_DEGREE | The distance, in radians, between each latitude and longitude. Determines the number of positions in the buffer.
`perPositionHeight` | Boolean | false | Use the height of options.positions for each position instead of using options.height to determine the height.
`closeTop` | Boolean | true | When false, leaves off the top of an extruded polygon open.
`closeBottom` | Boolean | true | When false, leaves off the bottom of an extruded polygon open.
`arcType` | Cesium.ArcType | Cesium.ArcType.GEODESIC | The type of line the polygon edges must follow. Valid options are `Cesium.ArcType.GEODESIC` and `Cesium.ArcType.RHUMB`.

See:
  - RiverGeometry#createGeometry
  - RiverGeometry#fromPositions

##### 示例

    // 1. create a polygon from points
    var polygon = new Cesium.RiverGeometry({
      polygonHierarchy : new Cesium.PolygonHierarchy(
        Cesium.Cartesian3.fromDegreesArray([
          -72.0, 40.0,
          -70.0, 35.0,
          -75.0, 30.0,
          -70.0, 30.0,
          -68.0, 40.0
        ])
      )
    });
    var geometry = Cesium.RiverGeometry.createGeometry(polygon);

    // 2. create a nested polygon with holes
    var polygonWithHole = new Cesium.RiverGeometry({
      polygonHierarchy : new Cesium.PolygonHierarchy(
        Cesium.Cartesian3.fromDegreesArray([
          -109.0, 30.0,
          -95.0, 30.0,
          -95.0, 40.0,
          -109.0, 40.0
        ]),
        [new Cesium.PolygonHierarchy(
          Cesium.Cartesian3.fromDegreesArray([
            -107.0, 31.0,
            -107.0, 39.0,
            -97.0, 39.0,
            -97.0, 31.0
          ]),
          [new Cesium.PolygonHierarchy(
            Cesium.Cartesian3.fromDegreesArray([
              -105.0, 33.0,
              -99.0, 33.0,
              -99.0, 37.0,
              -105.0, 37.0
            ]),
            [new Cesium.PolygonHierarchy(
              Cesium.Cartesian3.fromDegreesArray([
                -103.0, 34.0,
                -101.0, 34.0,
                -101.0, 36.0,
                -103.0, 36.0
              ])
            )]
          )]
        )]
      )
    });
    var geometry = Cesium.RiverGeometry.createGeometry(polygonWithHole);

    // 3. create extruded polygon
    var extrudedPolygon = new Cesium.RiverGeometry({
      polygonHierarchy : new Cesium.PolygonHierarchy(
        Cesium.Cartesian3.fromDegreesArray([
          -72.0, 40.0,
          -70.0, 35.0,
          -75.0, 30.0,
          -70.0, 30.0,
          -68.0, 40.0
        ])
      ),
      extrudedHeight: 300000
    });
    var geometry = Cesium.RiverGeometry.createGeometry(extrudedPolygon);

### 成员变量

#### # _indices

feat:2106 河流覆盖物类型 传入自定义顶点indices 传入自定义UV坐标

类型: Number

#### # packedLength

The number of elements used to pack the object into an array.

### 方法

#### # static computeRectangle(options, resultopt)

Returns the bounding rectangle given the provided options

#### 参数:

名称 | 类型 | 默认值 | 描述
--- | --- | --- | ---
`options` | Object |  | Object with the following properties:
`polygonHierarchy` | PolygonHierarchy |  | A polygon hierarchy that can include holes.
`granularity` | Number | Cesium.Math.RADIANS_PER_DEGREE | The distance, in radians, between each latitude and longitude. Determines the number of positions sampled.
`arcType` | Cesium.ArcType | Cesium.ArcType.GEODESIC | The type of line the polygon edges must follow. Valid options are `Cesium.ArcType.GEODESIC` and `Cesium.ArcType.RHUMB`.
`ellipsoid` | Cesium.Ellipsoid | Cesium.Ellipsoid.WGS84 | The ellipsoid to be used as a reference.
`result` | Cesium.Rectangle |  | An object in which to store the result.

返回值:

The result rectangle

类型: Cesium.Rectangle

#### # static createGeometry(polygonGeometry)

Computes the geometric representation of a polygon, including its vertices, indices, and a bounding sphere.

#### 参数:

名称 | 类型 | 描述
--- | --- | ---
`polygonGeometry` | RiverGeometry | A description of the polygon.

返回值:

The computed vertices and indices.

类型: Cesium.Geometry | undefined

#### # static fromPositions(options)

A description of a polygon from an array of positions. Polygon geometry can be rendered with both `Primitive` and `GroundPrimitive`.

#### 参数:

名称 | 类型 | 默认值 | 描述
--- | --- | --- | ---
`options` | Object |  | Object with the following properties:
`positions` | Array.<Cesium.Cartesian3> |  | An array of positions that Cesium.defined the corner points of the polygon.
`height` | Number | 0.0 | The height of the polygon.
`extrudedHeight` | Number |  | The height of the polygon extrusion.
`vertexFormat` | Cesium.VertexFormat | Cesium.VertexFormat.DEFAULT | The vertex attributes to be computed.
`indices` | Array.<Number> |  | 自定义顶点索引
`st` | Float32Array |  | 自定义UV坐标
`stRotation` | Number | 0.0 | The rotation of the texture coordinates, in radians. A positive rotation is counter-clockwise.
`ellipsoid` | Cesium.Ellipsoid | Cesium.Ellipsoid.WGS84 | The ellipsoid to be used as a reference.
`granularity` | Number | Cesium.Math.RADIANS_PER_DEGREE | The distance, in radians, between each latitude and longitude. Determines the number of positions in the buffer.
`perPositionHeight` | Boolean | false | Use the height of options.positions for each position instead of using options.height to determine the height.
`closeTop` | Boolean | true | When false, leaves off the top of an extruded polygon open.
`closeBottom` | Boolean | true | When false, leaves off the bottom of an extruded polygon open.
`arcType` | Cesium.ArcType | Cesium.ArcType.GEODESIC | The type of line the polygon edges must follow. Valid options are `Cesium.ArcType.GEODESIC` and `Cesium.ArcType.RHUMB`.

See:
  - RiverGeometry#createGeometry

返回值:
类型: RiverGeometry

##### 示例

    // create a polygon from points
    var polygon = Cesium.RiverGeometry.fromPositions({
      positions : Cesium.Cartesian3.fromDegreesArray([
        -72.0, 40.0,
        -70.0, 35.0,
        -75.0, 30.0,
        -70.0, 30.0,
        -68.0, 40.0
      ])
    });
    var geometry = Cesium.RiverGeometry.createGeometry(polygon);

#### # static pack(value, array, startingIndexopt)

Stores the provided instance into the provided array.

#### 参数:

名称 | 类型 | 默认值 | 描述
--- | --- | --- | ---
`value` | RiverGeometry |  | The value to pack.
`array` | Array.<Number> |  | The array to pack into.
`startingIndex` | Number | 0 | The index into the array at which to start packing the elements.

返回值:

The array that was packed into

类型: Array.<Number>

#### # static unpack(array, startingIndexopt, resultopt)

Retrieves an instance from a packed array.

#### 参数:

名称 | 类型 | 默认值 | 描述
--- | --- | --- | ---
`array` | Array.<Number> |  | The packed array.
`startingIndex` | Number | 0 | The starting index of the element to be unpacked.
`result` | RiverGeometry |  | The object into which to store the result.