reat + cesium。 实现 初始化时自动定位，鼠标移动实时展示坐标及视角高度， 淹没分析

只贴实现淹没分析这块的代码。

import styles from './cesium.less';
import React from 'react';
import Cesium from 'cesium/Cesium';

Cesium.BingMapsApi.defaultKey = '必应地图Key.具体请自己申请';

require('cesium/Widgets/widgets.css');

export default class CesiumPage extends React.Component {

  state = {
    log_String: '',
    lat_String: '',
    alti_String: '',
    adapCoordi: [],
    maxHeight: 0,
  }

  componentDidMount() {
   this.initCesium();
  }

  initCesium = () => {
    const url = 'https://dev.virtualearth.net';
    let viewer = new Cesium.Viewer('cesiumContainer', {
      scene3DOnly: true,
      selectionIndicator: false,
      //geocoder: false, //是否显示地名查找控件
      //homeButton: true,
      baseLayerPicker:false, //是否显示图层选择控件
      // navigationHelpButton:false,
      //animation: false, // 是否创建动画小器件，左下角仪表
      //timeline: false, //是否显示时间线控件
      //vrButton: false, //是否展示VR按钮
      //fullscreenButton: true, //右下角全屏按钮
    });
    viewer.cesiumWidget.creditContainer.style.display = 'none';
    //使用必应地图作为底图
    viewer.imageryLayers.addImageryProvider(new Cesium.BingMapsImageryProvider({
      url: url,
      mapStyle: Cesium.BingMapsStyle.AERIAL
    }))
    //增加地形、
    viewer.terrainProvider = new Cesium.CesiumTerrainProvider({
      url: "http://data.marsgis.cn/terrain",//中国地形
      //url: Cesium.IonResource.fromAssetId(1), //世界地形
      requestWaterMask: false, // 增加水文
      requestVertexNormals: false, //增加光线
    })
    //启用深度测试以使地形后的物体被挡住
    viewer.scene.globe.depthTestAgainstTerrain = false;
    //绑定鼠标移动时,实时显示坐标及高度
    this.coordinateShow(viewer);
    /* let initialPosition = new Cesium.Cartesian3.fromDegrees(107.5116,29.4605, 4120);
    let homeCameraView = {destination : initialPosition,};
    viewer.scene.camera.setView(homeCameraView); */
    //设置镜头到具体位置及角度
    this.setPointAdress(viewer);

    this.viewer = viewer;
  }

  //鼠标移动实时显示坐标及视角高度函数
  coordinateShow = (viewer) => {
    let _this = this,
        canvas= viewer.scene.canvas;
    //具体事件的实现
    let ellipsoid=viewer.scene.globe.ellipsoid;
    let handler = new Cesium.ScreenSpaceEventHandler(canvas);
    handler.setInputAction(function(movement){
        //捕获椭球体，将笛卡尔二维平面坐标转为椭球体的笛卡尔三维坐标，返回球体表面的点
        let cartesian=viewer.camera.pickEllipsoid(movement.endPosition, ellipsoid);
          if(cartesian){
              //将笛卡尔三维坐标转为地图坐标（弧度）
              let cartographic=viewer.scene.globe.ellipsoid.cartesianToCartographic(cartesian);
              //将地图坐标（弧度）转为十进制的度数
              let lat_String=Cesium.Math.toDegrees(cartographic.latitude).toFixed(4),
                  log_String=Cesium.Math.toDegrees(cartographic.longitude).toFixed(4),
                  alti_String=(viewer.camera.positionCartographic.height/1000).toFixed(2);
              _this.setState({
                log_String,
                lat_String,
                alti_String
              })
          }
    },Cesium.ScreenSpaceEventType.MOUSE_MOVE);
  }
  //设置视角位置及角度
  setPointAdress = (viewer) => {
    const centerPoint = [107.52, 29.422];
    viewer.camera.flyTo({
      destination :  Cesium.Cartesian3.fromDegrees(...centerPoint, 1500), // 设置位置
      orientation: {
          heading : Cesium.Math.toRadians(-10.0), // 方向
          pitch : Cesium.Math.toRadians(-5.0),// 倾斜角度
          roll : 0, //Cesium.Math.toRadians(-38.0)
      },
      duration:5, // 设置飞行持续时间，默认会根据距离来计算
      complete: function () {
          // 到达位置后执行的回调函数
          console.log('到达目的地');
      },
      cancle: function () {
          // 如果取消飞行则会调用此函数
          console.log('飞行取消')
      },
      pitchAdjustHeight: -90, // 如果摄像机飞越高于该值，则调整俯仰俯仰的俯仰角度，并将地球保持在视口中。
      maximumHeight:5000, // 相机最大飞行高度
      flyOverLongitude: 100, // 如果到达目的地有2种方式，设置具体值后会强制选择方向飞过这个经度
    });
  }

  setIf = () => {
    let _this = this;
    _this.drawPolygon((positions) => {
      let wgs84_positions = [],
          areaAdapCoordi = [],
          maxHeight = 0;
      for(var i=0; i<positions.length; i++){
          var wgs84_point = _this.Cartesian3_to_WGS84({
              x: positions[i].x,
              y: positions[i].y,
              z: positions[i].z
          });
          wgs84_positions.push(wgs84_point);
      }
      //获取鼠标点击的位置高度貌似有问题，为了呈现水的高度，所以手动调增*300米。
      maxHeight = Math.max(...wgs84_positions.map(item => item.alt * 300));
      wgs84_positions.map(item => [item.lng, item.lat, item.alt]).map(item => item.forEach(e => areaAdapCoordi.push(e)));
      this.setState({
        adapCoordi: areaAdapCoordi,//设置选取位置的坐标
        maxHeight: maxHeight // 设置最高高度，即水漫到多高
      })
    });
  }

  //画面
  drawPolygon = (callback) => {
    var _this = this;
    var PolygonPrimitive = (function () {
        function _(positions) {
            this.options = {
                id:'drawPolygonforwater',
                name: '多边形',
                polygon: {
                    hierarchy: [],
                    perPositionHeight: true,
                    material: Cesium.Color.RED.withAlpha(0.5),
                    outline : true,
                    outlineColor : Cesium.Color.WHITE,
                    outlineWidth : 4,
                }
            };
            this.hierarchy = positions;
            this._init();
        }

        _.prototype._init = function () {
            var _self = this;
            var _update = function () {
                return _self.hierarchy;
            };
            //实时更新polygon.hierarchy
            this.options.polygon.hierarchy = new Cesium.CallbackProperty(_update, false);
            _this.viewer.entities.add(this.options);
        };
        return _;
    })();

    var handler = new Cesium.ScreenSpaceEventHandler(_this.viewer.scene.canvas);
    var positions = [];
    var poly = undefined;

    //鼠标单击画点
    handler.setInputAction(function (movement) {
        let cartesian=_this.viewer.scene.camera.pickEllipsoid(movement.position, _this.viewer.scene.globe.ellipsoid);
        if (positions.length === 0) {
            positions.push(cartesian.clone());
        }
        positions.push(cartesian);
    }, Cesium.ScreenSpaceEventType.LEFT_CLICK);
    //鼠标移动
    handler.setInputAction(function (movement) {
        var cartesian = _this.viewer.scene.camera.pickEllipsoid(movement.endPosition, _this.viewer.scene.globe.ellipsoid);
        if (positions.length >= 2) {
            if (!Cesium.defined(poly)) {
                poly = new PolygonPrimitive(positions);
            } else {
                if(cartesian !== undefined){
                      positions.pop();
                      cartesian.y += (1 + Math.random());
                      positions.push(cartesian);
                }
            }
        }
    }, Cesium.ScreenSpaceEventType.MOUSE_MOVE);
    //鼠标右键单击结束绘制
    handler.setInputAction(function (movement) {
        handler.destroy();
        callback(positions);
    }, Cesium.ScreenSpaceEventType.RIGHT_CLICK);
  }

  //笛卡尔坐标系转WGS84坐标系
  Cartesian3_to_WGS84 = (point) =>  {
      let cartesian33 = new Cesium.Cartesian3(point.x, point.y, point.z),
          cartographic = Cesium.Cartographic.fromCartesian(cartesian33),
          lat = Cesium.Math.toDegrees(cartographic.latitude),
          lng = Cesium.Math.toDegrees(cartographic.longitude),
          alt = cartographic.height;
      return {lat: lat, lng: lng, alt: alt};
   }

   _drawWater = () => {
    const { maxHeight } = this.state;
    const targetHeight = maxHeight;
    let _this = this;
    //移除选取的多边形
    _this.viewer.entities.removeById('drawPolygonforwater');
    //将全局的 地形设置改为地形遮挡，这样山体可将水漫立方体挡住
    _this.viewer.scene.globe.depthTestAgainstTerrain = !0;
    const { adapCoordi } = this.state;
    this.viewer.entities.removeById('polygonforwaterYanmo');
    let WaterPolygonPrimitive = (function () {
        function _(height) {
            this.options = {
                id:'polygonforwaterYanmo',
                name: '水文立方体',
                polygon: {
                  hierarchy: Cesium.Cartesian3.fromDegreesArrayHeights(adapCoordi),
                  material: Cesium.Color.CORNFLOWERBLUE.withAlpha(0.8),
                  perPositionHeight: true,
                  extrudedHeight: 0,
                }
            };
            this.extrudedHeight = height;
            this._init();
        }

        _.prototype._init = function () {
            var _self = this;
            var _update = function () {
              return _self.extrudedHeight;
            };
            //实时更新polygon.extrudedHeight
            this.options.polygon.extrudedHeight = new Cesium.CallbackProperty(_update, false);
            _this.viewer.entities.add(this.options);
        };
        return _;
    })();
    let height = 0,
        warterEn = new WaterPolygonPrimitive(height),
        waterHeight = 0;
    this.timer = setInterval(() => {
      if (waterHeight < targetHeight) {
        waterHeight += 2
        if (waterHeight > targetHeight) {
          waterHeight = targetHeight
        }
        warterEn.extrudedHeight = waterHeight;
      }
    }, 100);
    }

  render() {
    const { log_String, lat_String, alti_String } = this.state;
    return (<div className={styles.cesium}>
      <button onClick={() => this.setIf()}>绘制区域</button>
      <button style={{marginLeft: 8}} onClick={() => this._drawWater()}>开始分析</button>
      <div id="cesiumContainer" className={styles.cesiumContainer}>
        <div className={styles.latlng_show}>
          <div className={styles.latlng_show_log}>
              <font size="3" color="white">经度：<span>{log_String}</span></font>
          </div>
          <div className={styles.latlng_show_lat}>
              <font size="3" color="white">纬度：<span>{lat_String}</span></font>
          </div>
          <div className={styles.latlng_show_alt}>
              <font size="3" color="white">视角高：<span>{alti_String}</span>km</font>
          </div>
        </div>
      </div>
    </div>);
  }
}