JT-CIM-SDK/packages/Widgets/SpatialAnalysis/HeightLimit.js

/* 引入Cesium */
// import * as Cesium from 'Cesium';

/* 引入算法 */
import * as turf from "@turf/turf";

/**
 * 限高分析
 */
class HeightLimit {
	/**
	 * 默认初始化
	 * @param {Object} viewer 三维场景
	 */
	constructor(viewer) {
		if (!viewer) throw new Cesium.DeveloperError('no viewer object!');
		this._viewer = viewer;

		this.targetY = 0;
	}

	/**
	 * 这里主要是为了添加一个高出地面的 polygon , 用到的经纬度数据和需要校验的建筑物数据一样
	 * @ignore 忽略注释，注释不生成Doc
	 * @param {Object} options
	 */
	_setPolygon(options) {
		let _self = this;
		_self.HiePolygon = _self._viewer.entities.add({
			polygon: {
				hierarchy: new Cesium.PolygonHierarchy(_self.data),
				material: _self._handleColor('#FFF8DC', options.alpha),
				height: new Cesium.CallbackProperty(_self._createPolygonUpdateFunction(), false),
				perPositionHeight: false,
				outline: true,
				outlineColor: _self._handleColor('red', options.alpha),
				outlineWidth: 1.0,
			}
		});
	}

	/**
	 * @ignore 忽略注释，注释不生成Doc
	 */
	_createPolygonUpdateFunction() {
		let _self = this;
		return function() {
			return _self.targetY;
		};
	}

	/**
	 * @ignore 忽略注释，注释不生成Doc
	 * @param {Object} color
	 * @param {Object} alpha
	 */
	_handleColor(color, alpha) {
		return Cesium.Color.fromCssColorString(color).withAlpha(alpha || 1);
	}

	/**
	 * @ignore 忽略注释，注释不生成Doc
	 * 获取最小高度
	 */
	_getMinHeight(points) {
		let height = 0;
		let positions = points.map(point => {
			let _height = point[2] || 0;
			height = _height;
			if (_height < height) {
				height = _height;
			}
		});
		return height;
	}
}

/**
 * 通用对外公开函数 
 */
Object.assign(HeightLimit.prototype, /** @lends HeightLimit.prototype */ {
	/**
	 * 绘制限高区域
	 */
	addPrimitive(points, options) {

		this.removePrimitive();

		options = options || {};
		options.height = Cesium.defaultValue(options.height, 50);

		//图上选点获取最小高度
		options.baseHeight = Cesium.defaultValue(options.baseHeight, 50);
		// //根据坐标获取最小高度
		// options.baseHeight = this._getMinHeight(points);

		options.color = Cesium.defaultValue(options.color, 'red');
		options.alpha = Cesium.defaultValue(options.alpha, 0.6);

		/* 转换坐标 */
		let positions = points.map(point => {
			return Cesium.Cartesian3.fromDegrees(point[0], point[1], point[2] || 0);
		});

		let _self = this;
		_self.data = positions;
		_self.baseHeight = options.baseHeight;
		_self.targetY = options.baseHeight + options.height;

		let polygonInstance = new Cesium.GeometryInstance({
			geometry: new Cesium.PolygonGeometry({
				polygonHierarchy: new Cesium.PolygonHierarchy(_self.data),
				height: _self.baseHeight, //分层底部海拔
				extrudedHeight: _self.baseHeight + 3000, //分层顶部海拔
			}),
			attributes: {
				color: Cesium.ColorGeometryInstanceAttribute.fromColor(
					Cesium.Color.fromCssColorString(options.color).withAlpha(options.alpha)
				), //设置高亮颜色
				show: new Cesium.ShowGeometryInstanceAttribute(true), //设置初始化后是否显示
			}
		});

		_self.limitHeightPrimitive = _self._viewer.scene.primitives.add(
			new Cesium.ClassificationPrimitive({ //ClassificationPrimitive 用来生成可以穿透
				geometryInstances: polygonInstance,
				releaseGeometryInstances: false,
				classificationType: Cesium.ClassificationType.CESIUM_3D_TILE, //只绘制在3dtiles上
			})
		);

		// 这里主要是为了添加一个高出地面的 polygon , 用到的经纬度数据和需要校验的建筑物数据一样
		_self._setPolygon(options)
	},

	/**
	 * 移除限高分析
	 */
	removePrimitive() {
		if (this.HiePolygon) {
			this._viewer.entities.remove(this.HiePolygon); //移除图层
		}
		if (this.limitHeightPrimitive) {
			this._viewer.scene.primitives.remove(this.limitHeightPrimitive); //移除图层
		}
	},

	/**
	 * 高度变化 
	 * @param {Object} height
	 */
	changeHeight(height) {

		if (!this.limitHeightPrimitive) return;

		// this._height = height - this.baseHeight;
		this.targetY = this.baseHeight + height;

		let cartographic = Cesium.Cartographic.fromCartesian(this.limitHeightPrimitive._primitive._boundingSpheres[0].center);
		let surface = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, this.baseHeight);
		let offset = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, this.baseHeight + height);
		let translation = Cesium.Cartesian3.subtract(offset, surface, new Cesium.Cartesian3());
		this.limitHeightPrimitive._primitive.modelMatrix = Cesium.Matrix4.fromTranslation(translation);
	},
});

export default HeightLimit;