@vtx/cs-map/lib/_util/parabola.js

React components for Vortex

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports["default"] = void 0;
var _cesium = require("cesium");
/**
 * @description: 抛物线构造函数（方程 y=-(4h/L^2)*x^2+h h:顶点高度 L：横纵间距较大者）
 * @param {*} startPosition: 起点
 * @param {*} endPosition: 终点
 * @param {*} height: 高度
 * @param {*} count: 数量
 * @return {*}
 */
var parabola = function parabola(_ref) {
  var startPosition = _ref.startPosition,
    endPosition = _ref.endPosition,
    _ref$height = _ref.height,
    height = _ref$height === void 0 ? 0 : _ref$height,
    _ref$count = _ref.count,
    count = _ref$count === void 0 ? 50 : _ref$count;
  if (!height) {
    return [new _cesium.Cartesian3.fromDegrees(startPosition[0], startPosition[1], startPosition[2] || 0), new _cesium.Cartesian3.fromDegrees(endPosition[0], endPosition[1], endPosition[2] || 0)];
  }
  var minHeight = startPosition[2] || endPosition[2] || 0;
  var result = [];
  height = Math.max(+height, 100);
  count = Math.max(+count, 50);
  var diffLon = Math.abs(startPosition[0] - endPosition[0]);
  var diffLat = Math.abs(startPosition[1] - endPosition[1]);
  var L = Math.max(diffLon, diffLat);
  var dlt = L / count;
  if (diffLon > diffLat) {
    //base on lon
    var delLat = (endPosition[1] - startPosition[1]) / count;
    if (startPosition[0] - endPosition[0] > 0) {
      dlt = -dlt;
    }
    for (var i = 0; i < count; i++) {
      var h = height - Math.pow(-0.5 * L + Math.abs(dlt) * i, 2) * 4 * height / Math.pow(L, 2);
      var lon = startPosition[0] + dlt * i;
      var lat = startPosition[1] + delLat * i;
      var point = new _cesium.Cartesian3.fromDegrees(lon, lat, h + minHeight);
      result.push(point);
    }
  } else {
    //base on lat
    var delLon = (endPosition[0] - startPosition[0]) / count;
    if (startPosition[1] - endPosition[1] > 0) {
      dlt = -dlt;
    }
    for (var _i = 0; _i < count; _i++) {
      var _h = height - Math.pow(-0.5 * L + Math.abs(dlt) * _i, 2) * 4 * height / Math.pow(L, 2);
      var _lon = startPosition[0] + delLon * _i;
      var _lat = startPosition[1] + dlt * _i;
      var _point = new _cesium.Cartesian3.fromDegrees(_lon, _lat, _h + minHeight);
      result.push(_point);
    }
  }
  result.push(new _cesium.Cartesian3.fromDegrees(endPosition[0], endPosition[1], endPosition[2] || 0));
  return result;
};
var _default = exports["default"] = parabola;
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