Cesium-Examples/examples/cesiumEx/util.js

var util = {};

util.isNumber = function (obj) {
    return (typeof obj == 'number') && obj.constructor == Number;
}

util.isString = function (str) {
    return (typeof str == 'string') && str.constructor == String;
}

/**
 * @function Util.extend
 * @description 对象拷贝赋值。
 * @param {Object} dest - 目标对象。
 * @param {Object} arguments - 待拷贝的对象。
 * @returns {Object} 赋值后的目标对象。
 */
util.extend = function (dest) {
    for (var index = 0; index < Object.getOwnPropertyNames(arguments).length; index++) {
        var arg = Object.getOwnPropertyNames(arguments)[index];
        if (arg == "caller" || arg == "callee" || arg == "length" || arg == "arguments") {
            continue;
        }
        var obj = arguments[arg];
        if (obj) {
            for (var j = 0; j < Object.getOwnPropertyNames(obj).length; j++) {
                var key = Object.getOwnPropertyNames(obj)[j];
                if (arg == "caller" || arg == "callee" || arg == "length" || arg == "arguments") {
                    continue;
                }
                dest[key] = obj[key];
            }
        }
    }
    return dest;
}

//url参数获取
util.getRequest = function () {
    var url = location.search; //获取url中"?"符后的字串   
    var theRequest = new Object();
    if (url.indexOf("?") != -1) {
        var str = url.substr(1);
        var strs = str.split("&");
        for (var i = 0; i < strs.length; i++) {
            theRequest[strs[i].split("=")[0]] = decodeURI(strs[i].split("=")[1]);
        }
    }
    return theRequest;
}

util.getRequestByName = function (name) {
    var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)", "i");
    var r = window.location.search.substr(1).match(reg);
    if (r != null) return decodeURI(r[2]);
    return null;
}


util.clone = function (obj) {
    if (null == obj || "object" != typeof obj) return obj;

    // Handle Date
    if (obj instanceof Date) {
        var copy = new Date();
        copy.setTime(obj.getTime());
        return copy;
    }

    // Handle Array
    if (obj instanceof Array) {
        var copy = [];
        for (var i = 0, len = obj.length; i < len; ++i) {
            copy[i] = clone(obj[i]);
        }
        return copy;
    }

    // Handle Object
    if (typeof obj === 'object') {
        var copy = {};
        for (var attr in obj) {
            if (attr == "_layer" || attr == "_layers" || attr == "_parent") continue;

            if (obj.hasOwnProperty(attr))
                copy[attr] = clone(obj[attr]);
        }
        return copy;
    }
    return obj;
}


util.isPCBroswer = function () {
    var sUserAgent = navigator.userAgent.toLowerCase();

    var bIsIpad = sUserAgent.match(/ipad/i) == "ipad";
    var bIsIphoneOs = sUserAgent.match(/iphone/i) == "iphone";
    var bIsMidp = sUserAgent.match(/midp/i) == "midp";
    var bIsUc7 = sUserAgent.match(/rv:1.2.3.4/i) == "rv:1.2.3.4";
    var bIsUc = sUserAgent.match(/ucweb/i) == "ucweb";
    var bIsAndroid = sUserAgent.match(/android/i) == "android";
    var bIsCE = sUserAgent.match(/windows ce/i) == "windows ce";
    var bIsWM = sUserAgent.match(/windows mobile/i) == "windows mobile";
    if (bIsIpad || bIsIphoneOs || bIsMidp || bIsUc7 || bIsUc || bIsAndroid || bIsCE || bIsWM) {
        return false;
    } else {
        return true;
    }
}

//检测浏览器webgl支持
util.webglreport = function () {
    var exinfo = getExplorerInfo();
    if (exinfo.type == "IE" && exinfo.version < 11) {
        return false;
    }

    try {
        var glContext;
        var canvas = document.createElement('canvas');
        var requestWebgl2 = (typeof WebGL2RenderingContext !== 'undefined');
        if (requestWebgl2) {
            glContext = canvas.getContext('webgl2') || canvas.getContext('experimental-webgl2') || undefined;
        }
        if (glContext == null) {
            glContext = canvas.getContext('webgl') || canvas.getContext('experimental-webgl') || undefined;
        }
        if (glContext == null) {
            return false;
        }
    } catch (e) {
        return false;
    }
    return true;
}

//计算贴地路线
util.terrainPolyline = function (params) {
    var viewer = params.viewer;
    var positions = params.positions;
    if (positions == null || positions.length == 0) {
        if (params.calback)
            params.calback(positions);
        return;
    }

    var flatPositions = Cesium.PolylinePipeline.generateArc({
        positions: positions,
        granularity: params.granularity || 0.00001
    });


    var cartographicArray = [];
    var ellipsoid = viewer.scene.globe.ellipsoid;
    for (var i = 0; i < flatPositions.length; i += 3) {
        var cartesian = Cesium.Cartesian3.unpack(flatPositions, i);
        cartographicArray.push(ellipsoid.cartesianToCartographic(cartesian));
    }

    //用于缺少地形数据时，赋值的高度
    var tempHeight = Cesium.Cartographic.fromCartesian(positions[0]).height;

    Cesium.when(Cesium.sampleTerrainMostDetailed(viewer.terrainProvider, cartographicArray), function (samples) {
        var noHeight = false;
        var offset = params.offset || 2; //增高高度，便于可视

        for (var i = 0; i < samples.length; ++i) {
            if (samples[i].height == null) {
                noHeight = true;
                samples[i].height = tempHeight;
            } else {
                samples[i].height = offset + (samples[i].height * viewer.scene._terrainExaggeration);
            }
        }

        var raisedPositions = ellipsoid.cartographicArrayToCartesianArray(samples);
        if (params.calback)
            params.calback(raisedPositions, noHeight);
        else if (positions.setValue)
            positions.setValue(raisedPositions);
    });


}

//地形构造
var _ellipsoid = new Cesium.EllipsoidTerrainProvider({
    ellipsoid: Cesium.Ellipsoid.WGS84
});

util.getEllipsoidTerrain = function () {
    return _ellipsoid;
}

util.getTerrainProvider = function (cfg) {
    if (!cfg.hasOwnProperty("requestWaterMask")) cfg.requestWaterMask = true;
    if (!cfg.hasOwnProperty("requestVertexNormals")) cfg.requestVertexNormals = true;

    var terrainProvider;

    if (cfg.url == "" || cfg.url == null || cfg.url == "cesium") {
        terrainProvider = new Cesium.CesiumTerrainProvider({
            url: Cesium.IonResource.fromAssetId(1)
        })
    } else if (cfg.url == "ellipsoid" || cfg.url == "null") {
        terrainProvider = _ellipsoid;
    } else {
        terrainProvider = new Cesium.CesiumTerrainProvider(cfg);
    }
    return terrainProvider;
}

//创建模型
util.createModel = function (cfg, viewer) {
    cfg = viewer.globe.point2map(cfg); //转换坐标系

    var position = Cesium.Cartesian3.fromDegrees(cfg.x, cfg.y, cfg.z || 0);
    var heading = Cesium.Math.toRadians(cfg.heading || 0)
    var pitch = Cesium.Math.toRadians(cfg.pitch || 0)
    var roll = Cesium.Math.toRadians(cfg.roll || 0);
    var hpr = new Cesium.HeadingPitchRoll(heading, pitch, roll);
    var orientation = Cesium.Transforms.headingPitchRollQuaternion(position, hpr);

    var model = viewer.entities.add({
        name: cfg.name || "",
        position: position,
        orientation: orientation,
        model: cfg,
        tooltip: cfg.tooltip,
        popup: cfg.popup,
    });
    return model;
}

util.formatDegree = function (value) {
    value = Math.abs(value);
    var v1 = Math.floor(value); //度  
    var v2 = Math.floor((value - v1) * 60); //分  
    var v3 = Math.round((value - v1) * 3600 % 60); //秒  
    return v1 + '° ' + v2 + '\'  ' + v3 + '"';
};

function getExplorerInfo() {
    var explorer = window.navigator.userAgent.toLowerCase();
    //ie 
    if (explorer.indexOf("msie") >= 0) {
        var ver = Number(explorer.match(/msie ([\d]+)/)[1]);
        return {
            type: "IE",
            version: ver
        };
    }
    //firefox 
    else if (explorer.indexOf("firefox") >= 0) {
        var ver = Number(explorer.match(/firefox\/([\d]+)/)[1]);
        return {
            type: "Firefox",
            version: ver
        };
    }
    //Chrome
    else if (explorer.indexOf("chrome") >= 0) {
        var ver = Number(explorer.match(/chrome\/([\d]+)/)[1]);
        return {
            type: "Chrome",
            version: ver
        };
    }
    //Opera
    else if (explorer.indexOf("opera") >= 0) {
        var ver = Number(explorer.match(/opera.([\d]+)/)[1]);
        return {
            type: "Opera",
            version: ver
        };
    }
    //Safari
    else if (explorer.indexOf("Safari") >= 0) {
        var ver = Number(explorer.match(/version\/([\d]+)/)[1]);
        return {
            type: "Safari",
            version: ver
        };
    }
    return {
        type: explorer,
        version: -1
    };
}
//解决浮点问题
function floatObj() {

    /*
     * 判断obj是否为一个整数
     */
    function isInteger(obj) {
        return Math.floor(obj) === obj
    }

    /*
     * 将一个浮点数转成整数，返回整数和倍数。如 3.14 >> 314，倍数是 100
     * @param floatNum {number} 小数
     * @return {object}
     *   {times:100, num: 314}
     */
    function toInteger(floatNum) {
        var ret = {
            times: 1,
            num: 0
        };
        if (isInteger(floatNum)) {
            ret.num = floatNum;
            return ret
        }
        var strfi = floatNum + '';
        var dotPos = strfi.indexOf('.');
        var len = strfi.substr(dotPos + 1).length;
        var times = Math.pow(10, len);
        var intNum = parseInt(floatNum * times + 0.5, 10);
        ret.times = times;
        ret.num = intNum;
        return ret
    }

    /*
     * 核心方法，实现加减乘除运算，确保不丢失精度
     * 思路：把小数放大为整数（乘），进行算术运算，再缩小为小数（除）
     *
     * @param a {number} 运算数1
     * @param b {number} 运算数2
     * @param op {string} 运算类型，有加减乘除（add/subtract/multiply/divide）
     *
     */
    function operation(a, b, op) {
        var o1 = toInteger(a);
        var o2 = toInteger(b);
        var n1 = o1.num;
        var n2 = o2.num;
        var t1 = o1.times;
        var t2 = o2.times;
        var max = t1 > t2 ? t1 : t2;
        var result = null;
        switch (op) {
            case 'add':
                if (t1 === t2) { // 两个小数位数相同
                    result = n1 + n2
                } else if (t1 > t2) { // o1 小数位 大于 o2
                    result = n1 + n2 * (t1 / t2)
                } else { // o1 小数位 小于 o2
                    result = n1 * (t2 / t1) + n2
                }
                return result / max;
            case 'subtract':
                if (t1 === t2) {
                    result = n1 - n2
                } else if (t1 > t2) {
                    result = n1 - n2 * (t1 / t2)
                } else {
                    result = n1 * (t2 / t1) - n2
                }
                return result / max;
            case 'multiply':
                result = (n1 * n2) / (t1 * t2);
                return result;
            case 'divide':
                result = (n1 / n2) * (t2 / t1);
                return result
        }
    }

    // 加减乘除的四个接口
    function add(a, b) {
        return operation(a, b, 'add')
    }

    function subtract(a, b) {
        return operation(a, b, 'subtract')
    }

    function multiply(a, b) {
        return operation(a, b, 'multiply')
    }

    function divide(a, b) {
        return operation(a, b, 'divide')
    }

    // exports
    return {
        add: add,
        subtract: subtract,
        multiply: multiply,
        divide: divide
    }
};
util.floatObj = floatObj();


//生成多边形范围内随机点polygon：折点集合
util.randomPointsWithinPolygon = function (polygon, num, type) {
    var xmin = 1000000000,
        xmax = -1000000000,
        ymin = 1000000000,
        ymax = -1000000000;
    //获取面的矩形
    for (var i = 0; i < polygon.length; i++) {
        xmin = Math.min(xmin, polygon[i].x);
        xmax = Math.max(xmax, polygon[i].x);
        ymin = Math.min(ymin, polygon[i].y);
        ymax = Math.max(ymax, polygon[i].y);
    }
    var points = [];
    if (type && type == "geojson") {
        points = {
            "type": "FeatureCollection",
            "features": []
        };
    }
    for (var j = 0; j < num; j++) {
        var point = util.randomPointsWithinBbox(xmin, xmax, ymin, ymax, 1)[0];
        if (!util.isDotInPolygon(point, polygon)) {
            j--;
        } else {
            if (type == "geojson") {
                var p = {
                    "type": "Feature",
                    "properties": {
                        "value": parseInt(Math.random() * 10000000)
                    },
                    "geometry": {
                        "type": "Point",
                        "coordinates": [point.x, point.y]
                    }
                }
                points.features.push(p);

            } else {
                points.push(point);
            }
        };
    }
    return points;
}
//生成矩形范围类随机点
util.randomPointsWithinBbox = function (xmin, xmax, ymin, ymax, num, type) {
    if (type && type == "geojson") {
        var points = {
            "type": "FeatureCollection",
            "features": []
        };
        for (var i = 0; i < num; i++) {
            var point = {
                "type": "Feature",
                "properties": {
                    "value": parseInt(Math.random() * 10000000)
                },
                "geometry": {
                    "type": "Point",
                    "coordinates": [(Math.random() * (xmax - xmin) + xmin), (Math.random() * (ymax - ymin) + ymin)]
                }
            }
            points.features.push(point);
        }
        return points;
    } else {
        var points = [];
        for (var i = 0; i < num; i++) {
            var point = {
                x: (Math.random() * (xmax - xmin) + xmin),
                y: (Math.random() * (ymax - ymin) + ymin)
            }
            points.push(point);
        }
        return points;
    }
}
//判断点在多边形上（平面）point:{x,y},polygonPoints:[{x,y},{x,y},{x,y}]
util.isDotInPolygon = function (point, polygonPoints, onborder = true) {
    var flag = false,
        p1,
        p2;
    if (!point.x) {
        point.x = point[0];
        point.y = point[1];
    }
    for (var i = 0, j = polygonPoints.length - 1; i < polygonPoints.length; j = i++) {
        p1 = polygonPoints[i];
        p2 = polygonPoints[j];
        p1 = p1.x ? {
            x: p1.x,
            y: p1.y
        } : {
            x: p1[0],
            y: p1[1]
        };
        p2 = p2.x ? {
            x: p2.x,
            y: p2.y
        } : {
            x: p2[0],
            y: p2[1]
        };
        if (onborder) {
            // 这里判断是否刚好被测点在多边形的边上
            if (util.onSegment(p1, p2, point)) return true;
        }
        if ((p1.y > point.y != p2.y > point.y) && (point.x < (point.y - p1.y) * (p1.x - p2.x) / (p1.y - p2.y) +
                p1.x)) {
            flag = !flag;
        }
    }
    return flag;
}
//判断点在线段上（平面）Pi:{x,y},Pj{x,y},Q{x,y}
util.onSegment = function (Pi, Pj, Q) {
    if ((Q.x - Pi.x) * (Pj.y - Pi.y) == (Pj.x - Pi.x) * (Q.y - Pi.y) //叉乘 
        //保证Q点坐标在pi,pj之间 
        &&
        Math.min(Pi.x, Pj.x) <= Q.x && Q.x <= Math.max(Pi.x, Pj.x) &&
        Math.min(Pi.y, Pj.y) <= Q.y && Q.y <= Math.max(Pi.y, Pj.y))
        return true;
    else
        return false;
}
//获取json文件
util.getJSON = function (url, callback) {
    const xhr = new XMLHttpRequest();
    xhr.responseType = 'json';
    xhr.open('get', url, true);
    xhr.onload = function () {
        if (xhr.status >= 200 && xhr.status < 300) {
            callback(xhr.response);
        } else {
            throw new Error(xhr.statusText);
        }
    };
    xhr.send();
}