Method toShaders

src/common/style/CartoCSS.js:895–997

* @function CartoCSS.prototype.toShaders * @description 将 CartoCSS 规则集转化为着色器。 * @returns {Array} CartoCSS 着色器集。

()

     * @returns {Array} CartoCSS 着色器集。
     */
    toShaders() {
        if (this.ruleSet) {
            var ruleset = this.ruleSet;
            if (ruleset) {
                var defs = ruleset.toList(this.env);
                defs.reverse();

                var shaders = {};
                var keys = [];
                this._toShaders(shaders,keys,defs);

                var ordered_shaders = [];

                var done = {};
                for (var i = 0, len0 = defs.length; i < len0; ++i) {
                    var def = defs[i];
                    var k = def.attachment;
                    var shader = shaders[keys[i]];
                    var shaderArray = [];
                    if (!done[k]) {
                        var j = 0;
                        for (var prop in shader) {
                            if (prop !== 'zoom' && prop !== 'frames' && prop !== "attachment" && prop != "elements") {
                                //对layer-index作特殊处理以实现图层的控制
                                if (prop === "layer-index") {
                                    /*var getLayerIndex = Function("attributes", "zoom", "var _value = null;" + shader[prop].join('\n') + "; return _value; ");*/
                                    var getLayerIndex = function (attributes, zoom) {//NOSONAR
                                        var _value = null;
                                        shader[prop].join('\n');
                                        return _value;
                                    };
                                    var layerIndex = getLayerIndex();
                                    Object.defineProperty(shaderArray, "layerIndex", {
                                        configurable: true,
                                        enumerable: false,
                                        value: layerIndex
                                    });
                                } else {
                                    shaderArray[j++] = function (ops, shaderArray) {//NOSONAR
                                        if (!Array.isArray(ops)) {
                                            return ops;
                                        }
                                        var body = ops.join('\n');
                                        var myKeyword = 'attributes["FEATUREID"]&&attributes["FEATUREID"]';
                                        var index = body.indexOf(myKeyword);
                                        if (index >= 0) {
                                            //对featureID作一些特殊处理，以将featureID提取出来
                                            if (!shaderArray.featureFilter) {
                                                var featureFilterStart = index + myKeyword.length;
                                                var featureFilterEnd = body.indexOf(")", featureFilterStart + 1);
                                                var featureFilterStr = "featureId&&(featureId" + body.substring(featureFilterStart, featureFilterEnd) + ")";
                                                /*var featureFilter = Function("featureId", "if(" + featureFilterStr + "){return true;}return false;");*/
                                                var featureFilter = function (featureId) {
                                                    if (featureFilterStr) {
                                                        return true;
                                                    }
                                                    return false;
                                                }