更新版本

CSGSubtract.worker.cjs

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+'use strict';
+
+var poly3 = require('@jscad/modeling/src/geometries/poly3');
+var booleans = require('@jscad/modeling/src/operations/booleans');
+
+/**
+ * @param compart true => t2  ,  false => t1
+ * @returns 索引
+ */
+function Max(arr, compart)
+{
+    let best = arr[0];
+    let bestIndex = 0;
+    for (let i = 1; i < arr.length; i++) {
+        let t1 = arr[i];
+        if (compart(best, t1)) {
+            best = t1;
+            bestIndex = i;
+        }
+    }
+    return bestIndex;
+}
+
+/** Epsilon used during determination of near zero distances.
+ * @default
+ */
+const EPS = 5e-2;
+
+// //////////////////////////////
+//   tolerance: The maximum difference for each parameter allowed to be considered a match
+class FuzzyFactory
+{
+    constructor(numdimensions = 3, tolerance = EPS)
+    {
+        this.lookuptable = {};
+        this.multiplier = 1.0 / tolerance;
+    }
+    // let obj = f.lookupOrCreate([el1, el2, el3], function(elements) {/* create the new object */});
+    // Performs a fuzzy lookup of the object with the specified elements.
+    // If found, returns the existing object
+    // If not found, calls the supplied callback function which should create a new object with
+    // the specified properties. This object is inserted in the lookup database.
+    lookupOrCreate(els, object)
+    {
+        let hash = "";
+        let multiplier = this.multiplier;
+        for (let el of els) {
+            let valueQuantized = Math.round(el * multiplier);
+            hash += valueQuantized + "/";
+        }
+        if (hash in this.lookuptable)
+            return this.lookuptable[hash];
+        else {
+            let hashparts = els.map(el =>
+            {
+                let q0 = Math.floor(el * multiplier);
+                let q1 = q0 + 1;
+                return ["" + q0 + "/", "" + q1 + "/"];
+            });
+            let numelements = els.length;
+            let numhashes = 1 << numelements;
+            for (let hashmask = 0; hashmask < numhashes; ++hashmask) {
+                let hashmaskShifted = hashmask;
+                hash = "";
+                hashparts.forEach(hashpart =>
+                {
+                    hash += hashpart[hashmaskShifted & 1];
+                    hashmaskShifted >>= 1;
+                });
+                this.lookuptable[hash] = object;
+            }
+            return object;
+        }
+    }
+}
+
+//并集path2dCsgs 差集 删除小面积结果
+function CSGSubtract(geom, path2dCsgs)
+{
+    let gemUnion = path2dCsgs[0];
+    for (let i = 1; i < path2dCsgs.length; i++)
+        gemUnion = booleans.union(gemUnion, path2dCsgs[i]);
+    let newGeom = booleans.subtract(geom, gemUnion);
+    //删除小面积(只留一个)
+    {
+        let fuzz = new FuzzyFactory;
+        let vmap = new Map;
+        for (let poly of newGeom.polygons) {
+            for (let v of poly.vertices) {
+                let key = fuzz.lookupOrCreate(v, v);
+                let arr = vmap.get(key);
+                if (!arr) {
+                    arr = [];
+                    vmap.set(key, arr);
+                }
+                arr.push(poly);
+                v["__key__"] = key;
+            }
+        }
+        let polys = newGeom.polygons.concat();
+        let polyGroups = [];
+        let calcs = new Set;
+        while (polys.length) {
+            let poly1 = polys.pop();
+            calcs.add(poly1);
+            let polyGroup = [poly1];
+            polyGroups.push(polyGroup);
+            for (let i = 0; i < polyGroup.length; i++) {
+                let poly = polyGroup[i];
+                for (let v of poly.vertices) {
+                    let key = v["__key__"];
+                    let arr = vmap.get(key);
+                    for (let vpoly of arr) {
+                        if (calcs.has(vpoly))
+                            continue;
+                        calcs.add(vpoly);
+                        polyGroup.push(vpoly);
+                    }
+                }
+            }
+            // arrayRemoveIf(polys, poly => !calcs.has(poly)); //加上这个无法提高性能
+        }
+        let areas = polyGroups.map(polys =>
+        {
+            let area = 0;
+            for (let poly of polys)
+                area += poly3.measureArea(poly);
+            return area;
+        });
+        let maxIndex = Max(areas, (t1, t2) => t2 > t1);
+        newGeom.polygons = polyGroups[maxIndex];
+    }
+    return newGeom;
+}
+
+addEventListener("message", e =>
+{
+    const [path2dCsgs, geom] = e.data;
+    try {
+        const newGeom = CSGSubtract(geom, path2dCsgs);
+        postMessage({
+            status: 0,
+            geom: newGeom
+        });
+    }
+    catch (error) {
+        postMessage({
+            status: 1,
+            error
+        });
+    }
+});
+var CSGSubtract_worker = {};
+
+module.exports = CSGSubtract_worker;
+//# sourceMappingURL=CSGSubtract.worker.cjs.map