曲线组求交

src/Geometry/CurveIntersection.ts

@@ -0,0 +1,72 @@
+import { Box3, Vector3 } from "three";
+import { Curve } from "../DatabaseServices/Curve";
+import { IntersectOption } from "../GraphicsSystem/IntersectWith";
+
+/**
+ * 
+ * 简化优化版本的曲线求交, 优化版本可以参考(算法导论33.2 确定任意一对线段是否相交 p599)
+ * 
+ * @class CurveIntersection
+ */
+class CurveIntersection
+{
+    //用来缓存的曲线包围盒
+    private boxMap: Map<Curve, Box3> = new Map();
+
+    /**
+     * 交点数据集,key 为曲线 value 为和它相交的(曲线和交点的Map)
+     * 
+     * @type {Map<Curve, Map<Curve, Vector3[]>>}
+     * @memberof CurveIntersection
+     */
+    intersect: Map<Curve, Map<Curve, Vector3[]>> = new Map();
+    constructor(cus: Curve[])
+    {
+        cus.forEach(c =>
+        {
+            this.boxMap.set(c, c.BoundingBox);
+        });
+
+        //按x排序
+        cus.sort((c1, c2) =>
+        {
+            return this.boxMap.get(c1).min.x - this.boxMap.get(c2).min.x;
+        });
+
+        let count = cus.length;
+        for (let i = 0; i < count; i++)
+        {
+            let c1 = cus[i];
+            let c1d = this.GetIntersect(c1);
+
+            let c1b = this.boxMap.get(c1);
+            for (let j = i + 1; j < count; j++)
+            {
+                let c2 = cus[j];
+
+                //过滤掉不需要计算的曲线
+                let c2b = this.boxMap.get(c2);
+                if (c2b.min.x > c1b.max.x)
+                    break;
+                if (c2b.min.y > c1b.max.y)
+                    continue;
+
+                let pts = c1.IntersectWith(c2, IntersectOption.OnBothOperands);
+                if (pts.length > 0)
+                {
+                    c1d.set(c2, pts);
+                    this.GetIntersect(c2).set(c1, pts);
+                }
+            }
+        }
+    }
+    GetIntersect(cu: Curve): Map<Curve, Vector3[]>
+    {
+        if (this.intersect.has(cu))
+            return this.intersect.get(cu);
+
+        let m = new Map();
+        this.intersect.set(cu, m);
+        return m;
+    }
+}