新增polygonmesh

source/src/Utils/Vector2Ext.ts

@@ -0,0 +1,20 @@
+class Vector2Ext {
+    /**
+     * 检查三角形是CCW还是CW
+     * @param a 
+     * @param center 
+     * @param c 
+     */
+    public static isTriangleCCW(a: Vector2, center: Vector2, c: Vector2){
+        return this.cross(Vector2.subtract(center, a), Vector2.subtract(c, center)) < 0;
+    }
+
+    /**
+     * 计算二维伪叉乘点(Perp(u)， v)
+     * @param u 
+     * @param v 
+     */
+    public static cross(u: Vector2, v: Vector2){
+        return u.y * v.x - u.x * v.y;
+    }
+}