修复boxcollider碰撞问题

source/src/Utils/RectangleExt.ts

@@ -1,16 +1,7 @@
 class RectangleExt {
     public static union(first: Rectangle, point: Vector2){
         let rect = new Rectangle(point.x, point.y, 0, 0);
-        return this.unionR(first, rect);
-    }
-
-    public static unionR(value1: Rectangle, value2: Rectangle){
-        let result = new Rectangle();
-        result.x = Math.min(value1.x, value2.x);
-        result.y = Math.min(value1.y, value2.y);
-        result.width = Math.max(value1.right, value2.right) - result.x;
-        result.height = Math.max(value1.bottom, value2.bottom) - result.y;
-
-        return result;
+        let rectResult = first.union(rect);
+        return new Rectangle(rectResult.x, rectResult.y, rectResult.width, rectResult.height);
     }
 }