Add BoundBox2d BoundBox2d BoundBox2d Contains Contains GetCenter Height Intersect Intersect Intersect IsEqual IsValid MaxX MaxY MinX MinY operator= operator== SetVoid Width

BoundBox2d() [1/3] BoundBox2d ( ) 默认构造函数 初始化一个默认的二维包围盒，最小和最大坐标均设置为无效值。