用opengl实现bresenham算法画圆，先画1/8个圆，再借助圆的对称性，画出其余部分-Use opengl achieve bresenham algorithm Circle, first draw the 1/8 round, and then with the symmetry of the circle to draw the rest

用opengl实现bresenham算法画椭圆，先画1/4个椭圆，然后借助椭圆的对称性，画出其余部分-Use opengl achieve bresenham algorithm painted oval, first draw 1/4 oval, and then with the symmetry of the ellipse, and draw the rest of the

本程序分为：UDP服务器与UDP客户端。服务器运行在公网上且绑定两个公网IP；客户端运行在本地。 可检测的NAT类型包括： 1. 完全锥形 NAT 2. 限制锥形 NAT 3. 端口限制锥形 NAT 4. 对称 NAT。-This procedure is divided into: UDP server and UDP client. Server in the public network and bind two client running on the local public IP.