用OpenGL实现中点Bresenham算法画直线与圆，改进Bresenham算法画直线-The midpoint of the Bresenham algorithm for drawing a straight line and circle, using OpenGL to improve the Bresenham algorithm draw a straight line

内含直线生成的dda,中点画线算法及Bresenham算法界面美观方便实用-Contains linear generated dda, dotted line algorithm and Bresenham algorithm interface in beautiful and convenient and practical