一个三维的饼图，可以用来统计显示，可以旋转看效果-A three-dimensional pie chart that can be used to statistics, can be rotated by the effect

C# OpenGL 三维立体图绘制 源码 用C#实现调用opengl实现三维图的绘制。-OpenGL C# three-dimensional mapping of the source code using C# to achieve call OpenGL to achieve three-dimensional drawing.