实现了MFC下OpenGL环境的设置，非模式对话框，DEM高程数据读取，鼠标滚轮控制放大缩小-MFC achieved under the OpenGL environment settings, non-modal dialog, DEM elevation data to read, the mouse wheel control the zoom

OPENGL与VC兼容，基于对话框的框架代码，建议初学者下载，简单的绘图代码-OPENGL compatible with VC, dialog-based framework code, it is recommended that beginners download, simple drawing code