基于C++，通过读取DEM文件（本文件中自带有DEM文件和相关纹理），采用OpenGL渲染出三维地形。下载之后使用方法可看说明，也可以阅读源码进行学习(Based on C++, by reading the DEM file (the file comes with DEM files and related textures), using OpenGL rendering of three-dimensional terrain. After downloading, you can us