用openGL实现的GeomipMapping算法。可以用VC7.1直接编译通过。GeomipMapping算法是在3D游戏引擎中处理地形时应用非常广泛的算法。-achieved using openGL GeomipMapping algorithm. Can be directly translated through VC7.1. GeomipMapping algorithm in three D game engine when processing the terrain is ve