这个程序演示了一个三维的天空，放置在一个纹理的观众

代码说明：

This program demonstrates a 3d sky by placing the viewer inside a texture-mapped cube. There s a demo at http://www.coolgroups.com/skycube/. -This program demonstrates a 3d sky by placing the viewer inside a texture-mapped cube. There s a demo at http://www.coolgroups.com/skycube/.