http://www.keithlantz.net/2011/10/rendering-a-skybox-using-a-cube-map-with-opengl-and-glsl/
http://ogldev.atspace.co.uk/www/tutorial25/tutorial25.html
http://blog.csdn.net/huangzhipeng/article/details/7957233
http://www.humus.name/index.php?page=Textures
原文：http://www.cnblogs.com/lilei9110/p/3515892.html