这个文档介绍了glut的各种函数，包括初始化，窗口管理，事件处理，菜单管理，注册回调，色彩管理，状态检索，字体渲染，实体绘制以及各种实例的代码-This document describes the glut of various functions, including initialization, window management, event handling, menu management, register callback, color management, state retrieval, font rendering, physical mapping as well as various examples of code