GLUT/Tk integrates these two very successful and portable systems: GLUT for portable 3D graphics, and Tcl/Tk for the development of sophisticated GUIs. Although both of these were originally developed under X windows and Unix, they now both offer a Windows version as well.
GLUT/Tk is a "light-weight" system that seeks to leverage GLUT and Tcl/Tk by tying them together in a stylistically consistent way with the addition of only a few commands to each. As a result, developers can code 3D applications, including graphical input, windows, and menus, that will port easily between Unix-based systems and Windows-based systems. Furthermore, there should be at most a negligible performance penalty, since the purely graphical operations are still programmed directly in OpenGL.