OpenGL Utility Toolkit


 * This article is about the OpenGL toolkit. GLUT can also stand for glucose transporter.

The OpenGL Utility Toolkit (GLUT) is a library of utilities for OpenGL programs, which primarily perform system-level I/O with the host operating system. Functions performed include window definition, window control, and monitoring of keyboard and mouse input. Routines for drawing a number of geometric primitives (both in solid and wireframe mode) are also provided, including cubes, spheres, and the Utah teapot. GLUT even has some limited support for creating pop-up windows.

GLUT was written by Mark J. Kilgard, author of OpenGL Programming for the X Window System and The CG Tutorial: The Definitive Guide to Programmable Real-Time Graphics while he was working for Silicon Graphics Inc.

The two aims of GLUT are to allow the creation of rather portable code between operating systems (GLUT is cross-platform) and to make learning OpenGL easier. Getting started with OpenGL programming while using GLUT often takes only a few lines of code and requires no knowledge of operating system–specific windowing APIs.

All GLUT functions start with the  prefix (for example,   rerenders the current screen).

Freeglut and its spin-off, OpenGLUT, are open source alternatives to GLUT. Freeglut attempts to be a fairly exact clone, OpenGLUT adds a number of new features to the API. Both have the advantage of licensing that permits users to modify and redistribute the library.