OpenGL Utility Toolkit - Limitations

Limitations

Some of GLUT's original design decisions made it hard for programmers to perform desired tasks. This led many to create non-canon patches and extensions to GLUT. Some free software or open source reimplementations also include fixes.

Some of the more notable limitations of the original GLUT library include:

• The library requires programmers to call glutMainLoop, a function which never returns. This makes it hard for programmers to integrate GLUT into a program or library which wishes to have control of its own event loop. A common patch to fix this is to introduce a new function, called glutCheckLoop (Mac OS X) or glutMainLoopEvent (freeglut/OpenGLUT), which runs only a single iteration of the GLUT event loop. Another common workaround is to run GLUT's event loop in a separate thread, although this may vary by operating system, and also may introduce synchronization issues or other problems: for example, the Mac OS X GLUT implementation requires that glutMainLoop be run in the main thread.
• The fact that glutMainLoop never returns also means that a GLUT program cannot exit the event loop. freeglut fixes this by introducing a new function, glutLeaveMainLoop.
• The library terminates the process when the window is closed; for some applications this may not be desired. Thus, many implementations include an extra callback, such as glutWMCloseFunc.

Since it is no longer maintained (essentially replaced by the open source freeglut) the above design issues are still not resolved in the original GLUT.