OpenGL Utility Toolkit

 GLUT is a window system independent toolkit for writing OpenGL programs,
 implementing a simple windowing API, which makes learning about and
 exploring OpenGL programming very easy.
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 GLUT is designed for constructing small to medium sized OpenGL programs,
 however it is not a full-featured toolkit, so large applications requiring
 sophisticated user interfaces are better off using native window system
 toolkits like GTK+ or Motif.