GLUT is the OpenGL Utility Toolkit, a window system independent toolkit for writing OpenGL programs. It implements a simple windowing application programming interface (API) for OpenGL. GLUT makes it considerably easier to learn about and explore OpenGL programming. GLUT provides a portable API so you can write a single OpenGL program that works across all PC and workstation OS platforms. GLUT is designed for constructing small to medium sized OpenGL programs. While GLUT is well-suited to learning OpenGL and developing simple OpenGL applications, GLUT is not a full-featured toolkit so large applications requiring sophisticated user interfaces are better off using native window system toolkits.
FreeGLUT
The OpenGL programming world owes a tremendous debt to Mr. Mark J. Kilgard for writing the OpenGL Utility Toolkit, or GLUT. The GLUT library of functions allows an application programmer to create, control, and manipulate windows independent of what operating system the program is running on. By hiding the dependency on the operating system from the application programmer, he allowed people to write truly portable OpenGL applications.
FreeGLUT VS GLUT
FreeGLUT is better than GLUT. As it was the better version of GLUT. FreeGLUT have more functions and new function.FreeGLUT is the replacement of GLUT. It have few differences in it.