The contents of PLIB are:

• GUI Widgets - A fully portable GUI interface that needs only OpenGL and C++.
• Sound/Music Replay - A fully portable Audio driver suited to C++, GLUT and realtime applications that need low latency.
• Matrix/Vector math - A set of matrix and vector math functions that was specifically written to simplify the writing of efficient OpenGL programs. You need to include this code into any SSG applications.
• Scene Graph - A scene graph library layered on top of OpenGL.
• Joystick - Supports more Joysticks with more axes and buttons than GLUT.
• Fonts/Text - Supports text output in OpenGL using texture mapped fonts. These are much faster to render than GLUT's fonts.
• Utilities - A simple portability library to hide basic operating system incompatibilities. UL is still in very early development.
• Scene Graph Auxiliary - Additional functionality layered onto SSG - not every SSG program will need these but they can perhaps save you some effort.
• C-like Scripting language - an efficient script execution environment that's designed to allow more control of the scripts execution by the application.
• A simple windowing library.

One major feature of PLIB is it's lack of external dependancies. Games can depend solely on PLIB and OpenGL - which make installation very much easier for you end-users.

License: free

Additional System Requirements: OpenGL or Mesa.