Allegro library

The Allegro library is a free video game software library, with functions for 2-dimensional imaging, basic audio, input, timers, and fixed-point and floating-point matrix arithmetic. As of version 4.0, programs that use the library work on MS-DOS, Microsoft Windows, BeOS, Mac OS, and various UNIX systems with X Window System, abstracting their application programming interfaces into one portable interface.

The library is written in, and designed to be used with, the C programming language. A sample non-interactive program can be found at Sierpinski triangle/Image credits; a sample interactive program can be found at the allegro home page, listed below. The simple, interactive demo is a basic Asteroids clone with the source open for viewing.

The library comes with full source code and is free software, using a simple permissive license which allows copying, modification and distribution for any purpose. Along with the source code, it comes with countless examples, so that even someone with hardly any video game programming knowledge can study the examples and come up with a simple video game in no time flat.

The community of Allegro users have contributed several library extensions to handle scrolling tile maps, import and export various file formats, and even connect to OpenGL.

Additional Resources

Allegro home page http://alleg.sourceforge.net/
Allegro library extensions, list of games written with Allegro http://www.allegro.cc/