Angel uses:

• OpenGL for rendering
• FMOD or OpenAL/Vorbis for audio (earlier versions used DirectSound)
• Box2D for physics
• FreeType2 and FTGL for text rendering
• DevIL or libpng for image loading (earlier versions used FreeImage)
• GLFW for windowing and input (earlier versions used FreeGLUT)
• Lua for scripting (earlier versions used Python)
• SWIG to bind the engine to Lua

We developed Angel primarily on and for Windows XP, but it's proven to be fairly portable (thanks to the portability of our supporting libraries). We use Microsoft Visual Studio 2008 for coding, debugging, etc., and Adobe Photoshop for graphics work. Source control was handled with Subversion, and most developers used TortoiseSVN for graphical access.

HTML and PDF documentation is generated by doxygen.

The bulk of Angel was developed over the course of a few months, from January 2008 to April 2008. Since then, development has continued, but at a slower pace. Prior to moving to Google Code Hosting, a Trac server was used internally to manage development tasks.