The "Grand Unified Toolkit" is a portable, low-level C++ API targeted toward the development of interactive 3D applications. It is based around a comprehensive OpenGL setup API with features like windowed and fullscreen displays, on-the-fly video mode switching, transparent support for 3Dfx standalone cards, and texture and font support. The Toolkit also includes a user input API, access to the system timer, basic 3D math objects, file I/O, and more. Full source code, HTML documentation, and several small sample applications are available.