Hardware accelerated 2D full featured middleware for all who want to develop commercial quality 2D games rapidly and easily. It covers all imaginable 2D game genres (DirectX)
(pronounced "fulltick") is a cross-platform C++ GUI toolkit for UNIX®/Linux® (X11), Microsoft® Windows®, and MacOS® X. FLTK provides modern GUI functionality without the bloat and supports 3D graphics via OpenGL® and its built-in GLUT emulation.
a free library providing windowing and widgets for graphics APIs / engines where such functionality is not natively available, or severely lacking. The library is object orientated, written in C++.