OpenGL window and compositing manager

 Compiz brings to life a variety of visual effects that make the Linux desktop
 easier to use, more powerful and intuitive, and more accessible for users
 with special needs.
 .
 Compiz combines together a window manager and a composite manager using
 OpenGL for rendering. A "window manager" allows the manipulation of the
 multiple applications and dialog windows that are presented on the screen. A
 "composite manager" allows windows and other graphics to be combined together
 to create composite images. Compiz achieves its stunning effects by doing
 both of these functions.