1. Mesa/XFree86 off-screen rendering library Mesa is a 3D graphics library which presents an API intended to be compatible with OpenGL. XFree86 maintains its own version of the Mesa library (which is regularly resynchronized with the official one) to permit development of the XFree86 X server's Direct Rendering Infrastructure (DRI), which makes the 3D acceleration features of many modern video cards available to X client programmers. The off-screen rendering library (OSMesa) is an extension to Mesa, not an implementation of any OpenGL standard; therefore, it is packaged separately, so that any OpenGL-conformant library may be installed on a Debian system, and OpenGL-based programs may depend on any of them. The OSMesa library, however, specifically depends on the Mesa library. From Debian 3.0r0 APT