Mesa3D is a free (
free beer and
free speech) implementation of the
OpenGL API. It has recently been approved by the
ARB as an official
OpenGL implementation after passing the
OpenGL conformance tests. However, its usefulness is in question since
SGI released as
Open Source its
sample implementation. It also included an implementation of the
GLU component.
Still, it was an incredibly useful piece of software and important, especially for the Linux community. It provided a 3D API that continues to live on in various installations, particularly its incorporation into XFree86 4 as part of the DRI. It was written by Brian Paul.