ahiliation:~$glxinfo
name of display: :0.0
display: :0 screen: 0
direct rendering: Yes
server glx vendor string: NVIDIA Corporation
server glx version string: 1.4
The glxinfo program shows information about the OpenGL and GLX implementations running on a given X display.
http://www.opengl.org/documentation/
http://en.wikipedia.org/wiki/OpenGL