free implementation of the OpenGL API -- DRI modules

 This version of Mesa provides GLX and DRI capabilities: it is capable of
 both direct and indirect rendering. For direct rendering, it can use DRI
 modules from the libgl1-mesa-dri package to accelerate drawing.
 .
 This package does not include the OpenGL library itself, only the DRI
 modules for accelerating direct rendering.
 .
 For a complete description of Mesa, please look at the
 libglx-mesa0 package.