http://www.inforamp.net/~poynton/notes/colour_and_gamma/GammaFAQ.html
+HPCR glClear(GL_COLOR_BUFFER_BIT) dithering
+
+ If you set the MESA_HPCR_CLEAR environment variable then dithering
+ will be used when clearing the color buffer. This is only applicable
+ to HP systems with the HPCR (Color Recovery) system.
+
Extensions:
The following OpenGL GLX extensions are currently implemented:
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-$Id: README.X11,v 3.0 1998/02/14 17:45:13 brianp Exp $
+$Id: README.X11,v 3.1 1998/07/29 01:19:15 brianp Exp $