C code from the article
"Direct Outcode Calculation for Faster Clip Testing"
by Walt Donovan and Tim Van Hook,
(donovan@eng.sun.com, tvh@sgi.com)
in "Graphics Gems IV", Academic Press, 1994


The files outcode2.c and outcode4.c are C code fragments for 2D and
4D outcode calculation that were extracted from the paper, which you
can insert in your own code.


The following test programs demonstrate the performance gains from using the
direct outcode method. 

For a SuperSparc (SS10), we get the following figures:

xcc2d1:	~27 clocks	(would be faster with overlap)
xcc2d2:	~40 clocks	

xcc4d1:	~54 clocks	(the paper says 50, but that's with a
				more tightly written version than here)
xcc4d2:	~94 clocks	(ditto)

All of the routines were run several times, and the lowest figure
reported.

						-- walt donovan
						donovan@eng.sun.com
