[comp.graphics] 3D rotation

sutherla@qtp.ufl.edu (scott sutherland) (10/13/89)

	I am no graphics programming expert (but I play one in my
dreams. ;^)) but I have been reading comp.graphics for a
year or so. I seem to recall that a similar series of articles
appeared some months ago. I am going on vague memory here, but
the consensus for the fastest (or one of the fastest) ways to
do rotation was something called the CORDIC algorithm (I think). 
Does anyone recall this series of articles? Would this apply to
the question currently under discussion? 

	I hope this is of some help.

Scott Sutherland
sutherla@qtp.ufl.edu


P.S. I am NOT looking to do this myself, so please do not respond via 
email to me about this topic. I am simply trying to help out the 
person who originally posted this question.
This time around, that is.  :)

turk@Apple.COM (Ken "Turk" Turkowski) (10/17/89)

In article <710@orange9.qtp.ufl.edu> sutherla@qtp.ufl.edu (scott sutherland) writes:
>the consensus for the fastest (or one of the fastest) ways to
>do rotation was something called the CORDIC algorithm (I think). 

CORDIC iterations give you one bit of precision each time through the loop.
Such linear convergence can be faster than other methods if multiplications
are slower than additions, which is less true of modern signal processors
that it was of PDP-11's.
-- 
Ken Turkowski @ Apple Computer, Inc., Cupertino, CA
Internet: turk@apple.com
Applelink: TURKOWSKI1
UUCP: sun!apple!turk