Path: utzoo!utgpu!watmath!clyde!att!ucbvax!ucsfcgl!pixar!efo
From: efo@pixar.uucp (efo)
Newsgroups: comp.graphics
Subject: Re: 3D Pixel Transforms
Keywords: Pixel arrays, 3D transformations
Message-ID: <2901@pixar.UUCP>
Date: 10 Jan 89 21:42:42 GMT
References: <17963@dhw68k.cts.com>
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Reply-To: efo@pixar.uucp (efo)
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Organization: Pixar -- Marin County, California
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In article <17963@dhw68k.cts.com> stein@dhw68k.cts.com (Rick Stein) writes:
>
>I'm curious to know about how one performs rotations on pixel
>data.
>Any suggestions/references for pixel manipulations (ala Pixar)?

Yes.  The seminal paper on this topic is:
	E. Catmull and A. R. Smith,
	"3-D Transformations of Images in Scanline Order,"
	Computer Graphics 14(3) (SIGGRAPH '80 Proceedings)
	July 1980, pp 278-285

And the other answer is, yes, you can decompose a rotation into shears
which can be done quite cheaply; see the above.


Eben Ostby
Pixar