Alejandro Saez (cano++at++krusty.engr.sgi.com)
Mon, 30 Jun 1997 20:13:18 -0400
Mmmh, about the math I would have to check, (you don't really need it anyways,
read on), but about the book go fo the source of it all, Foley, Van Dam and ...
(I never remeber the third author). Other way to go about this is to forget
Euler angles and go for Quaternions, check Angus's pages on the Aqua demo for
an explanation, this is sometimes a much intuitive approach. I guess what you
are looking for is direction vectors, so you should ask yourself which axis is
forward (this differs in, say, OpenGl and Performer) and then look for its
corresponding direction vector in the transformation matrix. That vector will
be a unit vector pointing in the direction of the now transformed "forward"
axis.
In Paradigm's Vega that vector is the second row (Mat[1][0], Mat[1][1],
Mat[1][2]), but I can't remember if Vega also uses x -> -y as Performer.
--
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Alejandro Saez
Software Engineer
Silicon Chile S.A.
Avda. Santa Maria 2560
E-mail: asaez++at++silicon.cl Providencia
Phone: +56 (2) 203 3371 Santiago
Fax: +56 (2) 203 3370 Chile
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