Path: chuka.playstation.co.uk!scea!peter_alau@playstation.sony.com
From: jamin1@psu.edu (Jamin Frederick)
Newsgroups: scee.yaroze.programming.3d_graphics
Subject: Re: RotMatrixBUG????
Date: Thu, 09 Jul 1998 02:32:33 GMT
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I'm still a little confused.  Why do all the matrix multiplication
correcting with the "incremental" approach (what Peter was talking
about) when you can just store the current rotation vector (where
(a,b,c) represents the model a, b,and c degrees from its local x, y,
and z axes respectively thus far) and make a "consummate" matrix from
the (a,b,c) vector and RotMatrix, which gets put in the
GsCOORDINATE2.coord matrix -- resulting in the proper orientation of
the model (since the model is in the original orientation if the coord
matrix is the identity matrix, and changing the coord matrix into a
different matrix effectively changes its orientation)?  

Now what do I have to do if I have a button for each rotation
direction, positive and negative around each axis, and i want to
rotate the object arbitrarily without using the "incremental" method?
Apparently I can't just increment/decrement the numbers in the (a,b,c)
vector when I push the corresponding buttons.  What else has to be
done?  Where do I have to worry about order of rotations? Sorry if I'm
asking the same questions!


Jamin