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Mail Archives: djgpp/1997/03/29/23:13:39

From: Tudor <tudor AT cam DOT org>
Newsgroups: comp.os.msdos.djgpp
Subject: rotation Q:
Date: Sat, 29 Mar 1997 20:54:31 -0800
Organization: Communications Accesibles Montreal
Lines: 25
Message-ID: <333DF207.8B3@cam.org>
Reply-To: tudor AT cam DOT org
NNTP-Posting-Host: dynamicppp-232.hip.cam.org
Mime-Version: 1.0
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

I got the grip on basic 3D in Allegro and now I wanna move on to more
serious stuff.
I have this Q: How can I do rotations however I want?
Like ,when I rotate a cube(classic :) I have no ideea after what point
the cube gets rotated(probably the origin).
Let's say you have a stick and the points A and B are its extremities:
(C is just another point)

 A ----------- B     C  :)

Now you can rotate the stick by the middle and A and B will move in
opposite directions. You can rotate it after C so A and B will move in
the same direction. Or you can take any other point to rotate your
stuff. (the example is stupid but at least it explains what I want)
How can I do something like this in Allegro?
I know about rotations after a vector but if all the vectors have the
origin in thecenter of the screen that doesn't help me very much (At
least I don't think it does..)
Anyone?
TIA,

-- 
tudor 'at' cam 'dot' org
http://www.cam.org/~tudor
'This is Scott Nudds of the Borg. C is irrelevant.'

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