From: Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: The Allegro get_camera_matrix_f 'aspect' variable
Date: Sun, 15 Jun 1997 17:37:43 +0100
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Thomas Harte writes:
>       Basically, I guess my question is - am I supposed to presume square
>pixels, or 4:3 ratio pixels when I calculate this value? Or can someone just
>give me a simple formula which does what I want? I tried one in 320x200 mode,
>and this definitely wasn't right, but then it doesn't appear correct within the
>ex25 demo when it is set to 1 with the 4:3 ratio window (ie 320x240). I 

Allegro adjusts for the 4:3 proportions of a standard monitor display,
so given a square pixel mode like 320x240, 640x480, 600x600, etc, you
can just pass an aspect of 1. For other modes, assuming you are drawing
onto the entire area of the screen, use (SCREEN_W*3)/(SCREEN_H*4). 


--
Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
Beauty is a French phonetic corruption of a short cloth neck ornament.