NetNews Usenet Archive 1992 #18/NN_1992_18.iso/spool/comp/graphics/8944

Internet Message Format | 1992-08-18 | 1.8 KB

Path: sparky!uunet!mcsun!uknet!canon.co.uk!ads
From: [e-mail] (Adam Billyard)
Newsgroups: comp.graphics
Subject: Re: wolf 3D
Message-ID: <[e-mail]>
Date: 18 Aug 92 15:29:25 GMT
References: <[e-mail]>
Reply-To: [e-mail]
Organization: Canon Research Centre Europe Ltd
Lines: 31

[e-mail] (Gary Howland) writes:

> I used to program games back in my younger days, and knew some ridiculous
> algorithms for squeezing fast graphics (3-dimensional as well as normal stuff)
> out of the hardware I was using, but the speed at which wolfenstein-3D (apogee)
> generates its images amazes me.  Can anyone give me a rough overview of how
> wolfenstein 3D generates its images?

The trick used in Wolf3d to get fast texture-mapping seems to be to use
a non-regular scaling of a pixmap.  If you look at the images generated
you'll see that the texels are not perspective projected - they're
simply scaled (axis-aligned) rectangles.  This gives an OK result but
has the nasty side effect that you're not really texturing polygons.
You're scaling images.  This means that the larger the texels the more
raggy the edge of the "polygon" is.  The people that did Wolf3D
cunningly arranged for the very "fat pixels/texels" to be clipped off
the edge of the viewport in most cases since they only get real big as
the scaled pixmap gets "close" to the view plane.  It is a really good
effect, but not much use for general 3D geometry.

Also, keep in mind that in your "younger days" the processors were a lot
slower - well thats what I tell myself when I see some of these games. :-)

    Adam.


-------------
Adam Billyard, Canon Research Centre Europe,
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