Uhhh, I forget. Ken would remember, he wrote that part. I think it uses a
simple Z test but it may have been optimized to use a simple ray casting
type tests at certain intervals. This is how the Dungeon was able to
support arches , windowed doors and windows. We had windows in wall at one
point which were supposed to give you a teaser view in a hard to get area,
but we didn't like the look. Without bumpmapping or anything else they
looked rather odd.

I say simple because it had to be, getting the priority and order of what
the viewer sees from what he is able to see is very CPU intensive or memory
intensive for pre-generated tables of what the user can see. The Dungeon
doesn't use the vertical wall mirroring trick the City was able to, arches
would look funny flipped upside down.

I'm not sure how easy it would be to make the 8 bit Dungeon view pan 360
degrees, but I did see it on 16 bit Amiga and Atari ST versions. One
thing Ken did which I still think is very cool is coming up with the idea
of mip-maps. The 16 bit guys went a different route. They opted for
single "texture" that had a table for which columns and rows would be
decimated as it was scaled. To my knowledge the Dungeon is certainly the
first game that ever used mip-maps, we didn't even have a name for
it. Perhaps the first use of it ever.

I'll go kick Ken's chair on Monday and see if he can shed some light on the
raycasting issue.

Dan
At 10:49 AM 9/21/2003 +0200, Robert wrote:

Ah, yes... I remember this too now. Why isn't this information in the FAQ?

Perhaps Dan Pinal would care to confirm it on Monday so I can add it?

/Robert

----- Original Message -----
From: "Eli Curtz" <eli--nuprometheus.com>
To: <<Address Masked>>
Sent: Saturday, September 20, 2003 6:33 PM
Subject: Re: FAQ url... + Wiki


> The Dungeon engine certainly looks like raycasting, especially taken
> with the comment theat they had 360 degree turning but took it out to
> stay the same as the City. Raycasting is an extremely fast and simple
> solution for drawing that kind of map, so it wouldn't surprise me at
> all if they were using something indistinguishable. I wonder if you
> could hack the turn code in the Dungeon and get a view from another
> angle?...
>
> The City didn't use raycasting from what I understand, but seemed more
> based on clever tricks and lookup tables. It's still annoying that the
> emulators choke on Phil's mirrored wall trick.
>
> - eli
>
>
> On Saturday, September 20, 2003, at 05:00 AM, Robert wrote:
>
> > Thanks!
> >
> > I accidently overwrote the AR page with my personal page yesterday, as
> > I was
> > updating both.
> >
> > It should be fixed now.
> >
> > And regarding that wiki... did AR really use raycasting? I think I only
> > describe it in the FAQ as "similar technology"...
> >
> > /Robert
> >
> > ----- Original Message -----
> > From: "Gregory Lattanzio" <ag6514--wayne.edu>
> > > > Sent: Saturday, September 20, 2003 12:08 AM
> > Subject: Re: FAQ url... + Wiki
> >
> >
> >> As far as I can tell, your page doesn't seem to be working...
> >>
> >> BTW: Who made this wiki entry? :-)
> >> http://www.wikipedia.org/wiki/Alternate_Reality
> >>
> >> Greg
> >>
> >> At 11:25 PM 9/19/03 +0200, you wrote:
> >>> My AR section is of course located at:
> >>>
> >>> http://w1.214.telia.com/~u21405572/alternate-reality/
> >>>
> >>> Sorry for that.
> >>>
> >>> Have fun! (And any error reports are appreciated, though not at all
> >>> required.)
> >>>
> >>> /Robert
>