From: morley@camins.camosun.bc.ca
Subject: Re: what do you want to know?
Organization: Camosun College
Date: Wed, 30 Sep 1992 19:16:00 GMT

In article <1992Sep30.014212.5715@cam.compserv.utas.edu.au>,
psmith@esk.compserv.utas.edu.au (Paul Jeffrey Smith) writes:
> Hi,
> 
> 	A few friends an I have been drooling over the latest release of the
> Unreal demo that Future Crew, as well as their release of the Fishtro Demo.
> And quite frankly, these guys are impressive.

No need to get your shirt wet, UNREAL isn't as impressive as it first seems...
The majority of their stuff seems to have been generated via Autodesk's
3D Studio 2.0  I have 3D Studio 1.0 and 2.0 and I recognise all the textures
and fonts, etc.  I have also been able to re-produce pretty well everything
in the demo.  See, each frame was generated ahead of time and stored in
a FLI/FLC format (or possibly their own internal format).  The "speed" is
being achieved by pre-computing everything (Notice how the demo is the
same everytime you run it?  No interactive stuff...)
Any one of you could do the same kind of demo (graphics-wise that is) just
by using tools like Autodesk Animator PRO and 3D Studio.  The music is
another story...

> If any of you have seen Fishtro, I have worked out how to do the exploding
> letters bit quite well, although not quite as well as theirs.

Haven't seen it... where is it?
 
> What I would like to know is how the hell the can do the World Vector part
> of the demo.  Its the rotation see, that gets me.  Sure, sure there are 
> algorithms evvery where that can rotate.  No problem there
>
> But how do you do it FAST!

I believe the World Vector part was the terrain of single pixels, right?
See above...  It's all pre-computed (probably).  Although, the day I got the
demo I thought that portion would be great in a game or two, so I quickly
wrote a small version of my own.  It generated a simple fractal landscape
and let you move around it in real time (more or less).
 
> I can do it using look up sin and cos tables, but even then its not THAT 
> quick.
>
> I don't have algorithms for rotating the viewers point, only other objects.

In this case, there is no need to rotate the view point.
 
> Here are a few questions.
> 
> 1.) Does one rotate all points or is there a spify alogrithm that can do
> them all real quick based on one rotation.

You'd only need to rotate the points that are within the "square" that is
currently viewable.  If your square area is only about 50x50 points, you
can rotate them *very* quickly in real time.  You can also use fixed point
instead of floating point... this'll give you a speed increase (unless you're
using a co-pro).

> 2.)How does one incorporate the rotation of the viewers view point in the
> calcultion.
> 
> 3.) How do they (or any one else) determine the shading for the different
> polyogns based on a light source.

These are questions more suited for comp.graphics (you'll find answers in
that group's FAQ.
 
> and last, and most importantly
> 
> 4.) How the hell is it done so quickly!
> 
> If you haven't seen Unreal, and you have the means (a 486 is REAL handy, as
> well as a Sound Blaster Pro, music's great), then I suggest you get it, and
> have a gander.
> 
> Thanks in advance.
> 
> And sorry if I'm posting it in the wron ara.
> 
> regards
> Paul Smith
> psmith@esk.compserv.utas.edu.au

MARK
morley@camins.camosun.bc.ca