Tech: Atari vector questions

[mikenemonic]

[ukvac] Tech: Atari vector questions
Hello UKVAC,
Here are a few questions, the answers to which have been nagging on my
mind for some time. I hope that somebody can put my mind at ease .... que XY
man.

1. What is the purpose of the programmable DAC reference current in games
such as Star Wars and BattleZone. DVG games upto and including Asteroids
Deluxe and Space Dual though using a similar circuit, have a fixed DAC
reference current. Why?

2. Why are later vector games called 'Analogue Vector Generator' rather
than 'Digital Vector Generator'. The 'Analogue Vector Generator' still uses
digital techniques to produce the XY signals, so why the misleading
description?

3. How many channels of sound does Asteroids Deluxe actually use. Upto 4
channels are available using the POKEY but are they all used?

4. Has anybody ever done a complete BattleZone ROM disassembly with
commented code ? Or any Atari game for that matter.

5. Is there any easy cross reference guide that shows what vector games
were derived from? e.g. Lunar Lander beget Asteroids beget Asteroids Deluxe
etc.

Regards

Mike Mnemonic
01327 842803
07866 837960

 

[John Bennett]

Re: [ukvac] Tech: Atari vector questions
| 4. Has anybody ever done a complete BattleZone ROM disassembly with
| commented code ? Or any Atari game for that matter.

There's the Tempest Code Project (http://arcade.tulsa.net/tempest-sw/). And Clay
Cowgill wrote a Breakout clone for Tempest hardware
(http://www.multigame.com/tempest.html).

--Luc

DATA Imported from archives: originally posted by Luc Van den Borre (luc@nuclide.com)

 

[P-Man]

Re: [ukvac] Tech: Atari vector questions
> Hello UKVAC,
> Here are a few questions, the answers to which have been nagging on my
> mind for some time. I hope that somebody can put my mind at ease .... que
XY
> man.

> 2. Why are later vector games called 'Analogue Vector Generator' rather
> than 'Digital Vector Generator'. The 'Analogue Vector Generator' still
uses
> digital techniques to produce the XY signals, so why the misleading
> description?

later? later than what? i don't know of any atari board labelled digital
vector gen. board

point taken, yes theoretically it should be called digital vector, but hey..
don't want to confuse people eh?

> 4. Has anybody ever done a complete BattleZone ROM disassembly with
> commented code ? Or any Atari game for that matter.

Tempest code project as stated by another poster..

battlezone has been extensively re-worked by clay cowgill, he has worked out
most of the code to the extent of now making a modified version of
battlezone to play with faster shots, and is now working on multiple tanks,
and other bonus items. If you mailed him and asked, you might get some info,
although he rarely leaks dissasembled code out commented because of the
multi-game kits he sells

> 5. Is there any easy cross reference guide that shows what vector games
> were derived from? e.g. Lunar Lander beget Asteroids beget Asteroids
Deluxe
> etc.

chronologically yes LL, ast, battlezone, ast delux etc...

technially? well i understood it might be different

> Regards
>
> Mike Mnemonic
> 01327 842803
> 07866 837960

Andy

 

[MarbleMad]

Re: [ukvac] Tech: Atari vector questions
>2. Why are later vector games called 'Analogue Vector Generator' rather
>than 'Digital Vector Generator'. The 'Analogue Vector Generator' still uses
>digital techniques to produce the XY signals, so why the misleading
>description?

It uses digital techniques to produce ANALOGUE XY signals?

>5. Is there any easy cross reference guide that shows what vector games
>were derived from? e.g. Lunar Lander beget Asteroids beget Asteroids Deluxe
>etc.

probably better asking these on the vector list. I heard somewhere
there's great chunks of lunar lander code hidden in gravitar.

If someone does disassemble these games I'd love someone to write a good
Space Wars for one of the b+w atari PCBs.
---
James G Watt

PLEASE NOTE the new email address:

kinetic-arts@ntlworld.com
http://www.kinetic-arts.co.uk
Part of the Video Arcade Game Collectors WebRing.

You are in a maze of twisty little passages, all alike.

 

[MarbleMad]

Re: [ukvac] Tech: Atari vector questions
>chronologically yes LL, ast, battlezone, ast delux etc...
^
Red Baron
although it was supposedly started before battlezone.
---
James G Watt

PLEASE NOTE the new email address:

kinetic-arts@ntlworld.com
http://www.kinetic-arts.co.uk
Part of the Video Arcade Game Collectors WebRing.

You are in a maze of twisty little passages, all alike.

 

[P-Man]

Re: [ukvac] Tech: Atari vector questions
> >description?
>
> It uses digital techniques to produce ANALOGUE XY signals?

BONG!!!!

nope... if you look at the hardware, it only produces incremental steps away
from the centre of the screen (0,0), therefore giving 786432 possible
co-ordinates for starting a vector from, and dragging the beam too. In
effect this gives a 1024x768 screen pointer system 1024 point wide by 768
points high.

so really, its not actually analogue as the definition of analogue in this
case would be an infinite number of points to start/stop the vectors from.
For the purposes of computers, this is not possible, there has to be a set
location that the computer can point to to start drawing, and a point it can
go to to stop, and some kind of numbering system so itcan work out matrices
calculations for acuratley displaying forms, working out collisions etc..

granted, the line drawn from one end to the other is a solid, unbroken beam
which could be classed as 'analogue-ey' ehhe

Also granted, 1024x768 points is a pretty darn close together point system,
and what with old clunky monitors, it cn appear the process is analogue

but it isn't technically speaking, of course, that was mike's original point


> probably better asking these on the vector list. I heard somewhere
> there's great chunks of lunar lander code hidden in gravitar.
>
> If someone does disassemble these games I'd love someone to write a good
> Space Wars for one of the b+w atari PCBs.
> ---
> James G Watt

blasphemy

Andy

 

[MarbleMad]

Re: [ukvac] Tech: Atari vector questions
>BONG!!!!
yeh but it is sort a' analogue in a way - sort off. a bit.
---
James G Watt

PLEASE NOTE the new email address:

kinetic-arts@ntlworld.com
http://www.kinetic-arts.co.uk
Part of the Video Arcade Game Collectors WebRing.

You are in a maze of twisty little passages, all alike.