Inside the Homebrew Atari 2600 Scene

Skeleton + by Neo-Rio-101 · 2004-05-23 00:06 · Score: 4, Informative

One game that stood out from the Atari 2600 home brew scene was this 3D maze game called "Skeleton +", which could be best described as something about as close to DOOM as the Atari 2600 was likely to get!

Makes me want to dust off the Commodore 64 classic 3D "Layrinth" game and mod it into a no-frills Doom-like game.

--
READY.
PRINT ""+-0

Re:Skeleton + by jsse · 2004-05-23 00:44 · Score: 4, Informative

Screenshot of Skeleton+ for Atari 2600. :)
Re:Skeleton + by RenaissanceGeek · 2004-05-23 04:25 · Score: 2, Interesting

That reminds me SO much of "Dungeons of Dagorath" for the Tandy TRS-80 CoCo2 (Color Computer 2)
Screenshot of "Dungeons of Dagorath" for TRS-80 CoCo2.
The interface was all key commands ( A L = Attack with whatever is in your Left hand) (P R WS = from your pack, Pull using your Right hand, the Wooden Sword.) However, the graphics were sufficiently detailed (using the faux-monochrome display method, and simple vector graphics.), and the game played a number of distinctive sounds at ascending volumes as enemies approached, so you could plan your defense (or retreat, as appropriate for the strength of the enemy and your own health) before you could even see your enemy. The variety of enemies (spider, ghost, knight, wizard, etc.) not only kept the gameplay interesting, but allowed strategies to deal with enemies stronger than yourself later in the game. Yes, I burned many hours playing "Dungeons of Dagorath." and it wasn't even my CoCo!
There was even a sequel for CoCo3: "Castle of Tharogad", which had solid-color graphics and used a point-and-click graphical interface using the joystick (or mouse, if you had one.) Unfortunately, the graphical interface was actually slower to use than the old key-based one and, worse yet, the CoCo platform used the same hardware to do the D/A conversions for the joystick/mouse ports as it did for the audio, so the audio was lost as well. Too bad, really.

--
What is the difference between a small revolutionary change and a large evolutionary change?

If i ran a software firm... by 222 · 2004-05-23 00:09 · Score: 4, Insightful

i would make it a requirement to code an enjoyable 2600 rom :p
The ammount of work that goes into creating an entertaining title while only working with 4k of rom space and 128 bytes of memory is staggering. Mind you, most of my emails are larger than 4k....
I dunno, maybe im just being sappy, but it really brings a smile to my face to see coders throwing themselves into what i can only characterize as a digital bootcamp, simply for the love of the game.
Long live passionate programmers :D.

Re:If i ran a software firm... by Blrfl · 2004-05-23 09:08 · Score: 2, Interesting

I call it "getting back to the basics." Anybody who's successfully coding good games on the 2600 has a bright future in the embedded systems world, where limitations like that are commonplace. The current crop of small microcontrollers (PICs and the like) have similar constraints, and cleverly-designed software is landing them in all sorts of places.

Don't take this personally, but that fact that people are staggered by things like this worries me. Limitations were what we had back then, and we dealt with it, in the snow, up hill, both ways. :-) The cheap and ever-expanding supply memory and disk is, I think, one of the reasons software has become as bloated as it is. We went to the moon on systems with less combined horsepower than a 1996-model Palm Pilot, and I think it would do wonders for this business if more people understood what made the machines they programmed tick at the lowest levels.

Oy by NeoPotato · 2004-05-23 00:13 · Score: 5, Insightful

What's with people ripping off the first paragraph and submitting it as their text? Do they just assume we're not going to read the article, and are therefore being clever, or are they just lazy? That whole submission, with the exception of six words, is ripped from the top paragraph of the article.

Re:Oy by sporty · 2004-05-23 00:37 · Score: 5, Funny

Do they just assume we're not going to read the article...

You're new here, aren't you? ;)

--
-
ping -f 255.255.255.255 # if only
Re:Oy by Anonymous Coward · 2004-05-23 01:41 · Score: 2, Funny

No, but he is!

This is passion at it's finest by beacher · 2004-05-23 00:15 · Score: 4, Interesting

"The system has no video buffer, the total code size cannot exceed 4K and can only use 128 bytes of RAM"... "the Atari 2600 requires 100 percent Assembler coding".. Wow. You gotta really love it or love challenges in order to constrain yourself so. In the age of bigger and faster machines, I think a lot of the bloat is due to the fact that people never understood or learned the inner workings of the processor and the code isn't as tight as it could be. I'm not recommending that assembly be required, but I think anyone that develops should be cognisant of what happens behind the curtain.

Still- Developing and making fun games from this tiny system is incredible. I have every platform I've ever owned since the 2600/Intellivision era and the 2600 has definately sat unused in the past few years... Maybe it's time to dust it off...

Re:This is passion at it's finest by Stween · 2004-05-23 00:25 · Score: 5, Insightful

A lot of "bloat" comes from increasing levels of abstraction away from the hardware, and numerous levels of interfaces between different system layers to allow for more modular code, more reusable code, and generally, safer code. Coding an application for a modern machine with all its fancy hardware would be pretty tricky without these interfaces already written for people. Sure, somebody has got to write the low-level interaction gubbins in the first place, but once it's done, it's done. If software houses wrote for the hardware to reduce bloat, we'd never see any games or software. Praise the bloat. The bloat be praised.

[That's not to say that an understanding of what the machine is actually doing with the code wouldn't help people when designing software systems, I agree that it would certainly be beneficial. It's just not necessarily where all the bloat comes from. The lack of understanding is probably more and more relevant as more and more layers of abstraction are added. And there's always room for one more layer of abstraction!]
Re:This is passion at it's finest by tomstdenis · 2004-05-23 01:02 · Score: 2, Informative

While it's true that HALs require space they are dynamically linked in both Linux and Windows. So there goes that theory.

In fact you can write GUI apps in Windows with menus, dialog, buttons that are smaller than a couple dozen KB.

A lot of bloat comes from huge MFC/C++/etc libraries that get linked in [all or nothing] and serve merely as another languages wrapper around a C API.

I recall from the Borland days [my first C compiler for Windows] a simple OWL based hello world application was 80KB lines of code [though it did count headers], was a few hundred KB in size, etc...

In the case of games most decent games have small executables and huge data files. At best they are storing things wrong [e.g textures as BMP, sounds as WAV] instead of using compression [JPEG, Vorbis, etc...].

So really a "game" merely has to dynamically link against the HALs. In a way this is provided in other platforms. For example, the Gameboys [all of them] have had hardware 2d graphics. You load tile memory, set a sprite register or two and voila on screen sprite. You didn't have to mess with the LCD driver directly, etc, etc, etc...

Tom

--
Someday, I'll have a real sig.
Re:This is passion at it's finest by Anonymous Coward · 2004-05-23 01:06 · Score: 2, Insightful

Well, since it's so limited, you only need to write 4K of code to make a game. This very limitation makes 2600 game development a more reasonable hobby than development on anything more modern... For one, there's lot less code to write so you do not have to spend much time on a complete game. Second, since it's a challenge to make everything fit, even the boring parts of the game become challenging as you simply have to optimize them for size. Thus, you get a limited amount of highly challenging thinking, and yet the end result can be a truly amazing game by the standards of the platform.
Re:This is passion at it's finest by IncohereD · 2004-05-23 07:51 · Score: 3, Insightful

What is all the portability for? In the end 99,9% of the products end up running on Wintel. I think that it would still be nice to have software developped in Assembly language, and it would even be profitable, but this goes against current market practices, that require cheap programmers (even if they are not too skilled), and short development periods.

Optimize last?? Hello?? Have you taken any programming courses?

How real, optimized engines are written (i.e. Quake, Doom, Unreal) is by:
- writing it first in a 'high' level language (probably C, which isn't high any more, but you get the picture)
- making sure it works
- finding out what parts are slow
- optimizing these in assembly, and making sure they get the same results as the slower, easier to debug version.

Writing the whole thing in assembly would just be ludicrous. Did you ever use the first version of wordperfect for windows?? Written in assembly, and boy was it buggy. And not noticeably faster than anything else.

If you optimize first you will never get anywhere meaningful.

Dedication or masochism? by Xargle · 2004-05-23 00:15 · Score: 4, Funny

Do they code these games sitting on broken glass whilst being branded with hot pokers whilst listening to Celine Dion?

No accounting for taste, I suppose.

Good Article! by Bender_ · 2004-05-23 00:18 · Score: 5, Informative

Good Article, seems to be quite accurate on details. And yes, I did actually read it.

I also made some attempts on vcs2600 programming some years ago. It could not be any more different from your daily C/php/... hacking. Think of microcontroller programming with even more demanding timing.

The machine has 128bytes (yes, bytes) of ram and 4-6kb of ROM. No video ram, everything is generated on the fly. The CPU does not support interrupts, all the timing is done by active waiting.

Re:Good Article! by bsDaemon · 2004-05-23 00:29 · Score: 2, Funny

and that is no different than php hacking?
Re:Good Article! by csirac · 2004-05-23 00:41 · Score: 2, Insightful

Obviously... it has no framebuffer, that's incredible. It couldn't have a framebuffer even if it wanted to, unless you only wanted 16x8 resolution.

And I thought C64 coding was hardcore... 128 bytes of total RAM? Just writing a character generator would be challenging, let alone a game!
Re:Good Article! by JanneM · 2004-05-23 00:52 · Score: 5, Informative

Note that you have 4k of ROM, that in addition can be bank-switched. "All" you need the RAM for is for changing variables, really. Not that it's not a pretty demanding limit (seeing how apparently the 6502 stack needs to fit as well), but you do have a bit more margin to play with that it seems at first. Most microcontrollers today look similar, with what seems like a ridiculously low amount of RAM compared to ROM.

Compare to the Commodore VIC20 - precursor to the C64 (and a wonderful machine in many ways). You had 5k total, of which 1.5k went for the video buffer. That left you with about the same amount of total codespace to play with, and there were no shortage of really good games for that machine either. The defining limitation of the 2600 really seems to be the lack of a framebuffer far more than the low amount of RAM.

--
Trust the Computer. The Computer is your friend.
Re:Good Article! by StormReaver · 2004-05-23 01:12 · Score: 3, Informative

"It couldn't have a framebuffer even if it wanted to, unless you only wanted 16x8 resolution."

I wrote a lot of assembler on the 6809 (CoCo 3), and a few text-based games. The text-screen was 32x16, and most of my useful assembler programs that manipulated that screen came in well under 4K (2K was my average) and used well under 128 bytes for data storage.

The machine had a video generator that could be pointed to any point in memory within the machine, regardless of what that memory area was actually used for (data storage, program execution, stack -- didn't matter).

I empathize with the homebrew developers. Developing with limited machine capacity is very fun, and sometimes very frustrating.

The CoCo had floppy drive support, but the read/write timing had to be exact since the drive had no interrupt support. The result being that while data were being read/written, the machine was in a very tight waiting loop to the exclusion of all else. Even system interrupts had to be turned off to get the needed clock cycles.

Only the NMI (Non-Maskable Interrupt) could be left on (it was impossible to turn off, hence "non-maskable"), but it was attached to the "failure" mode of the drive (the only actual interrupt it used, but only if the hardware failed).

Those were the days. :)
Re:Good Article! by Emil+Brink · 2004-05-23 05:00 · Score: 2, Interesting

I couldn't have imagined driving a TV with one of those.
Imagine harder! ;)

--
main(O){10<putchar(4^--O?77-(15&5128 >>4*O):10)&&main(2+O);}

The book "Hackers" by Henrik+S.+Hansen · 2004-05-23 00:22 · Score: 4, Informative

People interested in the early days of game hacking should read "Hackers: Heroes of the computer revolution" by Steven Levy.

It also has an accurate history of the early days of the MIT AI Lab (where Stallman and others started out), and the early days of BASIC.

It has several chapters about the birth of Sierra (then called On-Line Systems, IIRC). Great stuff, and should be required reading for anyone interested in the early days of computing. Truly great book.

I want an OLED for my Atari Lynx by Anonymous Coward · 2004-05-23 00:23 · Score: 3, Funny

The resolution is great but so flickery bright that it hurts my eyes. I sure would like to have a screen upgrade to OLED so I can play it again, it would also increase battery lifetime.

Why? Well two-player Lemmings sucked on my Atari ST, it's not available for my 2600. Wait that would also mean that I need a Lynx bluetooth module as I can't be bother to hook up wires :-)

Dennis

Re:I want an OLED for my Atari Lynx by kiddygrinder · 2004-05-23 12:46 · Score: 2, Insightful

If you want to play 2 player lemmings, get an amiga, it's the only way to play

--
This is a joke. I am joking. Joke joke joke.

Damn it by Anonymous Coward · 2004-05-23 00:27 · Score: 5, Informative

I've already moderated some posts here, so I have to post as AC from another machine (or else my moderations are removed)

I've been coding some stuff on the Atari and it's an extremly cool machine.
You can actually build one yourself, if you have a little knowledge in electronics.

Most of my coding is done in the Atari 2600 emulator called "Stella":
http://freshmeat.net/projects/stella/

Worth a try if you love the 6502 and minimalism

Re:Damn it by csirac · 2004-05-23 00:35 · Score: 4, Interesting

I've been coding some stuff on the Atari and it's an extremly cool machine. You can actually build one yourself, if you have a little knowledge in electronics. From the article it says that the 2600 has a custom chip - the TIA. How do you substitute that? With an MCU/FPGA?

Hmmmm.....time did advance, right? by mousse-man · 2004-05-23 01:28 · Score: 2, Interesting

If a machine has 128 Bytes of RAM, I'm wondering how one can even program a game that is remotely fun by yesterday's (1985) standards. Let's see - 1 frame on TV needs:

- 320x240 pixel or 76800 pixels. Let's say every one of these pixels has 2 bits (acceptable by 'yesterdays' standards. So alone to hold one frame in an accepatble resolution and color depth, one needs some 19200 bytes of RAM. If one looks at the 2600, we're far away from that, even if we say we can divide that by four since the Atari most probably had some area-drawing commands like any other hardware.

I have a C64 which at least capable to display that. OTOH, there are people who are complete minimalists and will be able to think that an Atari 2600 is fun, and since Atari games look even worse than C64 games and have less gameplay, they can live with even less resolution.

Re:Hmmmm.....time did advance, right? by ClippyHater · 2004-05-23 02:17 · Score: 2, Informative

Actually you could get *limited* colors at 320x200. I forget what the term for it was, but I remember coding a game in 320x200. It was a matter of alternating lit pixels. If you had a run of 8 pixels, and every odd-numbered pixel was lit, then you'd have one color. If every even-numbered pixel was lit, you'd have another color. And if every color was lit, you'd have white (every color).

Ok, ok, to it was only 4-color, but I remember creating a nifty (at the time) character-based game using those colors to pretty good effect (again, for the time). High res, and 4 color, 1337! Of course, then the Amiga came along and my efforts seemed pretty pathetic, but damn it was fun!

Anyone remember "De Rey Atari" book? I'm sure I got the spelling wrong, and the 3-ring binder with the book is stored in a garage in florida, so it's probably now bug-crumbs, but those were the days :)
Re:Hmmmm.....time did advance, right? by phozz+bare · 2004-05-23 02:57 · Score: 4, Informative

Actually you could get *limited* colors at 320x200. I forget what the term for it was
Yes. It was called 'artifacting', and occurred when using high resolution monochrome modes. It looked terrible, different computer models and different TV's produced different colors, and you were still stuck with 160 pixels of resolution anyway because you had to turn on every other pixel to get a certain color (an ugly khaki green or, alternatively, a shocking sky blue. or at least that's what it looked like on *my* system, depending on whether you used even or odd pixels).
This mode wasn't available for the 2600 though, so not really on topic.
Oh, and it's De Re Atari, reproduced in full for your pleasure.
Slashdot is like Playboy, everyone skips the articles and goes straight for the juicy stuff.

I've done this! by pngwen · 2004-05-23 03:27 · Score: 5, Informative

Of course my rom just flashes random colors and a line that remains constant going back and forth. Considering what the atari 2600 environment is like, I'm damn proud of this. It's not exactly like other architectures. Even if you are used to programming in assembly for embedded devices with tight memory constraints, the VCS is STILL a major wakeup call.

Here are some of the challenges that you will encounter:

There is no interrupt vector system. System functions are accomplished by means of the stella chip, which looks like a section in RAM. writing and/or reading from certain memory locations triggers events (such as drawing to the screen and such)
TIMING is YOUR responsibility! You have to count clock cycles while you program, and you have to write the code to redraw your screen scan line by scanline on each electron beam pass of the TV.
Computation has to be performed mostly during the blanking and return phases of the electron beam. You know you have 72 clock cycles in which to operate your game logic before you have to begin drawing the screen again
Once your program's timing gets off, you get something that looks nothing like what you intended. My moving line example had a line that stair stepped as it moved. It wasn't until I added a sufficient amount of NOPs that it lined back up.

All in all though, it is a rather ingenious system. Considering when it was made, and the maximum cost of each unit, I'd say kudos to those engineers! I hope to do some more meaningful stuff with it once I have more time. I've plans to hack hardware for it as well!

-Bob

--
I am the penguin that codes in the night.

*sniffle* by atari2600 · 2004-05-23 05:15 · Score: 2, Funny

I've been waiting for this article for years and now it is finally up, i am at a loss for words *sniffle*

Doesn't the 2600 have a line buffer? by baywulf · 2004-05-23 05:50 · Score: 3, Insightful

I thought the 2600 had a line buffer. Basically a 40 or 80 bit shift register into which the pixels are written and then they are written to the video screen. This is my recollection from a presentation that the creator of the 2600 (the same guy who did the Amiga I think) had on the hardware internals.

Re:Doesn't the 2600 have a line buffer? by Anonymous Coward · 2004-05-23 06:33 · Score: 2, Informative

Yes, it has some "line buffer", but it only has 20 bits which are displayed twice each line, giving only 40 pixel horizontal resolution.

True classics live forever by Alwin+Henseler · 2004-05-23 05:59 · Score: 4, Interesting

Once it was thought that such old game classics, and the machines they were played on, would go out of use once the original hardware would die, waiting to be replaced by new platforms & remakes. Not so.

Development of both hardware & software simply continues as time goes on, no matter what. If an original manufacturer pulls the hardware of the market, and games go off the shelves, development slows down, but continues anyway. If the manufacturer/copyright holders try to prevent remakes, emulators, don't release ROMs, hardware info, schematics etc, that slows things down. But they can also promote this, and enjoy having an active community further developing these old designs, like in the Sinclair ZX Spectrum case. Given enough time, all there is to know about the inner workings of these old machines becomes known, and new things are done with it.

I think the appeal to enthousiasts results from the simplicity of these old systems. If you put in enough time, you can write code that uses every single part to the max, doing incredible things with minimal hardware.
One of my favourites is the Sinclair ZX81. 1 KB of RAM, no sound, no colour, and: no videoprocessor. About 3/4 of CPU time is spent on directly writing black&white dot patterns to the TV screen, using some simple logic to turn it into a video signal. With only the remaining 1/4 CPU time left for doing useful things.

With the arrival of quickly reprogammable hardware like FPGA's, the border between hardware and software blurs further, nice example is FPGA Arcade, where old games are rewritten in hardware circuitry. So instead of having a CPU eat through instructions coded in ROM, your joystick input directly affects the logic programmed into a FPGA. Very cool!

I made JoustPong 2600 and "2600 101" link by kisrael · 2004-05-23 06:06 · Score: 2, Insightful

I actually made (and published through AtariAge) my own Atari homebrew, JoustPong -- Pong with a Flap Button. I kept a developer's journal of the experiece.

I also made a newbie's tutorial, linked to at the end of the O'Reilly article: 2600 101. And currently I'm (slowly) working on 2600 cookbook...O'Reilly fans should find the format very familiar.

Overall, that's a great techie introduction to the hobby.

--
SO YOU'RE GOING TO DIE: The Comic for Dealing with Death

Re:Strong Bad by Paul+Slocum · 2004-05-23 06:53 · Score: 2, Informative

Still working on it. Should be out sometime this Summer.

Why were there no analog joysticks? by RenaissanceGeek · 2004-05-23 08:31 · Score: 4, Interesting

Something that's always bothered me about the old "classic" video-gaming platforms (with exceptions like the Magnavox Odyssey 2) was that the joystick controllers were all digital, with either 8 directions or, sometimes, 16 (IntelliVision), but no control over the INTENSITY of the movement: any game that had you controlling a moving object in two dimensions (e.g. the aim-point in "Missile Command") had only one speed at which that point moved, making it difficult ot be either precise or fast in your positioning.

Now, what is a joystick, really? It's two potentiometers: one for horizontal (x-axis), and one for vertical (y-axis.) Atari 2600 joysticks aren't built like this, instead having on/off contacts only. But joysticks aren't the only controllers available for the 2600: there are also the paddles (and the keypads and the driving controller, but I digress.) And what is a Paddle? It's a potentiometer. And the Atari paddles are only available in PAIRS, which share a common connector to the 2600. This makes it possible to have four-player games like "Warlords" or "Video Olympics" by using two sets of paddles. Why did no one ever build the two potentiometers from the paddles into a single joystick? All of the necessary functionality is present on the 2600 side for analog 2D controls, so why not? (I'll grant that writing analog-control software on such a limited platform would be taxing, to say the least, but surely it's POSSIBLE.)

Heck, I've even soldered together a pair of capacitors into an adaptor-plug that lets you use PC joysticks on an Atari 5200 (using plans from the online Atari 5200 FAQ and an old Texas-Instruments calculator with the clicky keys for my keypad), surely such a project for the 2600 wouldn't be any harder?

So THERE's a challenge for the modern 2600 hacker: build a game that uses an analog joystick! (for a REAL challenge, make it two-player!) Heck, I'd even be willing to build a joystick adapter for the programmer who did it! (and gave me a ROM cart of it.) (OK, that's setting myself up, I know.)

Any takers?

--
What is the difference between a small revolutionary change and a large evolutionary change?

Re:2600 Games for sale now by tuffy · 2004-05-23 08:32 · Score: 2, Informative

Unfortunately, the titles on the 2600-in-a-Joystick are ports/remakes of the originals rather than the genuine article. It would've been nice if they were properly emulated for accuracy, but I suppose it's better than nothing.

--

Ita erat quando hic adveni.

Mmmm, speaking of homebrew 2600... by ghost1911 · 2004-05-23 12:01 · Score: 2, Interesting

I don't know if it's emphasized clearly enough in the article, but Homestar Runner has commissioned a few homebrew 2600 coders to make their own game... Imagine the precedence that this could set, IMHO, this is along the same lines as the Counterstrike modders getting published by Sierra (err Valve?)..

Imagine... homebrew people getting paid for their hobby... I think that wired magazine's mention of this makes it a little more interesting: homebrew games are becoming available on a grander scale than just for those in the scene.

--
.: 2+2 = PI SQRT(1+N) :. All together now, what is n?

Slashdot Mirror

Inside the Homebrew Atari 2600 Scene

38 of 86 comments (clear)