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How to hack roms information?


doron

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Hi guys

 

I love those hacks, and I think there's mabe a lot more potential in that erea. Does anyone know a link to technical information about that?

The link Atariage provide doesn't work.

 

BTW. To Thomas Jantzsch : Youre an amazing coder, in my opinion. how did you manage to cram so many screens into "jammed"?

What are you up to next? do you have a web site?

 

dor-x

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Hmm...AtariAge's links not working? You can go to Dan Boris's website

http://www.atarihq.com/danb/

He's got links to everything you need in order to hack a game. Click the 2600 icon from the sidebar and scroll downward.

What kind of hacks are you interested in? Graphics/sound or hacks that change the whole premise of a game?

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how did you manage to cram so many screens into "jammed"?

What are you up to next? do you have a web site?

I have tried to explain that on the [stella] mailing list, though I don't think it did make much sense. ;)

 

No, I don't have a website, my most recent project is Robot City (WIP, halted since late September) and I'm currently dreaming about Boulderdash 2600. :)

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Wow! The fastest replays I had ever got!

 

Anyways, thanks a lot. I've just downloaded that graphics extractor from Dan's page, and I'll be reading that explanation from Thomas now.

 

Nukey, I am interested in graphic changes that also have an impact on the gameply, like someone did with the Berzerk rom.

 

Music hack must be a lot more demanding.

 

Another thing to note is that no site has taken care of the demos that were made on to the VCS. surely people have interest in that?

 

Thomas, What about a descent driving game? Wipeout 2600? Better still Out Run - the stripped version? I'm completely serious this is no joke. I think the VCS hasn't got any real good driving game, and that is one thing that'll go well with the paddles.

 

dor-x

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Editing the graphics of a 2600 game is really easy, and it sounds like you have already downloaded the tools you need to do that (showgfx/editgfx).

 

Changing ANYTHING else pretty much requires some knowledge of assembly language. I started making my color changes in my Space Invaders hack by just changing random bytes and I don't really recommend that. You'll want to find a copy of "distella" which allows you to disassemble 4K games back to something resembling source code. Then, unless you're a masochist (as I apparently am), you'll want to find a copy of dasm to assemble your code changes back into a working BIN file.

 

More importantly, you'll want to understand the 2600's internals - trying to find the code where the color is set or the notes are played is going to be pretty tough for you if you don't know what memory locations you write to to set player 1's color or the DAC's frequency.

 

There used to be a page dedicated to the various demos and homebrew games produced for the 2600 called "The Dig". In fact, it's still around: http://www.neonghost.com/the-dig/ You'll find some pretty important links, docs and tools, as well as the BIN file and source code to pretty much every demo and homebrew game ever posted to the Stella-list.

 

Which brings up the single most important tool for coming to grips with Atari 2600 programming: the Stella mailing list. Thomas linked to a post above but I wanted to make sure you knew you should join the list.

 

I didn't bother joining for a long time because back then the mood on the list was very anti-hack (and you still shouldn't post hacks to it) but the work of people like Thomas Jentszch has done a lot to legitimize them as well as disassembling various games from back in the day. Find it at http://www.biglist.com/lists/stella/ and check out the archives, and consider signing up. It's been well-googled and as you get more into 2600 programming you may notice that if you google about a problem you're having someone will already have dealt with it on the Stella-list.

 

Hope you enjoy hacking the 2600.

 

Rob

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As a member of the Stella list, as long as you are not simply changing graphics, hacks and how-to-hack questions are more than welcome in my opinion. There is no way you are going to even come close to the quality of say... Beserk VE, or Missle Command TB, if you don't first learn how the 2600 works from the inside out.

 

You maybe don't need to be an expert, but you will need to understand it fundimentally, to make any type of progress.

 

Join the list, and ask questions, we are here to help. I should hope the other members agree with me... What's the point of even having a group to help people if we are going to seperate ourselves as elitests. :-) If you're elite, why do you need help?

 

Welcome aboard, and thanks for your interest!!! I'm excited to see what works you bring to the community!

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I've made my first hack! I changed Defender!

 

I have to say thank you very much, It means a lot to me.

 

This is the greatest forum, and the stella mailing list is excellent too, some very interesting read in there, but I have to say that, um, I'm actually a musician, so I just couldn't get into programming right now. I'm deep in that music production business, and I actually did this hack instead of some urgent things I should've done.

 

But I feel great!

 

So, I enclose the rom. It aint the best hack for sure, but I've seen worse.

 

Thanks again guys,

dor-x

defender_dor_x_version.zip

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I've made my first hack! I changed Defender!

 

I have to say thank you very much, It means a lot to me.  

 

This is the greatest forum, and the stella mailing list is excellent too, some very interesting read in there, but I have to say that, um, I'm actually a musician, so I just couldn't get into programming right now.  I'm deep in that music production business, and I actually did this hack instead of some urgent things I should've done.

 

But I feel great!

 

So, I enclose the rom. It aint the best hack for sure, but I've seen worse.

 

Thanks again guys,

dor-x

 

Our resident audio genious Paul Slocum has made some really awesome strides in 2600 audio.... It would be cool to see another musician/programmer on the block... think of the sounds!!!! I can just see a full symphany added to Strawberry Shortcake... can you see it?

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Yes. You can't just type SHOWGFX or EDITGFX...you need to add in command line stuff.

 

Example:

Let's assume that you want to change the graphic sprites in Pac Man (with the rom name pacman.bin). You first need to convert this file into a text file. Take a look at the size of the .bin file, and you will see that it is 4k (4096 bytes). So, you would type this...

 

 

 

SHOWGFX PACMAN.BIN 0 4096 > PACMAN.TXT

 

The showgfx and pacman.bin need no explaination, but how about the 0 and 4096? This is the range of values that will be placed into the results. You could, for example, make a partial dump of 2k by using 0 and 2048...but don't expect to be able to recompile it. The ">" character in the line is a Dos "pipe"...this character has the abilty to redirect the output to whatever device you want. If you wanted to send the dump to the printer, you could use "> LPT1". Without this pipe, the dump will be sent to the screen all at once. Finally, "pacman.txt" is the file to put the dump into. You open it just like any text file by using this...

 

 

 

EDIT PACMAN.TXT

 

In the editor, you can page around to find recognisable shapes (like the ghosts). The sprite pixels will be displayed as X characters. If you want to change them, you would OVERSTRIKE the characters in the listing. Be careful not to have too many on a single line...and use spaces and X's only. If you accidentally erase a line, you must use UNDO or the text file may not be able to compile back into a binary file. When you are done...save it.

 

 

 

EDITGFX PACMAN.TXT PACMAN.BIN

 

This one is pretty easy to figure out...it simply converts all of those spaces and X's in the text file into the binary values. You don't need to specify the start and end positions since it just does all of them.

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I've used SHOWGFX and EDITGFX to try and hack some roms but I have a hard time with it. Is there some easier way to figure out which rows of X's represent which graphic element of the game? I basically stare at the chains and try to find stuff but with varying degress of success. Any body know a secret to this or is there an address that graphics definetely start or end at? :?

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You might have stated which one you are looking at.

Seriously...just scroll around using the pageup/pagedown keys.

Pay particular attention to stuff near the end of the file.

Some pictures may be upside down...simply because that

is how that game was made to display them.

 

You'll find them.

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Yeah? What did Paul Slocum do? I'd love to hear it. Especially if you say he's a genious.

 

dor-x

 

Check out the hacks section on this very site...he's added

music so you can listen to The Clash while playing Combat!

He's put the Mr. Roboto song by Styx into Berzerk! He's

made the excellent homebrew Marble Craze (though that

version is in the AA store). And he's around here occasionally

...if you have a question, he might help you out :)

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You might have stated which one you are looking at.

Seriously...just scroll around using the pageup/pagedown keys.

Pay particular attention to stuff near the end of the file.

Some pictures may be upside down...simply because that

is how that game was made to display them.

 

You'll find them.

 

Thanks, I actually just read a little further into tha PDF somebody mentioned before and it tells you how to use a diassembler and then note the address' that end in .byte which should make it easier. :)

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Check out the hacks section on this very site...he's added

music so you can listen to The Clash while playing Combat!

He's added SPEECH to Berzerk!  (though that version is in

the AA store).  And he's around here occasionally...if you

have a question, he might help you out :)

 

I did Combat Rock, but Mike Mika did the hacking for Berzerk Voice Edition. I did another hack of Berzerk called Mr. Roboto that plays Mr. Robot by Styx. My webpage has a bunch of info about doing music on the 2600, including a kit to write your own music.

 

-Paul

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Well, ofcourse, I just didn't rememebr the name but I've enjoyed all those hacks, some brilliant ideas indeed!

 

I'm at Mr Slocum's page right now, I'll see deper into it, thogh I have downloaded the sequencer once, but it was mabe too difficult for me so I abandoned it.

 

dor-x

 

P.S. Just remembered: I downloaded a great tune from Paul Slocum's site some time ago that was made by just c64 and vcs, and a girl singing. A really great thing, but do you have further information about it? who wrote, sang etc?

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