Guidance on title screens, 4K vs. 8K rom size, etc...

[doctorclu]

Hi, I'm Doctor Clu, I'm new at rom hacking...

 

(Those in the circle of chairs) "Hi Doctor Clu."

 

...but having fun so far and want to learn more.

 

 

In hacking a rom image with Hack-O-Matic 3 and Hexfiend on the Mac I've been able to change sprites and modify the sprites colors to a game.

 

I'd like to modify sounds or music. The Hack-O-Matic readme file indicates that is more challenging that finding the color codes. Others I have talked to tell me this one is hit or miss. Any advice on rom modifying sound? Are there hex codes to look for?

 

Like color and how you have a hex chart for color codes...

 

 

Is there a similar hex chart for music notes/sound?

 

Other questions I have:

1) Currently have a 4K game I'm modifying, I would like to add more to it. If I do, will I need to make sure the game is a 8K image? In the past with rom hacking it seemed like they always needed to be set sizes.

 

If an 8K image or higher does it need to use bank switching at that point?

 

2) Any advice on how to add additional information to a rom image? Additional sounds, music, etc?

 

3) Anyone have much experience with the opening screen of E.T. or other games with a title screen? I would like the take a title screen, modifying graphics and music, and added to hacked game.

 

So much I don't know and barely know where to start on the above. Any advice will be appreciated.

 

[CDS Games]

Been a while since I've used Hackomatic--it's just a string of hex codes with a graphics editor right?

 

You are going to need something more elaborate unless you want to pull your hair out. For serious hacking like you're talking about I recommend Stella. It has its drawbacks, but you can change code and save files, so it works pretty well as a hacking platform. It has so many tools you can use to easily find things like color tables...you step by step through the screen until it draws your color and then you just look up where it's pulling the value from. Bang. There's your color table. Plus it compiles on the fly so you can tell data from code instantly. Super useful.

 

4k is the highest you can get without bankswitching. Anything 8k and up will have to be bankswitched. It's not super hard to add the bank in and have Stella recognize it but making the banks work well together is another story. It takes a bit of programming experience.

 

There are really good music resources out there...I don't have the refs handy but you can probably find them with a bit of searching.

 

Bottom line, if you hack in Stella or a disassembler you'll be able to do everything you want.

[doctorclu]

That is some awesome information. I liked what you had to say about more easily finding color values using Stella. Probably the same procedure for tracking sound values?

[CDS Games]

Yep! You can also set a trap for anytime the program writes to a register--sound, graphics, etc.