[Maeson]

First, Hello, and thanks for taking your time reading this post, I hope you can give me some advice because I can't figure it out.

I'm making a small visual modification, to change Little Mac's appearence for another (Basically, making him look more like Little Mac).



So far I had some troubles figuring the HUD (Your character's face was a little hard to find between so many random pixels) , fortunately I found how to do it, but the real problem comes with the "Game Over" and the "You win" screens:

Here's for example the You Win one.


The thing is that those tiles are nowhere to be found, unless you have to change something in the tile editors (For example I used YY-CHR for this hack) to actually see it, because I don't know that much about hacking. I looked through the entire the file several times, with different palettes, with trial and error, and I found absolutly nothing...

What can I do? What could it be? If it's something that can't be edited, could at least hide it somehow? I rather have a floating belt than a severe change in the character appearence without any reason, and the Game Over screen doesn't matter that much, lol.

Again, thank you. And sorry for my english, I have the feeling that I must have murdered it.

[Bregalad]

It's very common for graphics to be compressed in the ROM.

[Maeson]

That's what I thought, but I don't know what tool would let me extract/Import the tiles, because I only see "Game Especific Tools" to work around that, and sadly this game doesn't have one.

Is there a generic tool for that?

[Bregalad]

Nope, each game can potentially use it's own compression sheme. It could be common for a company to reuse compression among their games, so then you could potentially have "game set specific tools".

So the short answer is : Reverse engineer the compression algorithm, write your own decompressor you can work with the data, and then hack the game to expand the ROM and not use compression anymore, and use your modified data instead of the original.

You could of course re-compress the data and insert it without expending the ROM, but that's not the easiest route.

[KingMike]

I recompress, but then that's because I've written a basic LZ (by far the most common compression on SNES) recompressor I mod for each game (as the basic idea is the same, but each game has minor formatting variations).