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Author Topic: A Question about FCEUX and hex editor. (NES).  (Read 2 times)
SFSeiei
Guest
« on: June 17, 2009, 02:25:57 pm »
Hi again Smiley.
I still working in a Megaman 3 romhack, i think is 75% complete with a lot of changes (someone remember me?).
I have a problem now with the FCEUX Hex Editor, the problem is i go to Debug mode, in this i going to "Name table viewer", ok, i want to change some thinks in a game with this, in properties of the name table viewer i see the Adress of PPU (of the sprite or graphic i want to change) , ok, then in going to hex editor and i change a PPU Mode, all ok, i make the changes and i see the changes in real time, all ok, but when i going to save the changes really dont save the changes in the rom i made, never, in save rom or save rom as, dont work.
Using a Hex editor i cant find the codes of the PPU Mode... i dont know why not.

Someone can help me?, another program or something?
Thanks!! Wink
tummai
Guest
« Reply #1 on: June 17, 2009, 04:14:57 pm »
Try going to "View Rom File" mode and searching for the series of bytes you want to change and change them in that mode.  

BTW: I think the reason it won't let you make permanent changes in PPU Mode is that some games use CHR-RAM, where the CHR data could be stored anywhere in PRG-ROM (compressed even).
« Last Edit: June 17, 2009, 04:21:17 pm by tummai »
Gil Galad
Guest
« Reply #2 on: June 17, 2009, 04:20:02 pm »
If it comes down to it, there is always NESticle. As long as the game has CHR-ROM and not CHR-RAM, you'll be able to edit the graphic tiles. For the Nametable, I doubt that you can edit directly from the PPU, as the bytes are sometimes different in the ROM. As tummai suggested.
SFSeiei
Guest
« Reply #3 on: June 17, 2009, 05:05:04 pm »
Yeah the bytes are different in a Rom file view, a lot of hard find this way, the result when i find it , only change the tile but not the order of nametable. Then don`t exist a way to use the nametable for something in this rom?, i try with Nesticle but only can edit the pattern table , in the nametable only can view a coordenates but it is useful?, really i can use nesticle for this?.
Thanks a lot.
Gil Galad
Guest
« Reply #4 on: June 17, 2009, 11:14:23 pm »
I suggest to use the nametable viewer, note some tile numbers, write them down perhaps. Then set a PPU breakpoint, about $2000 - $2FFF is good enough. Make the write breakpoint conditional, for example, when A equals a certain number, chances are you're close to the data/code that you want to edit. A == #35 for example.

You can also use Unofficial Nintendulator to track down locations real easy. The emulator locates a lot of stuff, from the nametable viewer.

I use both methods when I can't find data as stated in my PPU document.
tummai
Guest
« Reply #5 on: June 18, 2009, 02:16:16 am »
Quote from: SFSeiei on June 17, 2009, 05:05:04 pm
Yeah the bytes are different in a Rom file view, a lot of hard find this way, the result when i find it , only change the tile but not the order of nametable. Then don`t exist a way to use the nametable for something in this rom?, i try with Nesticle but only can edit the pattern table , in the nametable only can view a coordenates but it is useful?, really i can use nesticle for this?.
Thanks a lot.


To expand on what Gil Galad was saying, nametables are not stored in the rom file at all.  Only the patterns tables are (assuming CHR-ROM).  The game code writes to the nametables at runtime, so you are going to have to find the asm routines that draw to the nametables.  These routines will read data from PRG-ROM, decompress it, and then write it to the nametables.  You find these routines by using a debugger and setting breakpoints like Gil Galad was saying.
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