The game I'm hacking is Dr. Robotnik's Mean Bean Machine where it stated off as a spoof hack replacing the dialogue. While working with my brother on this, I felt I needed to modify the font to include letters like * & ( ) etc.
Long story short, this game is a modified version of Puyo Puyo. In that game, it uses a custom graphics compression. The rest of the graphics that were added to DRMBM use Nemesis. I used Nemesis Search and found 53 graphics (one being the font, which I can now edit and found the table values).
My crazy idea is, any graphics that use that custom compression, I can compress with Nemesis compression instead (I'm guessing the game can detect the type of compression, or I have to tell it). Two graphics I want to edit are the Playing Field Background and the 8x16 Playing Field font.
So the problem I'm having is, how do I set a Breakpoint to check what gets written into the VRAM?
The two debuggers I've been using are:
- r57shell Mod Gens
Using Regen, I can see the custom compressed font graphics get stored at 0500:
Using the Main 6800 Debugger does allow Breakpoints to be set in the VRAM:
It says I can set the VRAM access between 00000-2FFFF, where at this point I got confused. Hopefully someone can clear it.
I have heard r57shell Mod is better for Breakpoints (although it is slower than Regen when more things are open).
This was also in the hook_log:
Genesis memory map (Mem_M68K.asm):
$00:0000-3f:ffff = ROM
$a0:0000-a7:ffff = Misc (I/O)
$c0:0000-c7:ffff = VDP
$ff:0000-ff:ffff = RAM