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A forum to show appreciation and respect for classic video game systems and games. Whether you're a modder, a programmer, or just a collector, this forum is about appreciating classic games and systems in a constructive community environment.
Posts : 1607 Join date : 2012-01-25 Location : Canada
Subject: Making non rgb compatible nes games run in rgb! Thu Jan 26, 2012 12:58 pm
That's right. I found a way to make games that normally don't run on the playchoice ppu chip capable of doing so! You basically need to edit the rom itself. Depending on the game this can range from being a little annoying to extremely difficult. I tested this out on mario adventure. Mario adventure has various weather conditions you get and the weather conditions seem to be random. One of the weather conditions in the game was using a colour gray that the rgb ppu chip doesn't have. Therefore graphics that normally would show up were literally all black making the game unplayable under that weather condition. Since you only have this problem under the 1 weather condition (atleast I think you do), changing 1 pallette set was easy. I actually only needed to change like 3-4 hex characters but I decided to have fun with it and I made a theme of my own. I call it "cool night blue" :lol: . The default theme in the game was just gray which was boring so I made it an all blue theme with many different shades.
Anyway what I had to do was I tracked down the "theme" on the powerpak. Basically I played the game on the rgb system until I got the not-so-fun all black screen. Then I paused, used the mighty kalle savestate mapper and saved the game in that state. Then I stuck the powerpak into a composite ppu nes and loaded the savestate. Once the savestate was loaded I could see what the game would look like in an emulator (all grey and black). Then I played the same rom in an emulator until I got the same theme in the emulator. In the emulator I also paused and saved the state. Then I made a copy of the rom, used fcuex to find where the pallette data is stored in the hex, found the same area using a hex editor with the copy of the rom. Then I changed the pallette values real time in the emulator until they looked how I liked. Then I copied the pallette hex values into the hex editor with the copy of the rom and saved the copy. Loaded the copy into the powerpak and it worked like a charm!
If this sounds like it's a royal pain to do well...that's because...it's a royal pain....but in the case of mario adventure it was completely worth it and I learned a lot about rom editing which is very useful!
Megaupload has been taken down so until I find free hosting I have nowhere to host this fixed rom.
And here's the demonstration video of the rom without and with my fix: