Hello guys! It's been a while since my last post!
We have been doing a lot recently in our Emulator, I hope soon we can make a source code release!
Ok, here is the thing, Foomarumota and I have been having trouble emulating this Game called G.I. Joe. At the beginning I thought it was a Mapper problem, but now since we started to debug the game from the PPU, watching the zero hit, and screen splits, and palettes, we don't have a clue of what is happening us!
So I came to the only place I know I can find some help, you guys!
What we are seeing is this:
1. The game crashes after walking a little to the right. We thought it was because of a missed zero hit, but now that we started to look into it, we think that game does not use the zero hit.
Does anybody knows it this is true?
2. At the very end of the screen there is a lot of tiles showing an "S" as the first attachment shows. We have been trying to debug this with FCEUX (i know it's not the best emulator though), and we couldn't find a reason for that tiles to do not show, because FCEUX it's showing them at any scanline we try to debut. And our emulator doesn't trap any loopy_v midframe to hide this tiles, and the background does not turn off too. Instead the background it's turn on twice in a frame, one at scanline 191 and the second time at scanline 248!
Does somebody knows what is the reason that those tiles doesn't show? what is hiding them or turning them off?
Screenshot-O-Nes-Sama-1.png [ 11.05 KiB | Viewed 6974 times ]
3. For some mysterious reason the time counter doesn't move, it stays at 200 but time does indeed run out!
Does anybody has seen this before?
4. The pause screen is wrong too. The same palette is used for all the screen, which for example nintendulator debugger shows that the characters use either palette 1 or 2, and the right part of the screen uses palette 0, but our emulator is using palette 0 for all the screen! And also we noticed that the CHR for the bottom 2 characters are not being switched correct, as seen in the screenshot.
Screenshot-O-Nes-Sama.png [ 8.8 KiB | Viewed 6974 times ]
We started to make a debugger for our emulator but it's way in early stages. we will be coding the debugger from now, while we get some help about these issues.
OK I know it's a lot, but i guess if we get some guidance here we will be able to find the root cause of this!
Thank you again Nesdev community for your help! You rock!
We have been doing a lot recently in our Emulator, I hope soon we can make a source code release!
Ok, here is the thing, Foomarumota and I have been having trouble emulating this Game called G.I. Joe. At the beginning I thought it was a Mapper problem, but now since we started to debug the game from the PPU, watching the zero hit, and screen splits, and palettes, we don't have a clue of what is happening us!
So I came to the only place I know I can find some help, you guys!
What we are seeing is this:
1. The game crashes after walking a little to the right. We thought it was because of a missed zero hit, but now that we started to look into it, we think that game does not use the zero hit.
Does anybody knows it this is true?
2. At the very end of the screen there is a lot of tiles showing an "S" as the first attachment shows. We have been trying to debug this with FCEUX (i know it's not the best emulator though), and we couldn't find a reason for that tiles to do not show, because FCEUX it's showing them at any scanline we try to debut. And our emulator doesn't trap any loopy_v midframe to hide this tiles, and the background does not turn off too. Instead the background it's turn on twice in a frame, one at scanline 191 and the second time at scanline 248!
Does somebody knows what is the reason that those tiles doesn't show? what is hiding them or turning them off?
Attachment:
Screenshot-O-Nes-Sama-1.png [ 11.05 KiB | Viewed 6974 times ]
3. For some mysterious reason the time counter doesn't move, it stays at 200 but time does indeed run out!
Does anybody has seen this before?
4. The pause screen is wrong too. The same palette is used for all the screen, which for example nintendulator debugger shows that the characters use either palette 1 or 2, and the right part of the screen uses palette 0, but our emulator is using palette 0 for all the screen! And also we noticed that the CHR for the bottom 2 characters are not being switched correct, as seen in the screenshot.
Attachment:
Screenshot-O-Nes-Sama.png [ 8.8 KiB | Viewed 6974 times ]
We started to make a debugger for our emulator but it's way in early stages. we will be coding the debugger from now, while we get some help about these issues.
OK I know it's a lot, but i guess if we get some guidance here we will be able to find the root cause of this!
Thank you again Nesdev community for your help! You rock!