There are two NTSC only Konami games i wish to port to a PAL console.
I understand that TMNT 3: the manhattan project's status bar uses raster effects but it's not programmed specifically for PAL. The status bar get completely broken during the introduction/ending cutscenes (when the manhattan island is lifted, as well as when it lands at the end of the game), The parallax water effect used in Scene 2-2 and at the very beginning of Scene 4. I wish to correct this issue. When running on a PAL console Gradius II's status bar is permanently stuck to the middle of the screen.
I have 2 questions:
1. What and how do i reorient the raster status bar in TMNT 3 to make it functional in PAL? (using Fceux) or what did PRG 1 of Mega Man 3 do to fix the final wily boss? (i could possibly apply the same technique to TMNT 3)
2. Does Gradius II use a raster effect and if it does, does the process change due to the VRC 4 mapper?
VRC IRQ counts in 341/3-cycle units. This is the length of a scanline on NTSC or Dendy. PAL NES scanline is 6.25% shorter. It also starts counting from 21 lines before the picture, which is the NMI-to-picture time for NTSC and Dendy. PAL NES NMI-to-picture time is 50 lines longer.
You'll need to change all the VRC IRQ values, and they won't be whole scanlines anymore. For the first split, add 50, then multiply by 15/16. For subsequent splits, multiply by 15/16.
MMC3 should not be affected, as it synchronizes directly to the PPU's sprite fetch pattern. I don't know about the TMNT games in particular though; they might use cycle counting instead of MMC3 for some effects. Cycle counting needs to be adjusted similarly to VRC IRQ: multiply by 15/16 and adjust from there.
I don't think there's any problem in the intro of Teenage Mutant Ninja Turtles III - The Manhattan Project (U) (MMC3) on PAL NES. Are you trying to use the Japanese ROM? (Which uses VRC4.)
I meant to specify, not the cutscene before the title screen, the one before the first scene. The manhattan island use a vertical scrolling effect which messes with the raster border.
I was talking about the scene that comes after pressing START on the title screen and selecting the turtle. It works fine in PAL mode in Nintendulator.
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You'll need to change all the VRC IRQ values, and they won't be whole scanlines anymore. For the first split, add 50, then multiply by 15/16. For subsequent splits, multiply by 15/16.
That's precisely what my PAL hack of Akumajô Densetsu does on the rising water level, I actually had to code a routine that multiply by 15 and shift right 4 times to implement the effect correctly.
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Does Gradius II use a raster effect
It does for the status bar, and if I am not mistaken it doesn't do that for anything else but I could be forgetfull of something.
Oh so you're the guy who made the PAL port of Akumajou Densetsu. What else did you do when porting the game to PAL?
(I know it's VRC 6 instead of VRC 4 but i would still like to know).
Have you tried the game on a actual PAL NES? PAL emulation is usually an afterthought and inaccuracies goes unnoticed.
TR3KT wrote:
Have you tried the game on a actual PAL NES? PAL emulation is usually an afterthought and inaccuracies goes unnoticed.
No. Have you?
I'm inclined to trust Nintendulator in this case because I have not come across a single case where it failed to emulate PAL properly (although I'm sure there are some minor inaccuracies in there).
Pictures or video of how you think it's breaking would be useful.
Here's the footage of the beginning of Scene 4, Directly captured using my crappy laptop camera. (i'm too cheap to use a capture card)
Similar effect are present in Scene 2-2 and at the very end of 5-2 (where the water rises before you fight leatherhead)
https://www.youtube.com/watch?v=z-StodR ... e=youtu.be
TR3KT wrote:
Oh so you're the guy who made the PAL port of Akumajou Densetsu. What else did you do when porting the game to PAL?
(I know it's VRC 6 instead of VRC 4 but i would still like to know).
Well I don't remember precisely, but I had to fix IRQ counter values for the status bar and possibly other raster effects which were fixed values. I also had to find the note pitch table and multiply all values there by 15/16 in order to make the pitch higher to compensate for PAL being slower. Music tempo is however not compensated.
Do you know if the Gradius II music engine's layout is similar to Akumajou Densetsu? and if it is where do i find the pitch table?
TR3KT wrote:
Here's the footage of the beginning of Scene 4, Directly captured using my crappy laptop camera. (i'm too cheap to use a capture card)
Similar effect are present in Scene 2-2 and at the very end of 5-2 (where the water rises before you fight leatherhead)
https://www.youtube.com/watch?v=z-StodR ... e=youtu.beWhy not show a clip of the cutscene before scene 1 where you claimed there was a problem?
thefox wrote:
TR3KT wrote:
Here's the footage of the beginning of Scene 4, Directly captured using my crappy laptop camera. (i'm too cheap to use a capture card)
Similar effect are present in Scene 2-2 and at the very end of 5-2 (where the water rises before you fight leatherhead)
https://www.youtube.com/watch?v=z-StodR ... e=youtu.beWhy not show a clip of the cutscene before scene 1 where you claimed there was a problem?
It being a Konami game, if you press U U D D L R L R A B Start on the title screen you're given a level select after choosing your character, so it's not really a problem to get there.
To clarify: Yes, that's a slightly different Konami code from the usual.
Gradius, Contra, Tetяis: ↑ ↑ ↓ ↓ ← → ← → B A
TMNT 2: B A B A ↑ ↓ B A ← → B A
TMNT 3: ↑ ↑ ↓ ↓ ← → ← → A B
Gradius 3: ↑ ↑ ↓ ↓ L R L R B A
FWIW Nintendulator seems to faithfully reproduce that problem at the start of Scene 4 (N.Y.) in PAL mode, but FCEUX does not.
in a responce to Thefox: Here's a second clip i recorded.
Very similar results to Scene 4
https://www.youtube.com/watch?v=YcZNzuz ... e=youtu.be
Thanks. That's quite interesting. Were you using an original cartridge, or a flash cart?
i was using an Everdrive N8 with a perfectly functional NES. Aside from TMNT 3 (U) Gradius II (JP) and a handful of NTSC games that suffer from similar problems, it works perfectly with any European ROM i throw at it. The hardware i'm using is out of the question. Judging from other responses i think it's an issue with the PAL video standard.
So for Gradius II: How do i change the setup for the VRC IRQ?
Tepples, you said the TMNT games may use cycle counting for the status bar (TMNT 1 uses sprite 0 hits). I read up on Vblank timing so i have a slightly better understanding of how raster effects work but where is cycle counting stored?
VRC mappers always count cycles, not scanlines, though they count cycles in units scaled to an NTSC scanline.
The following is all speculation, seeing as I haven't dumped and disassembled any TMNT game.
If the programmers don't know how to set up multiple IRQs in one frame, it may use MMC3 PIT for the first split and sprite 0 for the second or vice versa. Or if they didn't know the $2006-$2005-$2005-$2006 trick yet, it may use MMC3 PIT to find when to turn off the background for 8 lines, then use timed code to wait for when to write the address of a row of tiles to $2006, then use timed code for when to turn rendering back on.
TR3KT wrote:
i was using an Everdrive N8 with a perfectly functional NES. Aside from TMNT 3 (U) Gradius II (JP) and a handful of NTSC games that suffer from similar problems, it works perfectly with any European ROM i throw at it. The hardware i'm using is out of the question.
The hardware
could cause problems like that even if it seems to be working otherwise fine, because small issues in the mapper implementation (e.g. IRQ timing) could lead to bigger problems depending on how tolerant the game is for that kind of a thing.
I don't think that's the case here though. I tried the game on my PAL NES with PowerPak and was able to reproduce the same glitches (including the Manhattan rising glitch in the intro). Sorry for polluting the thread.
That's fine. i really should've included footage when starting this thread.
Hi Tepples,
I ran a couple of my own tests last night on my NES: Starting with TMNT 2: The Manhattan Project (JPN). I was surprised it could boot! The glitches were much worse than Gradius II (I guess because they both work on VRC 4.)
I also tried TMNT: Tournament Fighters (U) and when i booted a fight scene the bottom status bar (and maybe the top one too, i couldn't tell) were acting exactly the same way as the Vertical effect scenes in TMNT 3 (U). I can possibly confirm they share the same status bar system. Konami fixed this issue when releasing TMHT: Tournament Fighters (E). Could i possibly reverse engineer both versions of Tournament Fighters to see what Konami did to fix the status bar? and then replicate the system on TMNT 3 (U) (They both use the same mapper)