GT4 480p in race

[ameenross]

I've done some experimenting with Silent's deinterlacing patch which was removed here: 1873233

The last line which says "speed timer" slows down the race clock, but doesn't slow down the actual game/race. So effectively you'll be driving 20% faster and lap times will be 17% lower. This is immediately obvious when doing a license test (immediate gold by huge margin). Leaving out that line "fixes" the clock problem. But the game will still be running too quick. I got it to run "properly" (though unfortunately at 50fps) by simply setting the FPS limit at 83.3%. Combined with another deinterlacing patch by Silent, I've now got this:

// No interlacing
patch=1,EE,204A2A2C,extended,0000102D

// 480p mode in race
patch=1,EE,2035812C,extended,2442003C // (60 fps?)
patch=1,EE,20A57E70,extended,00000001

I should mention that this looks great compared to playing without patches, so even though the 60FPS benefit is lost with my trick, it still looks and functions good.

I had the idea to change the number 3C to 32, but that just causes the exact same problem with the clock. So I'm guessing the PAL build simply doesn't support 60FPS (due to tick rate, perhaps?). Unless nobody has found it up until now...

[ameenross]

Just noticed that the address is the same, so naturally it will have the same effect.

[Mode 480p]
author=Silent
comment=480p mode in race. Disable deinterlacing patch
patch=1,EE,20A57E70,extended,00000000
patch=1,EE,2035812C,extended,2442003C
patch=1,EE,E0020001,extended,00A57E7C
patch=1,EE,20A57E70,extended,00000001
patch=1,EE,2035812C,extended,24420032 //speed timer (line is the same as the second patch line, except `3C` is `32`)

[PeterDelta]

I am in the testing phase, speed of the vehicles you use corrected, I would say that on all circuits both in a-spec and b-spec mode, at 480p and 1080i, if you find any anomaly, tell me so I can correct it. So there are two of us to tested it is a very long game ;).
https://github.com/PeterDelta/PCSX2/blob/main/patches/SCES-51719_44A61C8F.pnach

[ameenross]

@PeterDelta I saw those. They're supposed to be 2 variants, right? As in, you cannot enable both lists of patches at the same time? If so, I tried both of those, and I thought they had the same speed problem as mentioned before. I can test again on thursday or friday to be sure.

[ameenross]

Also, as a programmer myself who likes minimalism, I was a bit wary about the list of patches being so long. Is that really strictly necessary?

[PeterDelta]

Yes, one patch enables 480p racing mode and the other 1080i mode, they are separate patches or you can enable one or the other. At first it was longer but I found more global values and I have reduced it to this. Each circuit has different physics, some share them but others do not. That is why there are so many conditions, so that it does not alter the game in any way since they change from one circuit to another. The only way to reduce it is to find the direction that regulates the overall speed of the game, something I haven't found yet. For now and unless I have missed a circuit, the speed is corrected in both b-spec and a-spec.

[ameenross]

Ah, right, that explains it. I do wonder, though: is there a way in 480p or 1080i mode to tell PCSX2 that the FPS limit needs to be 50 instead of 60? Of course I'd rather have 60fps, and I fortunately can with my Ryzen 7700 and DDR5 RAM (no discrete graphics required anymore, hurray!), however a workable 50FPS solution is a very welcome option. Especially for people whose machines cannot reliably run GT4 @ 60fps, but even I'd like to have the option.

[PeterDelta]

The game already runs at 50 fps by default, progressive mode can only run at 60. Additionally, the visual improvement as you can see is notable.

[ameenross]

Yes, what I mean is the visual improvement without the FPS improvement. Like I described in the OP which I already have working, although with a manual configuration change... I guess it's not possible via pnach as 480p is recognized by PCSX2 to be 60 FPS?

[PeterDelta]

I understand. I don't know how that's done honestly.

[ameenross]

I was afraid of that. No problem, I'll test your patches again Friday probably... although maybe it helps to add a few code comments what the lines do? I'm guessing it's a lot of opcode patches, or at least values of constants or something... but it's sufficiently complex that some explanation is welcome. Also, I guess you could make 1 block of "physics" patches which is required for both 480p and 1080p mode? Now there's quite some duplication from the looks of it.

Out of curiosity, what would happen if I save a replay with these patches, and load it without any? Would it perfectly reproduce the race, or are the engine/physics changes significant enough to break it?

[PeterDelta]

The progressive is only enabled when entering the race, you can do a race and save the replay, when you see it in the theatre you will see it at 50 fps. Except for the first lines of the patch, which are to enable progressives, the rest are for AI speeds and the car we take on the circuits. There is nothing that breaks or hangs, that is why I have conditioned everything so that it does not happen. The speed of the car we are driving is exact, the speed of the AI is approximate and that is what I am testing.

[ameenross]

So my first test today was not a great success. I tested A5 license, and fail within about a second because the car is way faster than the Skyline safety car. Also, I'm pretty sure the game is running too fast.

[ameenross]

So I did some more testing, and it seems that this is enough for 50fps in race, although with the minor caveat that the pre-race menu shakes slightly. But there's no shaking in the race. This might not give you 60fps which would be great to get working perfectly, but it does mean a significant improvement of the graphics with minimal code. EDIT: should note, this still requires frame limiting to be at 83.3%.

// No interlacing
patch=1,EE,204A2A2C,extended,0000102D

// 480p mode in race
patch=1,EE,20A57E70,extended,00000001

[PeterDelta]

I just checked the speed of the A5 license, both national and international and it is accurate, there is no error there.
If it works great for you, but that is, in addition to being incomplete, unnecessary due to the interlaced patch (which, except for some games, have become obsolete). Address 20A57E70 enables progressive mode, everything runs faster as you indicate, so minimalism is of no use here unless speed modifiers are found, and that is what I have done so far.

By the way, at 50 fps you are also faster than the safety car, in fact you can't overtake it because you suspend

[ameenross]

If it works great for you, but that is, in addition to being incomplete, unnecessary due to the interlaced patch [...]

Yes my 2 patches work great(-ish). The no interlacing patch is needed because the image is shaky in the menus (requiring deinterlacing)... whereas with the patch, the shaking stops (so deinterlacing can be disabled tyvm). If by obsolete you mean the "Enable No-Interlacing Patches" checkbox in the graphics settings, that doesn't work for me on GT4. Or at least doesn't have the same effect as my patch.

The other patch only changes the output mode in races/replays etc... anything where the actual simulation is run. But PCSX2 detects it as being NTSC and sets frame limiting to 60 (but the game engine assumes 50). Interestingly though, when I change the NTSC frame limit to 50 in the advanced settings, the game still runs at 60. Seems like a bug to me, or there's a detail I'm missing. But personally, I don't mind using the 83.3% trick anymore. And having real, actual 60FPS would be the icing on the cake at this point.

I just checked the speed of the A5 license, both national and international and it is accurate, there is no error there.

I disabled ALL other patches, only enabled your 480p patch... there's a clear speedup of the game. Look, with a horrible attempt on A-1, I got gold by a 4 second margin.

The (added) problem on A-5 is the AI drives extremely slowly. So maybe if it works for you, then there are some other lines in your patch that are not in the GitHub version?