Play! - Development Log

Play! is a PlayStation2 emulator for Windows, macOS, UNIX, Android, iOS & web browser platforms. For more information about this project please visit the "About" section of this site.

Fetching compatibility status...

Make 'Guilty Gear XX Accent Core Plus' work.
Posted on 2009-05-24 00:00:00

Well, I haven't updated this much as I've been doing progress very slowly. But, as for this game, I've decided that it was good enough for the moment. It's possible to play the game without any hangs, even though the frame rate is quite low.

The hangs were caused by some SPU registers problems while the game was trying to change the music. I had to hack something to make it work. I also improved the caching mechanism of the OpenGL renderer by calculating and saving hashes of cached textures. This improves the cases where the game uses the same address for two or more different textures.

I said I wanted to make the music and sound work for this, but I'm not too sure about the way of making the SPU update properly along with the rest of the stuff (GS, Input, etc.). Also, the SPU rendering is quite slow for now (as demonstrated in the PsfPlayer program), so that would need some improvement before being usable in the main emulator.

Well, this concludes this development. Next one coming right away.

Make 'Guilty Gear XX Accent Core Plus' work.
Posted on 2008-12-29 00:00:00

Finally found the cause of the bug that was making the characters not appear properly on the screen. It was a problem in the code generator that messed things up when dividing by a constant.

Next, I want to improve the main emulation loop. This game dumps all its stuff to render once a v-blank is generated and currently the emulator generates v-blanks as if the main CPU was running at a very low frequency, so it kinda makes things weird.

After that, I'd like to see why it's that slow. The game doesn't do anything intensive, so there's no reason it should be running at that speed.

Make 'Guilty Gear XX Accent Core Plus' work.
Posted on 2008-12-18 00:00:00

Been a while, but I made some more progress on that development.

I finally added the IOP core I was working on during the development of a PSF sound file player into the main project and plugged it in with the SIF stuff. Seems to fix the problem that was making the game to be stuck just before the main gameplay part.

Main problem right now is that we don't see any action at all. Sprites seem to be squished in the upper left corner for some reason. Gonna investigate that next.

Make 'Guilty Gear XX Accent Core Plus' work.
Posted on 2008-10-15 00:00:00

Finally got the controller driver to work properly. Dunno why there's so many differences between the version I was emulating and the version this game uses... In any case, I was able to make a quick hack that works for this game.

With a little patch used to skip movie playing, we can now go into the menus.

We can pretty much do everything, except for playing the actual game because it hangs while loading the combat mode. That's what I'm busy fixing right now.

Oh, and don't get fooled by the fps values, it's not the actual speed of the thing.

Make 'Guilty Gear XX Accent Core Plus' work.
Posted on 2008-10-03 00:00:00

The goal's pretty simple, I wanna make Guilty Gear work in the emulator. It's a 2D game, so it shouldn't be too much of a problem.

What I mostly want to do with this game is to make the IOP emulation a bit better. Right at the beginning I was faced with some problems since the game requires recent versions of the IOP modules that are currently emulated. The FILEIO module caused me a lot of problems because of the weird communication system it uses for returning its results to the EE. Basically, it involves a custom SIF command handler and some special packets, which took a bit of disassembly work to figure out.

I want to be able to support custom IOP modules which are mostly used to provide sound to the games. This game probably streams its music from the disk, so that shouldn't be a problem. Sound effects should be a little trickier and will probably require a more involved SPU support. We'll see when I'll get there... For now I want to be able to play the game properly.

I got the game to work up to the memory card checking phase (which fails as always). It's asking if we wanna play without a memory card, but unfortunately the controller IOP module doesn't work. So, that's what I'm busy with right now... More screen shots coming soon, hopefully.

Make 'Castlevania: Yami no Juin' work.
Posted on 2008-08-26 00:00:00

Well, after all this time, I wasn't really able to get the game to work a lot faster, but it did make me realize that threads aren't the way to go to gain speed. This is because of all the synchronization required to make it work properly and also because the threads doing the work are quickly running out of data to process, thus making it wait for the data producers to produce more and negating any speed gain...

I don't really know what else I could do to speed things up while the game is rendering stuff using the VU/VIF. I tried checking which part of the VU/VIF processing was the slowest and I can't really come up with a conclusion. Micro-program execution doesn't seem to be taking a lot of time and so is data decompression. Maybe it's the big amount of data sent to it that's making it choke like that. It seems to be the case with the Atelier Iris world map rendering at least.

In Castlevania it seems to be slow because something is keeping the CPU busy. I don't know what exactly, but I'm getting only 15fps if I turn the VIF off. So it might mean that some OS event isn't fired at the right time or that we might be better off working on getting the recompiler to generate faster code.

As a temporary measure, I added a frame skip option that will disable GIF and VIF processing for x frames out of (x + 1). If we set the emulator at frame skip 10, Atelier Iris runs at 50 "fps" during the map screen, while Castlevania runs at 10 during the main game screen. That correlates with the 2 types of slowness I've been talking about above.

I also revamped the input handler so that the bindings can be configured in the UI and so it can work with joysticks. I also added support for the analog sticks in iop:PADMAN : we can now move the character normally in Castlevania.

I'm still not exactly sure about what I'm going to attempt next... I think I'm going to try to make another game work to get more data about what can clog the CPU / VPU and maybe fix more of the broken things.

Make 'Castlevania: Yami no Juin' work.
Posted on 2008-06-23 00:00:00

Well, it's been a long time since I've posted here, but it doesn't mean I haven't been working on the emulator. It took me more than 1 month to finally get the game to get past its loading screen and to make it display its game mode.

I'm kinda happy to see that there isn't too many rendering problems and that the game seems to work correctly (action buttons and menus). We can't move around though, since the analog pad isn't emulated yet.

The hardest part in getting the game to load properly was to figure out that my emulation for a game specific IOP module wasn't good. After that, I needed to add support for DMA channels 0 and 8, for VU0 in micro-mode and for a lot of unsupported VU instructions.

The next step is going to consist in making the game work at decent frame rates. Currently, while being in the 3D game mode, the game runs maybe at 0.5 fps. The menus and UI also run very slowly (1 or 2 fps), so the speed problem probably isn't related to some "heavy" load the VU1 would have while drawing the scene...

Fix VIF/VU emulation
Posted on 2008-05-15 00:00:00

I diverged a lot from the initial goal, but here's where Atelier Iris at now:

So, to sum it up, the 3D map rendering works again, the game works on the MacOSX port and memory card emulation is working for the game.

I would have loved to show you the other parts of the games that use the VU, but most of these still don't work properly. The map rendering also still requires the patch to work properly... I decided to stop looking for the causes of the bugs because I had no idea where the causes might lie (no, they aren't related to the lack of DIV pipeline emulation). The bugs aren't major anyways and you can still play the game even if you encounter them. I'll probably stumble on something while working on other games that'll make me think of something that could fix the problems...

As for this development, I think I'll leave it as done for now. I need to start working on something fresh...

Fix VIF/VU emulation
Posted on 2008-04-27 00:00:00

After almost 3 weeks, the state of the VU emulation got a bit better. For Atelier Iris, all the required VU instructions are emulated and we can execute the microprograms the game needs. It's far from perfect though...

There's one problem that occurs while the game tries to show the animation that appears when Klein absorbs mana elements from props in the map that I don't know how to fix. The VU program feeds some negative coordinates to the GS and I have no idea how to deal with those without breaking other stuff... So I think I'll leave that problem as it is for the moment.

Instead, I'll try to concentrate my energies to get the overworld map rendering to work properly again : right now, it works with a patch, but I wanna get rid of it, and I think proper DIV pipeline emulation will do the trick...

Fix VIF/VU emulation
Posted on 2008-04-09 00:00:00

Both demo #2 and #3 work as before now:

What took me a lot of time was to get rid of the global variables that were used all over the place in the compiler. They were causing some trouble since it's possible for the compilation code to be ran by two threads (EE thread and VIF thread) simultaneously. I also took the occasion to remove heaps of old code.

The frame rate on both demos isn't too bad and it's a lot better compared to the previous version of the emulator. Also, demo #3 doesn't work quite well on MacOSX... I haven't investigated much, but I'll try to make sure it works for the next release.

Next challenge : the VU stuff in Atelier Iris. The previous version couldn't make the overworld map rendering code work properly without a patch in the game code. I don't wanna rely to that patch this time...

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