What would it take to get a dynarec into beetle-saturn?

General Development
#57

I looked at yabause core source, that looks crazy complex lol. 8.000 lines of code for vdp1 only iirc. Talking about 100.000+ lines of code probably.

Did some game tests on i7-7700 Linux laptop, Hexen looks like it runs more smooth on Yabause than the other 2 cores (beetle saturn, yabasanshiro). Like higher internal framerate or something, with some minor slowdowns. Would need some high determination and elite expertise on coding and Saturn internals to improve things. Probably drop anything you do on your free time for the next 6 months (if one has the elite level i mentioned).

#58

I would need to understand the VDP1 code better before I could make a lot of progress on this. Unfortunately, I probably won’t have a lot of free time to work on this over the next 6 months. This is why I suggested sponsoring another developer.

I saw the dynarec as a straightforward way to fix some of the performance problems, so that was the first thing I tried. It does work, and gives some speed boost, but it’s clear that this alone isn’t going to be enough to achieve the desired performance goals. The VDP1 and SCSP need a lot of work, and there are still quite a lot of other bugs.

Saturn emulation is currently somewhat acceptable with the right hardware, but there really isn’t a good solution for handheld or mobile, or even many laptops. Moreover, some games don’t work in certain emulators. This likely isn’t going to change soon, unless we can find someone who really understands this stuff and is able to work on it.

#59

Medanfen has some major input lag issues and I don’t see this with PS1 emulation, so this seems specific to the Saturn core. I don’t see a similar slowdown in Yabause.

(I’m not an emu dev. Just my experience and what I read)

Saturn games often (though not always) had more input lag than their PS1 counterpart. This apparently happened on hardware as well.

Resident Evil for example lags quite noticeably more on Saturn than on PS1. While Street Fighter Alpha (1) seems on part with PS1.

Likewise, some arcade ports lag quite a bit more on Saturn than on arcade (the Saturn King of Fighters ports for example) while other ports feel pretty much the same. Ex: Sat port of Super Gem Fighters Mini Mix. Maybe one additional frame. Usually, I found Capcom arcade ports are quite good in this regard while SNK’s ports…not so much.

There’s also Saturn exclusive such as SteamGear Mash that feels extremely responsive -almost next frame but most likely 1 frame.

So basically seems it was very dependent on how the games were programmed and optimized and whether or not the devs optimized the processing chain. If they didn’t, then yeah, it could lag quite a bit more than PS1.

All this to say I don’t believe Beetle Saturn adds any significant lag -it can be pretty much on part with hardware, provided the user uses lag reduction options like hard sync on their end of course (there’s also an option in Beetle Saturn called “Mid-frame Input Synchronization” which might help decrease it further but will add an additional CPU cost).

#60

The slowdown when keys are pressed seems to be specific to mednafen standalone, I don’t notice it with beetle-saturn (mednafen_saturn_libretro.so, built from github.com/libretro/beetle-saturn-libretro.git)

This seems to be an issue with how the emulator handles keyboard input, which is different than the issues with the Saturn hardware.

I’m not quite sure what the Mid-frame Input Synchronization setting does. There doesn’t seem to be an equivalent in Mednafen 1.32.1. Unlike mednafen standalone, beetle-saturn doesn’t seem to have any frameskip, it just slows down and the audio stutters.

Also, save states work in mednafen, and not in beetle-saturn. Beetle-saturn isn’t quite the same as mednafen that it’s based upon.

#61

Probably not even releasing the actual source code but some of the tweaks only so he is the one that knows the sacred secrets lol. Later fooling everyone they make some mistake when compiling, it works perfectly on his side.

Seen this kind of crap happening, some chucklefuck takes over/hijacks a project, slaps his name in or renames the core completely like it’s their own, with a common motivation which usually is profit from another person’s work. And this usually kills the project for good. And the funny thing is they don’t have a clue wtf they doing.

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#62

There may have been cases of developers not sharing patches, but the bigger issue is that Yabause, Yabasanshiro, and Kronos all have changes that fix some things and break others. That code is available, but reintegrating all of it into one usable emulator and getting everything working would take a lot of effort.

I could try making a list of the games that don’t work and other bugs, but it’s a long list. I posted many issues above. I’d estimate it would take a good developer at least six months to a year to fix all of this, and I don’t have the time to dedicate to it right now.

Several people have offered to help fund this, so if there’s a developer who’s interested in working on this project, we can talk about sponsorship.

#63

Kronos removed all the hacks used in yabause/yabasanshiro, and has the highest accuracy/compatibility among those 3. Over 2145 tested games, 1982 were playable (92.4%). I don’t think you know much about Kronos.

#64

“Playable” is a bit subjective, as games are listed as playable even if there are glitches.

In another thread, someone complained that the graphical glitches in Sonic R were too much of a problem, although the game does run.

A lot of this turns out to be more complicated than it seems.

#65

Being accurate to original hardware is not a glitch, it’s funny how people forgot about wobbling on those early 3D consoles just because pgxp was implemented on psx emulators.

This is Sonic R in Kronos : https://youtu.be/xI4gOdWa6UY

The “really bad wobbling” in mednafen is exactly the same, and you’ll find the same “really bad wobbling” on original hardware : https://www.youtube.com/watch?v=HlCBR46W_Qs

“Playable” usually means it can be played without issues affecting gameplay, and it is not nearly as subjective as making false statements about an emulator. I have to really wonder if you ever tested it.

#66

Regarding what I was quoted on (and absolutely nothing else)

The issue with the floor in Sonic R on Kronos is not present in Beetle_Saturn, or moreimportantly real hardware. The video linked is not a great representation of what is happening, as the camera is flying around in this demo and you can’t even get a good look at the ground plane.

I’m not tainted by the existence of PGXP on PSX emulation, what I’m talking about in what was quoted has nothing to do with the standard polygon wobbling from these games. The entire floor texture is floating up and down like a raft on waves.

Which, again, isn’t present on beetle_saturn, or more importantly, real hardware. It’s an emulation inaccuracy. I can try to record a video of it, but if you boot the game, start a race on that first level, and run through the ruins past the bridge on the left and JUMP you will see exactly what I’m talking about there.

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#67

I tried the game before recording that video, and didn’t notice anything. I ended up recording the demo because i suck at this game.

Issues should be reported on the project’s github, not on a 3rd-party forum. Unreported issues are less likely to get fixed. Also keep in mind you need to use original resolution if you plan to make a valid comparison against mednafen or real hardware, upscaling is only gonna magnify any problem natively present in the game’s code.

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#68

To be fair it’s not a very ‘good’ game to start with haha, even if I love it.

It wasn’t my intention to report a bug, as I mentioned I was only here because I got quoted and my quote wasn’t understood. That’s a good idea though, I’ll track down the git and see how to open one.

#69

The project’s github is at https://github.com/FCare/Kronos/issues

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#70

I tried and i have no clue what you are refering to.

I have a feeling this is exactly as i suspected and you are making some invalid comparison by using upscaling.

#71

I’m sorry you can’t see it. Maybe there’s something different between what we are doing. To be clear, I am not upscaling for this comparison. I’m playing at native resolution, and comparing to my Sega Saturn with a real copy in the same room.

I appreciate the link, and if I get around to it, I will post a video; because I just pulled it up and confirmed I am still seeing it in Kronos, but not in beetle_saturn.

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#72

If you can’t post a video, can you at least post a screenshot with some arrow indicating where i’m supposed to look at ? Maybe i didn’t understand your instructions about the location.

#73

After further testing with many games it’s true that current state of Saturn emulation is dreadful except if you use a good fast desktop PC to run Beetle Saturn well. Tons of issues on Yabasanshiro on PC/Android. Random crashes, random slowdowns, many graphical issues and more. Beetle Saturn seems the better core except it won’t run well even on a Snapdragon 865, due to missing arm64 dynarec probably. Simple games like Saturn Bomberman run pretty good on a sd865 with Beetle Saturn, but others like Sega Rally won’t.

#74

@SkyHighGam3r btw, i’m still looking forward to more information about this Sonic R bug in Kronos

#75

ymir also improved plus it has more conveniences like automatic gamepad support, fullscreen double click, CD speed etc For faster pcs it is also a viable option

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#76

Yes Ymir is the Saturn emulator to look for right now. Perhaps if it gets a dynarec it will be the top Saturn emulator, maybe even run well on something like the rk3566. Even now it looks like it’s the best on a good PC, my gamepad was automatically detected and configured, all games i tested run without issues. But no dynarec so you must have a good PC to run it without problems (for now).

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