Improved PicoDrive emulator

[freq-mod]

Hello. There exists a PicoDrive emulator wth much higher accuracy (and performance, even): https://github.com/irixxxx/picodrive/releases/tag/v1.99

Can t be added into this CFW?

[Rezzy-dev]

I don't understand all the requests for a faster PicoDrive. In my experience it hasn't been slow at all on Miyoo. It outperforms all other emulators on the platform.

I'd be curious to hear where you've experienced lower accuracy and slowdowns with PicoDrive, and of what kind?

[freq-mod]

Newer version has better performance on Sega 32X side. Accuracy also went up - YM2612 has properly emulated DAC distortion, waveform clipping, more accurate Z80 core - Master System and Game Gear support, support for large ROMs, like Demons of Asteborg, undocumented features of the hardware are also better emulated, so demos like Overdrive 2 work okay-ish...

[Rezzy-dev]

Ah, so we're talking advanced, demanding, high-performance stuff. And expansions to other ROM support. I see.

Yeah, because for regular Mega Drive ROMs I haven't had any issues with PicoDrive on the system whatsoever. In fact it's doing incredible speeds considering the limitations and low performance of the hardware.

[Apaczer]

Thanks @freq-mod for porting it!
The newest release fixes some issues with bad 6-button mapping in MD. The Game Gear support is great addition too for anyone interested in it, as it performes better than the stock SMS-plus-Gx app (and has Extended view feature!).
Master System games also play well, however the 'bad vertical scalling' issue haven't been fixed since 1.93 (would recommend RetroArch's picodrive core for this system).
Nevertheless, great addition for Miyoo owners!

[freq-mod]

Master System games also play well, however the 'bad vertical scalling' issue haven't been fixed since 1.93

Hmmm... will need to report it then, is it possible to provide more details about this problem?

P.S: Retroarch picodrive core on miyoo tends to lose some frames there and there, while playing sonic 3 I had around 55 fps on average.

[Rezzy-dev]

It may take a while for the changes to propagate to Miyoo, but it's definitely worth it. Is SMSPlus really that bad? o.O

For anyone who doesn't know what PicoDrive's official GitHub page is, could you please link to it here? Thanks. :)

[freq-mod]

The link is in the original post already.

[Rezzy-dev]

Ah, thanks, I didn't realise you linked to the original source. Should have paid closer attention. 👍

[Apaczer]

It turns out, that the "bad vertical scaling" I was describing is in a fact proper/intended scaling for those systems!
Basically original Master System's raw image is 4:3=1.3333 aspect ratio but it scales the final output to 1.5211 when displaying on real CRT (thus giving those black bars top/bottom on the Picodrive). GG similary treat that matter in extended view to keep correct proportions.

For anyone interested in more details:
irixxxx/picodrive#59

Thanks @freq-mod for stirring up conversation, I think it is fair to close that issue and be thankful to @irixxxx for being so forthcoming.

[Rezzy-dev]

Yep, pixel-perfect was not something people worried about back in the 90s with CRT TV screens and monitors. All sorts of weird scaling was going on, and the 4:3 ratio that we talk about didn't really apply to video games. It was roughly that, never exactly. You have to keep in mind that before Windows and LCD screens came along pixels were not so apparent. You couldn't really tell 320 x 240 from 320 x 200. (Or even 640 x 480 from 640 x 350.)

By default, PicoDrive actually displays Mega Drive games in the resolution they were made at, without any scaling. Which is why you get the black bars: 20 pixels in top, and 20 pixels on the bottom. This was what VGA was actually rendered at, and then stretched to the size of the CRT monitor/TV and beyond! Chuckles.

This is also why you often see all sorts of random gibberish on the edges of these games -- where the developers used the cut-off area after stretching as an extra RAM dump (not worrying too much if this will be seen or not -- in most cases not).

On most computer monitors you actually had dials you could turn to tweak the cut-off area and tweak and stretch the viewport. So no two computer monitors displayed the exact same aspect ratio and visible screen area -- because of these user customisations. And if something on the edge irritated you, you could stretch and tweak your viewport to get it out of the way (into the non-visible, cut-off area).

CRT screens were not fixed to amount of pixels and aspect ratio like today's screens are. They were more flexible.

And they had a certain unique charm/atmosphere to them, too -- even if they were quite unhealthy for the eyes. They drew you in into the game/content in a way that LCDs can't. It felt like there was a world inside that screen. It was a very different experience. LCDs are truly flat in comparison (in every sense of the word).

(Although I have to say how the different colours appear on different 3D depth layers on the Miyoo device IPS LCD screens I do find a sometimes immersive and entertaining experience -- and quite unique. It adds an unintended and great visual immersion/depth to some games.)

[Apaczer]

Hi Rezzy,

I wouldn't say it is bad but not suitable for low-spec devices, most MasterSystem games struggle keeping up with 60fps emulation and it lacks some of the features that others have (CPU overclock, GameGear extended view). Generally better options are Genesis Plus GX (not ported) and Picodrive (the fastest imo).

SMSPlusGx still is a good option for GG titles and it can even emulate Colecovision! So nevertheless it is good addition to the Miyoo

[Rezzy-dev]

I see. In that case looking into a version of PicoDrive that supports GG, MS, and 32X may be well worth it, even if it's branched off into different, specialised areas -- which I think better suits both Miyoo/GMenuNX and the Unix philosophy.

PicoDrive really is incredible, isn't it? Stunning performance. :D

What I wouldn't want to see is PicoDrive getting bogged down by too many features -- too many systems to support. Because if adding new features means making PicoDrive harder to maintain and performance hits on the software, then that may not be such a good idea.

Which is why I think specialised branches of PicoDrive for each of these systems may be a much better way to approach this, design-and-developent-wise -- especially given the Miyoo interface.