Amiga RTG support (Update: Released!)

[limi]

I’d recommend not using the HD720 driver anymore, and instead use the RTG support in MiSTer via the Picasso drivers, that way you can go all the way up to 1080p, and it’s much more performant. The HD720 driver relies on pushing the AGA chipset in a way that it wasn’t designed for, so it’s slower and can’t have a lot of colors.

To solve the “UI elements are too small” issue, I made a “540p” resolution, which doubles everything but still gives you a nice 16:9 desktop with plenty of space. It’s included in the latest MegaAGS, but I can also send you that particular ScreenMode configuration file once you have everything else working on the RTG front.

[HeavyHitter]

When I switch to 540p, the profile you created aspect ratio changes and the icons get stretched. Maybe it's a wrong ini setting causing the aspect ratio shift in 540p?

[limi]

That’s not happening here, just double checked — ensure that there isn’t anything weird in MiSTer.ini or in the saved configuration?

Do note that Amiga’s default Workbench resolution, UI widgets and icons are close to a 2:1 pixel aspect ratio (640×200/640×256), so if you want it exactly like it is, just scaled, you’ll have to create a resolution that does that. Otherwise, you can use an icon set + something like VisualPrefs to make things look better.

[ByteMavericks]

The PiStorm team have been busy implementing RTG using Raylib and the performance is excellent. It looks like the Minimig RTG driver is simply writing to the framebuffer through shared memory - would it be possible to take the same approach as PiStorm here as the difference does seem to be big...

[ByteMavericks]

OK, if I understand it correctly, RTG right now is merely writing directly into the frame buffer directly via the HPS: is that correct?
The way PiStorm handles this is that there's a full accelerated RTG implementation on the Amiga. This interfaces to the RPI side via a shared memory interface which writes commands and data to a certain address. On the RPI side there is a watcher on that memory that then decodes the instruction and passes to RayLib (or SDL). RayLib does the optimisation of line draw, blits, writes etc.

I think the RTG interface would need to change quite significantly to move the watcher functionality and RayLib into mister_main, and the Amiga RTG to be only slightly updated to reflect the appropriate shared memory ...

I know nothing about HPS... Anyone spot the errors in this?

[bbond007]

I know nothing about HPS... Anyone spot the errors in this?

The HPS does not support OpenGL which seems to be required by RayLib...

The use of OpenGL is probably responsible for the RTG performance gains on PiStorm.

[ByteMavericks]

Ah. That’s quite fundamental. I assume it supports sdl though? might that give some acceleration?

[bbond007]

Ah. That’s quite fundamental. I assume it supports sdl though? might that give some acceleration?

There is no hardware acceleration... adding more libraries/layers is not going to change that...

SDL would be running in framebuffer mode...

[ByteMavericks]

Right. Dang.

[markpaterson]

Thinking about getting a MiSTer (whenever the damn boards become available again!). I see that the MiniMig Amiga core has been updated to support RTG modes.

I've heard that it's possible to have a config that only adds scanlines to AGA screen modes 540 lines and lower (so that WHDLoad games have scanlines) but not have scanlines on RTG Amiga Workbench screens (ie, RTG 1920x1080 16M colors).

And can this be done in a way so you don't have to actually manually switch presets or settings? – ie, dream scenario > Boot into a beautiful RTG Workbench at 1920x1080, launch a WHDLoad Game, monitor changes to PAL with scanlines.

Is this part of what is done with the MegaAGS pack which has settings to optimize cropping/zooming for various games? ie, does it also add scanlines on a per game basis?

[limi]

No, scanlines are not on a per-game basis.

Yes, it should disable scanlines for RTG resolutions. I do think there might have been some regressions there — I think I remember seeing scanlines on a 720p resolution recently — but it definitely used to turn them off once you used any RTG resolution. Which makes sense, since when you add a graphics card, you aren’t really trying to emulate 15kHz CRTs anymore.

There is a new filter infrastructure now, so it might have gotten lost in the shuffle. I’ll file a bug if it doesn’t do that.

Update: There was already a bug filed — https://github.com/MiSTer-devel/Minimig ... issues/142

540p seems to be the best compromise in the meantime, that one doesn’t render any scanlines, and is a nice 2× scale of 1080p (native 1080p is really too high a resolution unless you change all the icons and fonts)

[markpaterson]

Thanks for the quick reply Limi! I also asked on Bay Area Retro Gaming about this and Treminaor told me he asked you about it for me. So I have the answer in both places now LOL.

You're right, a per-game basis is not required, I was just curious because I do not yet have a MiSTer. How you describe it, turning off for RTG modes, sounds perfect though.

My dream setup is to find a nice VGA CRT monitor, maybe one of those late period 21" Apple Trinitron ones, and run MiSTer on that (scan doubled of course). I assume I could configure all cores to have scanlines on 15kHz modes in this scenario too?

Again, looking forward to diving in to this world when the DE10-Nano boards become available again, hopefully not too long.

[limi]

Thanks for the quick reply Limi! I also asked on Bay Area Retro Gaming about this and Treminaor told me he asked you about it for me. So I have the answer in both places now LOL.

Look, mom — I’m famous!

My dream setup is to find a nice VGA CRT monitor, maybe one of those late period 21" Apple Trinitron ones, and run MiSTer on that (scan doubled of course). I assume I could configure all cores to have scanlines on 15kHz modes in this scenario too?

Yes, I believe so — but haven’t tested that yet myself. It may or may not support both the scan doubling and the filters, but I think there’s a different filter (Scandoubler FX or something?) that could at least give you some scanlines. They will have a different character, though — there’s nothing quite like the 15kHz scanlines of the 1084 and the bi-sync 1942 Commodore monitors, IMO

[markpaterson]

I know what you mean, I have the Amiga M1438S multisync monitor that supports 15kHz and VGA natively. I guess I could just use that and get the 15kHz scanlines natively, but get high res RTG workbench modes too.

[Solskogen]

My "new" screen has a max resolution of 1920x1200, but that resolution does not pop-up under Screen Mode. Is there anyway to enable that?

[SuperBabyHix]

My "new" screen has a max resolution of 1920x1200, but that resolution does not pop-up under Screen Mode. Is there anyway to enable that?

Look under System:Prefs, you should have Picasso96Mode.
That will let you define new screen modes.

[Solskogen]

Look under System:Prefs, you should have Picasso96Mode.
That will let you define new screen modes.

That worked. Thanks!

[mahen]

Hi !

I would like to share a tip and a bug !

1) TIP : in order to reduce eye strain and have a full screen Workbench with integer scaling, with scanlines and shadow masks properly applied, I created a 640*360 (1920/3*1080/3) mode in Picasso96Mode. Yes, this is LOW resolution but my eyes do not bleed anymore

Alternatively, you can create a 960*540 mode (1920/2*1080/2), which is a good compromise for people with better eyes than me.

2) ISSUE : quite frequently, when rebooting, I get a completely corrupt RTG screen. Completely grey, or grey with a corrupt WB on a part of the screen. Rebooting the Minimig core is not enough, I need to reboot the whole MiSTer.

I couldn't figure out a pattern, but it mostly seems to occur after reboots, or after modes switches, from AGA to RTG. That is a bit annoying. Anyone saw that ? I'm using WB 3.2.1 and Picasso 3 ATM but I had the same issue under 3.1.

[mahen]

I've filed a bug report regarding my random corrupt / gray screens in RTG mode but it's kinda approximate.

https://github.com/MiSTer-devel/Minimig ... issues/145

Does anyone here encounter this issue as well ? To make a better bug report ! That's pretty annoying as it happens once / several times a day.

[mahen]

Okay, I have an hypothesis but will have to wait a couple more days / weeks to be 100% sure.
I removed my vadjust file (which I used to get a 4X scaling constantly which enabled also to apply shadow masks properly).
Since this removal, I haven't been able to reproduce the bug.
Time will tell !
Might be a kind of complicated random RTG <-> vadjust interference. Hmmm...