Russian ATM Screen Preservation (ZX-Evo)

[Lethargeek]

2. "atmega" - ATM Turbo 2+ EGA graphics mode. 32128 file containing pixel data and palette.

please not again, every time ATM 16c mode is called "EGA" a cute fluffy kitten dies somewhere

[moroz1999]

please not again, every time ATM 16c mode is called "EGA" a cute fluffy kitten dies somewhere

Please let's not start holy war about naming. I don't care how it's named, I'm using it because it's clear what ATM mode I'm talking about.

[Lethargeek]

please not again, every time ATM 16c mode is called "EGA" a cute fluffy kitten dies somewhere

Please let's not start holy war about naming. I don't care how it's named, I'm using it because it's clear what ATM mode I'm talking about.

Please don't justify spreading of the old marketing misinformation under the pretext of avoiding a holy war. It has nothing in common with the real EGA in both hardware and software aspect. Also calling it just "ATM 16c APA mode" is much more clear in addition to being 100% true.

I really hope it won't be designated in ZXDB as "EGA"

[PeterJ]

On the discussion of the ZX-Evo, does anyone have one of these?

https://www.sellmyretro.com/offer/detai ... card-27537

I've read the English manual, but I would like a SCART cable rather than having to build one myself.

[moroz1999]

I have ZX-Evo as my main ZX, I'm using it almost daily.
I'm using it with modern LCD 50hz compatible monitor through built-in VGA. I haven't used it with RGB, it has a connector on a motherboard, but I'm not sure about how easily it can be connected to cable, never done it.

[moroz1999]

Hires images in .grf format (common for ATM and Profi):
http://alonecoder.nedopc.com/zx/MCX04.zip

Thank you! I will take a look and implement it in Zx-Image, so GRF files from both ATM and Profi could be displayed here on Spectrum Computing and on ZX-Art.
Is there any way to preview them? MCX viewer doesn't seem to open the format or I didn't find how to do it.

[moroz1999]

Alone Coder, one more question to you: I will add the control of BMP palette in ZX-Image, so only the real colors would be stored/processed.

Is this a real palette? If so, I will use it.

1. What should I do if BMP uses a "wrong" color? Should I ignore it and show black instead?
2. I can automatically replace it with the "closest" one from the ZX-Evo palette. But will this be right thing to do? How would such BMP be displayed on a real software? Will some correction be done or it will be ignored?

3. The palette values seem to be designed for linear RGB without color correction. Each of them represent 1/3 of RGB channel intensity: 85, 170, 255. It really makes sense for the linear RGB, but I think they should be gamma-corrected when displayed on PC hardware stack.
So instead of 85, 170, 255 I should display 156, 213, 255. These colors match 1/3, 2/3 and 3/3 of intensity on sRGB. Does that sound right to you? Please advise.

[Alone Coder]

MCX Viewer views .grf if your computer has ATM2+ compatibility. You can also try NedoView in NedoOS, sources: http://nedoos.ru/svn/listing.php?repnam ... e851c9c66f
As for the levels, the regular precision of resistors used in amateur hardware was +-10%, and the gamma curve of TVs was not controlled.
The only thing I remember, we only controlled that colors 0,1,2,3,4,5,6,7 in both bright and nobright went in ascending order in B/W.
I make ATM gfx in 0,85,170,255 (these are not sRGB or any other standard colors, just values in a file). Someone proposed me a palette with 0,93,162,255. Your picture shows 0,80/85,170,255. All three versions fall in +-10% range. So, don't bother. 0,85,170,255 is just regular.

[moroz1999]

MCX Viewer views .grf if your computer has ATM2+ compatibility. You can also try NedoView in NedoOS, sources: http://nedoos.ru/svn/listing.php?repnam ... e851c9c66f

rose.g, snowcat.g, doktorsk.g - are these GRF files or did I take the wrong ones? I've tried it on ZX-Evo with baseconf, but with no luck.
I'll try NedoOS one day, thanks, just not on this week.

As for the levels, the regular precision of resistors used in amateur hardware was +-10%, and the gamma curve of TVs was not controlled.
The only thing I remember, we only controlled that colors 0,1,2,3,4,5,6,7 in both bright and nobright went in ascending order in B/W.
I make ATM gfx in 0,85,170,255 (these are not sRGB or any other standard colors, just values in a file). Someone proposed me a palette with 0,93,162,255. Your picture shows 0,80/85,170,255. All three versions fall in +-10% range. So, don't bother. 0,85,170,255 is just regular.

Ok, thanks. I think I'll make some samples for comparison and then we'll decide what looks better. The problem is that if we use srgb values (0, 156, 213, 255), they would be far from 10% of precision. But these are the numbers if we want to divide palette values by 33% of luminance for srgb gamma-corrected displays.
The picture I have was just some picture I've found in internet, it's not mine. I was just curious if somebody really knows what are the true colors of the ZX-Evo palette.

[Alone Coder]

I don't have a ZX Evo, so I can't test, but I asked Sashapont to test, and he said it works on his ZX Evo.
In UnrealSpeccy in ATM3 mode it also works well.
UnrealSpeccy shows pictures with values 0,96,160,255 (palette "Alone", looks right) or with 0,118,205,255 (palette "Pulsar", looks wrong).

[PeterJ]

Apologies if I have missed something here, but is the only way of getting screens from emulators, as PNG from Unreal at the moment?

[Alone Coder]

You can switch pages in UnrealSpeccy manually to save the actual picture data from memory, but UnrealSpeccy doesn't allow to save the current palette...
Maybe Deathsoft will add a special function if you write him? deathsoft [a] yandex ru

[moroz1999]

I don't have a ZX Evo, so I can't test, but I asked Sashapont to test, and he said it works on his ZX Evo.
In UnrealSpeccy in ATM3 mode it also works well.

https://www.youtube.com/watch?v=Ip0HvPs ... e=youtu.be - strange, this is how it works for me. Same thing if I take Unreal Speccy, select ZX-Evo there and try to load it.

UnrealSpeccy shows pictures with values 0,96,160,255 (palette "Alone", looks right) or with 0,118,205,255 (palette "Pulsar", looks wrong).

Ok, thanks, I'll take 0,96,160,255 then for ATM BMP files.

[Alone Coder]

Maybe it depends on firmware? I see you have BASE&TS.
That's how it works in UnrealSpeccy 0.39.0 from NedoOS repository (the detect also affects 3-color pictures):
https://youtu.be/nE43nwp0V8M
Similar ATM2 detection routine is also present in ACNews and maybe somewhere else. You can open MCX sources in ALASM, the cursor in the source just points to it.

[moroz1999]

It may easily be the problem of firmware indeed. Hires itself is working fine in ANSI viewer, I've selected ATM2 80*25 mode and it worked.
Thanks for examples, now I now how images should look like, I can now implement it in viewer.

[Alone Coder]

Also tried:
- the same emulator in ATM2 mode
- UnrealSpeccy 0.38.0 in ATM3 mode
- Pentagon 2.666LE
All of them show pictures correctly.

[Alone Coder]

Added a patch to UnrealSpeccy 0.37.1CFIX to save the palette when you save a snapshot: http://alonecoder.nedopc.com/zx/US0371FIX.ZIP
It's just 3 lines in snapshot.c, you can copy it in any other version: http://alonecoder.nedopc.com/zx/US0371FIXSRC.ZIP
There are 4 bytes per palette entry, only one is used, and the format is unusual gg0rr0bb.

[PeterJ]

Thanks [mention]Alone Coder[/mention],

When I start taking screens for ZXDB I will use this version.