CPS1 Dark Grey tiles in text and background

pjft

Hi all,

Apologies if this has been answered before but I found nothing on Google nor here, and I'm plain curious about it.

In most CPS1 games I find that the background "black" isn't really black but dark grey. That wouldn't be a problem if actual black wasn't used as well.

This is what I mean:

http://mametesters.org/file_download.php?file_id=1103&type=bug

This is most noticeable in text tiles, some games where you can spot it are Mega Twins, Carrier Air Wing, 3 Wonders (the American version) and likely several others.

This happens both on MAME 2003 and lr-fbalpha. I find no mention of this elsewhere, and the MAME bug from 2006/2008 where I got that screenshot from seems to suggest this is the actual expected behavior.

Anyone has any thoughts or comments on this? It feels more of an unexpected emulation artefact rather than something deliberate. I doubt this would have been done on purpose for the arcade games, unless it wasn't really noticeable on a CRT, but I'd love to hear others' perspective. I couldn't find any video of the games running on an actual original cabinet to confirm that.

I haven't tested it on more modern iterations of MAME to see if the behavior goes away, as the ROMs I tested seemed to be different and failed to load.

If anyone knows more about it, please let me know - would love to understand the reason for this, especially if it turns out it was present in the original hardware :)

UDb23

Here's a video of actual (not emulated) carrier air wing. Couldn't notice that gray background but it could be due to darkness of the video or my macbook's lcd.

pjft

@udb23 Thanks for sharing! You're right, I can't see those dark grey tiles.

I just tested out the Japanese version and indeed it still shows up there, so I'll assume it's an emulation artefact or something that wouldn't be visible in a CRT. (see 1 min 18s)

I suppose my OCD and curiosity get the most of me :)

Thanks for entertaining this though, and if anyone does have any further thoughts or perspective, do share! Happy Sunday.

grant2258

@pjft said in CPS1 Dark Grey tiles in text and background:

@udb23 Thanks for sharing! You're right, I can't see those dark grey tiles.

I just tested out the Japanese version and indeed it still shows up there, so I'll assume it's an emulation artefact or something that wouldn't be visible in a CRT. (see 1 min 18s)

I suppose my OCD and curiosity get the most of me :)

Thanks for entertaining this though, and if anyone does have any further thoughts or perspective, do share! Happy Sunday.

I wonder if a real arcade hooked up to a lcd would provide the same result I think if you put your brightness down it would go away or there is something wrong with the tranparency settings. I would try the brightness option first lcd tv (hdmi) have different settings to handle black maybe try setting them different

pjft

@grant2258 Might certainly be a brightness setting thing as well. I might look into it, out of curiosity and see if anything changes. Maybe even a MAME gamma option or something.

dankcushions

this is a very typical thing in CRT-era games on LCD screens. such greys wouldn't be visible via CRT. i've seen them on some console games, also.

barbudreadmon

I'll take a look in fbalpha codebase, i kinda remember seeing a gamma variant in the functions handling colors depending on the video output, i didn't use it in lr-fbalpha though, because i never knew if there was some kind of benefit from using it.

grant2258

@barbudreadmon said in CPS1 Dark Grey tiles in text and background:

a codebase, i kinda re

well when this happens on a cable/satelite box you put the tv brightness down its just a matter of adjusting the tv to the source properly as well. In general though crt is far more forgiving

youxia

This is a CRT via composite: Brightness about 40
alt text

And this one with Brightness: 25
alt text

Problem is, this is a really low Brightness, even if I bump Contrast to ~80. There's one more variable in my telly (S-Bright), but overall I play with the brighter version on. It all depends on a game though: for example in this title (CAW) the low brightness is mostly fine, but in other, darker titles you will start losing details. It's also dead hard to calibrate properly, I'm not even sure if its possible, to have one profile for all games and systems.