Viewing Issue Advanced Details
ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
05780 Graphics Minor Always Nov 11, 2014, 08:25 Nov 26, 2014, 13:46
Tester kamilz View Status Public Platform MAMEUI
Assigned To Kale Resolution Fixed OS Windows Vista/7/8 (64-bit)
Status [?] Resolved Driver
Version 0.155 Fixed in Version 0.156 Build 64-bit
Fixed in Git Commit Github Pull Request #
Summary 05780: raiden2 and clones: Screen parameters/refresh rate
Description This is not a bug, just a suggestion. I'm one of the Soft15KHz users. I like to manually tune up perfect detailed screen resolutions for CRT 15Khz monitors.

Most cases I can able to do this and generate a modeline.
In this game (Raiden2) I couldn't manage set perfect settings (or very close). In these cases I examine the source file to see timings. For this game what I found is:

"MCFG_SCREEN_RAW_PARAMS(XTAL_32MHz/4,546,0,40*8,264,0,32*8) /* hand-tuned to match Note: 00055.47 */"

It seems game is manually tuned, I tried to same to match 8 mhz pixel clock and 15.625 KHz horizontal refresh rate (this used by many games) and I get 55.407. Since game uses 55.47, I begin to think there may be a typo in source. Please examine picture below to see my settings.

My suggestion is this game Vertical Refresh rate maybe 55.407 Hz not 55.470.

Just a suggestion. I didn't test this on CRT. But I'm pretty sure picture will show up.
Steps To Reproduce
Additional Information
Github Commit
Flags
Regression Version
Affected Sets / Systems raiden2 and clones
Attached Files
jpg file icon raiden2_320x240@55.407Hz.jpg (96,857 bytes) Nov 11, 2014, 08:25 Uploaded by kamilz
kamilz
png file icon 55.470.png (19,979 bytes) Nov 11, 2014, 22:00 Uploaded by zaxxon
zaxxon
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Notes
7
User avatar
No.11239
NekoEd
Senior Tester
Nov 11, 2014, 19:16
I'll give this to the devs to look at.
User avatar
No.11241
Kale
Developer
Nov 12, 2014, 21:43
Looks legit, and that tool proved to be quite useful.
User avatar
No.11242
kamilz
Tester
Nov 13, 2014, 02:13
Thanks. That tool I use (and you might already know) CRU, Custom Resolution Utility by ToastyX.

While I'm examining the source code I see many games doesn't have raw parameters, and usually refresh rates are hard coded as like this:

MCFG_SCREEN_REFRESH_RATE(60)

I won't bother you unless I see some legit evidence in source like known Pixel Clock to check/test.

Some games and systems are impossible to exactly match, this is because of I believe hardware and driver limitation.
For example Pixel Clock precision is 2 digit after point. For example; C64 Pal pixel clock is 7.882 MHz, that becomes 7.88 and it slightly
affects refresh rate exactness.

Lastly one of the systems (cave.c) has this setting:

MCFG_SCREEN_REFRESH_RATE(15625/271.5)

and games reports 57.550644, but 271.5 vertical scan line isn't seems legit on PC (expects integer) although real H/W probably can do that.
And in these situations (my opinion) it's best to round it to 272 or 271 scan lines.
Groovymame and similar ports I'm pretty sure just tries to match refresh rate, to do this alters Vertical and H.lines at will.

Thanks again.
User avatar
No.11245
Haze
Senior Tester
Nov 13, 2014, 13:37
> and games reports 57.550644, but 271.5 vertical scan line isn't seems legit on PC (expects integer) although real H/W probably can do that.
> And in these situations (my opinion) it's best to round it to 272 or 271 scan lines

we have to use the proper rates where they are known, this is especially true on home systems where you have copy protection mechanisms that expect *exact* timings, not 'almost' not 'rounded' but exact to the degree where 0.5 would matter. we aim to be correct where possible, not convenient for us on a PC.
User avatar
No.11248
AWJ
Developer
Nov 13, 2014, 18:20
I've actually been curious about that cave.c "271.5" for a while. It would make sense if (and only if) the hardware actually outputted an interlaced signal... does it? None of the games runs at an interlaced resolution, they're all 240 lines.
User avatar
No.11255
Calamity
Developer
Nov 17, 2014, 11:29
> I've actually been curious about that cave.c "271.5" for a while. It would make sense if (and only if) the hardware actually outputted an interlaced signal... does it?

I'm not saying this is the case but it could be perfectly possible for the hardware to alternate between odd/even frames with 271-272 total lines, and still get a progressive signal.
User avatar
No.11268
Haze
Senior Tester
Nov 26, 2014, 13:46
fwiw I don't think this was fixed in 0.156, the fix caused some major graphical problems (it was probably incomplete and an automatic timed sprite buffer is needed ) it needs reviewing again now that the release is out