04736: wboy, choplift, many others: screen resolution incorrect for system1 sets like wonder boy or choplifter

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
04736	Graphics	Major	Always	Mar 23, 2012, 14:02	Mar 23, 2012, 15:09

Tester	cyberbaud	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Invalid report	OS	Windows XP (32-bit)
Status [?]	Closed			Driver	sega/system1.cpp
Version	0.145	Fixed in Version		Build	Normal
		Fixed in Git Commit		Github Pull Request #

Summary	04736: wboy, choplift, many others: screen resolution incorrect for system1 sets like wonder boy or choplifter
Description	system 1 screen resolution (wboy, choplift for example) has been changed from 256x224 to 512x224. This change seems to have occurred in 0144u4 (I noticed it in 0.145). - MCFG_SCREEN_RAW_PARAMS(MASTER_CLOCK/4, 320, 0, 256, 260, 0, 224) + MCFG_SCREEN_RAW_PARAMS(MASTER_CLOCK/2, 640, 0, 512, 260, 0, 224) Why was this changed? 512 seems incorrect and causes issues with correct video mode selection. system 1 hardware was 256x224 as far as I know.
Steps To Reproduce
Additional Information
Github Commit

Flags	Noted in Source, Verified with Code
Regression Version
Affected Sets / Systems	wboy, choplift, many others

Attached Files

No.08397 Haze Senior Tester Mar 23, 2012, 14:17 edited on: Mar 23, 2012, 14:17	Systems don't have horizontal resolutions, it's a bit of a misconception that they do based on what they appear to output as standard (usually based on the number of pixels created by the output clock of one layer) In this case I'm guessing it's something like the sprites are actually misaligned by half a pixel compared to the tilemaps on real hardware, so the effective resolution output has to be doubled to allow that to be represented (that's usually why such things happen in MAME at least) Could be a bug (haven't checked) but it's equally possible it's correct.
No.08398 hap Developer Mar 23, 2012, 15:07	It's 256x224 pixels indeed, but scroll and sprite offsets are not at pixel granularity. Compare for example with galaxian games where MAME had to adjust the overall resolution due to the starfield, though bg scanline length is still 256 pixels.
No.08399 hap Developer Mar 23, 2012, 15:09 edited on: Mar 23, 2012, 15:11	see 04558 for more info