05961: gotcha: [possible] Layer offsets.

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
05961	Graphics	Minor	Always	Jun 10, 2015, 16:26	10 days ago

Tester	darq	View Status	Public	Platform	MAME (Self-compiled)
Assigned To		Resolution	Open	OS	Windows Vista/7/8 (64-bit)
Status [?]	Confirmed			Driver	misc/gotcha.cpp
Version	0.162	Fixed in Version		Build
		Fixed in Git Commit		Github Pull Request #

Summary	05961: gotcha: [possible] Layer offsets.
Description	The bg layer is shifted by 1 pixel 'left' and the fg layer is shifted by 1 pixel 'up' (See attachments). If this isn't an original PCB behavior, the correct shifts should be (-1, 1) for fg_set_scrolldx and (-4, 0) for bg_set_scrolldx.
Steps To Reproduce
Additional Information
Github Commit

Flags	Possible
Regression Version
Affected Sets / Systems	gotcha

Attached Files	0000.png (43,914 bytes) Jun 10, 2015, 16:26 Uploaded by darq
Attached Files	0001.png (22,573 bytes) Jun 10, 2015, 16:28 Uploaded by darq

No.11749 Tafoid Administrator Jun 10, 2015, 23:40	Confirming as possible pending PCB examination
No.22490 hap Developer 14 days ago	For foreground, I think you meant: m_fg_tilemap->set_scrolldy(1, 0); (2nd param is for flipscreen) The tiles for the control panel with the 3 white holes in it, where sprites for the r/g/b buttons go on top, are used for both the bg and fg layer. So if you tweak the bg layer by 1 pixel, the fg layer needs to move the same way. Otherwise the 2 layers are not aligned with eachother and the sprite buttons on the cpanel will be placed 1 pixel off. But if you do that, you will get glitches elsewhere on the other edge of the screen. I think the driver author picked what looks best overall.
No.22504 cuavas Administrator 10 days ago	I think the behaviour is correct – that stuff would be hidden in the overscan area. Adjusting the layer positions makes things misaligned.