01803: Possible issue with prescale option under Vista.

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
01803	Interface	Minor	Always	May 15, 2008, 15:53	May 16, 2008, 03:16

Tester	Machone	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Unable to reproduce	OS	Windows XP/Vista 64-bit
Status [?]	Closed			Driver
Version	0.125u1	Fixed in Version		Build	Normal
		Fixed in Git Commit		Github Pull Request #

Summary	01803: Possible issue with prescale option under Vista.
Description	This could well be a graphics driver bug, but if it's a MAME bug then it's an important one, so I think it's worth a post. When '-video d3d' and 'prescale 2' or higher are enabled under Vista I get a weird effect on scrolling games. It seems as though when the scrolling graphics hit a certain horizontal line on the screen the last line drawn gets doubled, which gives the appearance of a continual tear on one fixed horizontal display line. This doesn't happen using XP, but occurs in both the 32 and 64 bit builds under Vista. It's only really noticeable during continuously smooth scrolling games. Note, everything's fine with '-prescale 0' or '-prescale 1'. The best test I could come up with was using Paperboy's playfield test as this allows for a continuous scrolling background. In the attached picture you can see the doubled line running through the middle of the 'hello' mat all the way through to the kerb. Hopefully someone can confirm whether this is a MAME issue or not. Btw, I am using an Nvidia 8800GTS graphics card with the latest drivers.
Steps To Reproduce	on Windows Vista: launch MAME using: mame paperboy -nofilter -effect none -prescale 2 -video d3d -triplebuffer hit F2 to enter service mode push key 2 until you enter 'Scrolling Playfield Test' Hold down either the up or down arrow keys to scroll the screen Look carefully for any weird line doubling happening at a specific point on the screen. It's quite subtle, so look closely.
Additional Information
Github Commit

Flags
Regression Version
Affected Sets / Systems

Attached Files	Untitled3.png (3,126 bytes) May 15, 2008, 15:53

No.00970 Tafoid Administrator May 15, 2008, 19:23	I've tried to duplicate with your command above and I do not notice any oddness. Windows 2000, Radeon 9600 Pro, 32-bit build - looks fine. Left open for more user observation. The "-effect 0" flag is not required.. unless you have a 0.png file you are using, otherwise you get the error: Unable to load PNG file '0.png'.
No.00972 Machone Tester May 15, 2008, 19:41	Thanks for testing but I believe that if this is an issue, it's a Vista only issue. As for the -effect command, I should've put '-effect none' - it's important to test this without filters or effects as they'll obscure the problem.
No.00985 Fujix Administrator May 16, 2008, 03:16 edited on: May 16, 2008, 03:18	This is not a bug. You run MAME with -nofilter, but your PC display or MAME window don't match the game resolution (512x384 in paperboy, 1024x768 with -prescale 2), MAME tries to insert or draw some lines to fit your display. You should use -prescale along with -filter to minimize the blurring of stretch. Closing report.