04593: aerofgt: Sprites vs background alignment is sometimes off when scrolling.

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
04593	Graphics	Minor	Always	Jan 4, 2012, 19:25	Feb 6, 2019, 09:15

Tester	hap	View Status	Public	Platform
Assigned To		Resolution	Open	OS
Status [?]	Confirmed			Driver	vsystem/aerofgt.cpp
Version	0.144u4	Fixed in Version		Build
		Fixed in Git Commit		Github Pull Request #

Summary	04593: aerofgt: Sprites vs background alignment is sometimes off when scrolling.
Description	Sprites vs background alignment is sometimes off when scrolling. This is especially noticeable when it's crowded on screen with the game having slowdowns.
Steps To Reproduce	- just play - easiest to reproduce bug with: Take the Japanese plane and power it up to the max, shoot a lot to make it taxing on the game and have it slow down. More chance for the bug to occur then, look at ground object sprites.
Additional Information	driver says: MCFG_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(400)) /* wrong but improves sprite-background synchronization */ Setting vblank time to anything else may improve or worsen the problem, but won't fix the problem completely. This is more likely a blatant hack than accurate emulation.
Github Commit

Flags
Regression Version
Affected Sets / Systems	aerofgt

Attached Files

No.08013 Haze Senior Tester Jan 4, 2012, 22:00	I do wonder if these games ever had proper sprite / bg sync on real hw. If you look at the PSX version (Sonic Wings Special) it has horrific desync (at least in MAME/MESS), and afaik the PSX doesn't even have a concept of different layers... Some evidence as to how bad the sync is (or if it remains perfect all the time) on real hardware would be interesting.
No.08014 hap Developer Jan 5, 2012, 14:24	agreed, I'll set the bug to [possible] btw, you have the ability/right to change bug status, for example setting this one to 'confirmed' if you know the bugreport is valid. It doesn't necessarily have to be an admin (like Tafoid) that does it.
No.13506 Kale Developer Dec 26, 2016, 00:22	VBlank is controlled by that funny CRTC device, also reinstating this being something to be done anyway.
No.16108 MetalGod Senior Tester Feb 5, 2019, 17:35	Here's a pcb video:
No.16112 Haze Senior Tester Feb 6, 2019, 09:15 edited on: Feb 6, 2019, 09:15	This is the type of thing where you'd need a 60fps video to really notice it, 30fps videos on YouTube are going to mask the issue even if it does occur on hardware.