Screen tearing on small portion of display

lordofchaos · 07 January 2015, 00:32

Whilst using latest official release (WinUAE 3.0.0) I've been noticing screen tear occurring at the top (not quite the top) portion of the screen. I've tried different games but everything seems affected. The only way I can stop it from happening is switching the Graphics API from Direct3D to DirectDraw. I`m not sure how far this goes back with older versions of WinUAE, but seems fairly recent.

GeForce GTX 550 Ti
Intel(R) Core (TIM) i5-2500K @ 3.30GHz
8.00 GB RAM
Windows 7 (64bit)

My DirectX and G-Force drivers are up to date. Thought this might be the problem but appears not.

Toni Wilen · 07 January 2015, 09:44

Thats normal in low latency vsync + no buffer mode if buffer switch gets delayed. It is not guaranteed to work in all systems.

Also power saving features can cause it. Make sure nvidia control does not have "adaptive power saving" or any other power saving enabled.

lordofchaos · 07 January 2015, 17:28

Well seems my GFX card is running at optimal settings, it's a shame this has just started to happen despite my hardware remaining the same.

After some tinkering with screen resolutions I've manage to find one that prevents the tearing. 720x576. Curious if others have experienced this though with similar hardware.

Toni Wilen · 07 January 2015, 17:39

Driver update? Windows update? To get "manual" ("no buffer") buffer swap exactly right requires extremely tight timing.

WinUAE has not any recent vsync or graphics rendering changes.

lordofchaos · 07 January 2015, 17:51

Quote:

Originally Posted by Toni Wilen

Driver update? Windows update? To get "manual" ("no buffer") buffer swap exactly right requires extremely tight timing.

WinUAE has not any recent vsync or graphics rendering changes.

Yup, sounds like driver/windows updates are the culprit. Maybe future updates from windows/nvidia will reverse the effect :-) Fortunately everything seems fine at 720x576.

Toni Wilen · 07 January 2015, 18:38

Is it "stable" tearing (does not jump up or down more than few pixels)? If it is stable, it can be worked around by adjusting buffer swap scan line number. (Not yet possible but can be easily added)

lordofchaos · 07 January 2015, 19:13

The best I can describe is, it's limited to a narrow band located at the top part of the screen, most noticeable on smooth 8-way scrolling games.

The example picture attached shows the region where it's occurring. I can't capture it happening real-time with snapshot.

Toni Wilen · 07 January 2015, 20:48

Unfortunately it is way too tall. If it was about 1/4 or 1/5 in size, there may have been possibility to hide it inside vblank.

lordofchaos · 07 January 2015, 21:14

I`ll have to take another look, the area marked in red was a rough approximation where is was but not it's size. Won't pin any hope on it being much smaller though. Thanks for looking.

lordofchaos · 16 January 2015, 16:35

I've had another look at this problem and may have found a work around. Seems if I enable double buffering along with low-latency VS the tearing goes away, even at my native 1080p.

Also I`m not noticing any extra latency as a result of using double buffering combined with of low-latency VS? Doesn't using double buffer create extra latency?

Hewitson · 16 January 2015, 17:27

Quote:

Originally Posted by lordofchaos

Also I`m not noticing any extra latency as a result of using double buffering combined with of low-latency VS? Doesn't using double buffer create extra latency?

I have no idea, but even if we assume it creates lag of an entire frame, that is not going to be noticable to any human.

lordofchaos · 16 January 2015, 20:43

Well seems you may be right

I loaded up Pinball Dreams and had a few games, didn't notice any real tangible lag. I remember playing this before Toni implemented the low-latency VS and it was really noticeable.

Toni Wilen · 17 January 2015, 10:04

One buffer = 1 frame extra latency (50Hz=20ms, 60Hz=16.6ms). Usually playability gets too bad if latency is over 2 frames, at least in pinball games.

07 January 2015, 19:13	#7
lordofchaos TinkerTailorContentMaker Join Date: Nov 2009 Location: Bedfordshire Age: 45 Posts: 1,205	The best I can describe is, it's limited to a narrow band located at the top part of the screen, most noticeable on smooth 8-way scrolling games. The example picture attached shows the region where it's occurring. I can't capture it happening real-time with snapshot. Attached Thumbnails

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07 January 2015, 09:44	#2
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,507	Thats normal in low latency vsync + no buffer mode if buffer switch gets delayed. It is not guaranteed to work in all systems. Also power saving features can cause it. Make sure nvidia control does not have "adaptive power saving" or any other power saving enabled.

07 January 2015, 17:28	#3
lordofchaos TinkerTailorContentMaker Join Date: Nov 2009 Location: Bedfordshire Age: 45 Posts: 1,205	Well seems my GFX card is running at optimal settings, it's a shame this has just started to happen despite my hardware remaining the same. After some tinkering with screen resolutions I've manage to find one that prevents the tearing. 720x576. Curious if others have experienced this though with similar hardware.

07 January 2015, 17:39	#4
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,507	Driver update? Windows update? To get "manual" ("no buffer") buffer swap exactly right requires extremely tight timing. WinUAE has not any recent vsync or graphics rendering changes.

07 January 2015, 18:38	#6
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,507	Is it "stable" tearing (does not jump up or down more than few pixels)? If it is stable, it can be worked around by adjusting buffer swap scan line number. (Not yet possible but can be easily added)

07 January 2015, 20:48	#8
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,507	Unfortunately it is way too tall. If it was about 1/4 or 1/5 in size, there may have been possibility to hide it inside vblank.

07 January 2015, 21:14	#9
lordofchaos TinkerTailorContentMaker Join Date: Nov 2009 Location: Bedfordshire Age: 45 Posts: 1,205	I`ll have to take another look, the area marked in red was a rough approximation where is was but not it's size. Won't pin any hope on it being much smaller though. Thanks for looking.

16 January 2015, 16:35	#10
lordofchaos TinkerTailorContentMaker Join Date: Nov 2009 Location: Bedfordshire Age: 45 Posts: 1,205	I've had another look at this problem and may have found a work around. Seems if I enable double buffering along with low-latency VS the tearing goes away, even at my native 1080p. Also I`m not noticing any extra latency as a result of using double buffering combined with of low-latency VS? Doesn't using double buffer create extra latency?

16 January 2015, 20:43	#12
lordofchaos TinkerTailorContentMaker Join Date: Nov 2009 Location: Bedfordshire Age: 45 Posts: 1,205	Well seems you may be right I loaded up Pinball Dreams and had a few games, didn't notice any real tangible lag. I remember playing this before Toni implemented the low-latency VS and it was really noticeable.

17 January 2015, 10:04	#13
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,507	One buffer = 1 frame extra latency (50Hz=20ms, 60Hz=16.6ms). Usually playability gets too bad if latency is over 2 frames, at least in pinball games.

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