ViewGroup - very strange issue, LM please help !

[Pete Dowson]

I am also seeing this exact same problem, using NatVis's "TruView" version of the Fly Elise product. In my case this is with a viewgroup of two windows projected onto a 210 degree curved screen.

The synchronization between the two was perfect until the latest 5.2 user release, and as in the other user's reports, it seems to correct itself by using ESC - ESC, so I have to do this after any scenario load or position setting.

It is the same in Windowed and Full Screen modes.

This really does need fixing, please.

Pete

[Beau Hollis]

If you have vsync enabled, you could try finding this entry in the Prepar3D.cfg DISPLAY section and setting it to 0:
SwapChainVSyncOnlyMainWindow=1

In the past we wait for every swap chain (undocked window) when vsync was enabled, but using D3D12 and Win10, this behavior often causes a large FPS drop. Starting in 5.2 we default the behavior so that we only enable vsync on the main app window. This does not cause tearing on the other windows because the OS already syncs the desktop. (Unless you are using variable refresh rate and are in full screen, but in that case vsync should be turned off in the settings).

As for Rob's request about the Auto-fill view group, that view group is included in the default ViewGroups.xml that ships with P3D and should show up in your right-click context menu under the view groups section. If not, you add-on may have replaced the ViewGroups.xml rather than adding to it.

I'm unable to see any view alignment issues using a standard view group created through the view group management UI. I tried both autofill/grid and frustum based. Can one of you post the contents of you ViewGroups.xml. Perhaps there is something unique about the view groups being generated by your blending solution.

[micschneider]

Dear Beau,

I've tried the setting SwapChainVSyncOnlyMainWindow=0. It doesnt fix the problem for me. Furthermore it seems that the fix ESC-ESC (I tried it after Petes post) only works half...so one view of my 3 projectors is in sync after that where the other is not. ESC-ESC again fixes then the other view ? strange.....

Please find below the content of my ViewGroup.xml (created with Immersive Calibration PRO from FlyElise):

<?xml version="1.0" encoding="UTF-8"?>

<SimBase.Document Type="ConfigurationFile" version="5,2">
<Descr>AceXML Document</Descr>
<ViewGroups.ViewGroupSet>
<ViewGroup>
<Name>Immersive Calibration PRO</Name>
<AllowZoom>False</AllowZoom>
<View>
<Name>Projector1</Name>
<ViewFrustum>
<SideAngles>-42.000000,40.000000,28.500000,-28.500000</SideAngles>
<OffsetPBH>-6.526100,0.000000,-62.382301</OffsetPBH>
</ViewFrustum>
</View>
<View>
<Name>Projector2</Name>
<DisplayID>2</DisplayID>
<ViewFrustum>
<SideAngles>-40.000000,43.500000,29.000000,-28.000000</SideAngles>
<OffsetPBH>-6.212840,0.000000,-1.090290</OffsetPBH>
</ViewFrustum>
</View>
<View>
<Name>Projector3</Name>
<DisplayID>4</DisplayID>
<ViewFrustum>
<SideAngles>-42.000000,39.000000,28.500000,-29.000000</SideAngles>
<OffsetPBH>-6.043480,0.000000,65.589996</OffsetPBH>
</ViewFrustum>
</View>
</ViewGroup>
</ViewGroups.ViewGroupSet>
</SimBase.Document>

Thanks for your help !

Best regards
Michael

[micschneider]

Dear Beau,

do you have any updates on this topic ?

Today I tested a bit around. I uninstalled and installed different P3D versions and found the following:

Prepar3D_v5_Professional_5.2.22.27615 = ViewGroups damaged after reload, reposition or reset scenario

Prepar3D_v5_Professional_5.2.18.27565 = ViewGroups damaged after reload, reposition or reset scenario

Prepar3D_v5_Professional_5.1.12.26829 = ViewGroups damaged after reload, reposition or reset scenario

Prepar3D_v4_Professional_4.5.14.34698 = no Problem and it is working as it should !!!

So, here in my setup the problem started with P3D v5 !
I havent recognized it before because v5 wasnt really useable for me before 5.2HF1.

Obviously something got broken with version 5 maybe related to DX12 ?

I tested all Versions above with the same Nvidia driver and the same ViewGroup.xml....

I really hope that you are able to find the root cause for this bug as it makes my sim nearly unusable. I need to press ESC -ESC for several times to fix it after every reposition or reload...

Thanks in advance and best regards

Michael

[capteinjack737p3d]

Same here. I have the same Issue!! Since V5.

Regards
Jörg

[Beau Hollis]

I can't seem to reproduce this and I'm wondering if it might be something specific about the camera definition. Do you see this issue in the default scenario with the default aircraft?
Also, are you running any add-ons that might be using the PDK or SimConnect to manipulate windows and cameras?

[micschneider]

Hi Beau,
yes in V5 the problem is visible also with the default aircraft in the default scenario.I tested it with a fresh installed P3D without any addons or other tools ! The only thing which is changed is the ViewGroup.xml.
I replaced the original one with the one coming from the calibration and warping software.
That`s the only change, everything else is freshly installed.
As so many other users with different setups reported the same issue I think we are talking about a major bug. I guess other using a curved screem with projectors and warping software may have not recognized this by now. As I wrote before, sometimes it is not existent after initial load, The problome start when reposition the aircraft (reload). However, sometimes it is also visible after inital load of the scenario. I havent figured out a pattern.
Same with the also described fix (ESC-ESC) sometime it works, sometimes it moves the problem from one side to the other, and after doing this 5 times the problem is gone until next reload.....very frustating !
Thanks for not giving up and letting us alone with this ;-)
Michael

[micschneider]

Dear Beau,

any news or update regarding this issue ?

@all other users with the same problem: Did anyone find maybe another solution or workaround ?

Thanks and best regards

Michael

[Beau Hollis]

I've used your ViewGroups.xml and tested with 3 displays in a few different combinations (same GPU, two different GPUs, etc). On my system the view groups are producing identical images on startup and scenario reset. I'm wondering if there is something at play with the OS or video drivers. Perhaps there are other software or driver features such as NV Surround that are modifying p3d windows. Perhaps the issue is tied to a specific version of Win10. (I tested with 20H2) Are there any 3D views in use that are not part of the view group?

Thanks,

[micschneider]

Hi Beau, thanks a lot for further investigation.
No, I do not use any other view in P3D except those 3 outside views
The point is, that you can not see this problem when aircraft is not moving. If aircaft stands still then I also get a perfectly aligned picture across all 3 projectors on my curved screen.
If aircraft starts to move, only then you see objects like rwy lights or buildings jumping from one view to the next view exactly in these overlapping areas of the projectors.
Or if you are in the air and fly quicker turns. Then you cleary see this vertical screen tearing in these overlapping areas once you have reloaded or reset a flight.
I also tested different GPUs, drivers and so on. As I wrote above I can clearly reproduce this issue in all tested configs with installing any of the P3D v5 versions.
P3D 4.5 does not produce this issue and everything works well like in the years before !!! When installing P3D v5 this issue starts no matter which GPU, Win10 version, GPU driver I tested with.
Of course, the root cause might be coming from something outside P3D but for me it is clear that it happens in combination with P3D v5 ! Maybe related to DX12 or something else. It is really hard for me to determine the root cause as a relatively normal P3D user. I am not an system expert or developer.
The only thing I can say is that in my simulator setup this issue is really a pain and P3D v5 is, so much I like it vs. V4.5, not really useable.
Thanks and best regards
Michael

[Beau Hollis]

Is Vsync on of off? Do the views snap back into alignment when you pause the sim? If you only see this while moving, it may be that one display is a frame behind the others with swap chain presentation. I did test while moving although i've been verifying the results by using print screen and comparing the edges of the image.

The OS/Drivers handle the swap chain presentation and display update. Maybe the way Win10 and Dx12 handles multiple swap chains ends up with a lower likelihood that all displays flip at the same time. This was never really guaranteed before without using special sync hardware but it may have been more consistently in dx11.

[micschneider]

Dear Beau,
yes Vsync is on. The screen tearing is only visible when flying turns, once leveled off the views seem to be correct again. I need to try what happens when I press pause in the millisecond the screen is teared....I try do make a little video
The jumping of objects from one view to the other is only visible when you roll for example. If the aircraft is not moving all views seems to be perfectly aligned.
I have no idea what you mean with swap chain presentation. The only thing I surely can say is that this issue started with v5. Maybe you find a way somehow to figure this out how Win10 and DX12 behave. Otherwise I think all users using a multi projector setup with v5 might revert to v4 and can never use any future P3D version !? I think this should not be the final solution !
Best regards
Michael

[micschneider]

Dear Beau,
I made a little video clip which hopefully demonstrates the problem a bit further.
It is the default aircraft and the default location.
My camera is positioned inside my homecockpit pointing to the area where mid view and right hand view overlap.
I am using slew mode to move on the runway. Take a look at the white runway lights. When they move into the overlapping area of both views they look like splitted into two objects. Once they come out of this zone you see it again as just a single object.
Take also a look at the control tower !
At 0:33 I bring the aircraft up in the air, again with slew mode. Once reached a certain altitude I stop slew mode and flying turns with my sidestick.
You should clearly see the screen tearing between both views !
Then I pressed pause at 0:57 and applied the "fix" by pressing ESC and pressing RESUME in the litle box. With slew mode I brought the aircraft back to a certain alititude.
Take a look what happend to the screen tearing ! It is gone,....until I would reset or reposition the aircraft. Then I have to do the "fix" again, sometimes a couple of times until there is no screen tearing anymore.

https://youtu.be/TYEuO-2GrrY

By the way, I tried to press pause at the moment when the screen was teared. However at the moment the pause applied the screen is not teared anymore.

Please, I really hope you can figure out what the culprit is !!!

Thanks
Michael

[Beau Hollis]

Ah ok. Does disabling Vsync help at all?

I thought the initial report was that there was some kind of permanent offset once you moved the vehicle enough. I can clearly see in some cases that just pitching the camera up and down will cause visible tearing even inside the cockpit view where objects are static. I'll see if there's a way we could try to wait on all the swap chains before we present any of them, but Win10 vsync behavior seems to be different on every new Win10 release so we tend to be cautious about making changes.

You could try playing with these values in the Prepar3D.cfg
SwapChainBufferCount=4
We increased default buffer count to 4 to work around FPS drops in full screen (or with borderless windows that view groups use). If memory serves though this value is used when Vsync is off. If you turn Vsync off and reduce the buffer count, you'll end up getting vsync like behavior because the system has to wait for an available buffer. Depending on vindows version though, you might see the FPS issues i mentioned above.
SwapChainUseWaitableObject=0
Try changing this to 1 and turning vsync on. This uses a different vsync method where we wait for an OS event that should tell us when a buffer is ready. For whatever reason, when I tested this, it seemed like windows would always say a buffer was ready. The wait seems to be introduced when you start rendering to the swap chain.

[micschneider]

Dear Beau,
thanks a lot for your answer. The problem has always been like shown in the last video clip.
I already tried nearly all combinations with vsync on/of using fast sync adaptive sync (in Nvidia control panel) etc. nothing helped.
I will try out all your recommendations with SwapChainBufferCount and SwapChainUseWaitableObject and will report back if anything helped..
The only thing I can not understand is why I can heal the situation (in the most cases) with pressing ESC key and click on resume ??? Doing so fixes the issue and I can use P3D without this tearing and jumping issues until next reload of scenario or reposition ?
Thanks and best regards
Michael