[Paraview] FPS drop in stereo mode

[Stephan Rogge]

Aashish,

the quad buffer explenation does make sense. But after some more testing
with the "old" PV version (ParaView_4.0-RC1-51-g2965c8) on a machine with
*  a NVidia Quadro 5000 and 
* a machine with 2 NVidia Quadro K5000 (SLI),
I observed a FPS drop in all stereo modes except "Crystal Eyes" which is
hard to measure with fraps. The FPS overly is not visible in that stereo
mode. 

When I use "SplitViewportHorizontal" as stereo mode on my Kepler GPUs I can
see a FPS drop. Interestingly the rate depends on the ParaView's window
size. The smaller the window is the higher the rate and vice versa. I guess
that a post process, which copies pixel between buffers, need some more time
for execution. Is it possible?

Regards,
Stephan

Von: Aashish Chaudhary [mailto:aashish.chaudhary at kitware.com] 
Gesendet: Donnerstag, 13. Juni 2013 17:51
An: Stephan Rogge
Cc: ParaView list
Betreff: Re: [Paraview] FPS drop in stereo mode

Hi Stephan, 

GeForce GTX 580 are not great for stereo rendering as I believe they don't
support Quad buffered stereo
 (http://3dvision-blog.com/3840-nvidia-with-a-new-high-end-gpu-namely-the-ge
force-gtx-580/). 
In that case, I believe VTK will perform software stereo implementation and
that's why your performance will go down quite a bit. 

I don't have the latest card but normally the consumer level card don't
support stereo that well (although this might not be the case with recent
NVIDIA cards). 

Let us know if you find this performance degradation on your Quadro cards as
well with latest paraview. 

Thanks,


On Thu, Jun 13, 2013 at 11:13 AM, Stephan Rogge
<Stephan.Rogge at tu-cottbus.de> wrote:
Aashish,

it doesn't matter which stereo type is activated. I've got only 20 FPS...
This is tested on GeForce GTX 580. The ParaView version is pulled from
latest git-master.

Surprisingly, this problem does not occurs on my Render-PC of our
CAVE-system. There I have 2 K5000 NV Quadro cards. But the code base is
older (PV RC1), though I have to check it, with an updated code base and
see, whether this fps drop remains.

Cheers,
Stephan

Von: Aashish Chaudhary [mailto:aashish.chaudhary at kitware.com]
Gesendet: Donnerstag, 13. Juni 2013 16:49
An: Stephan Rogge
Cc: ParaView list
Betreff: Re: [Paraview] FPS drop in stereo mode

Hi Stephan, 

What particular stereo type you chose for this comparison? Also what
graphics hardware you have? 

Thanks,


On Mon, Jun 10, 2013 at 10:47 AM, Stephan Rogge
<Stephan.Rogge at tu-cottbus.de> wrote:
Hello,

I observed an unexpected frame rate drop when using one of PV's supported
stereo modes within an empty scene.

Considering
* OS: Windows
* V-Sync: On
* Application to display FPS (e.g. www.fraps.com)
* Latest ParaView from git-master

Following steps should emphasizes the frame rate drop:
1. Open ParaView without any stereo mode
2. Rotate or drag the camera in the 3D view for several seconds and watch at
the frame rate (should be around 60 FPS)
3. Close ParaView
4. Open ParaView with "--stereo" flag enabled
5. Rotate or drag the camera in the 3D view for several seconds and watch at
the frame rate (should be around 22 FPS)

Obviously, stereo rendering should take twice the time of a monocular
rendering. But this should only occurs in more complex scenes. Can anyone
reproduce this behavior? Is this a BUG?

Best regards,
Stephan


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--
| Aashish Chaudhary
| R&D Engineer        
| Kitware Inc.           
| www.kitware.com   




-- 
| Aashish Chaudhary 
| R&D Engineer         
| Kitware Inc.            
| www.kitware.com