[osg-users] Framerate changes with different zoom

[Robert Osfield]

Hi Ale,

The stats show that you are GPU limited.  The frame rates are a bit odd
though.  The individual frame stats for OSG-3.4 are all quite a bit better
than for OSG-3.2 which is good news.  Now why that doesn't result in higher
frame rates when zoomed is odd, and would generally suggest something a bit
strange happening with the viewer.

Try loading the same dataset into osgviewer and see what the behaviour is,
it might be that Qt is affecting things.

The large GPU stats is something I can't explain as I don't know anything
about the actual data you are working and the how optimal this might being
rendered.  There are lots of different possible causes of bottlenecks and
even more different ways to address them.

One possible way to push up GPU stats significantly is to have a lots of
data being transfer to and from the GPU on each frame, or using a blocking
operation like a glReadPixels.  This is a general statement though, as... I
know nothing about the details on your particular app+data.

It is pretty likely there are quite a few things you can do about improving
things, but for the OSG community to help we'll need to know a bit more
about the type and scale of data you are working with.

Robert.



On 21 December 2015 at 11:34, Ale Maro <sasha71 at teletu.it> wrote:

> Hi Robert,
>
> I am working with Windows 7 64 bit, NVIDIA Quadro 4000 and Qt 5.4.
> No difference between using and not using vsync
>
> I noticed that, if I merge objects in the scene from around 10 objects to
> one, framerate increases when I zoom out.
>
> Attached is a comparison test between my software with osg 3.4 and 3.2
> with zoom 1:1 and zoom 1:5
>
> Do you think it depends on a culling technique so I can set in in some way?
>
> Thank you!
>
> Cheers,
> Ale
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=65918#65918
>
>
>
>
> Attachments:
> http://forum.openscenegraph.org//files/performance_test_459.pdf
>
>
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