[osg-users] OSG + Qt performance issue

[Robert Osfield]

Hi Ale,

Please update to 3.6.1 as it contains a change to how Drawable sets up
display lists and VBO's to avoid creating VBO's inside as this was
causing an issue for some users on certain hardware/drivers.

Robert.

On 30 May 2018 at 16:13, Ale Maro <sasha71 at teletu.it> wrote:
> Hi all,
>
> we recently updated our project from OSG 3.4.0 + Qt 5.5 to OSG 3.6.0 + Qt 5.11.
> We noticed a framerate slowdown without changing our code.
>
> After some investigation we found that using VBO as we did until now the performance is bad but using display lists performance are equal or better than before.
>
> The bottleneck seems to be in Draw step (in my test using VBO on screen statistics shows Draw timing greater than 100 since other timings are 0.3)
>
> We choose to use VBO in the past becouse we potentially have very big geometries in a single node so choosing VBO we can increment visualization performance at first frame and avoid memory problems.
>
> Now we saw very different code inside Drawable.cpp for display list management. So I guess if our choice of using VBO is still valid or do you think we can switch to display lists?
>
>
> On the other side did someone experience this kind of problem with Qt 5.11 (or a version greater than 5.5)? Maybe there is a solution changing some Qt settings.
>
> Thank you in advance.
>
> Best regards
> Ale
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=73896#73896
>
>
>
>
>
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