[osg-users] Improving performances

[Sebastian Messerschmidt]

Am 23.02.2017 um 11:07 schrieb Ale Maro:
> Hi all,
>
> thanks for the hints and sorry for the late reply.
>
> Attached is a screenshot of OSG stats on a sample scene with 5 instances of an object (camera#1 is a secondary camera, not important).
> The scene have about 109M vertices (~22M x 5 instances) and 36M triangles (~7M x 5 instances) at 4FPS on an old nVidia Quadro 4000 (Windows 10)
Holy smokes! 22Million?  I guess your hitting a driver limit on the 
vertex count here. Usually a vertexbuffer is around ~65k vertices. Try 
to split your geometries in to smaller pieces to find the sweet-spot.
Maybe you should consider testing with different vertex-counts to find 
out if there is a limit at which the GPU/driver starts to drop massively.
Splitting will also help to display only what you need and not 
transfering the whole scene more or less every frame.

Another thought: the GPU might simply hitting a memory limit. With 
vertex colors, normals and texture-coordinates your geometry alone uses 
more than a gig of video ram. Can you check how much VRAM there is on 
your card?

Last thought:  Use VBO instead of display lists. Quadro drivers might be 
different here.

Cheers
Sebastian
>
> As you can see GPU cycle is the bottleneck (243.40 against less than 0.5 of all other cycles)
>
> OSG is single threaded becouse I am using Qt and I am not able to setup multi-threading with Qt.
>
> Cheers,
> Ale
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=70320#70320
>
>
>
>
> Attachments:
> http://forum.openscenegraph.org//files/grab1_194.png
>
>
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