[osg-users] Improving performances

[Robert Osfield]

On 23 February 2017 at 10:07, Ale Maro <sasha71 at teletu.it> wrote:
> 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)
>
> 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.

>From the screen stats it's clear that you are GPU limited and given
the scene stats it's almost certainly down to amount of data.

Running single threaded or multi-threading won't affect performance as
you aren't CPU limited in any way.

To improve performance you need to do a combination of the following:

    1) Reduce the number of vertices and primitives that are being
rendered.  Either LOD's or adaptive meshes, or simply generating a
mesh with an appropriate density required for rendering.

    2) Improve the way that the vertex and primitives are passed to
the GPU.  Use of VBO's and batching of geometry into sizes that work
best are both important ways of achieving this.

Robert.