[osg-users] [About VertexArrayObject Branch] FeedBack and Insight

[Jannik Heller]

Hi,

I have tested out the VAO branch on my Nvidia graphics card. As you said, VAO+VBO is slightly faster than VBO but not as fast as display lists. Would be curious on the performance results with AMD cards.

Unfortunately, I am unable to use VAO for animated meshes because you've introduced a new meaning of the dataVariance flag. https://github.com/openscenegraph/OpenSceneGraph/blob/vertex_array_object/include/osg/Drawable#L523

I do *not* set the dataVariance to DYNAMIC for all my animated meshes because the performance overhead of DYNAMIC is not acceptable for me. If Drawables are set to DYNAMIC, OSG would not break frame until all the draws are submitted. I manage the updates using a double buffering scheme that prevents the buffer from being modified while the draw thread is using it. So essentially I don't need the DYNAMIC flag, but now I'm forced to use it (and incur the performance overhead associated with it) because OSG won't update the arrays if I don't. :( Previously it was sufficient to dirty() the vertex arrays to get OSG to update things. Hopefully that can be fixed.

Cheers,
Jannik

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