[Interest] QML: Flage QSGNode::DirtyGeometry and recreation of batches

Sean Harmer sean.harmer at kdab.com
Wed Jun 10 16:42:39 CEST 2015

On Wednesday 10 Jun 2015 16:09:54 kim kulling wrote:
> Hello ML,
> I am working on a QSGGeometryNode, which geo needs to get updated every
> frame ( visualization of data ). At the moment I am changing the vertices
> via the QSGNode::update-method and mark it as QSGNode::DirtyGeometry. I
> have several 100 vertices which are unchanged, only a couple of vertices
> will get changed.
> Is this ther most perfromant way to do this? I am not sure if the
> scenegraph needs to update the whole batching each frame? Special on an
> embedded device I can observe that my performance is pretty bad ( 16 FPS ).

Is the buffering of data the bottle neck?

> Which is the recommended way to do this? Anny recommendations?

Iirc OpenGL ES 2 doesn't have glMapBuffer() or glMapBufferRange() so it's not 
possible to update subsets of a buffer with unextended ES 2.


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