On the Qt forums a couple of months ago someone posted a message regarding trying to use multiple vertex Qt3DRender::QBuffers per Qt3DRender::QGeometry ( https://forum.qt.io/topic/64770/implement-multiple-vertex-buffers-per-one-renderable-entity), they pointed towards this mailing list but I can't find any entry on the subject.
I'm currently trying to visualise FDTD data, which consists of a large number of grid nodes, each with a static position and a rapidly changing scalar pressure value. Naturally I created two vertex buffers, one StaticDraw for the positions, and another DynamicDraw for the pressures. I never understood why my pressure vertex never seems to be accessed, until I read the above post. So now for a workaround. I tried to create one large buffer with the position data occupying the first 75%, and the scalar data the latter 25%. I never got as far as trying it as there seems to be no way to update a subset of the Qt3DRender::QBuffer, as Qt3DRender::QAbstractBuffer::data() returns a copy of the data. So I would have to copy all the unchanging position data to the GPU as well - which obviously woefully inefficient. What is the way to do this? I can't find any examples that use buffer subsets or multiple vertex buffers. Thanks
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