[Interest] [QT3D] Multiple vertex buffers per Qt3DRender::QGeometry

[Oleg Evseev]

I think my suggestion https://bugreports.qt.io/browse/QTBUG-50720 (and
attached commit on gerrit) will help solve your task with updating the
subset of QBuffer.

I did it for 5.7 branch, but currently I use almost same code in 5.6.

Regards, Oleg
12 мая 2016 г. 18:54 пользователь "Camden Mannett" <camden.mannett at gmail.com>
написал:

> 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
>
> _______________________________________________
> Interest mailing list
> Interest at qt-project.org
> http://lists.qt-project.org/mailman/listinfo/interest
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.qt-project.org/pipermail/interest/attachments/20160512/4f8d8565/attachment.html>