[Interest] Qt3D - Render to QImage

[Juan Jose Casafranca]

Oh thanks!

Yes, in fact my first thought was to use it for a compute shader. It would
make Qt3D a great tool not only for rendering but also for GPGPU.
I will try to have a look on it during the Christmas vacations :-)

2016-11-28 11:31 GMT+01:00 Sean Harmer <sean.harmer at kdab.com>:

> Hi,
>
> On Monday 28 November 2016 11:22:30 Juan Jose Casafranca wrote:
> > Hi Sean,
> >
> > is there any example on how to do that? I tried to use a QRenderCapture
> but
> > I failed two weeks ago.
>
> http://code.qt.io/cgit/qt/qt3d.git/tree/tests/manual/rendercapture-qml
> http://code.qt.io/cgit/qt/qt3d.git/tree/tests/manual/rendercapture-cpp
>
> > Is there any way to access the buffers content data using a similar
> > approach to the QRenderCapture method?
> > For example, in an animation system, use a graphics pipeline to compute
> the
> > deformed mesh and then get the new vertex positions for export.
>
> Right, that is missing at the moment. It would be very useful to be able
> to do
> this to read back the results of a compute shader too for e.g.. If you
> wish to
> have a go at adding such a feature analogous the the RenderCapture node
> then
> that would be awesome. If not, we can try to do it for 5.9 but the feature
> freeze is approaching. In either case could you file a JIRA for it please?
>
> Thanks!
>
> Sean
>
> >
> > Cheers
> > Juan José
> >
> > 2016-11-28 11:13 GMT+01:00 Sean Harmer <sean.harmer at kdab.com>:
> > > On Monday 28 November 2016 02:23:59 Philip Schuchardt wrote:
> > > > I'm trying to port my OpenGL code (https://github.com/Cavewhere/
> > >
> > > cavewhere/)
> > >
> > > > to use Qt3D. I think Qt3D will allow me to quickly improve and
> modify my
> > > > rendering pipeline. The one requirement I need is to be able to
> render
> > >
> > > to a
> > >
> > > > QImage and save it to disk. Currently, have a method that renders
> > > > high-resolution images from OpenGL. I do this by tiling a projection
> > >
> > > matrix
> > >
> > > > and rendering the scene one tile at a time and combining them into on
> > >
> > > huge
> > >
> > > > PNG. The problem is I'm not sure how to render Qt3D pipeline to a
> > > > texture
> > > > and then download if from the GPU into memory in Qt3D. Is there an
> easy
> > >
> > > way
> > >
> > > > to do that? Do I need to create my own Aspect?
> > >
> > > Hi, you can use a custom frame graph that includes a QRenderCapture
> node
> > > (coming in Qt 5.8). If you combine this with a camera and some logic
> for
> > > tiling the frustum (NodeInstantiator) you should be able to replicate
> your
> > > existing logic. I'd like to get something like this wrapped up along
> with
> > > Qt
> > > 5.9.
> > >
> > > > Also, many parts of the documentation seem to be missing, very light,
> > > > and
> > > > not up to the same standard as the rest of Qt's documentation.
> > >
> > > Yes this is something I really want to have a push on in the near
> future.
> > >
> > > Cheers,
> > >
> > > Sean
> > >
> > > > Perhaps,
> > > > I'm just missing something from the undocumented documentation.
> > > >
> > > > Thanks,
> > > > Phi|ip
> > >
> > > --
> > > Dr Sean Harmer | sean.harmer at kdab.com | Managing Director UK
> > > KDAB (UK) Ltd, a KDAB Group company
> > > Tel. +44 (0)1625 809908; Sweden (HQ) +46-563-540090
> > > Mobile: +44 (0)7545 140604
> > > KDAB - Qt Experts
> > > _______________________________________________
> > > Interest mailing list
> > > Interest at qt-project.org
> > > http://lists.qt-project.org/mailman/listinfo/interest
>
> --
> Dr Sean Harmer | sean.harmer at kdab.com | Managing Director UK
> KDAB (UK) Ltd, a KDAB Group company
> Tel. +44 (0)1625 809908; Sweden (HQ) +46-563-540090
> Mobile: +44 (0)7545 140604
> KDAB - Qt Experts
>
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