[vtkusers] Black renderwindow with vtkGPUVolumeRayCastMapper/MaximumIntensityProjection
Sankhesh Jhaveri
sankhesh.jhaveri at kitware.com
Wed Feb 21 07:58:04 EST 2018
Hi Sophonet,
Glad that you could solve the problem.
I agree that the documentation is missing to mention that the volume mapper
does not support multisampling. There is also a bug report for this on the
VTK issue tracker - https://gitlab.kitware.com/vtk/vtk/issues/17095
Best,
Sankhesh
On Wed, Feb 21, 2018, 7:31 AM Sophonet <vtk12af6bc42 at kant.sophonet.de>
wrote:
> Hi Sankhesh and all, that
>
> just found a related problem in the developer-list:
>
> https://www.vtk.org/pipermail/vtk-developers/2017-May/035107.html
>
> Indeed, when doing both, setting defaultFormat.setSamples(0) when
> setting the surface format as well as
> vtkRenderWindow->SetMultiSamples(0), the volume appears as intended. I a
> bit puzzled there seems to be little documentation about it, and that no
> error message occurs pointing the developer to the right direction...
> Nevertheless, good that things work again here.
>
> Thanks,
>
> Sophonet
>
>
> On 2018-02-20 16:33, Sophonet wrote:
> > Hi Sankhesh,
> >
> > thanks for pushing me towards the next step of testing. Indeed, the
> > VTK test which I have mentioned below works. After having spent some
> > time on trying to localize the problem, it seems that this is related
> > to the fact that my application is using Qt (5.10 - with desktop
> > OpenGL backend, which works for all my other VTK-based
> > visualizations).
> >
> > I have followed all the suggestions for setting up a QVTKOpenGLWidget,
> > but using the same code as in the test, the four viewers remain empty
> > (which is what I am observing in my application as well). Code
> > snippets are below...
> >
> > Any hints on how to use vtkGPUVolumeRayCastMapper in a Qt 5
> > application with the OpenGL2 backend?
> >
> > Thanks,
> >
> > Sophonet
> >
> > ---
> > void TestGPURayCastBlendModes(vtkRenderWindow *renwin)
> > {
> > // The code from the corresponding function in
> > //
> >
> https://github.com/Kitware/VTK/blob/master/Rendering/Volume/Testing/Cxx/TestGPURayCastFourComponentsMIP.cxx
> > // with minor modifications to use the given renderwindow, and after
> > removing
> > // the few testing-statements
> > }
> >
> > int main(int argc, char *argv[])
> > {
> >
> QSurfaceFormat::setDefaultFormat(QVTKOpenGLWidget::defaultFormat());
> > QApplication app(argc, argv);
> >
> > QMainWindow *mainWindow = new QMainWindow();
> >
> > QVTKOpenGLWidget *widget = new QVTKOpenGLWidget(mainWindow);
> >
> > auto *renwin = vtkGenericOpenGLRenderWindow::New();
> > widget->SetRenderWindow(renwin);
> > mainWindow->setCentralWidget(widget);
> >
> > mainWindow->show();
> > TestGPURayCastBlendModes(renwin);
> > return app.exec();
> > }
> >
> >
> >
> > On 2018-02-19 13:38, Sankhesh Jhaveri wrote:
> >> Hi,
> >>
> >> Well the difference between in my suggestion was that the minimum
> >> scalar value was also getting an opacity weighing ensuring that you
> >> should at least see a white cube if the volume has all the same
> >> values. However, it that also doesn't show you anything, perhaps
> >> there's something else going on.
> >>
> >> Could you try running the VTK tests to see if the volume rendering
> >> ones run and pass?
> >>
> >> Thanks,
> >> Sankhesh
> >>
> >> On Mon, Feb 19, 2018, 4:05 AM Sophonet <vtk12af6bc42 at kant.sophonet.de>
> >> wrote:
> >>
> >>> Hi Sankhesh,
> >>>
> >>> thanks for your message - just tried your suggestion, which is
> >>> basically
> >>> what I have already tried in the commented part of the code below.
> >>> As
> >>> expected, it did not change the result, my renderwindow is still
> >>> black.
> >>>
> >>> Any other hint?
> >>>
> >>> Best regards,
> >>>
> >>> Sophonet
> >>>
> >>> On 2018-02-09 17:57, Sankhesh Jhaveri wrote:
> >>>> Hi Sophonet,
> >>>>
> >>>> Try setting the scalar opacity function over the whole range of
> >>> scalar
> >>>> values.
> >>>>
> >>>> Something like:
> >>>>
> >>>> double * range = data->GetScalarRange();
> >>>> vtkNew<vtkPiecewiseFunction> f;
> >>>> f->AddPoint(range[0], 0.1);
> >>>> f->AddPoint(range[1], 1.0);
> >>>> property->SetScalarOpacity(f);
> >>>>
> >>>> Hope that helps,
> >>>> Sankhesh
> >>>>
> >>>>
> >>>>
> >>>> On Sat, Feb 3, 2018 at 5:37 AM Sophonet
> >>>> <vtk12af6bc42 at kant.sophonet.de> wrote:
> >>>>
> >>>>> Hi list,
> >>>>>
> >>>>> in an earlier version of my software using VTK7.x and the OpenGL
> >>>>> backend, MIP rendering was working using
> >>> vtkGPUVolumeRayCastMapper
> >>>>> and
> >>>>> MaximumIntensityProjection.
> >>>>>
> >>>>> However, in VTK 8.x (e.g. VTK 8.1.0), using the OpenGL2 backend,
> >>> the
> >>>>> renderwindow stays black/empty - VTK does not show an error
> >>> message,
> >>>>> and
> >>>>> the IsRenderSupported (see below) does not seem to fail.
> >>>>>
> >>>>> Any hints what is wrong with the code below? By the way: I have
> >>>>> added
> >>>>> the volumeProperty (and the piecewise function) after following a
> >>>>> current VTK test program
> >>>>>
> >>>>
> >>>
> >> (
> https://github.com/Kitware/VTK/blob/master/Rendering/Volume/Testing/Cxx/TestGPURayCastFourComponentsMIP.cxx
> ).
> >>>>>
> >>>>> vtkimagedata is a scalar medical image (unsigned short), so
> >>> nothing
> >>>>> special.
> >>>>>
> >>>>> Thanks,
> >>>>>
> >>>>> Sophonet
> >>>>>
> >>>>> vtkNew<vtkGPUVolumeRayCastMapper> mapper;
> >>>>> mapper->SetInputData(vtkimagedata);
> >>>>> mapper->SetBlendModeToMaximumIntensity();
> >>>>>
> >>>>> vtkNew<vtkVolume> volume;
> >>>>> volume->SetMapper(mapper);
> >>>>> // ... connect to renderer etc.
> >>>>>
> >>>>> //NOTE: The following lines from VTK's
> >>>>> TestGPURayCastFourComponentsMIP.cxx did not solve the problem
> >>>>> //vtkNew<vtkVolumeProperty> volumeProperty;
> >>>>> //volumeProperty->IndependentComponentsOn();
> >>>>>
> >>>>> //volumeProperty->SetInterpolationType(VTK_LINEAR_INTERPOLATION);
> >>>>> //volumeProperty->SetShade(1);
> >>>>>
> >>>>> //vtkNew<vtkPiecewiseFunction> f;
> >>>>> //f->AddPoint(0, 0.0);
> >>>>> //f->AddPoint(255, 1.0);
> >>>>> //volumeProperty->SetScalarOpacity(f);
> >>>>>
> >>>>> //int valid =
> >>>>> mapper->IsRenderSupported(vtkrenderer_->GetRenderWindow(),
> >>>>> volumeProperty);
> >>>>>
> >>>>> // NOTE: No exception was thrown on my system
> >>>>> //if (valid == 0)
> >>>>> // throw std::runtime_error("MIP rendering is not supported");
> >>>>> //volume->SetProperty(volumeProperty);
> >>>>> _______________________________________________
> >>>>> Powered by www.kitware.com [1] [1]
> >>>>>
> >>>>> Visit other Kitware open-source projects at
> >>>>> http://www.kitware.com/opensource/opensource.html
> >>>>>
> >>>>> Please keep messages on-topic and check the VTK FAQ at:
> >>>>> http://www.vtk.org/Wiki/VTK_FAQ
> >>>>>
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> >>>>>
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> >>>> --
> >>>>
> >>>> SANKHESH JHAVERI
> >>>>
> >>>> _SR. RESEARCH & DEVELOPMENT ENGINEER_ | KITWARE [2] | (518)
> >>> 881-4417
> >>>>
> >>>>
> >>>>
> >>>> Links:
> >>>> ------
> >>>> [1] http://www.kitware.com
> >>>> [2] http://www.kitware.com/
> >> --
> >>
> >> SANKHESH JHAVERI
> >>
> >> _SR. RESEARCH & DEVELOPMENT ENGINEER_ | KITWARE [2] | (518) 881-4417
> >>
> >>
> >>
> >> Links:
> >> ------
> >> [1] http://www.kitware.com
> >> [2] http://www.kitware.com/
> > _______________________________________________
> > Powered by www.kitware.com
> >
> > Visit other Kitware open-source projects at
> > http://www.kitware.com/opensource/opensource.html
> >
> > Please keep messages on-topic and check the VTK FAQ at:
> > http://www.vtk.org/Wiki/VTK_FAQ
> >
> > Search the list archives at: http://markmail.org/search/?q=vtkusers
> >
> > Follow this link to subscribe/unsubscribe:
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> _______________________________________________
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>
> Visit other Kitware open-source projects at
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>
> Please keep messages on-topic and check the VTK FAQ at:
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>
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>
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--
Sankhesh Jhaveri *Sr. Research & Development Engineer* | Kitware
<http://www.kitware.com/> | (518) 881-4417
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