[vtkusers] Problem with volume rendering inside of Qt application

Wed Feb 18 08:46:39 EST 2015

Yes, that would be because the older graphics card don't have the core
profile. It seems to me that Qt creates a core profile which does not
support older call / extensions which is used by the old volume mapper.

- So the solution would be is
1) load the compatibility profile
2) use the new mapper

On Wed, Feb 18, 2015 at 5:31 AM, Andrea Brambilla <andrea.bram at gmail.com>
wrote:

> Right, my bad, vtkOpenGLRenderWindow does not even override New(), so
> vtkRenderWindow is actually called.
> I use VTK 5.10 and Qt 4.8 on windows 7 x64
> The reason why I had to use the GL_ARB_compatibility is that the opengl
> compatibility profile seems to be required by the QVTKWidget (I guess). It
> also seems that the driver of my graphics card (GeForce GTX 580) disables
> the compatibility profile by default.
> Notice that, if I use only VTK (without Qt), everything works fine without
> explicitly loading the compatibility profile.
> Also, if I run the same code (with QVTKWidget) on my laptop (which has an
> older graphics card) I don't need to load the compatibility profile either.
>
>
> On Tue, Feb 17, 2015 at 6:36 PM, Aashish Chaudhary <
> aashish.chaudhary at kitware.com> wrote:
>
>> On Tue, Feb 17, 2015 at 11:12 AM, Ernesto Guevara <elguevara at uci.cu>
>> wrote:
>>
>>> Hi, I'm afraid cannot use OpenGL2 backend since I'm using VTK 5.10, is
>>> there any other way to do this???
>>> I tried Andrea’s solution but I’m getting the message that the
>>> application couldn’t load the GL_ARB_compatibility extension. I checked
>>> with glxinfo and that extension is supported in my system, I can render the
>>> volume quite well without QT. I’m using VTK 5.10 with Ubuntu 14.10. do to
>>> this I cannot use QVTKWidget2.
>>> I can’t use vtkOpenGLRenderWindow because it is an abstract class I used
>>> vtkGenericOpenGLRenderWindow.
>>> I’ll keep trying.
>>>
>>
>> You shouldn't use the vtkOpenGLRenderWindow class, just use the
>> vtkRenderWindow::New() which will create the concrete class for you. You
>> may want to debug why its loading the compatability profile.
>>
>>
>>>
>>> Thanks
>>> Ernesto
>>>
>>> PS: I just sent this message to Andrea, sorry about duplicates.
>>>
>>> De: Andrea Brambilla [mailto:andrea.bram at gmail.com]
>>> Enviado el: Tuesday, February 17, 2015 9:11 AM
>>> Para: Aashish Chaudhary
>>> CC: Ernesto; vtkusers at public.kitware.com
>>> Asunto: Re: [vtkusers] Problem with volume rendering inside of Qt
>>> application
>>>
>>> I had a similar issue with QVTKWidget some time ago, which was due to
>>> OpenGL
>>> I solved the issue by checking for the available extensions when
>>> creating the QVTKWidget:
>>>
>>> QVTKWidget* createQVTKWidget(QWidget *parent)
>>> {
>>>     // create a RenderWindow and loads the compatibility profile on it
>>>     auto extManager= vtkSmartPointer<vtkOpenGLExtensionManager>::New();
>>>     auto renWin = vtkOpenGLRenderWindow::New();
>>>     extManager->SetRenderWindow(renWin);
>>>     if(extManager->ExtensionSupported("GL_ARB_compatibility" ) != 0)
>>>         extManager->LoadExtension("GL_ARB_compatibility");
>>>     else
>>>         ep::log << "Warning: GL_ARB_compatibility extension cannot be
>>> loaded" << endl;
>>>
>>>     // Create and add a renderer to the managed render window
>>>     auto ren = vtkOpenGLRenderer::New();
>>>     ren->SetBackground(1, 1, 1);
>>>     renWin->AddRenderer(ren);
>>>     /// Create the QVTKWidget and adds the managed render window to it
>>>     auto outWidget = new QVTKWidget(parent);
>>>     outWidget->SetRenderWindow(renWin);
>>>
>>>     assert(renWin->GetInteractor());
>>>     renWin->Delete();
>>>     ren->Delete();
>>>     return outWidget;
>>> }
>>>
>>> On Tue, Feb 17, 2015 at 2:57 PM, Aashish Chaudhary <
>>> aashish.chaudhary at kitware.com> wrote:
>>> If you are using older version of volume mapper (OpenGL backend) then it
>>> is possible that when using QT window, it's not finding the extensions its
>>> needed. Is it possible for you to try the OpenGL2 backend?
>>>
>>> Also, Do you see any error message on the console?
>>>
>>> Thanks,
>>>
>>>
>>> On Mon, Feb 16, 2015 at 4:59 PM, Ernesto <elguevara at uci.cu> wrote:
>>> Jakub Łągwa <kubalagwa <at> gmail.com> writes:
>>>
>>> >
>>> > Hello,
>>> > I have a strange problem with showing VTK volume in QVTKWidget. I can
>>> compile example such as as:
>>> >
>>> http://vtk.org/gitweb?p=VTK.git;a=blob;f=Examples/Medical/Cxx/Medical4.cxxand
>>>
>>>
>>> >  it work fine. But when I want to use exactly the same code in my
>>> sample
>>> >  Qt application (let's say - render only after user press a button)
>>> > nothing is shown in QVTKWidget (I tried also with QVTKInteractor
>>> instead
>>> >  of the one from example). I have this problem only when I want to use
>>> > vtkVolume and than add the volume to renderer with AddVolume. If I make
>>> > other 3D visualisation for example with vtkContourFilter and than I add
>>> > it to renderer with AddActor method - everything works fine.
>>> > I was trying to solve this problem for a couple of days but I found
>>> > some things that I can't understand in any way. If I take, for example,
>>> > Medical4.cxx file and add there
>>> > #include <QApplication>
>>> > and than
>>>
>>>
>>> Hello Jakub I have the same problem with QVTKWidget and can't find a
>>> solution I've been stopped for 4 days. I need to know whether you
>>> managed to
>>> solve this problem and how did you solved it.
>>>
>>> Thanks in advance.
>>> Ernesto
>>>
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>>>
>>>
>>> --
>>> | Aashish Chaudhary
>>> | Technical Leader
>>> | Kitware Inc.
>>> | http://www.kitware.com/company/team/chaudhary.html
>>>
>>> _______________________________________________
>>> 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
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>>> Search the list archives at: http://markmail.org/search/?q=vtkusers
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>>>
>>>
>>
>>
>> --
>>
>>
>>
>> *| Aashish Chaudhary | Technical Leader         | Kitware Inc.
>> *
>> *| http://www.kitware.com/company/team/chaudhary.html
>> <http://www.kitware.com/company/team/chaudhary.html>*
>>
>
>

-- 

*| Aashish Chaudhary | Technical Leader         | Kitware Inc.            *
*| http://www.kitware.com/company/team/chaudhary.html
<http://www.kitware.com/company/team/chaudhary.html>*
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