Re: anti-aliasing

Hello Andras,

Thank you very much, in fact, calling the antialisaing code of 
pqContextView::createWidget() after creating a QVTKOpenGLWidget fixed my 
aliasing problem 
(https://github.com/Kitware/ParaView/blob/master/Qt/Core/pqContextView.cxx#L143)

BTW, I am using an old version of ParaView (and also VTK) as I'm working 
under Centos 7 (but I will update VTK/Paraview when the version 8 is 
released).

Happy New Year 2019.

Amine.

Le 28/12/2018 à 19:03, Andras Lasso a écrit :
>
> Plot axes are not painted correctly when multi-sampling is enabled due 
> to an OpenGL error in vtkTextureObject::CopyFromFrameBuffer, which 
> seems to be related to copying data from the frame buffer.
>
> [ERROR][VTK] 28.12.2018 12:51:01 [vtkTextureObject (0000026457878B60)] 
> (C:\D\S4D\VTK\Rendering\OpenGL2\vtkTextureObject.cxx:1990) - failed at 
> glCopyTexImage2D 32856 1 OpenGL errors detected
>
> 0 : (1282) Invalid operation
>
> Andras
>
> *From:* Andras Lasso
> *Sent:* Friday, December 28, 2018 12:52 PM
> *To:* 'Mohamed Amine Mzoughi' <[email protected]>; Paulo 
> Carvalho <[email protected]>; [email protected]
> *Subject:* RE: [vtkusers] anti-aliasing
>
> Multi-sampling works well for me (it smoothes lines, etc.) except axes 
> areas appear black. This is probably a VTK bug that should be fixed, 
> but maybe I just have not configured everything correctly.
>
> ParaView uses multi-sampling for anti-aliasing in plots and not FXAA 
> (https://github.com/Kitware/ParaView/blob/master/Qt/Core/pqContextView.cxx#L143, 
> https://gitlab.kitware.com/paraview/paraview/issues/17202). 
> Anti-aliasing in plots works well in Paraview 5.5.2 (smooth lines, 
> properly rendered axes). *There is no antialiasing in plots in 
> ParaView 5.6.0 (lines are jagged), so there may be some multi-sampling 
> related issues in recent VTK version.*
>
> Andras
>
> *From:* Mohamed Amine Mzoughi <[email protected] 
> <mailto:[email protected]>>
> *Sent:* Friday, December 28, 2018 10:01 AM
> *To:* Andras Lasso <[email protected] <mailto:[email protected]>>; Paulo 
> Carvalho <[email protected] 
> <mailto:[email protected]>>; [email protected] 
> <mailto:[email protected]>
> *Subject:* Re: [vtkusers] anti-aliasing
>
> As you can see in the screenshots below, I was unable to smooth 
> vtkChartXY's plot line (displayed on a QVTKOpenGLWidget) plot with 
> UseFXAAOn and setMultiSamples(8) (multi samples is defaulted to 8 anyway).
>
> Changing the surface format's samples number messed badly the 2D 
> charts with black areas. This is what I've done in constructor :
>
> QSurfaceFormat surface = m_widget->format();
> std::cout << "[debug] Qt widget samples = " << surface.samples() << 
> std::endl; // 0 by default (disabled)
> surface.setSamples(8);
> m_widget->setFormat(surface);
>
> Regards.
>
> Le 27/12/2018 à 22:45, Andras Lasso a écrit :
>
>     To activate anti-aliasing, you can enable FXAA in the renderer
>     using renderer.UseFXAAOn() or set number of samples in the render
>     window using renderWindow.setMultiSamples(8) (if you render in a
>     Qt widget, adjust samples property in the window’s surface format
>     - http://doc.qt.io/qt-5/qsurfaceformat.html#setSamples
>     <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdoc.qt.io%2Fqt-5%2Fqsurfaceformat.html%23setSamples&data=02%7C01%7Classo%40queensu.ca%7C753aca6286994b17a15d08d66cd53b4f%7Cd61ecb3b38b142d582c4efb2838b925c%7C1%7C0%7C636816060432571103&sdata=kKNCZ2h%2FT81oqw77gwhW4lT%2BcLqeLtxOlvFuHOciieY%3D&reserved=0>).
>     Anti-aliasing has impact on performance and may not be compatible
>     with some rendering options.
>
>     Andras
>
>     *From:* vtkusers <[email protected]>
>     <mailto:[email protected]> *On Behalf Of *Mohamed Amine Mzoughi
>     *Sent:* Wednesday, December 26, 2018 10:38 AM
>     *To:* Paulo Carvalho <[email protected]>
>     <mailto:[email protected]>; [email protected]
>     <mailto:[email protected]>
>     *Subject:* Re: [vtkusers] anti-aliasing
>
>     Hello again,
>
>     If I do that, the chart is not visible anymore (the Qt widget is
>     all black), if I change the renderer of the vtkContextView also 
>     (the Qt widget is all white) !
>
>     I give up for the moment !
>
>     ParaView is a such complex software, that I can't trace the stuff
>     related to anti-alisaing in it (reverse engineering ParaView it is
>     tough : a complex build system, many layers, proxies, in fact,
>     it's an oriented object mix of a lasagna and spaghetti code !).
>
>     Thanks anyway.
>
>     Le 26/12/2018 à 16:02, Paulo Carvalho a écrit :
>
>         Hi, Mohammed,
>
>            Strange indeed.  Did you create the vtkRender object
>         yourself or you just used the default one returned by
>         GetRenderer()?   If the latter is your case, I recommend
>         creating your own vtkRender:
>
>
>         m_renderer=vtkSmartPointer<vtkRenderer>::New();
>         m_renderer->/UseFXAAOn/();
>
>             vtkFXAAOptions* const aaOpts = m_renderer->GetFXAAOptions();
>         aaOpts->SetRelativeContrastThreshold(0.125);
>              aaOpts->SetHardContrastThreshold(0.045);
>              aaOpts->SetSubpixelBlendLimit(0.75);
>         aaOpts->SetSubpixelContrastThreshold(0.25);
>         aaOpts->SetUseHighQualityEndpoints(true);
>              aaOpts->SetEndpointSearchIterations(12);
>
>         m_view->/GetRenderWindow/()->/AddRenderer/(m_renderer );
>
>         cheers,
>
>         Paulo
>
>         Em qua, 26 de dez de 2018 às 12:15, Mohamed Amine Mzoughi
>         <[email protected]
>         <mailto:[email protected]>> escreveu:
>
>             Hello Paulo,
>
>             Even without SmoothingOn* instructions, I still have a
>             problem in my 2D charts (I use a subclass of vtkChartXY,
>             same issue with vtkHistogramChart2D, I have rectangles in
>             screen).
>
>             In ParaView, the line is smooth :
>
>
>             whereas in my VTK app, it isn't :
>
>
>
>             I don't know the issue...
>
>             I'm calling the FXAA instructions before Render() in the
>             constructor, I tried even to call them before each call to
>             Render().
>
>             Best regards.
>
>             Le 26/12/2018 à 14:21, Paulo Carvalho a écrit :
>
>                 Hello, Mohamed!
>
>                   It seems that your last calls (*SmoothingOn())
>                 conflict with UseFXAAOn().
>
>                 Here is the output I get when I add a call to
>                 PolygonSmoothingOn().  Not only it is not antialiased,
>                 but you can notice the edges triangle strips, visually
>                 ruining the results:
>
>                 image.png
>
>                 This one is rendered with only UseFXAAOn() and some
>                 configuration to the vtkFXAAOptions object like you did:
>
>                 image.png
>
>                 kind regards,
>
>                 Paulo
>
>                 Em qua, 26 de dez de 2018 às 10:03, Mohamed Amine
>                 Mzoughi <[email protected]
>                 <mailto:[email protected]>> escreveu:
>
>                     Hello,
>
>                     I want to enable Anti-alisaing in my VTK app, so I
>                     took some parameters
>                     from ParaView and it still doesn't work :
>
>                          m_view->GetRenderer()->UseFXAAOn(); // enable AA
>
>                          vtkFXAAOptions* const aaOpts =
>                     m_view->GetRenderer()->GetFXAAOptions();
>                     aaOpts->SetRelativeContrastThreshold(0.125);
>                     aaOpts->SetHardContrastThreshold(0.045);
>                          aaOpts->SetSubpixelBlendLimit(0.75);
>                     aaOpts->SetSubpixelContrastThreshold(0.25);
>                     aaOpts->SetUseHighQualityEndpoints(true);
>                     aaOpts->SetEndpointSearchIterations(12);
>
>                     what am I missing ?
>
>                     Also, m_view->GetRenderWindow()->GetMultiSamples()
>                     => returns 8.
>
>                     and I called also :
>
>                     m_view->GetRenderWindow()->LineSmoothingOn();
>                     m_view->GetRenderWindow()->PolygonSmoothingOn();
>                     m_view->GetRenderWindow()->PointSmoothingOn();
>
>                     Thanks.
>
>                     _______________________________________________
>                     Powered by www.kitware.com
>                     <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.kitware.com&data=02%7C01%7Classo%40queensu.ca%7C753aca6286994b17a15d08d66cd53b4f%7Cd61ecb3b38b142d582c4efb2838b925c%7C1%7C0%7C636816060432571103&sdata=jBV4IH%2BQQc1bpyuRtZOlM%2Bowogpb4Cy8A4jmUkU4C48%3D&reserved=0>
>
>                     Visit other Kitware open-source projects at
>                     http://www.kitware.com/opensource/opensource.html
>                     <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.kitware.com%2Fopensource%2Fopensource.html&data=02%7C01%7Classo%40queensu.ca%7C753aca6286994b17a15d08d66cd53b4f%7Cd61ecb3b38b142d582c4efb2838b925c%7C1%7C0%7C636816060432581112&sdata=52HKzi9ShkYag67JeS8ouv4wis13CIIL6GvioUNBtJk%3D&reserved=0>
>
>                     Please keep messages on-topic and check the VTK
>                     FAQ at: http://www.vtk.org/Wiki/VTK_FAQ
>                     <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.vtk.org%2FWiki%2FVTK_FAQ&data=02%7C01%7Classo%40queensu.ca%7C753aca6286994b17a15d08d66cd53b4f%7Cd61ecb3b38b142d582c4efb2838b925c%7C1%7C0%7C636816060432591117&sdata=lGcYuj%2F57RWY8xjUFrMIJ0ltK7Xasp1ZJV5kvozqE74%3D&reserved=0>
>
>                     Search the list archives at:
>                     http://markmail.org/search/?q=vtkusers
>                     <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmarkmail.org%2Fsearch%2F%3Fq%3Dvtkusers&data=02%7C01%7Classo%40queensu.ca%7C753aca6286994b17a15d08d66cd53b4f%7Cd61ecb3b38b142d582c4efb2838b925c%7C1%7C0%7C636816060432591117&sdata=ccWnZ3Z0SdmnP532RYbNvZOLUzp%2Bio8VdnO%2Bb%2B%2BTzUk%3D&reserved=0>
>
>                     Follow this link to subscribe/unsubscribe:
>                     https://vtk.org/mailman/listinfo/vtkusers
>                     <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fvtk.org%2Fmailman%2Flistinfo%2Fvtkusers&data=02%7C01%7Classo%40queensu.ca%7C753aca6286994b17a15d08d66cd53b4f%7Cd61ecb3b38b142d582c4efb2838b925c%7C1%7C0%7C636816060432601126&sdata=VOmUEluRAQurEKfCKg3wAo4KlQwDo4PUiruMWUzuM6I%3D&reserved=0>
>

_______________________________________________
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:
https://vtk.org/mailman/listinfo/vtkusers