[Paraview] Performance using ImmediateModeRenderingOff in pure vtk vs. Paraview

[Berk Geveci]

triangle strips?

On 9/20/05, Max Schoebinger <m.schoebinger at dkfz-heidelberg.de> wrote:
> Hallo,
> 
> thanks for your quick reply. Your comment is right, but what i observed
> implies, that there must be some implementation/parameterization issue
> influencing performance besides immediate mode rendering.
> 
> If I disable immediate mode rendering in paraview it behaves 10 times
> faster as my pure vtk example where immediate mode rendering is also
> off. So there must be an additional switch or trick which improves
> rendering preformance in paraview when immediate mode rendering is
> disabled...
> 
> Thanks,
> 
> Max
> 
> 
> Mattijs Janssens wrote:
> >  From what I remember from 3D graphics:
> >
> > immediate mode rendering:render the primitives straight from the main
> > memory.
> > non-immediate mode rendering: build a display list (kept in the graphics
> > card memory). Is faster except when the list does not fit in the
> > graphics memory. Also has to be rebuilt if any of the (properties of
> > the) primitives changes.
> >
> > So depending on your graphics card memory and also whether it natively
> > supports opacity there might be big differences in performance between
> > the two modes and between graphics cards.
> >
> > Max Schoebinger wrote:
> >
> >> Hello,
> >>
> >> In our lab we have a home grown vtk/itk based application framework
> >> for medical applications. I discovered a performance problem while
> >> working with Triangular meshes loaded from STL-Files. If the
> >> vtkProperties change (e.g. opacity), each rendering update takes
> >> extremely long (>10s). Using paraview, updates are possible at
> >> interactive speed (<0.5s). I tracked down the problem to a minimal
> >> example only using pure vtk (see attachment) and discovered, that in
> >> the function vtkOpenGLPolyDataMapper::RenderPiece(...) new display
> >> lists are generated each time the properties of the actor have been
> >> modified. This is not the case, if ImmediateModeRendering is on. So my
> >> situation is: if ImmideateModeRendering is on, everything works as
> >> fast as expected, if ImmediateModeRendering is off, rendering updates
> >> are is really slow.
> >>
> >> Now my question: how is rendering in paraview organized (optimized)?
> >> The render updates at opacity changes are always fast, no matter if
> >> ImmediateModeRendering is on or off.
> >>
> >> Some Notes:
> >>
> >> I am working on a laptop (2Ghz Pentium M, 2Gb RAM) under windows xp
> >> service pack 2.
> >> My Compiler is Visual Studio .NET 2002
> >> My graphics card is an ATI Mobility Radeon X600 with 128 MB RAM.
> >> I am using the latest driver for the graphics adapter.
> >> The STL-File I am working with has 30947 points and 61818 cells.
> >> The problem does not appear on NVidia graphics adapters.
> >>
> >> Thanks for any hints,
> >>
> >> Max
> >>
> >>
> >> ------------------------------------------------------------------------
> >>
> >> #include "vtkSTLReader.h"
> >> #include "vtkPolyDataMapper.h"
> >> #include "vtkRenderWindow.h"
> >> #include "vtkCamera.h"
> >> #include "vtkActor.h"
> >> #include "vtkRenderer.h"
> >> #include "vtkProperty.h"
> >> #include "vtkMapper.h"
> >>
> >> int main( int argc, char *argv[] )
> >> {
> >>   vtkSTLReader* reader = vtkSTLReader::New();
> >>   reader->SetFileName("model.stl");
> >>   reader->Update();
> >>
> >>   vtkPolyDataMapper* mapper = vtkPolyDataMapper::New();
> >>   mapper->SetInput( reader->GetOutput() );
> >>
> >>   vtkActor* actor = vtkActor::New();
> >>   actor->SetMapper(mapper);
> >>
> >>   vtkRenderer* renderer= vtkRenderer::New();
> >>   renderer->AddActor( actor );
> >>
> >>   vtkRenderWindow* renderWindow = vtkRenderWindow::New();
> >>   renderWindow->AddRenderer( renderer );
> >>   renderWindow->SetSize( 300, 300 );
> >>
> >>   //
> >>   // if immediate mode rendering is off evereything is very slow
> >>   //
> >>   //vtkMapper::GlobalImmediateModeRenderingOn();
> >>
> >>   for (double opacity = 1.0; opacity >= 0.0; opacity-=0.1)
> >>   {
> >>     actor->GetProperty()->SetOpacity(opacity);
> >>     renderWindow->Render();
> >>   }
> >>   return 0;
> >> }
> >>
> >>
> >>
> >>
> >> ------------------------------------------------------------------------
> >>
> >> _______________________________________________
> >> ParaView mailing list
> >> ParaView at paraview.org
> >> http://www.paraview.org/mailman/listinfo/paraview
> >
> >
> > Kind regards,
> >
> > Mattijs
> >
> 
> 
> --
> Dipl.-Inform. Med. Max Schöbinger
> Deutsches Krebsforschungszentrum       (German Cancer Research Center)
> Div. Medical & Biological Informatics          Tel: (+49) 6221-42 2370
> Im Neuenheimer Feld 280                        Fax: (+49) 6221-42 2345
> D-69120 Heidelberg                       E-Mail: M.Schoebinger at dkfz.de
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