[vtkusers] isosurface update issue

[David E DeMarle]

Can't tell from this code fragment what is going on but these look fishy to
me:


> vtkSmartPointer<vtkPolyDataMapper> mapper =
> vtkSmartPointer<vtkPolyDataMapper>::New();
>  mapSphere->SetInputConnection( filter->GetOutputPort() );


You make "mapper" and then work with "mapSphere". Where did mapSphere come
from?

You call renderer->AddActor(m_pActor) everytime in this function. If
"renderer" is persistent or in otherwords not created from scratch in
between calls to redraw, you should only have to do that once.


On Fri, Nov 30, 2018 at 12:12 AM newcfd via vtkusers <
vtkusers at public.kitware.com> wrote:

> I have the following code to draw isosurface. No problem when this func is
> called by the first time.
> However, two isosurfaces show up when this func is called with a different
> value by the second time.
> The first isosurface is not replaced by the second one although I am using
> the same actor. What is
> wrong?
>
> void MyApp::redraw( const double value )
> {
>   vtkStructuredGrid * mesh =...
>
>   vtkSmartPointer<vtkContourFilter> filter =
> vtkSmartPointer<vtkContourFilter>::New();
>   filter->SetInputData( mesh );
>   filter->SetNumberOfContours( 1 );
>   filter->Setvalue( 0, value ); // value is passed in
>
>  vtkSmartPointer<vtkPolyDataMapper> mapper =
> vtkSmartPointer<vtkPolyDataMapper>::New();
>  mapSphere->SetInputConnection( filter->GetOutputPort() );
>  mapSphere->SetScalarRange(0.0, 1.0);
>
>  if ( m_pActor == nullptr )
>  {
>     m_pActor = vtkActor::New();
>     m_pActor->SetMapper( mapper );
>   }
>
>  renderer->AddActor( m_pActor );
>  renderer->SetBackground(1,1,1); // Background color white
>
>  renderWindow->Render();
> }
>
>
>
> --
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