[vtkusers] Crashing on GetGlobalIds

[David E DeMarle]

vtkSmartPointer<vtkIdTypeArray> globalIds =
vtkSmartPointer<vtkIdTypeArray>::New();
globalIds =
vtkIdTypeArray::SafeDownCast(selected->GetPointData()->GetGlobalIds());
assert(globalIds);

I think the assert tells you that the smartpointer itself exists, but it
doesn't say anything about the vtkIdTypeArray pointed to by the
smartpointer. I suspect if you assert(globalIds.GetPointer()) it will fail.
If that is the case, since it is null, gloablids->* crashes on the next
line.

Why it is null will take some more tracking down.

One thing to note about globalids is that VTK is conservative about
preserving their meaning and throws them away when it can't do that. For
example they won't be interpolated like most arrays are because averaging
ids or (i.e. names) is undefined. Likewise filters that don't simply copy
cells/points across won't attempt to preserve globalids. So what you should
do is trace through the filters you are using to see where specifically the
globalids are lost.

hth

David E DeMarle
Kitware, Inc.
Principal Engineer
21 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-881-4909


On Sat, Nov 24, 2018 at 9:47 AM meakcey <meakcey at gmail.com> wrote:

> Cleaner comparison to problem
>
> *Code below is working*
>
> vtkPlanes* frustum =
>
> static_cast<vtkAreaPicker*>(this->GetInteractor()->GetPicker())->GetFrustum();
> vtkSmartPointer<vtkExtractGeometry> extractGeometry =
> vtkSmartPointer<vtkExtractGeometry>::New();
> extractGeometry->SetImplicitFunction(frustum);
> extractGeometry->SetInputData(this->Points);
> extractGeometry->Update();
> extractGeometry->GetOutput()->GetPointData()->CopyGlobalIdsOn();
>
> vtkSmartPointer<vtkVertexGlyphFilter> glyphFilter =
> vtkSmartPointer<vtkVertexGlyphFilter>::New();
> glyphFilter->SetInputConnection(extractGeometry->GetOutputPort());
> glyphFilter->Update();
> glyphFilter->GetOutput()->GetPointData()->CopyGlobalIdsOn();
> vtkPolyData* selected = glyphFilter->GetOutput();
>
> vtkSmartPointer<vtkIdTypeArray> globalIds =
> vtkSmartPointer<vtkIdTypeArray>::New();
> globalIds =
> vtkIdTypeArray::SafeDownCast(selected->GetPointData()->GetGlobalIds());
> assert(globalIds);
> std::cout << "Nof globalIds " << globalIds->GetNumberOfComponents() << " "
> << globalIds->GetNumberOfTuples() << std::endl;
>
> *Code below is crashing at the line of cout
> *
> vtkPlanes* frustum =
>
> static_cast<vtkAreaPicker*>(this->GetInteractor()->GetPicker())->GetFrustum();
> vtkSmartPointer<vtkExtractGeometry> extractGeometry =
> vtkSmartPointer<vtkExtractGeometry>::New();
> extractGeometry->SetImplicitFunction(frustum);
> extractGeometry->SetInputData(this->Points);
> extractGeometry->Update();
> extractGeometry->GetOutput()->GetPointData()->CopyGlobalIdsOn();
>
> vtkSmartPointer<vtkSelectVisiblePoints> visiblePoints =
> vtkSmartPointer<vtkSelectVisiblePoints>::New();
> visiblePoints->SetInputConnection(extractGeometry->GetOutputPort());
>
> visiblePoints->SetRenderer(this->GetInteractor()->GetRenderWindow()->GetRenderers()->GetFirstRenderer());
> visiblePoints->Update();
> visiblePoints->GetOutput()->GetPointData()->CopyGlobalIdsOn();
>
> vtkSmartPointer<vtkVertexGlyphFilter> visibleFilter =
> vtkSmartPointer<vtkVertexGlyphFilter>::New();
> visibleFilter->SetInputConnection(visiblePoints->GetOutputPort());
> visibleFilter->Update();
> visibleFilter->GetOutput()->GetPointData()->CopyGlobalIdsOn();
> vtkPolyData* visibles = visibleFilter->GetOutput();
>
> vtkSmartPointer<vtkIdTypeArray> globalIds =
> vtkSmartPointer<vtkIdTypeArray>::New();
> globalIds =
> vtkIdTypeArray::SafeDownCast(visibles->GetPointData()->GetGlobalIds());
> assert(globalIds);
> std::cout << "Nof globalIds " << globalIds->GetNumberOfComponents() << " "
> << globalIds->GetNumberOfTuples() << std::endl;
>
>
>
>
>
>
> --
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