[vtkusers] vtkDataArray segmentation fault with GetRange

[Charlotte Curtis]

Hi all,

I'm trying to use a vtkDataArray to colour vtkGlyph3Ds. The following
code works perfectly when there is only one component (the comp
parameter is set to zero). However, when I have multiple components, I
get a segmentation fault on the call to values->GetRange(comp).
Strangely, the cout loop to print the values works just fine, so I'm
pretty confident that the data exists. I've tried calling
values->Modified(), with no change.

Any ideas?

Thanks,

Charlotte

P.S. As a side note, I'm not sure if I'm correctly colouring by the
selected component, but I can't test that yet because the range isn't
working!

DrawSpheres(vtkSmartPointer<vtkPoints> points, double size,
                            vtkSmartPointer<vtkDoubleArray> values, int comp)
{
// create a polydata object to pack the points into
vtkSmartPointer<vtkPolyData> pd = vtkSmartPointer<vtkPolyData>::New();
pd->SetPoints(points);

// define the sphere source and the glyphs
vtkSmartPointer<vtkSphereSource> spheresource =
vtkSmartPointer<vtkSphereSource>::New();
spheresource->SetRadius(size);
vtkSmartPointer<vtkGlyph3D> glyphs = vtkSmartPointer<vtkGlyph3D>::New();
glyphs->SetInput(pd);
glyphs->SetSource(spheresource->GetOutput());
        glyphs->SetScaleModeToDataScalingOff();

    if (values != NULL)
    {
        for (int i = 0; i < values->GetNumberOfTuples(); i++)
            std::cout << values->GetComponent(i,comp) << std::endl;

        double *range = values->GetRange(comp);
        pd->GetPointData()->SetScalars(values);
        glyphs->Update();

        // since we need to modify the mapper, we can't just use the
Display method
        vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
        vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();

        // create the lookup table
        vtkSmartPointer<vtkLookupTable> lut =
        vtkSmartPointer<vtkLookupTable>::New();
        lut->SetTableRange(range);
        lut->Build();

        mapper->SetScalarRange(range);
        mapper->SetLookupTable(lut);
        mapper->ColorByArrayComponent(0,comp);
        mapper->SetInputConnection(glyphs->GetOutputPort());
        actor->SetMapper(mapper);

        renderer->AddActor(actor);
    }
}