[vtkusers] Coloring polydata with scalars

[Mdl]

Hi everybody,

I'm trying to display a sphere colored according to scalar attributes I
assign to its points; I can't see anything wrong in the code, but it doesn't
work... here it is:


vtkSphereSource *s = vtkSphereSource::New();
    s->SetPhiResolution (20);
    s->SetThetaResolution (20);

vtkFloatArray *fa = vtkFloatArray::New();
    fa->SetNumberOfValues (400);
    for (int j=0; j < 400; j++)
        fa->SetValue ((vtkIdType) j, values[j]);    // values[] is an array
of floats in the range 0..100

s->GetOutput()->GetPointData()->SetScalars(fa);

vtkDataSetMapper *m = vtkDataSetMapper::New();
    m->SetInput(s->GetOutput());
    m->SetScalarRange (0, 100);

vtkActor *a = vtkActor::New();
    a->SetMapper (m);

.....and the usual rendering stuff.

I get a black display... can anyone bring some color in my life? :-)

I also tried to create another vtkPolyData:

vtkPolyData *pd = vtkPolyData::New();
    pd->SetSource (s);
    pd->GetPointData()->SetScalars(fa);

but no way.
The same if I use GetCellData() instead of GetPointData().


Thanks in advance,
________________________________________

                            Marco Di Lorenzo
                            (mdl78 at libero.it)
________________________________________

Tesista presso IAC-CNR di Roma
Istituto per le Applicazioni del Calcolo "M. Picone"
Viale del Policlinico, 137
00161, Roma
________________________________________