[vtkusers] Coloring PolyDatas depending on various (externally computed) values

[Arnaud GELAS]

  On 10/26/2010 10:02 AM, David Doria wrote:
>
>     David,
>
>     It works fine with PointData and CellData; however I could not
>     figure out how to proceed with FieldData (There is no method
>     SetActive at this level in the hierarchy :-/, and my values are
>     attributes to one mesh (constant for a single mesh).
>     Is there a way to proceed with vtkFieldData?
>
>     ---
>
>     If not, I can use CellData instead. In this case, I can switch
>     from active scalar array to original mesh colors by setting it to
>     one that does not belong to the mesh:
>
>     polydata->GetCellData->SetActiveScalars( "" );
>
>     Is there a better way to proceed?
>
>     Thanks,
>     Arnaud
>
>
> The reason that you can't set active scalars on the FieldData is 
> probably that it doesn't always make sense to apply arrays from the 
> FieldData to the data because it is not necessarily "aligned" (the 
> same length).
>
> Since it is a single color per object/mesh, can you color the actor 
> based on the field data value (the 0th value in the array)?
>
> Something like:
>
> vtkFloatArray* colorArray 
> = vtkFloatArray::SafeDownCast(polydata->GetFieldData()->GetArray("color1"));
> float color[3];
> colorArray->GetTupleValue(0, color);
>
> actor->GetProperty()->SetColor(color);
>
> ?
>
> David

I have tried to set a color (see attached code), but I still need to 
remove the active scalar array ?

Arnaud


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