Hi,
I am writing a custom filter that takes polydata as input and outputs
polydata
that contains a subset of the cells in the input polydata.
I would like the output polydata to include all the vector/scalar etc arrays
associated with the input, appropriately subsetted.
I think I have working code, but I think it only grabs e.g. 1 scalar array
associated with point data (via input->GetPointData()->GetScalars();)
How would I access multiple associated scalar arrays ?
The only way I found to implement getting even just the single scalar array
is a sort of brute force loop that saves point/cell ids I want to keep
(code snippet below).
Is this the best way to implement this ?
thanks
kate
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// code snippet for filter to take polydata as input and output polydata
// with a subset of input polydata cells
int vtkMyFilter::RequestData(vtkInformation *vtkNotUsed(request),
vtkInformationVector **inputVector,
vtkInformationVector *outputVector)
{
// allocate vectors to store vtk ids of cells and points I want to keep
vtkIdList *outcellids = vtkIdList::New ();
outcellids->Allocate(num_cells_in,0);
vtkIdList *outptids = vtkIdList::New ();
outptids->Allocate(num_points_in,0);
// loop over input lines, decide what to keep
for(lines->InitTraversal(); lines->GetNextCell(npts,pts); num_poly++) {
if (I want this cell) {
out_line_cnt++;
out_tot_pt_ctr = out_tot_pt_ctr + npts;
// collect pt ids for output vectors
for (k=0; k < npts; k++) {
outptids->InsertNextId ((const vtkIdType)
in_tot_pt_ctr++);
}
// collect cell ids for output
outcellids->InsertNextId ((const vtkIdType) num_poly);
}
// not adding this line, just update points counter for input points
array
else {
in_tot_pt_ctr = in_tot_pt_ctr + npts;
}
}
// copy line/point data to output
outcellids->Squeeze();
outptids->Squeeze();
output->Allocate(input,num_cells_in,0);
output->CopyCells(input, outcellids, NULL);
output->Squeeze();
/////// copy point data active??? vectors
invec = input->GetPointData()->GetVectors();
if (invec != NULL) {
num_comp = invec->GetNumberOfComponents();
outvec = invec->NewInstance();
outvec->SetNumberOfComponents(num_comp);
outvec->SetNumberOfTuples(out_tot_pt_ctr);
outvec->SetName(invec->GetName());
for (i=0; i<out_tot_pt_ctr; i++) {
outvec->InsertTuple(i,invec->GetTuple(outptids->GetId(i)));
}
output->GetPointData()->SetVectors(outvec);
}
// repeat for
// input->GetPointData()->GetScalars();
// input->GetCellData()->GetVectors();
// input->GetCellData()->GetScalars();
// etc
}
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