Method SetSelectionScalarsToOutput

Filters/Modeling/vtkSelectPolyData.cxx:656–803

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void vtkSelectPolyData::SetSelectionScalarsToOutput(vtkPointData* originalPointData,
  vtkCellData* originalCellData, vtkPolyData* mesh, vtkIdList* edgePointIds,
  vtkIntArray* pointMarks, vtkPolyData* output)
{
  vtkPoints* inPts = mesh->GetPoints();
  vtkIdType numPts = inPts->GetNumberOfPoints();

  vtkNew<vtkFloatArray> selectionScalars;
  selectionScalars->SetName(this->SelectionScalarsArrayName);
  selectionScalars->SetNumberOfTuples(numPts);

  // "Boundary" here refers to a polyline that connects the loop point positions.

  // Compute signed distance to loop for non-boundary points.
  vtkIdType numLoopPts = this->Loop->GetNumberOfPoints();
  for (vtkIdType pointId = 0; pointId < numPts; pointId++)
  {
    if (this->CheckAbort())
    {
      break;
    }

    if (pointMarks->GetValue(pointId) == 0)
    {
      // boundary point, we'll deal with these later
      continue;
    }

    // Not an edge point.
    double x[3];
    inPts->GetPoint(pointId, x);
    double closestDist2 = VTK_DOUBLE_MAX;
    for (vtkIdType i = 0; i < numLoopPts; i++)
    {
      double x0[3];
      double x1[3];
      this->Loop->GetPoint(i, x0);
      this->Loop->GetPoint((i + 1) % numLoopPts, x1);
      double t;
      double xLoop[3];
      double dist2 = vtkLine::DistanceToLine(x, x0, x1, t, xLoop);
      closestDist2 = std::min(dist2, closestDist2);
    }
    // Set signed distance
    double closestDist = 0.0;
    if (pointMarks->GetValue(pointId) < 0)
    {
      closestDist = -sqrt(closestDist2);
    }
    else
    {
      closestDist = sqrt(closestDist2);
    }
    selectionScalars->SetComponent(pointId, 0, closestDist);
  }

  // Compute signed distance to loop for boundary points.
  vtkIdType numMeshLoopPts = edgePointIds->GetNumberOfIds();