Using AdaptiveSubdivisionFilter to triangulate polygon

Support
1

I’m new to VTK and trying to triangulate a polygon using vtkAdaptiveSubdivisionFilter having failed using vtkPolygon->Triangulate and BoundedTriangulate. There doesn’t seem to be anything produced. Any idea what I’m missing?

Thanks,
Scott

#include <iostream>

#include <vtkAdaptiveSubdivisionFilter.h>
#include <vtkAlgorithmOutput.h>
#include <vtkCellArray.h>
#include <vtkFiltersModelingModule.h>
#include <vtkInformation.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPolygon.h>
#include <vtkTriangleFilter.h>

int main()
{
	vtkNew<vtkPolygon> polygon;
	polygon->GetPoints()->InsertNextPoint(0.0, 0.0, 0.0);
	polygon->GetPoints()->InsertNextPoint(0.0, 20.0, 0.0);
	polygon->GetPoints()->InsertNextPoint(-20.0, 20.0, 0.0);
	polygon->GetPoints()->InsertNextPoint(-20.0, 0.0, 0.0);
	polygon->GetPoints()->InsertNextPoint(-40.0, 0.0, 0.0);
	polygon->GetPoints()->InsertNextPoint(-40.0, 20.0, 0.0);
	polygon->GetPoints()->InsertNextPoint(-60.0, 20.0, 0.0);
	polygon->GetPoints()->InsertNextPoint(-60.0, -60.0, 0.0);
	polygon->GetPoints()->InsertNextPoint(-20.0, -60.0, 0.0);
	polygon->GetPoints()->InsertNextPoint(-20.0, -20.0, 0.0);

	vtkIdType numPoints = polygon->GetPoints()->GetNumberOfPoints();
	polygon->GetPointIds()->SetNumberOfIds(numPoints);
	for (int i = 0; i < numPoints; i++) {
		polygon->GetPointIds()->SetId(i, i);
	}
	vtkNew<vtkCellArray> cells;
	cells->InsertNextCell(numPoints);
	for (int i = 0; i < numPoints; i++) {
		cells->InsertCellPoint(i);
	}
	vtkNew<vtkPolyData> polys;
	polys->SetPoints(polygon->GetPoints());
	polys->SetPolys(cells);

	vtkNew<vtkAdaptiveSubdivisionFilter> asf;
	asf->SetInputData(polys);
	asf->SetMaximumEdgeLength(0.1);
	asf->Update();
	vtkInformation* asfOutputInfo = asf->GetOutputInformation(0);
	asfOutputInfo->Print(std::cout);
	vtkPolyData* asfOutput = asf->GetOutput();
	asfOutput->Print(std::cout);
}