triangulate.cpp

#include <vtkTriangleFilter.h>
#include "triangulate.h"

vtkSmartPointer<vtkPolyData> triangulate::buildValidTriangulation(vtkSmartPointer<vtkPolyData> polyData)
{
    vtkSmartPointer<vtkPolyData> triPolyData = vtkSmartPointer<vtkPolyData>::New();

    // if mesh is composed of quads, builds a valid triangulation
    if (polyData->GetMaxCellSize() == 4)
    {
        // we're using a vtkQuadToTriangle filter to convert quads in triangles
        vtkSmartPointer<vtkTriangleFilter> quadToTri = vtkSmartPointer<vtkTriangleFilter>::New();
        quadToTri->SetInputData(polyData);
        quadToTri->Update();

        triPolyData = quadToTri->GetOutput();
    }
    else if (polyData->GetMaxCellSize() == 3) // if mesh is already triangulated, return origin's vtkPolyData
    {
        triPolyData = polyData;
    }
    else
    {
        std::cout << "This mesh is not handled by this program, allows only triangulated and quadrilated meshes.\n";
        std::cout << "Maximum cell size for this mesh: " << polyData->GetMaxCellSize() << ".\n";
        exit(0);
    }
    // adding a vtkTriangleFilter to ensure that the output is a well triangulated mesh
    vtkSmartPointer<vtkTriangleFilter> triangleFilter = vtkSmartPointer<vtkTriangleFilter>::New();
    triangleFilter->SetInputData(triPolyData);
    triangleFilter->Update();

    return triangleFilter->GetOutput();
}