VoronoiGenerator.cpp

/*

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#include <math.h>
#define _BACKWARD_BACKWARD_WARNING_H 1 //Cut out the vtk deprecated warning for now (gcc4.3)
#include <vtkBox.h>
#include <vtkTetra.h>
#include <vtkPoints.h>
#include <vtkSmartPointer.h>
#include "RandomNumberGenerator.hpp"
#include "Polygon.hpp"
#include "BaseUnits.hpp"

#include "VoronoiGenerator.hpp"

// Hang Si's tetgen.

#define REAL double
#define VOID void
#include "tetgen.h"
#undef REAL
#undef VOID

struct triangulateio;

template<unsigned DIM>
VoronoiGenerator<DIM>::VoronoiGenerator() :
    mReferenceLength(BaseUnits::Instance()->GetReferenceLengthScale())
{
}

template<unsigned DIM>
VoronoiGenerator<DIM>::~VoronoiGenerator()
{

}

template<unsigned DIM>
boost::shared_ptr<Part<DIM> > VoronoiGenerator<DIM>::Generate(boost::shared_ptr<Part<DIM> > pPart,
                                                              std::vector<boost::shared_ptr<DimensionalChastePoint<DIM> > > seeds,
                                                              unsigned numSeeds)
{
    if(DIM==2)
    {
        EXCEPTION("This generator works in 3D only");
    }

    boost::shared_ptr<Part<DIM> > p_tesselation = Part<DIM>::Create();
    std::vector<units::quantity<unit::length> > extents = pPart->GetBoundingBox();
    double x_min = double(extents[0]/ mReferenceLength);
    double x_max = double(extents[1]/ mReferenceLength);
    double y_min = double(extents[2]/ mReferenceLength);
    double y_max = double(extents[3]/ mReferenceLength);
    double z_min = double(extents[4]/ mReferenceLength);
    double z_max = double(extents[5]/ mReferenceLength);

    c_vector<double, 6> dimensionless_extents;
    dimensionless_extents[0] = x_min;
    dimensionless_extents[1] = x_max;
    dimensionless_extents[2] = y_min;
    dimensionless_extents[3] = y_max;
    dimensionless_extents[4] = z_min;
    dimensionless_extents[5] = z_max;

    // If no seeds have been provided generate some random ones
    if(seeds.size() == 0)
    {
        for(unsigned idx = 0; idx< numSeeds; idx++)
        {
            c_vector<double, DIM> location;
            for(unsigned jdx=0; jdx<DIM; jdx++)
            {
                location[jdx] = (dimensionless_extents[2*jdx] + (dimensionless_extents[2*jdx + 1] - dimensionless_extents[2*jdx])*RandomNumberGenerator::Instance()->ranf());
            }
            seeds.push_back(DimensionalChastePoint<DIM>::Create(location, mReferenceLength));
        }
    }

    // Use tetgen to make the tessellation
    class tetgen::tetgenio mesher_input, mesher_output;

    mesher_input.initialize();
    mesher_output.initialize();
    mesher_input.numberofpoints = seeds.size();
    mesher_input.pointlist = new double[mesher_input.numberofpoints * DIM];
    for (unsigned idx=0; idx<seeds.size(); idx++)
    {
        c_vector<double, DIM> seed_location = seeds[idx]->GetLocation(mReferenceLength);
        for (unsigned jdx=0; jdx < DIM; jdx++)
        {
            mesher_input.pointlist[DIM*idx + jdx] = double(seed_location[jdx]);
        }
    }

    tetgen::tetrahedralize((char*)"veeQ", &mesher_input, &mesher_output);

    // Create 2-point polygons corresponding to each edge
    std::vector<boost::shared_ptr<Polygon<DIM> > > polygons;
    for (int n=0; n<mesher_output.numberofvedges; ++n)
    {
      tetgen::tetgenio::voroedge e =  mesher_output.vedgelist[n];
      int n0 = e.v1;
      int n1 = e.v2;
      double* u = &mesher_output.vpointlist[DIM*n0];
      double* v = n1 == -1 ? e.vnormal : &mesher_output.vpointlist[DIM*n1]; // -1 indicates ray
      boost::shared_ptr<DimensionalChastePoint<DIM> > p_vertex1 = DimensionalChastePoint<DIM>::Create(u[0], u[1], u[2], mReferenceLength);
      boost::shared_ptr<DimensionalChastePoint<DIM> > p_vertex2 = DimensionalChastePoint<DIM>::Create(v[0], v[1], v[2], mReferenceLength);

      // Only include edges that are inside the domain - use the bounding box.
      double zero_location_tol = 20.0;
      double t1;
      double t2;
      int plane1;
      int plane2;
      c_vector<double,DIM> intercept_1;
      c_vector<double,DIM> intercept_2;

      int in_box = vtkBox::IntersectWithLine(&dimensionless_extents[0], &p_vertex1->GetLocation(mReferenceLength)[0],
                                             &p_vertex2->GetLocation(mReferenceLength)[0], t1, t2, &intercept_1[0], &intercept_2[0], plane1, plane2);

      // If the line is not outside the box
      if(in_box!=0)
      {
          // if the line does not intersect the box it must be fully inside
          if(in_box==-1)
          {
              // Check that we haven't hit the zero location and remove very short edges
              if((norm_2(p_vertex1->GetLocation(mReferenceLength)) > zero_location_tol) && (norm_2(p_vertex2->GetLocation(mReferenceLength)) > zero_location_tol))
              {
                  if(norm_2(p_vertex1->GetLocation(mReferenceLength) - p_vertex2->GetLocation(mReferenceLength)) > 2.0 * zero_location_tol)
                  {
                      boost::shared_ptr<Polygon<DIM> > p_polygon = Polygon<DIM>::Create(p_vertex1);
                                p_polygon->AddVertex(p_vertex2);
                                polygons.push_back(p_polygon);
                  }
              }
          }
          else
          {
              // Find where the points are
              bool vert1_inside = true;
              bool vert2_inside = true;
              if(p_vertex1->GetLocation(mReferenceLength)[0] < dimensionless_extents[0] || p_vertex1->GetLocation(mReferenceLength)[0] > dimensionless_extents[1])
              {
                  vert1_inside = false;
              }
              if(p_vertex1->GetLocation(mReferenceLength)[1] < dimensionless_extents[2] || p_vertex1->GetLocation(mReferenceLength)[1] > dimensionless_extents[3])
              {
                  vert1_inside = false;
              }
              if(p_vertex2->GetLocation(mReferenceLength)[0] < dimensionless_extents[0] || p_vertex2->GetLocation(mReferenceLength)[0] > dimensionless_extents[1])
              {
                  vert2_inside = false;
              }
              if(p_vertex2->GetLocation(mReferenceLength)[1] < dimensionless_extents[2] || p_vertex2->GetLocation(mReferenceLength)[1] > dimensionless_extents[3])
              {
                  vert2_inside = false;
              }
              if(DIM==3)
              {
                  if(p_vertex1->GetLocation(mReferenceLength)[2] < dimensionless_extents[4] || p_vertex1->GetLocation(mReferenceLength)[2] > dimensionless_extents[5])
                  {
                      vert1_inside = false;
                  }
                  if(p_vertex2->GetLocation(mReferenceLength)[2] < dimensionless_extents[4] || p_vertex2->GetLocation(mReferenceLength)[2] > dimensionless_extents[5])
                  {
                      vert2_inside = false;
                  }
              }

              if(vert1_inside && !vert2_inside)
              {
                  // move vert 2 to intsersection point
                  c_vector<double,DIM> gap = intercept_1-p_vertex2->GetLocation(mReferenceLength);
                  p_vertex2->Translate(DimensionalChastePoint<DIM>(gap, mReferenceLength));
              }
              else if(vert2_inside && !vert1_inside)
              {
                  // move vert 1 to intersection point
                  c_vector<double,DIM> gap = intercept_1-p_vertex1->GetLocation(mReferenceLength);
                  p_vertex1->Translate(DimensionalChastePoint<DIM>(gap, mReferenceLength));
              }
              else
              {
                  // Otherwise both points are either on or outside
                  c_vector<double,DIM> tv1 = intercept_1-p_vertex1->GetLocation(mReferenceLength);
                  c_vector<double,DIM> tv2 = intercept_2-p_vertex2->GetLocation(mReferenceLength);
                  if(norm_2(tv1) > zero_location_tol)
                  {
                      p_vertex1->Translate(DimensionalChastePoint<DIM>(tv1, mReferenceLength));
                  }
                  if(norm_2(tv2) > zero_location_tol)
                  {
                      p_vertex2->Translate(DimensionalChastePoint<DIM>(tv2, mReferenceLength));
                  }
              }

              // Check that we haven't hit the zero location and remove very short edges
              if((norm_2(p_vertex1->GetLocation(mReferenceLength)) > zero_location_tol) && (norm_2(p_vertex2->GetLocation(mReferenceLength)) > zero_location_tol))
              {
                  if(norm_2(p_vertex1->GetLocation(mReferenceLength) - p_vertex2->GetLocation(mReferenceLength)) > 2.0 * zero_location_tol)
                  {
                        boost::shared_ptr<Polygon<DIM> > p_polygon = Polygon<DIM>::Create(p_vertex1);
                        p_polygon->AddVertex(p_vertex2);
                        polygons.push_back(p_polygon);
                  }
              }
          }
      }
    }

    // Add the polygons to the part
    for (unsigned idx=0; idx<polygons.size(); idx++)
    {
        p_tesselation->AddPolygon(polygons[idx]);
    }

    return p_tesselation;
}

//Explicit instantiation
template class VoronoiGenerator<2> ;
template class VoronoiGenerator<3> ;