Delaunay.h

/*
 *
 * This file is part of Tulip (www.tulip-software.org)
 *
 * Authors: David Auber and the Tulip development Team
 * from LaBRI, University of Bordeaux
 *
 * Tulip is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *
 * Tulip is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 */
///@cond DOXYGEN_HIDDEN

#ifndef DELAUNAY_H
#define DELAUNAY_H
#include <vector>
#include <set>

#include <tulip/Coord.h>

namespace tlp {

/**
 * @ingroup Graph
 * \brief functions for Delaunay Triangulations
 *
 * \author : David Auber/Daniel Archambault/Antoine Lambert : auber@tulip-software.org
 *
 * Computes the delaunay triangulation and returns the set of delaunay edges in the
 * vector edges and delaunay simplices (triangles in 2d, tetrahedra in 3d) of the triangulation in the vector simplices.
 * Edges and simplices are defined using a indexes into the original
 * set of points.
 */
TLP_SCOPE bool delaunayTriangulation(std::vector<Coord> &points,
                                     std::vector<std::pair<unsigned int, unsigned int> > &edges,
                                     std::vector<std::vector<unsigned int> > &simplices,
                                     bool voronoiMode = false);

/**
 * @ingroup Graph
 * @brief The VoronoiDiagram class
 */
class TLP_SCOPE VoronoiDiagram {
public:

  // A voronoi site.
  typedef Coord Site;

  // A voronoi vertex.
  typedef Coord Vertex;

  // A voronoi edge defined by the indexes of its extremities in the vertices vector
  typedef std::pair<unsigned int, unsigned int> Edge;

  // A voronoi Cell defined by the indexes of its vertices in the vertices vector
  typedef std::set<unsigned int> Cell;

  // Returns the number of voronoi sites
  unsigned int nbSites() const {
    return sites.size();
  }

  // Returns the number of voronoi vertices
  unsigned int nbVertices() const {
    return vertices.size();
  }

  // Returns the number of voronoi edges
  unsigned int nbEdges() const {
    return edges.size();
  }

  // Returns the ith site
  const Site &site(const unsigned int siteIdx) {
    return sites[siteIdx];
  }

  // Returns the ith voronoi vertex
  const Vertex &vertex(const unsigned int vertexIdx) {
    return vertices[vertexIdx];
  }

  // Returns the ith voronoi edge
  const Edge &edge(const unsigned int edgeIdx) {
    return edges[edgeIdx];
  }

  // Returns the ith voronoi cell
  const Cell &cell(const unsigned int cellIdx) {
    return cells[cellIdx];
  }

  // Returns the degree of the ith voronoi vertex
  unsigned int degreeOfVertex(const unsigned int vertexIdx) {
    return verticesDegree[vertexIdx];
  }

  // Returns the edges of the voronoi cell for the ith site
  std::vector<Edge> voronoiEdgesForSite(const unsigned int siteIdx) {
    std::vector<Edge> ret;

    for (size_t i = 0 ; i < siteToCellEdges[siteIdx].size() ; ++i) {
      ret.push_back(edges[siteToCellEdges[siteIdx][i]]);
    }

    return ret;
  }

  // Returns the cell for the ith site
  const Cell &voronoiCellForSite(const unsigned int siteIdx) {
    return cells[siteToCell[siteIdx]];
  }

  // Stores lists of each of these types defining the voronoi diagram
  std::vector<Site> sites;
  std::vector<Vertex> vertices;
  std::vector<Edge> edges;
  std::vector<Cell> cells;
  TLP_HASH_MAP<unsigned int, std::vector<unsigned int> > siteToCellEdges;
  TLP_HASH_MAP<unsigned int, unsigned int> siteToCell;
  TLP_HASH_MAP<unsigned int, unsigned int> verticesDegree;
};

/**
 * Computes the voronoi diagram of a set of points (for 2d and 3d layouts).
 * The set of input points are given in sites.  The resultant voronoi diagram is returned
 * in voronoiDiagram.  It automatically computes the set of all voronoi
 * vertices, edges and cells. In order to not have to deal with infinite
 * voronoi rays, the input layout is enclosed in its convex hull in 2d or
 * in its bounding box in 3d. It enables to have a connected voronoi cell
 * for each input site.
 */
TLP_SCOPE bool voronoiDiagram(std::vector<Coord> &sites, VoronoiDiagram &voronoiDiagram);


}
#endif
///@endcond