Tri.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2020 Paul Ramsey <pramsey@cleverelephant.ca>
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU Lesser General Public Licence as published
 * by the Free Software Foundation.
 * See the COPYING file for more information.
 *
 **********************************************************************/
 
#pragma once
 
#include <geos/geom/Coordinate.h>
 
#include <memory>
 
// Forward declarations
namespace geos {
namespace geom {
class Geometry;
class GeometryFactory;
class Polygon;
}
}
 
using geos::geom::Coordinate;
using geos::geom::Polygon;
using geos::geom::GeometryFactory;
 
typedef int TriIndex;
 
namespace geos {        // geos.
namespace triangulate { // geos.triangulate
namespace tri {         // geos.triangulate.tri
 
 
class GEOS_DLL Tri {
 
private:
 
    // Members
    Coordinate p0;
    Coordinate p1;
    Coordinate p2;
 
    Tri* tri0;
    Tri* tri1;
    Tri* tri2;
 
    void replace(Tri* triOld, Tri* triNew);
 
    std::vector<Tri*> getAdjacentTris(Tri* tri, TriIndex index0, TriIndex index1);
 
    void setCoordinates(const Coordinate& p0, const Coordinate& p1, const Coordinate& p2);
 
    void flip(Tri* tri, TriIndex index0, TriIndex index1,
        const Coordinate& adj0, const Coordinate& adj1,
        const Coordinate& opp0, const Coordinate& opp1);
 
 
public:
 
    Tri(const Coordinate& c0, const Coordinate& c1, const Coordinate& c2)
        : p0(c0)
        , p1(c1)
        , p2(c2)
        , tri0(nullptr)
        , tri1(nullptr)
        , tri2(nullptr)
        {};
 
    void setAdjacent(Tri* p_tri0, Tri* p_tri1, Tri* p_tri2);
    void setTri(TriIndex edgeIndex, Tri* tri);
    void setAdjacent(const Coordinate& pt, Tri* tri);
 
    void flip(TriIndex index);
 
    void validate();
    void validateAdjacent(TriIndex index);
 
    std::pair<const Coordinate&, const Coordinate&> getEdge(Tri* neighbor) const;
 
    const Coordinate& getEdgeStart(TriIndex i) const;
    const Coordinate& getEdgeEnd(TriIndex i) const;
 
    bool hasCoordinate(const Coordinate& v) const;
    const Coordinate& getCoordinate(TriIndex i) const;
 
    TriIndex getIndex(const Coordinate& p) const;
    TriIndex getIndex(Tri* tri) const;
 
    Tri* getAdjacent(TriIndex i) const;
    bool hasAdjacent(TriIndex i) const;
    bool isAdjacent(Tri* tri) const;
    int numAdjacent() const;
 
    static TriIndex next(TriIndex i);
    static TriIndex prev(TriIndex i);
    static TriIndex oppVertex(TriIndex edgeIndex);
    static TriIndex oppEdge(TriIndex vertexIndex);
    Coordinate midpoint(TriIndex edgeIndex) const;
 
    std::unique_ptr<Polygon> toPolygon(const GeometryFactory* gf) const;
 
    friend std::ostream& operator << (std::ostream& os, const Tri&);
 
};
 
 
 
 
} // namespace geos.triangulate.tri
} // namespace geos.triangulate
} // namespace geos