DYT/Tool/OpenSceneGraph-3.6.5/include/geos/noding/IntersectionAdder.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2006      Refractions Research Inc.
 *
 * 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.
 *
 **********************************************************************
 *
 * Last port: noding/IntersectionAdder.java rev. 1.6 (JTS-1.9)
 *
 **********************************************************************/

#pragma once

#include <geos/export.h>

#include <vector>
#include <iostream>
#include <cstdlib> // for abs()

#include <geos/geom/Coordinate.h>
#include <geos/noding/SegmentIntersector.h> // for inheritance

// Forward declarations
namespace geos {
namespace noding {
class SegmentString;
}
namespace algorithm {
class LineIntersector;
}
}

namespace geos {
namespace noding { // geos.noding

/** \brief
 * Computes the intersections between two line segments in SegmentString
 * and adds them to each string.
 *
 * The SegmentIntersector is passed to a Noder.
 * The NodedSegmentString::addIntersections(algorithm::LineIntersector* li, std::size_t segmentIndex, std::size_t geomIndex)
 * method is called whenever the Noder
 * detects that two SegmentStrings *might* intersect.
 * This class is an example of the *Strategy* pattern.
 *
 */
class GEOS_DLL IntersectionAdder: public SegmentIntersector {

private:

    /**
     * These variables keep track of what types of intersections were
     * found during ALL edges that have been intersected.
     */
    bool hasIntersectionVar;
    bool hasProper;
    bool hasProperInterior;
    bool hasInterior;

    // the proper intersection point found
    geom::CoordinateXYZM properIntersectionPoint;

    algorithm::LineIntersector& li;
    // bool isSelfIntersection;
    // bool intersectionFound;

    /**
     * A trivial intersection is an apparent self-intersection which
     * in fact is simply the point shared by adjacent line segments.
     * Note that closed edges require a special check for the point
     * shared by the beginning and end segments.
     */
    bool isTrivialIntersection(const SegmentString* e0, std::size_t segIndex0,
                               const SegmentString* e1, std::size_t segIndex1);

    // Declare type as noncopyable
    IntersectionAdder(const IntersectionAdder& other) = delete;
    IntersectionAdder& operator=(const IntersectionAdder& rhs) = delete;

public:

    int numIntersections;
    int numInteriorIntersections;
    int numProperIntersections;

    // testing only
    int numTests;

    IntersectionAdder(algorithm::LineIntersector& newLi)
        :
        hasIntersectionVar(false),
        hasProper(false),
        hasProperInterior(false),
        hasInterior(false),
        properIntersectionPoint(),
        li(newLi),
        numIntersections(0),
        numInteriorIntersections(0),
        numProperIntersections(0),
        numTests(0)
    {}

    algorithm::LineIntersector&
    getLineIntersector()
    {
        return li;
    }

    /**
     * @return the proper intersection point, or `Coordinate::getNull()`
     *         if none was found
     */
    const geom::CoordinateXYZM&
    getProperIntersectionPoint()
    {
        return properIntersectionPoint;
    }

    bool
    hasIntersection()
    {
        return hasIntersectionVar;
    }

    /** \brief
     * A proper intersection is an intersection which is interior to
     * at least two line segments.
     *
     * Note that a proper intersection is not necessarily in the interior
     * of the entire Geometry, since another edge may have an endpoint equal
     * to the intersection, which according to SFS semantics can result in
     * the point being on the Boundary of the Geometry.
     */
    bool
    hasProperIntersection()
    {
        return hasProper;
    }

    /** \brief
     * A proper interior intersection is a proper intersection which is
     * *not* contained in the set of boundary nodes set for this SegmentIntersector.
     */
    bool
    hasProperInteriorIntersection()
    {
        return hasProperInterior;
    }

    /** \brief
     * An interior intersection is an intersection which is
     * in the interior of some segment.
     */
    bool
    hasInteriorIntersection()
    {
        return hasInterior;
    }


    /** \brief
     * This method is called by clients of the SegmentIntersector class to
     * process intersections for two segments of the SegmentStrings being intersected.
     *
     * Note that some clients (such as MonotoneChains) may optimize away
     * this call for segment pairs which they have determined do not
     * intersect (e.g. by an disjoint envelope test).
     */
    void processIntersections(
        SegmentString* e0,  std::size_t segIndex0,
        SegmentString* e1,  std::size_t segIndex1) override;


    static bool
    isAdjacentSegments(std::size_t i1, std::size_t i2)
    {
        return (i1 > i2 ? i1 - i2 : i2 - i1) == 1;
    }

    /** \brief
     * Always process all intersections.
     *
     * @return false always
     */
    bool
    isDone() const override
    {
        return false;
    }
};


} // namespace geos.noding
} // namespace geos