OctahedronPolygon.hpp

/*
 * Stellarium
 * Copyright (C) 2009 Fabien Chereau
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA  02110-1335, USA.
 */

#ifndef _OCTAHEDRON_REGION_HPP_
#define _OCTAHEDRON_REGION_HPP_

#include "StelVertexArray.hpp"
#include "VecMath.hpp"

#include <QVector>
#include <QDebug>
#include <QVarLengthArray>

struct EdgeVertex
{
    EdgeVertex() : edgeFlag(false) {;}
    EdgeVertex(bool b) : edgeFlag(b) {;}
    EdgeVertex(const Vec3d& v, bool b) : vertex(v), edgeFlag(b) {;}
    Vec3d vertex;
    bool edgeFlag;
};

Q_DECLARE_TYPEINFO(EdgeVertex, Q_PRIMITIVE_TYPE);

QDataStream& operator<<(QDataStream& out, const EdgeVertex&);
QDataStream& operator>>(QDataStream& in, EdgeVertex&);

class SubContour : public QVector<EdgeVertex>
{
public:
    // Create a SubContour from a list of vertices
    SubContour(const QVector<Vec3d>& vertices, bool closed=true);
    SubContour() {;}
    SubContour(int size, const EdgeVertex& v) : QVector<EdgeVertex>(size, v) {;}
    SubContour reversed() const;
    QString toJSON() const;
};

class OctahedronPolygon
{
public:
    OctahedronPolygon() : fillCachedVertexArray(StelVertexArray::Triangles), outlineCachedVertexArray(StelVertexArray::Lines), capN(1,0,0), capD(-2.)
    {sides.resize(8);}

    OctahedronPolygon(const SubContour& subContour);
    OctahedronPolygon(const QVector<QVector<Vec3d> >& contours);
    OctahedronPolygon(const QVector<Vec3d>& contour);
    OctahedronPolygon(const QList<OctahedronPolygon>& octContours);

    double getArea() const;

    Vec3d getPointInside() const;

    StelVertexArray getFillVertexArray() const {return fillCachedVertexArray;}
    StelVertexArray getOutlineVertexArray() const {return outlineCachedVertexArray;}

    void getBoundingCap(Vec3d& v, double& d) const {v=capN; d=capD;}

    void inPlaceIntersection(const OctahedronPolygon& mpoly);
    void inPlaceUnion(const OctahedronPolygon& mpoly);
    void inPlaceSubtraction(const OctahedronPolygon& mpoly);

    bool intersects(const OctahedronPolygon& mpoly) const;
    bool contains(const OctahedronPolygon& mpoly) const;

    bool contains(const Vec3d& p) const;
    bool isEmpty() const;

    static const OctahedronPolygon& getAllSkyOctahedronPolygon();
    static const OctahedronPolygon& getEmptyOctahedronPolygon() {static OctahedronPolygon poly; return poly;}

    static double sphericalTriangleArea(const Vec3d& v0, const Vec3d& v1, const Vec3d& v2)
    {
        const Vec3d& p1 = v0 ^ v1;
        const Vec3d& p2 = v1 ^ v2;
        const Vec3d& p3 = v2 ^ v0;
        return 2.*M_PI - p1.angle(p2) - p2.angle(p3) - p3.angle(p1);
    }

    QString toJson() const;

private:
    // For unit tests
    friend class TestStelSphericalGeometry;

    friend QDataStream& operator<<(QDataStream&, const OctahedronPolygon&);
    friend QDataStream& operator>>(QDataStream&, OctahedronPolygon&);
    friend OctahedronPolygon createAllSkyOctahedronPolygon();

    static OctahedronPolygon createAllSkyOctahedronPolygon();

    void append(const OctahedronPolygon& other);
    void appendReversed(const OctahedronPolygon& other);
    void appendSubContour(const SubContour& contour);

    enum TessWindingRule
    {
        WindingPositive=0,  
        WindingAbsGeqTwo=1  
    };

    bool sideContains2D(const Vec3d& p, int sideNb) const;

    void tesselate(TessWindingRule rule);

    QVector<SubContour> tesselateOneSideLineLoop(struct GLUEStesselator* tess, int sidenb) const;
    QVector<Vec3d> tesselateOneSideTriangles(struct GLUEStesselator* tess, int sidenb) const;
    QVarLengthArray<QVector<SubContour>,8 > sides;

    void updateVertexArray();
    StelVertexArray fillCachedVertexArray;
    StelVertexArray outlineCachedVertexArray;
    void computeBoundingCap();
    Vec3d capN;
    double capD;

    static const Vec3d sideDirections[];
    static int getSideNumber(const Vec3d& v) {return v[0]>=0. ?  (v[1]>=0. ? (v[2]>=0.?0:1) : (v[2]>=0.?4:5))   :   (v[1]>=0. ? (v[2]>=0.?2:3) : (v[2]>=0.?6:7));}
    static bool isTriangleConvexPositive2D(const Vec3d& a, const Vec3d& b, const Vec3d& c);
    static bool triangleContains2D(const Vec3d& a, const Vec3d& b, const Vec3d& c, const Vec3d& p);

    static void projectOnOctahedron(QVarLengthArray<QVector<SubContour>,8 >& inSides);
    static void splitContourByPlan(int onLine, const SubContour& contour, QVector<SubContour> result[2]);
};

// Serialization routines
QDataStream& operator<<(QDataStream& out, const OctahedronPolygon&);
QDataStream& operator>>(QDataStream& in, OctahedronPolygon&);

#endif // _OCTAHEDRON_REGION_HPP_