UT/UT_Convex.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * Produced by:
 *      Mark Elendt
 *      Side Effects Software Inc
 *      477 Richmond Street West
 *      Toronto, Ontario
 *      Canada   M5V 3E7
 *      416-504-9876
 *
 * NAME:        UT_Convex.h ( UT Library, C++)
 *
 * COMMENTS:    This code does general polygon convexing.  It's down here
 *              in UT since there are places other than the GEO lib which
 *              may need to use convexing code (i.e. the RE lib, or UI).
 *              This code convexes 2D polygons.
 */

#ifndef __UT_Convex__
#define __UT_Convex__

#include "UT_API.h"
#include <SYS/SYS_Types.h>
#include <stdlib.h>

class UT_ConvexPoint;
class UT_Interrupt;

class UT_API UT_Convex {
public:
             UT_Convex()
             {
                 myData = 0;
                 myConvexInfo = 0;
                 myConvexSize = 0;
                 myConvexEntries = 0;
                 myPointList = 0;
                 myPointSize = 0;
             }
    virtual ~UT_Convex()
             {
                 if (myConvexInfo) free(myConvexInfo);
                 if (myPointList) free(myPointList);
             }

    int                 isConcave();
    void                convex(int maxsides);

    virtual void        initialize();
    // It's the sub-class responsibility to fill these out...
    virtual int         getPointCount() const = 0;
    virtual void        getPoint(int num, float &x, float &y) const = 0;

    // Begin Polygon will be told when the last polygon is being added
    virtual void        beginPolygon(int npoints, int lastone) = 0;
    virtual void        polyVertex(int num) = 0;
    virtual void        endPolygon() = 0;

    // If the last polygon to be added is degenerate, then the
    // earlyTermination() method will be called.  This is so that the caller
    // can clean up properly.  By default, this method does nothing.
    virtual void        earlyTermination();

private:
    UT_ConvexPoint      *polySetup();
    int                 leftOrRight(int v1, int v2, int v3, int &double_back);
    int                 leftOrRight(int v1, int v2, int v3)
                        {
                            int double_back;
                            return leftOrRight(v1, v2, v3, double_back);
                        }
    unsigned            leftMost(unsigned a, unsigned b, int &ccwise);
    unsigned            testConcave(unsigned m, unsigned n);
    int                 arePointsDifferent(unsigned m, unsigned n);
    int                 isDegenerate(unsigned m, unsigned n);
    int                 addPolygon(
                                UT_Interrupt *boss, unsigned m,
                                unsigned n, unsigned, unsigned &next);
    void                doSplit(unsigned m, unsigned m1,
                                unsigned n1, unsigned n);
    unsigned            cornerTest(int side, unsigned la, unsigned lb,
                                   unsigned m, unsigned n);
    unsigned            insideOut(unsigned k, unsigned la,
                                  unsigned lb, unsigned m, unsigned n);
    unsigned            chooseCoincidentIntruder(
                                unsigned l, unsigned k1, unsigned k2,
                                unsigned m, unsigned n, unsigned ccwise);
    unsigned            findBest(unsigned lb, unsigned la,
                                 unsigned ls, unsigned m, unsigned n);
    unsigned            testIntersect(unsigned l, unsigned lb, unsigned la,
                                      unsigned m, unsigned n, int &ccwise);

protected:
    UT_ConvexPoint      *myData;

private:
    UT_ConvexPoint      *myConvexInfo;
    unsigned             myConvexSize;
    unsigned             myConvexEntries;
    int                 *myPointList;
    unsigned             myPointSize;
};

#endif

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