cubicbeziercurve.h

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#ifndef cubicbeziercurve_h
#define cubicbeziercurve_h
                                                                                
/*+
________________________________________________________________________
(C) dGB Beheer B.V.; (LICENSE) http://opendtect.org/OpendTect_license.txt
Author:        K. Tingdahl
Date:          2005
Contents:      Ranges
RCS:           $Id$
________________________________________________________________________

-*/

#include "geometrymod.h"
#include "parametriccurve.h"
#include "sets.h"

namespace Geometry
{

mExpClass(Geometry) CubicBezierCurve : public ParametricCurve
{ mODTextTranslationClass(CubicBezierCurve);
public:
                        CubicBezierCurve( const Coord3&, const Coord3&,
                                          int firstparam=0, int step=1 );
    CubicBezierCurve*   clone() const;
    IntervalND<float>   boundingBox(bool) const;

    Coord3              computePosition( float ) const;
    Coord3              computeTangent( float ) const;

    StepInterval<int>   parameterRange() const;

    Coord3      getPosition( GeomPosID ) const;
    bool        setPosition( GeomPosID, const Coord3&);
    bool        unsetPosition( GeomPosID );
    bool        insertPosition( GeomPosID, const Coord3& );
    bool        removePosition( GeomPosID );
    bool        isDefined( GeomPosID ) const;

    Coord3      getBezierVertex( GeomPosID, bool before ) const;

    Coord3      getTangent( GeomPosID, bool computeifudf ) const;
    bool        setTangent( GeomPosID, const Coord3& );
    bool        unsetTangent( GeomPosID );
    bool        isTangentDefined( GeomPosID ) const;
    float       directionInfluence() const;
    void        setTangentInfluence(float);

    bool        isCircular() const;
    bool        setCircular(bool yn);

protected:
    int         getIndex( GeomPosID param ) const
                { return mCast(int,(param-firstparam)/paramstep); }

    Coord3      computeTangent( GeomPosID ) const;

    int                 firstparam;
    int                 paramstep;
    TypeSet<Coord3>     positions;
    TypeSet<Coord3>     directions;
    float               directioninfluence;

    bool                iscircular;
};

inline Coord3 cubicDeCasteljau( const Coord3* p, char i0, char di, float u )
{
    p += i0;
    if ( mIsZero(u,1e-3) ) return *p;
    else if ( mIsEqual(u,1,1e-3) ) return p[3*di];

    const float one_minus_u = 1-u;
    Coord3 interpolpos1 =       p[di]*one_minus_u+p[di*2]       * u;

    const Coord3 interpolpos0 = (*p*one_minus_u+p[di]*u)        * one_minus_u +
                                interpolpos1                    * u;

    interpolpos1 =              interpolpos1                    * one_minus_u +
                                (p[di*2]*one_minus_u+p[3*di]*u) * u;

    return interpolpos0*one_minus_u+interpolpos1*u;
}


inline Coord3 cubicDeCasteljauTangent( const Coord3* p, char i0, char di,
                                       float u)
{
    p += i0;
    if ( mIsZero(u,1e-3) ) return p[di]-*p;
    else if ( mIsEqual(u,1,1e-3) ) return p[3*di]-p[2*di];

    const float one_minus_u = 1-u;
    Coord3 interpolpos1 =       p[di]*one_minus_u+p[2*di]       * u;

    const Coord3 interpolpos0 = (*p*one_minus_u+p[di]*u)        * one_minus_u +
                                interpolpos1                    * u;

    interpolpos1 =              interpolpos1                    * one_minus_u +
                                (p[2*di]*one_minus_u+p[3*di]*u) * u;

    return interpolpos1-interpolpos0;
}

};

#endif