OpenSceneGraph/include/osgUtil/PerlinNoise

/* -*-c++-*-
*
*  OpenSceneGraph example, osgshaders.
*
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/************************************************************************
 *                                                                      *
 *                   Copyright (C) 2002  3Dlabs Inc. Ltd.               *
 *                                                                      *
 ***********************************************************************/

/* Adapted from osgshaders example by Robert Osfield for use as part of osgUtil.*/

#ifndef PERLINENOISE_H
#define PERLINENOISE_H

#include <osg/Texture3D>
#include <osgUtil/Export>

namespace osgUtil
{

class OSGUTIL_EXPORT PerlinNoise
{
public:

    PerlinNoise();

    void SetNoiseFrequency(int frequency);

    double noise1(double arg);
    double noise2(double vec[2]);
    double noise3(double vec[3]);
    void normalize2(double vec[2]);
    void normalize3(double vec[3]);

    /*
    In what follows "alpha" is the weight when the sum is formed.
    Typically it is 2, As this approaches 1 the function is noisier.
    "beta" is the harmonic scaling/spacing, typically 2.
    */

    double PerlinNoise1D(double x,double alpha, double beta, int n);
    double PerlinNoise2D(double x,double y,double alpha, double beta, int n);
    double PerlinNoise3D(double x,double y,double z,double alpha, double beta, int n);

    osg::Image* create3DNoiseImage(int texSize);
    osg::Texture3D* create3DNoiseTexture(int texSize );

protected:

    void initNoise(void);

    enum { MAXB = 0x100 };

    int p[MAXB + MAXB + 2];
    double g3[MAXB + MAXB + 2][3];
    double g2[MAXB + MAXB + 2][2];
    double g1[MAXB + MAXB + 2];

    int start;
    int B;
    int BM;

};

inline osg::Image* create3DNoiseImage(int texSize)
{
    PerlinNoise pn;
    return pn.create3DNoiseImage(texSize);
}

inline osg::Texture3D* create3DNoiseTexture(int texSize )
{
    PerlinNoise pn;
    return pn.create3DNoiseTexture(texSize);
}

}

#endif // PERLINENOISE_H