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Noise.h

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/* SimData: Data Infrastructure for Simulations
 * Copyright (C) 2002 Mark Rose <tm2@stm.lbl.gov>
 * 
 * This file is part of SimData.
 * 
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */


#ifndef __SIMDATA_NOISE_H__
#define __SIMDATA_NOISE_H__

#include <cmath>
#include <vector>

#include <SimData/Export.h>
#include <SimData/Namespace.h>


NAMESPACE_SIMDATA


class SIMDATA_EXPORT Perlin1D {
        
public:

        typedef enum { LINEAR, COSINE, CUBIC } Interpolation;

        Perlin1D(double persistence=0.5, int octaves=1, Interpolation interpolation=LINEAR);

        void setParameters(double persistence, int octaves);

        void setInterpolation(Interpolation interpolation);

        void setOffset(int idx);
        
        void randomize();

        double _simpleRandom(int x) const {
                x = (x << 13) ^ x;
                return (1.0 -
                        ((x * (x * x * 15731 + 789221) + 1376312589) & 0x7fffffff) /
                        1073741824.0);
        } 

        double _getSmoothedNoise(int x) {
                return 0.5 * (_simpleRandom(x) + 0.5 * (_simpleRandom(x - 1) + _simpleRandom(x + 1)));
        } 

        double _linearInterpolate(double a, double b, double x) {
                return  a*(1.0-x) + b*x;
        }
        
        double _cosineInterpolate(double a, double b, double x) {
                x = (1.0 - cos(x * 3.14159265)) * 0.5;
                return  a*(1.0-x) + b*x;
        }
        
        double _cubicInterpolate(double v0, double v1, double v2, double v3, double x) {
                double P = (v3 - v2) - (v0 - v1);
                double Q = (v0 - v1) - P;
                double R = v2 - v0;
                return  (((P*x + Q) * x) + R) * x + v1;
        }

        double _getInterpolatedNoise(double x);

        double getValue(double x);

        std::vector<float> generate(int n, bool periodic, double scale=1.0, double amplitude=1.0, double offset=0.0);

private:
        double m_persistence;
        int m_octaves;
        int m_offset;
        int m_interpolation;
        
};


NAMESPACE_SIMDATA_END


#endif //__SIMDATA_NOISE_H__

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