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/*
* ***** BEGIN GPL LICENSE BLOCK *****
*
* 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, Fifth Floor, Boston, MA 02110-1301, USA.
*
* The Original Code is Copyright (C) 2010 Blender Foundation.
* All rights reserved.
*
* The Original Code is: all of this file.
*
* Contributor(s): none yet.
*
* ***** END GPL LICENSE BLOCK *****
*/
/** \file blender/freestyle/intern/system/PseudoNoise.cpp
* \ingroup freestyle
* \brief Class to define a pseudo Perlin noise
* \author Fredo Durand
* \date 16/06/2003
*/
#include <math.h>
#include "PseudoNoise.h"
#include "RandGen.h"
static const unsigned NB_VALUE_NOISE = 512;
real *PseudoNoise::_values;
PseudoNoise::PseudoNoise() {}
void PseudoNoise::init(long seed)
{
_values = new real[NB_VALUE_NOISE];
RandGen::srand48(seed);
for (unsigned int i = 0; i < NB_VALUE_NOISE; i++)
_values[i] = -1.0 + 2.0 * RandGen::drand48();
}
real PseudoNoise::linearNoise(real x)
{
real tmp;
int i = modf(x, &tmp) * NB_VALUE_NOISE;
real x1 = _values[i], x2 = _values[(i + 1) % NB_VALUE_NOISE];
real t = modf(x * NB_VALUE_NOISE, &tmp);
return x1 * (1 - t) + x2 * t;
}
static real LanczosWindowed(real t)
{
if (fabs(t) > 2)
return 0;
if (fabs(t) < M_EPSILON)
return 1.0;
return sin(M_PI * t) / (M_PI * t) * sin(M_PI * t / 2.0) / (M_PI * t / 2.0);
}
real PseudoNoise::smoothNoise(real x)
{
real tmp;
int i = modf(x, &tmp) * NB_VALUE_NOISE;
int h = i - 1;
if (h < 0) {
h = NB_VALUE_NOISE + h;
}
real x1 = _values[i], x2 = _values[(i + 1) % NB_VALUE_NOISE];
real x0 = _values[h], x3 = _values[(i + 2) % NB_VALUE_NOISE];
real t = modf(x * NB_VALUE_NOISE, &tmp);
real y0 = LanczosWindowed(-1 -t);
real y1 = LanczosWindowed(-t);
real y2 = LanczosWindowed(1 - t);
real y3 = LanczosWindowed(2 - t);
#if 0
cerr << "x0=" << x0 << " x1=" << x1 << " x2=" << x2 << " x3=" << x3 << endl;
cerr << "y0=" << y0 << " y1=" << y1 << " y2=" << y2 << " y3=" << y3 << " :" << endl;
#endif
return (x0 * y0 + x1 * y1 + x2 * y2 + x3 * y3) / (y0 + y1 + y2 + y3);
}
real PseudoNoise::turbulenceSmooth(real x, unsigned nbOctave)
{
real y = 0;
real k = 1.0;
for (unsigned int i = 0; i < nbOctave; i++) {
y = y + k * smoothNoise(x * k);
k = k / 2.0;
}
return y;
}
real PseudoNoise::turbulenceLinear(real x, unsigned nbOctave)
{
real y = 0;
real k = 1.0;
for (unsigned int i = 0; i < nbOctave; i++) {
y = y + k * linearNoise(x * k);
k = k / 2.0;
}
return y;
}
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