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/*
* 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.
*/
/** \file
* \ingroup freestyle
* \brief Class to define a pseudo Perlin noise
*/
#include "BLI_math.h"
#include "BLI_utildefines.h"
#include "PseudoNoise.h"
#include "RandGen.h"
static int modf_to_index(Freestyle::real x, unsigned int range)
{
if (isfinite(x)) {
Freestyle::real tmp;
int i = abs((int)(modf(x, &tmp) * range));
BLI_assert(i >= 0 && i < range);
return i;
}
return 0;
}
namespace Freestyle {
real PseudoNoise::_values[];
PseudoNoise::PseudoNoise()
{
}
void PseudoNoise::init(long seed)
{
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_to_index(x, 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_to_index(x, NB_VALUE_NOISE);
int h = i - 1;
if (UNLIKELY(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;
}
} /* namespace Freestyle */
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