124 lines
3.0 KiB
C++
124 lines
3.0 KiB
C++
/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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/** \file
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* \ingroup freestyle
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* \brief Class to define a pseudo Perlin noise
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*/
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#include "BLI_math.h"
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#include "BLI_utildefines.h"
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#include "PseudoNoise.h"
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#include "RandGen.h"
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static int modf_to_index(Freestyle::real x, unsigned int range)
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{
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if (isfinite(x)) {
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Freestyle::real tmp;
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int i = abs((int)(modf(x, &tmp) * range));
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BLI_assert(i >= 0 && i < range);
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return i;
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}
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else {
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return 0;
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}
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}
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namespace Freestyle {
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real PseudoNoise::_values[];
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PseudoNoise::PseudoNoise()
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{
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}
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void PseudoNoise::init(long seed)
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{
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RandGen::srand48(seed);
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for (unsigned int i = 0; i < NB_VALUE_NOISE; i++) {
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_values[i] = -1.0 + 2.0 * RandGen::drand48();
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}
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}
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real PseudoNoise::linearNoise(real x)
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{
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real tmp;
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int i = modf_to_index(x, NB_VALUE_NOISE);
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real x1 = _values[i], x2 = _values[(i + 1) % NB_VALUE_NOISE];
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real t = modf(x * NB_VALUE_NOISE, &tmp);
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return x1 * (1 - t) + x2 * t;
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}
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static real LanczosWindowed(real t)
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{
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if (fabs(t) > 2) {
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return 0;
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}
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if (fabs(t) < M_EPSILON) {
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return 1.0;
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}
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return sin(M_PI * t) / (M_PI * t) * sin(M_PI * t / 2.0) / (M_PI * t / 2.0);
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}
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real PseudoNoise::smoothNoise(real x)
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{
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real tmp;
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int i = modf_to_index(x, NB_VALUE_NOISE);
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int h = i - 1;
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if (UNLIKELY(h < 0)) {
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h = NB_VALUE_NOISE + h;
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}
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real x1 = _values[i], x2 = _values[(i + 1) % NB_VALUE_NOISE];
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real x0 = _values[h], x3 = _values[(i + 2) % NB_VALUE_NOISE];
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real t = modf(x * NB_VALUE_NOISE, &tmp);
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real y0 = LanczosWindowed(-1 - t);
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real y1 = LanczosWindowed(-t);
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real y2 = LanczosWindowed(1 - t);
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real y3 = LanczosWindowed(2 - t);
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#if 0
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cerr << "x0=" << x0 << " x1=" << x1 << " x2=" << x2 << " x3=" << x3 << endl;
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cerr << "y0=" << y0 << " y1=" << y1 << " y2=" << y2 << " y3=" << y3 << " :" << endl;
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#endif
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return (x0 * y0 + x1 * y1 + x2 * y2 + x3 * y3) / (y0 + y1 + y2 + y3);
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}
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real PseudoNoise::turbulenceSmooth(real x, unsigned nbOctave)
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{
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real y = 0;
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real k = 1.0;
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for (unsigned int i = 0; i < nbOctave; i++) {
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y = y + k * smoothNoise(x * k);
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k = k / 2.0;
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}
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return y;
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}
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real PseudoNoise::turbulenceLinear(real x, unsigned nbOctave)
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{
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real y = 0;
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real k = 1.0;
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for (unsigned int i = 0; i < nbOctave; i++) {
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y = y + k * linearNoise(x * k);
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k = k / 2.0;
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}
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return y;
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}
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} /* namespace Freestyle */
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