130 lines
4.1 KiB
C
130 lines
4.1 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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* Copyright 2019, Blender Foundation.
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*/
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/** \file
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* \ingroup EEVEE
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*/
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#include "eevee_private.h"
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#include "BLI_rand.h"
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/**
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* Special ball distribution:
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* Point are distributed in a way that when they are orthogonally
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* projected into any plane, the resulting distribution is (close to)
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* a uniform disc distribution.
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*/
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void EEVEE_sample_ball(int sample_ofs, float radius, float rsample[3])
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{
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double ht_point[3];
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double ht_offset[3] = {0.0, 0.0, 0.0};
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const uint ht_primes[3] = {2, 3, 7};
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BLI_halton_3d(ht_primes, ht_offset, sample_ofs, ht_point);
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/* Decorelate AA and shadow samples. (see T68594) */
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ht_point[0] = fmod(ht_point[0] * 1151.0, 1.0);
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ht_point[1] = fmod(ht_point[1] * 1069.0, 1.0);
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ht_point[2] = fmod(ht_point[2] * 1151.0, 1.0);
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float omega = ht_point[1] * 2.0f * M_PI;
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rsample[2] = ht_point[0] * 2.0f - 1.0f; /* cos theta */
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float r = sqrtf(fmaxf(0.0f, 1.0f - rsample[2] * rsample[2])); /* sin theta */
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rsample[0] = r * cosf(omega);
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rsample[1] = r * sinf(omega);
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radius *= sqrt(sqrt(ht_point[2]));
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mul_v3_fl(rsample, radius);
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}
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void EEVEE_sample_rectangle(int sample_ofs,
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const float x_axis[3],
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const float y_axis[3],
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float size_x,
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float size_y,
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float rsample[3])
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{
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double ht_point[2];
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double ht_offset[2] = {0.0, 0.0};
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const uint ht_primes[2] = {2, 3};
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BLI_halton_2d(ht_primes, ht_offset, sample_ofs, ht_point);
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/* Decorelate AA and shadow samples. (see T68594) */
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ht_point[0] = fmod(ht_point[0] * 1151.0, 1.0);
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ht_point[1] = fmod(ht_point[1] * 1069.0, 1.0);
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/* Change ditribution center to be 0,0 */
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ht_point[0] = (ht_point[0] > 0.5f) ? ht_point[0] - 1.0f : ht_point[0];
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ht_point[1] = (ht_point[1] > 0.5f) ? ht_point[1] - 1.0f : ht_point[1];
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zero_v3(rsample);
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madd_v3_v3fl(rsample, x_axis, (ht_point[0] * 2.0f) * size_x);
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madd_v3_v3fl(rsample, y_axis, (ht_point[1] * 2.0f) * size_y);
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}
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void EEVEE_sample_ellipse(int sample_ofs,
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const float x_axis[3],
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const float y_axis[3],
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float size_x,
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float size_y,
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float rsample[3])
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{
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double ht_point[2];
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double ht_offset[2] = {0.0, 0.0};
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const uint ht_primes[2] = {2, 3};
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BLI_halton_2d(ht_primes, ht_offset, sample_ofs, ht_point);
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/* Decorelate AA and shadow samples. (see T68594) */
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ht_point[0] = fmod(ht_point[0] * 1151.0, 1.0);
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ht_point[1] = fmod(ht_point[1] * 1069.0, 1.0);
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/* Uniform disc sampling. */
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float omega = ht_point[1] * 2.0f * M_PI;
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float r = sqrtf(ht_point[0]);
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ht_point[0] = r * cosf(omega) * size_x;
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ht_point[1] = r * sinf(omega) * size_y;
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zero_v3(rsample);
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madd_v3_v3fl(rsample, x_axis, ht_point[0]);
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madd_v3_v3fl(rsample, y_axis, ht_point[1]);
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}
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void EEVEE_random_rotation_m4(int sample_ofs, float scale, float r_mat[4][4])
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{
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double ht_point[3];
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double ht_offset[3] = {0.0, 0.0, 0.0};
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const uint ht_primes[3] = {2, 3, 5};
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BLI_halton_3d(ht_primes, ht_offset, sample_ofs, ht_point);
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/* Decorelate AA and shadow samples. (see T68594) */
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ht_point[0] = fmod(ht_point[0] * 1151.0, 1.0);
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ht_point[1] = fmod(ht_point[1] * 1069.0, 1.0);
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ht_point[2] = fmod(ht_point[2] * 1151.0, 1.0);
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rotate_m4(r_mat, 'X', ht_point[0] * scale);
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rotate_m4(r_mat, 'Y', ht_point[1] * scale);
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rotate_m4(r_mat, 'Z', ht_point[2] * scale);
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}
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