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Diffstat (limited to 'intern/cycles/render/bssrdf.cpp')
| -rw-r--r-- | intern/cycles/render/bssrdf.cpp | 134 |
1 files changed, 0 insertions, 134 deletions
diff --git a/intern/cycles/render/bssrdf.cpp b/intern/cycles/render/bssrdf.cpp deleted file mode 100644 index 69cab5e1824..00000000000 --- a/intern/cycles/render/bssrdf.cpp +++ /dev/null @@ -1,134 +0,0 @@ -/* - * Copyright 2011-2013 Blender Foundation - * - * Licensed under the Apache License, Version 2.0 (the "License"); - * you may not use this file except in compliance with the License. - * You may obtain a copy of the License at - * - * http://www.apache.org/licenses/LICENSE-2.0 - * - * Unless required by applicable law or agreed to in writing, software - * distributed under the License is distributed on an "AS IS" BASIS, - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - * See the License for the specific language governing permissions and - * limitations under the License - */ - -#include "bssrdf.h" - -#include "util_algorithm.h" -#include "util_math.h" -#include "util_types.h" - -#include "kernel_types.h" -#include "kernel_montecarlo.h" - -CCL_NAMESPACE_BEGIN - -static float bssrdf_cubic(float ld, float r) -{ - if(ld == 0.0f) - return (r == 0.0f)? 1.0f: 0.0f; - - return powf(ld - min(r, ld), 3.0f) * 4.0f/powf(ld, 4.0f); -} - -/* Cumulative density function utilities */ - -static float cdf_lookup_inverse(const vector<float>& table, float2 range, float x) -{ - int index = upper_bound(table.begin(), table.end(), x) - table.begin(); - - if(index == 0) - return range[0]; - else if(index == table.size()) - return range[1]; - else - index--; - - float t = (x - table[index])/(table[index+1] - table[index]); - float y = ((index + t)/(table.size() - 1)); - - return y*(range[1] - range[0]) + range[0]; -} - -static void cdf_invert(vector<float>& to, float2 to_range, const vector<float>& from, float2 from_range) -{ - float step = 1.0f/(float)(to.size() - 1); - - for(int i = 0; i < to.size(); i++) { - float x = (i*step)*(from_range[1] - from_range[0]) + from_range[0]; - to[i] = cdf_lookup_inverse(from, to_range, x); - } -} - -/* BSSRDF */ - -static void bssrdf_lookup_table_create(float ld, vector<float>& sample_table, vector<float>& pdf_table) -{ - const int size = BSSRDF_RADIUS_TABLE_SIZE; - vector<float> cdf(size); - vector<float> pdf(size); - float step = 1.0f/(float)(size - 1); - float max_radius = ld; - float pdf_sum = 0.0f; - - /* compute the probability density function */ - for(int i = 0; i < pdf.size(); i++) { - float x = (i*step)*max_radius; - pdf[i] = bssrdf_cubic(ld, x); - pdf_sum += pdf[i]; - } - - /* adjust for area covered by each distance */ - for(int i = 0; i < pdf.size(); i++) { - float x = (i*step)*max_radius; - pdf[i] *= M_2PI_F*x; - } - - /* normalize pdf, we multiply in reflectance later */ - if(pdf_sum > 0.0f) - for(int i = 0; i < pdf.size(); i++) - pdf[i] /= pdf_sum; - - /* sum to account for sampling which uses overlapping sphere */ - for(int i = pdf.size() - 2; i >= 0; i--) - pdf[i] = pdf[i] + pdf[i+1]; - - /* compute the cumulative density function */ - cdf[0] = 0.0f; - - for(int i = 1; i < size; i++) - cdf[i] = cdf[i-1] + 0.5f*(pdf[i-1] + pdf[i])*step*max_radius; - - /* invert cumulative density function for importance sampling */ - float2 cdf_range = make_float2(0.0f, cdf[size - 1]); - float2 table_range = make_float2(0.0f, max_radius); - - cdf_invert(sample_table, table_range, cdf, cdf_range); - - /* copy pdf table */ - for(int i = 0; i < pdf.size(); i++) - pdf_table[i] = pdf[i]; -} - -void bssrdf_table_build(vector<float>& table) -{ - vector<float> sample_table(BSSRDF_RADIUS_TABLE_SIZE); - vector<float> pdf_table(BSSRDF_RADIUS_TABLE_SIZE); - - table.resize(BSSRDF_LOOKUP_TABLE_SIZE); - - /* create a 2D lookup table, for reflection x sample radius */ - for(int i = 0; i < BSSRDF_REFL_TABLE_SIZE; i++) { - float radius = 1.0f; - - bssrdf_lookup_table_create(radius, sample_table, pdf_table); - - memcpy(&table[i*BSSRDF_RADIUS_TABLE_SIZE], &sample_table[0], BSSRDF_RADIUS_TABLE_SIZE*sizeof(float)); - memcpy(&table[BSSRDF_PDF_TABLE_OFFSET + i*BSSRDF_RADIUS_TABLE_SIZE], &pdf_table[0], BSSRDF_RADIUS_TABLE_SIZE*sizeof(float)); - } -} - -CCL_NAMESPACE_END - |