00001 /*************************************************************************** 00002 * Copyright (C) 1998-2008 by authors (see AUTHORS.txt ) * 00003 * * 00004 * This file is part of LuxRender. * 00005 * * 00006 * Lux Renderer is free software; you can redistribute it and/or modify * 00007 * it under the terms of the GNU General Public License as published by * 00008 * the Free Software Foundation; either version 3 of the License, or * 00009 * (at your option) any later version. * 00010 * * 00011 * Lux Renderer is distributed in the hope that it will be useful, * 00012 * but WITHOUT ANY WARRANTY; without even the implied warranty of * 00013 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * 00014 * GNU General Public License for more details. * 00015 * * 00016 * You should have received a copy of the GNU General Public License * 00017 * along with this program. If not, see <http://www.gnu.org/licenses/>. * 00018 * * 00019 * This project is based on PBRT ; see http://www.pbrt.org * 00020 * Lux Renderer website : http://www.luxrender.net * 00021 ***************************************************************************/ 00022 00023 // contrast.cpp* 00024 #include "contrast.h" 00025 00026 using namespace lux; 00027 00028 // ContrastOp Method Definitions 00029 void ContrastOp::Map(const float *y, int xRes, int yRes, 00030 float maxDisplayY, float *scale) const { 00031 // Compute world adaptation luminance, _Ywa_ 00032 float Ywa = 0.; 00033 for (int i = 0; i < xRes * yRes; ++i) 00034 if (y[i] > 0) Ywa += logf(y[i]); 00035 Ywa = expf(Ywa / (xRes * yRes)); 00036 // Compute contrast-preserving scalefactor, _s_ 00037 float s = powf((1.219f + powf(displayAdaptationY, 0.4f)) / 00038 (1.219f + powf(Ywa, 0.4f)), 2.5f); 00039 for (int i = 0; i < xRes*yRes; ++i) 00040 scale[i] = s; 00041 } 00042 ToneMap * ContrastOp::CreateToneMap(const ParamSet &ps) { 00043 float day = ps.FindOneFloat("displayadaptationY", 50.f); 00044 return new ContrastOp(day); 00045 }