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 // nonlinear.cpp* 00024 #include "tonemap.h" 00025 #include "paramset.h" 00026 00027 namespace lux 00028 { 00029 00030 // NonLinearOp Declarations 00031 class NonLinearOp : public ToneMap { 00032 public: 00033 // NonLinearOp Public Methods 00034 NonLinearOp(float my) { maxY = my; } 00035 void Map(const float *y, int xRes, int yRes, 00036 float maxDisplayY, float *scale) const { 00037 float invY2; 00038 if (maxY <= 0.f) { 00039 // Compute world adaptation luminance, _Ywa_ 00040 float Ywa = 0.; 00041 for (int i = 0; i < xRes * yRes; ++i) 00042 if (y[i] > 0) Ywa += logf(y[i]); 00043 Ywa = expf(Ywa / (xRes * yRes)); 00044 Ywa /= 683.f; 00045 invY2 = 1.f / (Ywa * Ywa); 00046 } 00047 else invY2 = 1.f / (maxY * maxY); 00048 for (int i = 0; i < xRes * yRes; ++i) { 00049 float ys = y[i] / 683.f; 00050 scale[i] = maxDisplayY / 683.f * 00051 (1.f + ys * invY2) / (1.f + ys); 00052 } 00053 } 00054 00055 static ToneMap *CreateToneMap(const ParamSet &ps); 00056 private: 00057 float maxY; 00058 }; 00059 00060 }//namespace lux 00061