00001 /*************************************************************************** 00002 * Copyright (C) 1998-2009 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 // fresnelgeneral.cpp* 00024 #include "fresnelgeneral.h" 00025 #include "spectrum.h" 00026 00027 using namespace lux; 00028 00029 void FresnelGeneral::Evaluate(const TsPack *tspack, float cosi, SWCSpectrum *const f) const { 00030 SWCSpectrum cost(sqrtf(max(0.f, 1.f - cosi * cosi))); 00031 if (cosi > 0.f) 00032 cost = cost / (eta * eta + k * k).Sqrt(); 00033 else 00034 cost = cost * (eta * eta + k * k).Sqrt(); 00035 cost.Clamp(0.f, 1.f); 00036 cost = (SWCSpectrum(1.f) - cost * cost).Sqrt(); 00037 FrFull(fabsf(cosi), cost, eta, k, f); 00038 }