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 #ifndef LUX_FRESNELBLEND_H 00024 #define LUX_FRESNELBLEND_H 00025 // fresnelblend.h* 00026 #include "lux.h" 00027 #include "bxdf.h" 00028 #include "spectrum.h" 00029 00030 namespace lux 00031 { 00032 00033 class FresnelBlend : public BxDF 00034 { 00035 public: 00036 // FresnelBlend Public Methods 00037 FresnelBlend(const SWCSpectrum &Rd, 00038 const SWCSpectrum &Rs, 00039 MicrofacetDistribution *dist); 00040 SWCSpectrum f(const Vector &wo, const Vector &wi) const; 00041 SWCSpectrum SchlickFresnel(float costheta) const { 00042 return 00043 Rs + powf(1 - costheta, 5.f) * (SWCSpectrum(1.) - Rs); 00044 } 00045 SWCSpectrum Sample_f(const Vector &wi, Vector *sampled_f, float u1, float u2, float *pdf, float *pdfBack = NULL) const; 00046 float Pdf(const Vector &wi, const Vector &wo) const; 00047 00048 private: 00049 // FresnelBlend Private Data 00050 SWCSpectrum Rd, Rs; 00051 MicrofacetDistribution *distribution; 00052 }; 00053 00054 }//namespace lux 00055 00056 #endif // LUX_FRESNELBLEND_H 00057