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 #ifndef LUX_BLINN_H 00024 #define LUX_BLINN_H 00025 // blinn.h* 00026 #include "lux.h" 00027 #include "bxdf.h" 00028 #include "microfacetdistribution.h" 00029 00030 namespace lux 00031 { 00032 00033 class Blinn : public MicrofacetDistribution { 00034 public: 00035 Blinn(float e) { if (e > 100000.f || isnan(e)) e = 100000.f; exponent = e; } 00036 virtual ~Blinn() { } 00037 // Blinn Public Methods 00038 virtual float D(const Vector &wh) const { 00039 float costhetah = fabsf(CosTheta(wh)); 00040 return (exponent+2) * 00041 INV_TWOPI * 00042 powf(costhetah, exponent); 00043 } 00044 virtual void Sample_f(const Vector &wi, Vector *sampled_f, float u1, float u2, float *pdf) const; 00045 virtual float Pdf(const Vector &wi, const Vector &wo) const; 00046 private: 00047 float exponent; 00048 }; 00049 00050 }//namespace lux 00051 00052 #endif // LUX_BLINN_H 00053