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_MITCHELL_H 00024 #define LUX_MITCHELL_H 00025 00026 // mitchell.cpp* 00027 #include "filter.h" 00028 #include "paramset.h" 00029 00030 namespace lux 00031 { 00032 00033 // Mitchell Filter Declarations 00034 class MitchellFilter : public Filter { 00035 public: 00036 // MitchellFilter Public Methods 00037 MitchellFilter(float b, float c, float xw, float yw) 00038 : Filter(xw, yw) { B = b; C = c; } 00039 virtual ~MitchellFilter() { } 00040 virtual float Evaluate(float x, float y) const; 00041 00042 static Filter *CreateFilter(const ParamSet &ps); 00043 private: 00044 float Mitchell1D(float x) const { 00045 x = fabsf(2.f * x); 00046 if (x > 1.f) 00047 return (((-B/6.f - C) * x + (B + 5.f*C)) * x + 00048 (-2.f*B - 8.f*C)) * x + (4.f/3.f*B + 4.f*C); 00049 else 00050 return ((2.f - 1.5f*B - C) * x + 00051 (-3.f + 2.f*B + C)) * x*x + 00052 (1.f - B/3.f); 00053 } 00054 float B, C; 00055 }; 00056 00057 }//namespace lux 00058 00059 #endif 00060