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 // sinc.cpp* 00024 #include "sinc.h" 00025 00026 using namespace lux; 00027 00028 // Sinc Filter Method Definitions 00029 float LanczosSincFilter::Evaluate(float x, float y) const{ 00030 return Sinc1D(x * invXWidth) * Sinc1D(y * invYWidth); 00031 } 00032 float LanczosSincFilter::Sinc1D(float x) const { 00033 x = fabsf(x); 00034 if (x < 1e-5) return 1.f; 00035 if (x > 1.) return 0.f; 00036 x *= M_PI; 00037 float sinc = sinf(x * tau) / (x * tau); 00038 float lanczos = sinf(x) / x; 00039 return sinc * lanczos; 00040 } 00041 Filter* LanczosSincFilter::CreateFilter(const ParamSet &ps) { 00042 float xw = ps.FindOneFloat("xwidth", 4.); 00043 float yw = ps.FindOneFloat("ywidth", 4.); 00044 float tau = ps.FindOneFloat("tau", 3.f); 00045 return new LanczosSincFilter(xw, yw, tau); 00046 }