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.org * 00021 ***************************************************************************/ 00022 00023 // blackbody.cpp* 00024 #include "blackbodyspd.h" 00025 00026 using namespace lux; 00027 00028 void BlackbodySPD::init(float t) { 00029 temp = t; 00030 00031 lambdaMin = BB_CACHE_START; 00032 lambdaMax = BB_CACHE_END; 00033 delta = (BB_CACHE_END - BB_CACHE_START) / (BB_CACHE_SAMPLES-1); 00034 invDelta = 1.f / delta; 00035 nSamples = BB_CACHE_SAMPLES; 00036 00037 AllocateSamples(BB_CACHE_SAMPLES); 00038 00039 // Fill samples with BB curve 00040 for(int i=0; i<BB_CACHE_SAMPLES; i++) { 00041 float w = 1e-9f * (BB_CACHE_START + (delta*i)); 00042 // Compute blackbody power for wavelength w and temperature temp 00043 samples[i] = 0.4e-9f * (3.74183e-16f * powf(w, -5.f)) 00044 / (expf(1.4388e-2f / (w * temp)) - 1.f); 00045 } 00046 00047 Normalize(); 00048 Clamp(); 00049 }