PBRT
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00001 00002 /* 00003 pbrt source code Copyright(c) 1998-2012 Matt Pharr and Greg Humphreys. 00004 00005 This file is part of pbrt. 00006 00007 Redistribution and use in source and binary forms, with or without 00008 modification, are permitted provided that the following conditions are 00009 met: 00010 00011 - Redistributions of source code must retain the above copyright 00012 notice, this list of conditions and the following disclaimer. 00013 00014 - Redistributions in binary form must reproduce the above copyright 00015 notice, this list of conditions and the following disclaimer in the 00016 documentation and/or other materials provided with the distribution. 00017 00018 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 00019 IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 00020 TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 00021 PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 00022 HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 00023 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 00024 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 00025 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 00026 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 00027 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 00028 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 00029 00030 */ 00031 00032 #if defined(_MSC_VER) 00033 #pragma once 00034 #endif 00035 00036 #ifndef PBRT_VOLUMES_HOMOGENEOUS_H 00037 #define PBRT_VOLUMES_HOMOGENEOUS_H 00038 00039 // volumes/homogeneous.h* 00040 #include "volume.h" 00041 00042 // HomogeneousVolumeDensity Declarations 00043 class HomogeneousVolumeDensity : public VolumeRegion { 00044 public: 00045 // HomogeneousVolumeDensity Public Methods 00046 HomogeneousVolumeDensity(const Spectrum &sa, const Spectrum &ss, float gg, 00047 const Spectrum &emit, const BBox &e, const Transform &v2w) { 00048 WorldToVolume = Inverse(v2w); 00049 sig_a = sa; 00050 sig_s = ss; 00051 g = gg; 00052 le = emit; 00053 extent = e; 00054 } 00055 BBox WorldBound() const { 00056 return Inverse(WorldToVolume)(extent); 00057 } 00058 bool IntersectP(const Ray &r, float *t0, float *t1) const { 00059 Ray ray = WorldToVolume(r); 00060 return extent.IntersectP(ray, t0, t1); 00061 } 00062 Spectrum sigma_a(const Point &p, const Vector &, float) const { 00063 return extent.Inside(WorldToVolume(p)) ? sig_a : 0.; 00064 } 00065 Spectrum sigma_s(const Point &p, const Vector &, float) const { 00066 return extent.Inside(WorldToVolume(p)) ? sig_s : 0.; 00067 } 00068 Spectrum sigma_t(const Point &p, const Vector &, float) const { 00069 return extent.Inside(WorldToVolume(p)) ? (sig_a + sig_s) : 0.; 00070 } 00071 Spectrum Lve(const Point &p, const Vector &, float) const { 00072 return extent.Inside(WorldToVolume(p)) ? le : 0.; 00073 } 00074 float p(const Point &p, const Vector &wi, const Vector &wo, float) const { 00075 if (!extent.Inside(WorldToVolume(p))) return 0.; 00076 return PhaseHG(wi, wo, g); 00077 } 00078 Spectrum tau(const Ray &ray, float, float) const { 00079 float t0, t1; 00080 if (!IntersectP(ray, &t0, &t1)) return 0.; 00081 return Distance(ray(t0), ray(t1)) * (sig_a + sig_s); 00082 } 00083 private: 00084 // HomogeneousVolumeDensity Private Data 00085 Spectrum sig_a, sig_s, le; 00086 float g; 00087 BBox extent; 00088 Transform WorldToVolume; 00089 }; 00090 00091 00092 HomogeneousVolumeDensity *CreateHomogeneousVolumeDensityRegion(const Transform &volume2world, 00093 const ParamSet ¶ms); 00094 00095 #endif // PBRT_VOLUMES_HOMOGENEOUS_H