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00024 #if defined(_MSC_VER)
00025 #pragma once
00026 #endif
00027
00028 #ifndef PBRT_VOLUMES_HOMOGENEOUS_H
00029 #define PBRT_VOLUMES_HOMOGENEOUS_H
00030
00031
00032 #include "volume.h"
00033
00034
00035 class HomogeneousVolumeDensity : public VolumeRegion {
00036 public:
00037
00038 HomogeneousVolumeDensity(const Spectrum &sa, const Spectrum &ss, float gg,
00039 const Spectrum &emit, const BBox &e, const Transform &v2w) {
00040 WorldToVolume = Inverse(v2w);
00041 sig_a = sa;
00042 sig_s = ss;
00043 g = gg;
00044 le = emit;
00045 extent = e;
00046 }
00047 BBox WorldBound() const {
00048 return Inverse(WorldToVolume)(extent);
00049 }
00050 bool IntersectP(const Ray &r, float *t0, float *t1) const {
00051 Ray ray = WorldToVolume(r);
00052 return extent.IntersectP(ray, t0, t1);
00053 }
00054 Spectrum sigma_a(const Point &p, const Vector &, float) const {
00055 return extent.Inside(WorldToVolume(p)) ? sig_a : 0.;
00056 }
00057 Spectrum sigma_s(const Point &p, const Vector &, float) const {
00058 return extent.Inside(WorldToVolume(p)) ? sig_s : 0.;
00059 }
00060 Spectrum sigma_t(const Point &p, const Vector &, float) const {
00061 return extent.Inside(WorldToVolume(p)) ? (sig_a + sig_s) : 0.;
00062 }
00063 Spectrum Lve(const Point &p, const Vector &, float) const {
00064 return extent.Inside(WorldToVolume(p)) ? le : 0.;
00065 }
00066 float p(const Point &p, const Vector &wi, const Vector &wo, float) const {
00067 if (!extent.Inside(WorldToVolume(p))) return 0.;
00068 return PhaseHG(wi, wo, g);
00069 }
00070 Spectrum tau(const Ray &ray, float, float) const {
00071 float t0, t1;
00072 if (!IntersectP(ray, &t0, &t1)) return 0.;
00073 return Distance(ray(t0), ray(t1)) * (sig_a + sig_s);
00074 }
00075 private:
00076
00077 Spectrum sig_a, sig_s, le;
00078 float g;
00079 BBox extent;
00080 Transform WorldToVolume;
00081 };
00082
00083
00084 HomogeneousVolumeDensity *CreateHomogeneousVolumeDensityRegion(const Transform &volume2world,
00085 const ParamSet ¶ms);
00086
00087 #endif // PBRT_VOLUMES_HOMOGENEOUS_H