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