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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 RGBColor &sa, const RGBColor &ss, float gg,
00034 const RGBColor &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 virtual ~HomogeneousVolume() { }
00044 virtual BBox WorldBound() const {
00045 return WorldToVolume.GetInverse()(extent);
00046 }
00047 virtual bool IntersectP(const Ray &r, float *t0, float *t1) const {
00048 Ray ray = WorldToVolume(r);
00049 return extent.IntersectP(ray, t0, t1);
00050 }
00051 virtual RGBColor sigma_a(const Point &p, const Vector &) const {
00052 return extent.Inside(WorldToVolume(p)) ? sig_a : 0.;
00053 }
00054 virtual RGBColor sigma_s(const Point &p, const Vector &) const {
00055 return extent.Inside(WorldToVolume(p)) ? sig_s : 0.;
00056 }
00057 virtual RGBColor sigma_t(const Point &p, const Vector &) const {
00058 return extent.Inside(WorldToVolume(p)) ? (sig_a + sig_s) : RGBColor(0.f);
00059 }
00060 virtual RGBColor Lve(const Point &p, const Vector &) const {
00061 return extent.Inside(WorldToVolume(p)) ? le : 0.;
00062 }
00063 virtual float P(const Point &p, const Vector &wi, const Vector &wo) const {
00064 if (!extent.Inside(WorldToVolume(p))) return 0.;
00065 return PhaseHG(wi, wo, g);
00066 }
00067 virtual RGBColor Tau(const Ray &ray, float, float) const {
00068 float t0, t1;
00069 if (!IntersectP(ray, &t0, &t1)) return 0.;
00070
00071 return Distance(ray(t0), ray(t1)) * (sig_a + sig_s);
00072 }
00073
00074 static VolumeRegion *CreateVolumeRegion(const Transform &volume2world, const ParamSet ¶ms);
00075 private:
00076
00077 RGBColor sig_a, sig_s, le;
00078 float g;
00079 BBox extent;
00080 Transform WorldToVolume;
00081 };
00082
00083 }