PBRT
/home/felix/UBC/projects/AdaptiveLightfieldSampling/pbrt_v2/src/core/volume.h
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_CORE_VOLUME_H
00037 #define PBRT_CORE_VOLUME_H
00038 
00039 // core/volume.h*
00040 #include "pbrt.h"
00041 #include "spectrum.h"
00042 #include "geometry.h"
00043 #include "transform.h"
00044 #include "integrator.h"
00045 
00046 // Volume Scattering Declarations
00047 float PhaseIsotropic(const Vector &w, const Vector &wp);
00048 float PhaseRayleigh(const Vector &w, const Vector &wp);
00049 float PhaseMieHazy(const Vector &w, const Vector &wp);
00050 float PhaseMieMurky(const Vector &w, const Vector &wp);
00051 float PhaseHG(const Vector &w, const Vector &wp, float g);
00052 float PhaseSchlick(const Vector &w, const Vector &wp, float g);
00053 class VolumeRegion {
00054 public:
00055     // VolumeRegion Interface
00056     virtual ~VolumeRegion();
00057     virtual BBox WorldBound() const = 0;
00058     virtual bool IntersectP(const Ray &ray, float *t0, float *t1) const = 0;
00059     virtual Spectrum sigma_a(const Point &, const Vector &,
00060                              float time) const = 0;
00061     virtual Spectrum sigma_s(const Point &, const Vector &,
00062                              float time) const = 0;
00063     virtual Spectrum Lve(const Point &, const Vector &,
00064                          float time) const = 0;
00065     virtual float p(const Point &, const Vector &,
00066                     const Vector &, float time) const = 0;
00067     virtual Spectrum sigma_t(const Point &p, const Vector &wo, float time) const;
00068     virtual Spectrum tau(const Ray &ray, float step = 1.f,
00069                          float offset = 0.5) const = 0;
00070 };
00071 
00072 
00073 class DensityRegion : public VolumeRegion {
00074 public:
00075     // DensityRegion Public Methods
00076     DensityRegion(const Spectrum &sa, const Spectrum &ss, float gg,
00077                   const Spectrum &emit, const Transform &VolumeToWorld)
00078         : sig_a(sa), sig_s(ss), le(emit), g(gg),
00079           WorldToVolume(Inverse(VolumeToWorld)) { }
00080     virtual float Density(const Point &Pobj) const = 0;
00081     Spectrum sigma_a(const Point &p, const Vector &, float) const {
00082         return Density(WorldToVolume(p)) * sig_a;
00083     }
00084     Spectrum sigma_s(const Point &p, const Vector &, float) const {
00085         return Density(WorldToVolume(p)) * sig_s;
00086     }
00087     Spectrum sigma_t(const Point &p, const Vector &, float) const {
00088         return Density(WorldToVolume(p)) * (sig_a + sig_s);
00089     }
00090     Spectrum Lve(const Point &p, const Vector &, float) const {
00091         return Density(WorldToVolume(p)) * le;
00092     }
00093     float p(const Point &p, const Vector &w, const Vector &wp, float) const {
00094         return PhaseHG(w, wp, g);
00095     }
00096     Spectrum tau(const Ray &r, float stepSize, float offset) const;
00097 protected:
00098     // DensityRegion Protected Data
00099     Spectrum sig_a, sig_s, le;
00100     float g;
00101     Transform WorldToVolume;
00102 };
00103 
00104 
00105 class AggregateVolume : public VolumeRegion {
00106 public:
00107     // AggregateVolume Public Methods
00108     AggregateVolume(const vector<VolumeRegion *> &r);
00109     ~AggregateVolume();
00110     BBox WorldBound() const;
00111     bool IntersectP(const Ray &ray, float *t0, float *t1) const;
00112     Spectrum sigma_a(const Point &, const Vector &, float) const;
00113     Spectrum sigma_s(const Point &, const Vector &, float) const;
00114     Spectrum Lve(const Point &, const Vector &, float) const;
00115     float p(const Point &, const Vector &, const Vector &, float) const;
00116     Spectrum sigma_t(const Point &, const Vector &, float) const;
00117     Spectrum tau(const Ray &ray, float, float) const;
00118 private:
00119     // AggregateVolume Private Data
00120     vector<VolumeRegion *> regions;
00121     BBox bound;
00122 };
00123 
00124 
00125 bool GetVolumeScatteringProperties(const string &name, Spectrum *sigma_a,
00126                                    Spectrum *sigma_prime_s);
00127 class VolumeIntegrator : public Integrator {
00128 public:
00129     // VolumeIntegrator Interface
00130     virtual Spectrum Li(const Scene *scene, const Renderer *renderer,
00131         const RayDifferential &ray, const Sample *sample, RNG &rng,
00132         Spectrum *transmittance, MemoryArena &arena) const = 0;
00133     virtual Spectrum Transmittance(const Scene *scene,
00134         const Renderer *renderer, const RayDifferential &ray,
00135         const Sample *sample, RNG &rng, MemoryArena &arena) const = 0;
00136 };
00137 
00138 
00139 void SubsurfaceFromDiffuse(const Spectrum &Kd, float meanPathLength, float eta,
00140         Spectrum *sigma_a, Spectrum *sigma_prime_s);
00141 
00142 #endif // PBRT_CORE_VOLUME_H