photon_mapping.h

#ifndef _PHOTON_MAPPING_H_
#define _PHOTON_MAPPING_H_

#include <vector>
#include "vectors.h"
#include "photon.h"

class Mesh;
class ArgParser;
class KDTree;
class Ray;
class Hit;
class RayTracer;
class Radiosity;
class Sphere;
// =========================================================================
// The basic class to shoot photons within the scene and collect and
// process the nearest photons for use in the raytracer

extern Vec3f global_energy;

class PhotonMapping {

 public:

  // CONSTRUCTOR & DESTRUCTOR
  PhotonMapping(Mesh *_mesh, ArgParser *_args) {
    mesh = _mesh;
    args = _args;
    raytracer = NULL;
    kdtree = NULL;
  }
  ~PhotonMapping();

  void setRayTracer(RayTracer *r) { raytracer = r; }
  void setRadiosity(Radiosity *r) { radiosity = r; }

  // step 1: send the photons throughout the scene
  void TracePhotons();
  // step 2: collect the photons and return the contribution from indirect illumination
  Vec3f GatherIndirect(const Vec3f &point, const Vec3f &normal, const Vec3f &direction_from) const;
  Vec3f CalculateEnergy(Sphere* s);
  // for visualization
  void RenderPhotons();
  void RenderKDTree();
  void RenderEnergy();

 private:

  // trace a single photon
  void TracePhoton(const Vec3f &position, const Vec3f &direction, const Vec3f &energy, int iter) const;

  // helper functions for visualization
  void RenderPhotonPositions();
  void RenderPhotonDirections();

  // REPRESENTATION
  KDTree *kdtree;
  Mesh *mesh;
  ArgParser *args;
  RayTracer *raytracer;
  Radiosity *radiosity;
};

#endif