/******************************************************************/
/* This file is part of the homework assignments for CSCI-427/527 */
/* at The College of William & Mary and authored by Pieter Peers. */
/* No part of this file, whether altered or in original form, can */
/* be distributed or used outside the context of CSCI-427/527     */
/* without consent of either the College of William & Mary or     */
/* Pieter Peers.                                                  */
/******************************************************************/
#ifndef _LIGHTSAMPLE_H_
#define _LIGHTSAMPLE_H_

#include "vec3d.h"
#include "color.h"
#include "constants.h"

class lightSample {
 public:
  //////////////////
  // Constructors //
  //////////////////
  lightSample(const vec3d& direction=vec3d(0.0f, 0.0f, 0.0f),
	      const color& emittance=color(0.0f, 0.0f, 0.0f),
	      float distance=+LARGE,
	      float pdf=1.0f,
	      float foreshortening=1.0f);

  lightSample(const lightSample& ls);

  ///////////////
  // Operators //
  ///////////////
  lightSample& operator=(const lightSample& ls);

  const color& operator()(void) const;

  ////////////////
  // Inspectors //
  ////////////////
  const vec3d& directionToPoint(void) const;
  vec3d directionToLight(void) const;
  
  const color& emittance(void) const;
  float distance(void) const;

  float pdf(void) const;
  float foreshortening(void) const;

  /////////////
  // Friends //
  /////////////
  friend void swap(lightSample& a, lightSample& b) { a._swap(b); }
  friend std::ostream& operator<<(std::ostream& s, const lightSample& ls)
  {
    s << "LightSample: direction=" << ls.directionToPoint() << ", emittance=" << ls() << ", distance=" << ls.distance() << ", pdf=" << ls.pdf() << ", foreshortening=" << ls.foreshortening();
    return s;
  }

 private:
  /////////////////////
  // Private Methods //
  /////////////////////
  void _assign(const lightSample& ls);
  void _swap(lightSample& ls);
  
  //////////////////
  // Data Members //
  //////////////////
  vec3d _direction;
  color _emittance;
  float _distance;
  float _pdf;
  float _foreshortening;
};

#endif /* _LIGHTSAMPLE_H_ */