/******************************************************************/
/* 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.                                                  */
/******************************************************************/
#include <cmath>
#include "brdfSample.h"

//////////////////
// Constructors //
//////////////////
brdfSample::brdfSample(void)
{
  _out = vec3d(0.0f, 0.0f, 1.0f);
  _pdf = 0.0f;
  _reflectance = color(0.0f);
}

brdfSample::brdfSample(const vec3d& out, const float pdf, const color& reflectance)
{
  _out = out;
  _pdf = std::max(pdf, 0.0f);
  _reflectance = reflectance;
}


brdfSample::brdfSample(const brdfSample& bs)
{
  _out = bs._out;
  _pdf = bs._pdf;
  _reflectance = bs._reflectance;
}


///////////////
// Operators //
///////////////
brdfSample& brdfSample::operator=(const brdfSample& bs)
{
  _assign(bs);
  return *this;
}


brdfSample brdfSample::operator*(float pdf) const
{
  return brdfSample(_out, _pdf * pdf, _reflectance);
}


brdfSample& brdfSample::operator*=(float pdf)
{
  _pdf *= pdf;
  return *this;
}
  

////////////////
// Inspectors //
////////////////
const vec3d& brdfSample::exitantDirection(void) const
{
  return _out;
}


float brdfSample::pdf(void) const
{
  return _pdf;
}


const color& brdfSample::reflectance(void) const
{
  return _reflectance;
}


/////////////
// Methods //
/////////////
brdfSample& brdfSample::transform(const transformation3d& t)
{
  _out = t.transformDirection(_out);
  return *this;
}


brdfSample& brdfSample::inverseTransform(const transformation3d& t)
{
  _out = t.inverseTransformDirection(_out);
  return *this;
}


/////////////////////
// Private Methods //
/////////////////////
void brdfSample::_swap(brdfSample& bs)
{
  swap(_out, bs._out);
  std::swap(_pdf, bs._pdf);
  swap(_reflectance, bs._reflectance);
}


void brdfSample::_assign(const brdfSample& bs)
{
  _out = bs._out;
  _pdf = bs._pdf;
  _reflectance = bs._reflectance;
}