/******************************************************************/
/* 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 "constants.h"
#include "pointLightsource.h"

//////////////////
// Constructors //
//////////////////
pointLightsource::pointLightsource(const vec3d& position, const color& power, const vec3d& attenuation)
{
  _position = position;
  _power = power;
  _attenuation = attenuation;
}


/////////////
// Methods //
/////////////
lightSample pointLightsource::intensityAt(const vec3d& point) const
{
  // HW5: Implement this. Computes the intensity from the point
  //      light source toward the 'point' taking in account attenuation.
  // Modifies: nothing.
  // Returns: light sample (pass: 1) direction, 2) power/color
  //          of the incident lighting, and 3) distance between
  //          the light source and the point).
  vec3d direction = (point - _position).normalize();
  float distance = _position.distance(point);
  color emittance = _power / (_attenuation.x +
                              _attenuation.y * distance +
                              _attenuation.z * _position.squared_distance(point));
  return lightSample(direction, emittance, distance);
}


/////////////////////
// Private Methods //
/////////////////////
void pointLightsource::_print(std::ostream& s) const
{
  s << "Point Lightsource: position=" << _position << ", power=" << _power << ", attenuation=" << _attenuation;
}