//----------------------------------------------------------------------------
// William Baxter III's Ray Tracer
//
//     Project for Comp 238, Raster Graphics
//     University of North Carolina at Chapel Hill
//     
// $Id:$
//----------------------------------------------------------------------------

#ifndef WB3LIGHT_H
#define WB3LIGHT_H

#include <vec3f.hpp>
#include "ray3f.hpp"

//----------------------------------------------------------------------------

class wb3Scene;
class wb3Artifact;

class wb3Light
{
public:

  wb3Light(const Vec3f& positon);
  wb3Light(const Vec3f& positon, const Vec3f& color);
  wb3Light(const Vec3f& positon, const Vec3f& AmbientColor, 
                                 const Vec3f& DiffuseColor,
                                 const Vec3f& SpecularColor);
  ~wb3Light() {};

  const Vec3f& GetAmbientColor() const;
  const Vec3f& GetDiffuseColor() const;
  const Vec3f& GetSpecularColor() const;
  void SetAmbientColor(const Vec3f& color);
  void SetDiffuseColor(const Vec3f& color);
  void SetSpecularColor(const Vec3f& color);

  const Vec3f& GetPosition() const;
  void SetPosition(const Vec3f& pos);

  // Attenuation = 1/(Axd^2 + Bxd + C)
  void GetAttenuationFactors(float *A, float *B, float *C) const;
  void SetAttenuationFactors(float A, float B, float C);
  float ComputeAttenuation(float dist) const;

  void Contribute(const wb3Scene *scene, const wb3Artifact *hit, const Ray3f& r, 
                  const Vec3f &isect, const Vec3f &N, Vec3f& color) const;

protected:
  Vec3f m_pos;
  Vec3f m_AColor;
  Vec3f m_DColor;
  Vec3f m_SColor;
  float m_fA, m_fB, m_fC;
};

//----------------------------------------------------------------------------
inline const Vec3f& wb3Light::GetAmbientColor() const
{
  return m_AColor;
}
//----------------------------------------------------------------------------
inline void wb3Light::SetAmbientColor(const Vec3f& color)
{
  m_AColor = color;
}
//----------------------------------------------------------------------------
inline const Vec3f& wb3Light::GetDiffuseColor() const
{
  return m_DColor;
}
//----------------------------------------------------------------------------
inline void wb3Light::SetDiffuseColor(const Vec3f& color)
{
  m_DColor = color;
}
//----------------------------------------------------------------------------
inline const Vec3f& wb3Light::GetSpecularColor() const
{
  return m_SColor;
}
//----------------------------------------------------------------------------
inline void wb3Light::SetSpecularColor(const Vec3f& color)
{
  m_SColor = color;
}
//----------------------------------------------------------------------------
inline const Vec3f& wb3Light::GetPosition() const
{
  return m_pos;
}
//----------------------------------------------------------------------------
inline void wb3Light::SetPosition(const Vec3f& pos)
{
  m_pos = pos;
}
//----------------------------------------------------------------------------
inline void wb3Light::SetAttenuationFactors(float A, float B, float C)
{
  m_fA = A;
  m_fB = B;
  m_fC = C;
}
//----------------------------------------------------------------------------
inline void wb3Light::GetAttenuationFactors(float*A, float*B, float*C) const
{
   *A = m_fA;
   *B = m_fB;
   *C = m_fC;
}
//----------------------------------------------------------------------------
inline float wb3Light::ComputeAttenuation(float dist) const
{
  return 1.0f/(m_fA * dist * dist + m_fB * float(fabs(dist)) + m_fC);
}
//----------------------------------------------------------------------------
#endif