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

#ifndef WB3AREALIGHT_H
#define WB3AREALIGHT_H

#include <vec3f.hpp>
#include "ray3f.hpp"
#include "wb3Light.hpp"

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

class wb3Scene;
class wb3Artifact;

class wb3AreaLight : public wb3Light
{
public:

  wb3AreaLight();
  wb3AreaLight(const Vec3f& color);
  wb3AreaLight(const Vec3f& color, 
               const Vec3f& origin, const Vec3f& U, const Vec3f& V,
               unsigned int Usamp, unsigned int Vsamp);
  ~wb3AreaLight() {};

  const Vec3f& GetOrigin() const;
  void SetOrigin(const Vec3f& pos);
  
  void GetUV(Vec3f& U, Vec3f& V) const;
  void SetUV(const Vec3f& U, const Vec3f& V);

  void GetSampling(unsigned int *uSamp, unsigned int *vSamp) const;
  void SetSampling(unsigned int uSamp, unsigned int vSamp);

  void PerturbSample(Vec3f& pt) const;

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

protected:
  Vec3f m_O; // Coords of O, origin
  Vec3f m_U; // Coords of U
  Vec3f m_V; // Coords of V
  Vec3f m_OU; // vec from O to U
  Vec3f m_OV; // vec from O to V
  unsigned int m_iUSamp;
  unsigned int m_iVSamp;
};

//----------------------------------------------------------------------------
inline const Vec3f& wb3AreaLight::GetOrigin() const
{
  return m_O;
}
//----------------------------------------------------------------------------
inline void wb3AreaLight::SetOrigin(const Vec3f& orig)
{
  m_O = orig;
  m_OU = m_U - m_O;
  m_OV = m_V - m_O;
}
//----------------------------------------------------------------------------
inline void wb3AreaLight::GetUV(Vec3f& U, Vec3f& V) const
{
  U = m_U;
  V = m_V;
}
//----------------------------------------------------------------------------
inline void wb3AreaLight::SetUV(const Vec3f& U, const Vec3f& V)
{
  m_U = U;
  m_V = V;
  m_OU = m_U - m_O;
  m_OV = m_V - m_O;
}
//----------------------------------------------------------------------------
inline void wb3AreaLight::GetSampling(
  unsigned int *uSamp, unsigned int *vSamp) const
{
  *uSamp = m_iUSamp;
  *vSamp = m_iVSamp;
}
//----------------------------------------------------------------------------
inline void wb3AreaLight::SetSampling(
  unsigned int uSamp, unsigned int vSamp)
{
  m_iUSamp = uSamp;
  m_iVSamp = vSamp;
}
//----------------------------------------------------------------------------
#endif