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

#ifndef WB3TRIANGLE_H
#define WB3TRIANGLE_H

#include <vec3f.hpp>
#include <vec2f.hpp>
#include "wb3Plane.hpp"

class wb3Triangle : public wb3Plane
{
public:
  wb3Triangle(const Vec3f& p1, const Vec3f& p2, const Vec3f& p3);
  wb3Triangle();
  wb3Triangle(const Vec3f verts[3]);
  ~wb3Triangle();

  virtual const wb3Artifact* Intersect(const Ray3f& r, float *dist,
                                       const wb3Artifact* ignore =0) const;
  
  float Dist(const Vec3f& point) const;

  void Set(const Vec3f& normal, const Vec3f& point);
  void SetPoint(const Vec3f& point);
  void SetVerts(const Vec3f& v1, const Vec3f& v2, const Vec3f& v3);
  void SetNormals(const Vec3f& v1, const Vec3f& v2, const Vec3f& v3);
  void SetTexCoords(const Vec2f& uv1, const Vec2f& uv2, const Vec2f& uv3);
  void Normalize();

protected:
  virtual Vec3f& GetColorComponent(
    Vec3f& color, wb3Component::ComponentType type, const Vec3f& Pw) const;
  virtual float GetScalarComponent(
      wb3Component::ComponentType type, const Vec3f& Pw) const;
  int ptInTri3D(const Vec3f& P) const;

  bool m_bBFCull;  // backface culling or not
  Vec3f m_vert[3]; // verticies of triangle
  Vec3f *m_norm;   // per-vertex normals
  Vec2f *m_uv;     // UV coordinates for texture mapping
};


//----------------------------------------------------------------------------
inline void wb3Triangle::SetPoint(const Vec3f& point)
{
  m_fD = -(point * m_N);
}
//----------------------------------------------------------------------------
inline void wb3Triangle::Normalize()
{
  float len = m_N.Length();
  if (len>0) {
    float leninv = 1.0f/len;
    m_N *= leninv;
    m_fD *= leninv;
  }
}
//----------------------------------------------------------------------------
inline float wb3Triangle::Dist(const Vec3f &point) const
{
  // i don't think this is correct
  return (point * m_N) + m_fD;
} 
//----------------------------------------------------------------------------
inline void wb3Triangle::Set(const Vec3f& normal, const Vec3f& point)
{
  m_N = normal;
  m_fD = -(point * m_N);
}
//----------------------------------------------------------------------------
#endif