//////////////
//
// tri.hpp
//
//   basic triangle polygon object
//


#ifndef _TRI_
#define _TRI_

#include "object.hpp"
#include <iostream.h>

class tri : public object
{
 public:

  Vec3f verta, vertb, vertc, norm;        //three vertices plus normal

  tri() {}

  void set(Vec3f a, Vec3f b, Vec3f c, Vec3f ia, Vec3f d, Vec3f s, Vec3f t, 
	   float m)
  {
    verta=a; vertb=b; vertc=c; Ia = ia; kd = d; ks = s; kt = t; M = m;
//  norm = (vertb-verta) / (vertc-verta);
    norm = vertb;                          //faster?
    norm -= verta;
    norm = norm / (vertc - verta);
    norm.Normalize();
  }

  tri(Vec3f a, Vec3f b, Vec3f c, Vec3f ia, Vec3f d, Vec3f s, Vec3f t, float m)
  {
    set(a,b,c,ia,d,s,t,m);
  }



// (note: was having trouble with tri intersect routine; modifications
// based on Kenny's.)

  int getIntersect(Vec3f &start, Vec3f &dir, float *time)
  {
    float dot = dir*norm;
    if (dot==0) return(0);             //ray parallel to tri plane

    //    cout << "dot " << dot << endl;

    *time = ( norm * (verta-start) ) / dot;   //intersect w/ plane
    if (*time < 0.01) return(0);                 //discard if behind ray

    //    cout << "hittime " << *time << endl;

    Vec3f hitPt = dir;
    hitPt *= (*time);   // get potential intersect point
    hitPt += start;

            // finally, discard if hit is outside tri

    if ( ((vertb-verta)/(hitPt-verta))*norm < 0) return(0);
    else if ( ((vertc-vertb)/(hitPt-vertb))*norm < 0) return(0);
    else if ( ((verta-vertc)/(hitPt-vertc))*norm < 0) return(0);
    return(1);
    
  }

  Vec3f getNormal(Vec3f hitPt)
  {
    return norm;
  }

};

#endif