////////////
//
// sphere.hpp
//
//  basic sphere object
//

#ifndef _SPHERE_
#define _SPHERE_

#include "object.hpp"

class sphere : public object
{
 public:

  Vec3f cent;   // center of sphere
  float rad;    // sphere radius

  sphere() {}

  void set(Vec3f c, float r, Vec3f a, Vec3f d, Vec3f s, Vec3f t, float m)
  {
    cent = c; rad = r; Ia = a; kd = d; ks = s; kt = t; M = m;
  }

  sphere(Vec3f c, float r, Vec3f a, Vec3f d, Vec3f s, Vec3f t, float m)
  {
    set(c,r,a,d,s,t,m);
  }

  int getIntersect(Vec3f &start, Vec3f &dir, float *time)
  {
    // equation is t = -B +- sqrt(B^2-4C)   / 2
    Vec3f temp;

//    float B = 2 * ( dir * ( start - cent ) );
//    float C = (start - cent).LengthSqr() - (rad*rad);
    temp = start;                     // faster?
    temp -= cent;
    float B = 2 * ( dir * temp );
    float C = temp.LengthSqr() - (rad*rad);

    float inner = B*B - 4*C;    // inside the sqrt
    if (inner < 0.0) return(0);

    *time = ( -B - (float)sqrt(inner) ) / 2.0;   //first try with -
    if (*time > 0.01)                            //avoid accidents
      return (1);
    else 
      *time = ( -B + (float)sqrt(inner) ) / 2.0;   //next try with +
    
    if (*time > 0.01)
      return (1);
    else
      return (0);
  }

  Vec3f getNormal(Vec3f hitPt)
  {
    Vec3f norm;
    norm = hitPt;
    norm -= cent;
    norm.Normalize();
    return norm;
  }

};

#endif