quadric.h File Reference

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Classes
struct	quadmatrix
struct	quadric
Functions
quadric *	newquadric (void)
void	quadric_intersect (quadric *, ray *)
void	quadric_normal (quadric *, vector *, ray *, vector *)

---

Function Documentation

quadric* newquadric

(

void

)

Definition at line 83 of file quadric.cpp.

References quadric::ctr, quadric::methods, quadric_methods, rt_getmem(), vector::x, vector::y, and vector::z.

Referenced by rt_quadsphere().

                       {
  quadric * q;
 
  q=(quadric *) rt_getmem(sizeof(quadric));
  memset(q, 0, sizeof(quadric));
  q->ctr.x=0.0;
  q->ctr.y=0.0;
  q->ctr.z=0.0;
  q->methods = &quadric_methods;
 
  return q;
}

void quadric_intersect	(	quadric *	,
		ray *
	)

Definition at line 96 of file quadric.cpp.

References quadmatrix::a, add_intersection(), quadmatrix::b, quadmatrix::c, quadric::ctr, quadmatrix::d, ray::d, quadmatrix::e, quadmatrix::f, quadmatrix::g, quadmatrix::h, quadmatrix::i, quadmatrix::j, quadric::mat, ray::o, VNorm(), vector::x, vector::y, and vector::z.

                                              {
  flt Aq, Bq, Cq;
  flt t1, t2;
  flt disc;
  vector rd;
  vector ro;
 
  rd=ry->d;
  VNorm(&rd);

  ro.x =  ry->o.x - q->ctr.x;
  ro.y =  ry->o.y - q->ctr.y;
  ro.z =  ry->o.z - q->ctr.z;


  Aq = (q->mat.a*(rd.x * rd.x)) +
        (2.0 * q->mat.b * rd.x * rd.y) +
        (2.0 * q->mat.c * rd.x * rd.z) +
        (q->mat.e * (rd.y * rd.y)) +
        (2.0 * q->mat.f * rd.y * rd.z) +
        (q->mat.h * (rd.z * rd.z));

  Bq = 2.0 * (
        (q->mat.a * ro.x * rd.x) +
        (q->mat.b * ((ro.x * rd.y) + (rd.x * ro.y))) +
        (q->mat.c * ((ro.x * rd.z) + (rd.x * ro.z))) +
        (q->mat.d * rd.x) +
        (q->mat.e * ro.y * rd.y) +
        (q->mat.f * ((ro.y * rd.z) + (rd.y * ro.z))) +
        (q->mat.g * rd.y) +
        (q->mat.h * ro.z * rd.z) +
        (q->mat.i * rd.z)
        );

  Cq = (q->mat.a * (ro.x * ro.x)) +
        (2.0 * q->mat.b * ro.x * ro.y) +
        (2.0 * q->mat.c * ro.x * ro.z) +
        (2.0 * q->mat.d * ro.x) +
        (q->mat.e * (ro.y * ro.y)) +
        (2.0 * q->mat.f * ro.y * ro.z) +
        (2.0 * q->mat.g * ro.y) +
        (q->mat.h * (ro.z * ro.z)) +
        (2.0 * q->mat.i * ro.z) +
        q->mat.j;

  if (Aq == 0.0) {
          t1 = - Cq / Bq;
          add_intersection(t1, (object *) q, ry);
          }
  else {
    disc=(Bq*Bq - 4.0 * Aq * Cq);
    if (disc > 0.0) {
          disc=sqrt(disc);
          t1 = (-Bq + disc) / (2.0 * Aq);
          t2 = (-Bq - disc) / (2.0 * Aq);
          add_intersection(t1, (object *) q, ry);
          add_intersection(t2, (object *) q, ry); 
          }
  }
}

void quadric_normal	(	quadric *	,
		vector *	,
		ray *	,
		vector *
	)

Definition at line 157 of file quadric.cpp.

References quadmatrix::a, quadmatrix::b, quadmatrix::c, quadric::ctr, ray::d, quadmatrix::d, quadmatrix::e, quadmatrix::f, quadmatrix::g, quadmatrix::h, quadmatrix::i, quadric::mat, VDot(), VNorm(), vector::x, vector::y, and vector::z.

                                                                           {

  N->x = (q->mat.a*(pnt->x - q->ctr.x) + 
      q->mat.b*(pnt->y - q->ctr.y) + 
      q->mat.c*(pnt->z - q->ctr.z) + q->mat.d);

  N->y = (q->mat.b*(pnt->x - q->ctr.x) + 
      q->mat.e*(pnt->y - q->ctr.y) + 
      q->mat.f*(pnt->z - q->ctr.z) + q->mat.g);

  N->z = (q->mat.c*(pnt->x - q->ctr.x) + 
      q->mat.f*(pnt->y - q->ctr.y) + 
      q->mat.h*(pnt->z - q->ctr.z) + q->mat.i);

  VNorm(N);

  if (VDot(N, &(incident->d)) > 0.0)  {
    N->x=-N->x;
    N->y=-N->y;
    N->z=-N->z;
  } 
}