/* See {rdo_geometry.h}. */
#define rdo_geometry_C_COPYRIGHT "Copyright © 2008 Danillo Pereira and J. Stolfi, UNICAMP"
/* Last edited on 2024-12-21 11:52:44 by stolfi */ 

#include <r3.h>

#include <rdo_geometry.h>

double r3_dir_safe(r3_t *a)
  { double dir = r3_dir(a,a);
    if (dir == 0) { r3_zero(a); }
    return dir;
  }

vector3_t rdo_geometry_vector3_from_polar(double theta, double phi)
  { vector3_t dir;
    double st = sin(theta);
    dir.c[0] = st*cos(phi);
    dir.c[1] = st*sin(phi);
    dir.c[2] = cos(theta);
    return dir;
  }

void rdo_geometry_ortho(vector3_t *a, vector3_t *b, vector3_t *r)
  {
    double alpha = r3_dot(a,b)/r3_dot(a,a);
    r->c[0] = b->c[0] - alpha*a->c[0];
    r->c[1] = b->c[1] - alpha*a->c[1];
    r->c[2] = b->c[2] - alpha*a->c[2];
    return;
  }

vector3_t rdo_geometry_pt_pt_dir(point3_t *p, point3_t *q)
  { vector3_t v;
    v.c[0] = q->c[0] - p->c[0];
    v.c[1] = q->c[1] - p->c[1];
    v.c[2] = q->c[2] - p->c[2];
    r3_dir_safe(&v);
    return v;
  }

void *NotNull(void *p, char *file, int line)
{
  if (p == NULL)
    { fprintf(stderr, "out of memory\n");
      exit(1);
    }
  return p;
}