#ifndef rdo_geometry_H
#define rdo_geometry_H
/* Extra geometry tools. */

#define rdo_geometry_H_COPYRIGHT "Copyright © 2008 Danillo Pereira and J. Stolfi, UNICAMP"
/* Last edited on 2024-12-21 11:52:41 by stolfi */

#include <r3.h>
#include <vec.h>

typedef r3_t point3_t;   /* A point of {R^3}. */
typedef r3_t vector3_t;  /* A vector of {R^3}. */

double r3_dir_safe(r3_t *a);
  /* Normalizes the Euclidan length of {*a} to be 1.0, as {r3_dir(a,a)};
    except that if {a} is {(0,0,0)} then it leaves {a} unchanged,
    instead of filling it with {NaN}s.  Returns the original
    length of {a}. */

vector3_t rdo_geometry_pt_pt_dir(point3_t *p, point3_t *q);
  /* Unit vector pointing from {p} to {q}, or {(0,0,0)} if {p == q}. */

void rdo_geometry_ortho(vector3_t *a, vector3_t *b, vector3_t *r);
  /* Places in {*r} the component of {*b} that is orthogonal to {*a}. */

vector3_t rdo_geometry_vector3_from_polar(double theta, double phi);
  /* Unit vector that makes angle {theta} wiith the Z axis, and whose
    projection on the XY plane makes angle {phi} with the X axis. */
    
#define NOTNULL(p) NotNull((p),__FILE__,__LINE__)
  /*  If the argument {p} is NULL, stops the program with an error
    message showing the current source location. Othwerwise returns {p}.
    !!! This macro should replace {notnull} in {affirm.h}. !!! */

void *NotNull(void *p, char *file, int line);
  /* If the argument {p} is NULL, stops the program with an error
    message including the source file anme {file} and line number
    {line}. Othwerwise returns {p}. */

#endif