/* Mathematiques de l'informatique graphique    */
/* Direction en 3D                              */
/*                                              */
/* Auteur: Nicolas JANEY                        */
/* nicolas.janey@univ-fcomte.fr                 */
/* Octobre 2010                                 */

#include <stdlib.h>
#include <stdio.h>
#include <math.h>

#include "CoordonneesHomogenes.h"
#include "Direction3D.h"
#include "Position3D.h"

Direction3D::Direction3D(void):CoordonneesHomogenes(0.0,0.0,0.0,0.0) {
}

Direction3D::Direction3D(double x,double y,double z):CoordonneesHomogenes(x,y,z,0.0) {
}

Direction3D::Direction3D(Direction3D *p):CoordonneesHomogenes(p) {
}

Direction3D::Direction3D(Position3D *p1,Position3D *p2):CoordonneesHomogenes() {
  c[0] = p2->c[0]-p1->c[0];
  c[1] = p2->c[1]-p1->c[1];
  c[2] = p2->c[2]-p1->c[2];
  c[3] = 0.0;
}

Direction3D::~Direction3D(void) {
}

double Direction3D::normalise(void) {
  double d = sqrt(c[0]*c[0]+c[1]*c[1]+c[2]*c[2]);
  if ( d != 0.0 ) {
    c[0] /= d;
    c[1] /= d;
    c[2] /= d; }
  return(d);
}

void Direction3D::produitVectoriel(Direction3D *d1,Direction3D *d2) {
  double x = d1->c[1]*d2->c[2] - d1->c[2]*d2->c[1];
  double y = d1->c[2]*d2->c[0] - d1->c[0]*d2->c[2];
  double z = d1->c[0]*d2->c[1] - d1->c[1]*d2->c[0];
  c[0] = x;
  c[1] = y;
  c[2] = z;
  c[3] = 0.0;
}

double Direction3D::produitScalaire(Direction3D *d) {
  return(c[0]*d->c[0]+c[1]*d->c[1]+c[2]*d->c[2]);
}

Direction3D *Direction3D::reflexion(Direction3D *n) {
  double ps = produitScalaire(n);
  if ( ps < 0.0 )
    return(NULL);
  Direction3D *r = new Direction3D();
  r->c[0] = 2.0*ps*n->c[0]-c[0];
  r->c[1] = 2.0*ps*n->c[1]-c[1];
  r->c[2] = 2.0*ps*n->c[2]-c[2];
  return(r);
}