/* Auteur: Nicolas JANEY             */
/* nicolas.janey@univ-fcomte.fr      */
/* Octobre 2005                      */
/* Classe de gestion de surfaces     */
/* spheriques                        */

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

#include <GL/glut.h>
#include <GL/gl.h>
#include <GL/glu.h>

#include "ModuleFont.h"

#include "Sphere.h"
#include "Droite.h"
#include "Rayon.h"

Sphere::Sphere(void) {
  centre = new Position();
  rayon = 1.0F;
}

Sphere::Sphere(float x,float y,float z,float r) {
  centre = new Position(x,y,z);
  rayon = r;
}

Sphere::Sphere(Position *p,float r) {
  centre = new Position(p);
  rayon = r;
}

Sphere::~Sphere(void) {
  delete(centre);
}

static float vmin(float a,float b) {
  return(( a < b ) ? a : b);
}

static float vmax(float a,float b) {
  return(( a > b ) ? a : b);
}

int Sphere::testIntersection(Droite *d) {
  float a = d->d->x*d->d->x+
            d->d->y*d->d->y+
            d->d->z*d->d->z;
  float b = 2*(d->d->x*(d->p->x-centre->x)+
               d->d->y*(d->p->y-centre->y)+
               d->d->z*(d->p->z-centre->z));
  float c = (d->p->x-centre->x)*(d->p->x-centre->x)+
            (d->p->y-centre->y)*(d->p->y-centre->y)+
            (d->p->z-centre->z)*(d->p->z-centre->z)-
            rayon*rayon;
  float delta = b*b-4*a*c;
  if ( fabs(delta) < 0.0001F )
    return(1);
  if ( delta < 0.0F )
    return(0);
  return(2);
}

Position **Sphere::intersection(Droite *d) {
  float a = d->d->x*d->d->x+
            d->d->y*d->d->y+
            d->d->z*d->d->z;
  float b = 2*(d->d->x*(d->p->x-centre->x)+
               d->d->y*(d->p->y-centre->y)+
               d->d->z*(d->p->z-centre->z));
  float c = (d->p->x-centre->x)*(d->p->x-centre->x)+
            (d->p->y-centre->y)*(d->p->y-centre->y)+
            (d->p->z-centre->z)*(d->p->z-centre->z)-
            rayon*rayon;
  float delta = b*b-4*a*c;
  if ( fabs(delta) < 0.0001F ) {
    float t = -b/(2.0F*a);
    Position **pts =(Position **) calloc(2,sizeof(Position *));
    pts[0] = d->position(t);
    pts[1] = NULL;
    return(pts); }
  if ( delta < 0.0F )
    return(NULL);
  float t1 = (-b-sqrt(delta))/(2.0F*a);
  float t2 = (-b+sqrt(delta))/(2.0F*a);
  Position **pts =(Position **) calloc(2,sizeof(Position *));
  pts[0] = d->position(t1);
  pts[1] = d->position(t2);
  return(pts);
}

int Sphere::testIntersection(Rayon *r) {
  float b = 2*(r->d->x*(r->p->x-centre->x)+
               r->d->y*(r->p->y-centre->y)+
               r->d->z*(r->p->z-centre->z));
  float c = (r->p->x-centre->x)*(r->p->x-centre->x)+
            (r->p->y-centre->y)*(r->p->y-centre->y)+
            (r->p->z-centre->z)*(r->p->z-centre->z)-
            rayon*rayon;
  float delta = b*b-4*c;
  if ( fabs(delta) < 0.0001F ) {
    float t = -b/2.0F;
    if ( t >= 0.0F )
      return(1);
    return(0); }
  if ( delta < 0.0F )
    return(0);
  float t1 = (-b-sqrt(delta))/2.0F;
  float t2 = (-b+sqrt(delta))/2.0F;
  if ( ( t1 < 0.0F ) && ( t2 < 0.0F ) )
    return(0);
  if ( ( t1 >= 0.0F ) && ( t2 >= 0.0F ) )
    return(2);
  return(1);
}

Position *Sphere::intersection(Rayon *r) {
  float b = 2*(r->d->x*(r->p->x-centre->x)+
               r->d->y*(r->p->y-centre->y)+
               r->d->z*(r->p->z-centre->z));
  float c = (r->p->x-centre->x)*(r->p->x-centre->x)+
            (r->p->y-centre->y)*(r->p->y-centre->y)+
            (r->p->z-centre->z)*(r->p->z-centre->z)-
            rayon*rayon;
  float delta = b*b-4*c;
  if ( fabs(delta) < 0.0001F ) {
    float t = -b/2.0F;
    if ( t >= 0.0F )
      return(r->position(t));
    return(NULL); }
  if ( delta < 0.0F )
    return(NULL);
  float t1 = (-b-sqrt(delta))/2.0F;
  float t2 = (-b+sqrt(delta))/2.0F;
  if ( ( t1 < 0.0F ) && ( t2 < 0.0F ) )
    return(NULL);
  if ( ( t1 >= 0.0F ) && ( t2 >= 0.0F ) )
    return(r->position(min(t1,t2)));
  return(r->position(max(t1,t2)));
}

void Sphere::dessine(void) {
  glPushMatrix();
  glTranslatef(centre->x,centre->y,centre->z);
  glutSolidSphere(rayon,36,36);
  glPopMatrix();
}

void Sphere::print(char *format) {
  simpleBitmapOutput(1,REGULAR8x13,format,
                     centre->x,centre->y,centre->z,rayon);
}