/* Segment en 2D                                */
/*                                              */
/* Auteur: Nicolas JANEY                        */
/* nicolas.janey@univ-fcomte.fr                 */
/* Novembre 2010                                */

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

#include "Segment2D.h"
#include "Position2D.h"
#include "Rectangle2D.h"
#include "Trace.h"

Segment2D::Segment2D(void) {
  pi = new Position2D();
  pf = new Position2D();
}

Segment2D::Segment2D(Position2D *p1,Position2D *p2) {
  pi = new Position2D(p1);
  pf = new Position2D(p2);
}

Segment2D::Segment2D(Segment2D *s) {
  pi = new Position2D(s->pi);
  pf = new Position2D(s->pf);
}

Segment2D::~Segment2D(void) {
  delete(pi);
  delete(pf);
}

void Segment2D::print(void) {
  pi->print();
  printf("\n");
  pf->print();
  printf("\n");
}

static int round(double v) {
  return((int) (v + (( v > 0.0 ) ? 0.4999 : -0.4999)));
}

void Segment2D::trace(void) {
  traceSegment(round(pi->c[0]),round(pi->c[1]),
               round(pf->c[0]),round(pf->c[1]));
}

double intersection(double ai,double bi,
                    double af,double bf,double val) {
  if ( af-ai != 0 )
    return(bi + (val-ai)/(af-ai)*(bf-bi));
    else
    return(1000000.0);
}

int code(Position2D *p,Rectangle2D *r) {
  int code = 0; 
  if ( p->c[0] < r->ig->c[0] )
    code += 1;
  if ( p->c[0] > r->sd->c[0] )
    code += 2;
  if ( p->c[1] < r->ig->c[1] )
    code += 4;
  if ( p->c[1] > r->sd->c[1] )
    code += 8;
  return(code);
}

int Segment2D::clip(Rectangle2D *r) {
  int c1,c2;
  c1 = code(pi,r);
  c2 = code(pf,r);
  while ( ( c1 || c2 ) && ( (c1&c2) == 0 ) ) {
    if ( !c1 ) {
      Position2D p = *pi;
      *pi = *pf;
      *pf = p;
      int aux = c1;
      c1 = c2;
      c2 = aux; }
    if ( (c1&0x01) != 0 ) {
      pi->c[1] = intersection(pi->c[0],pi->c[1],
                              pf->c[0],pf->c[1],
                              r->ig->c[0]);
      pi->c[0] = r->ig->c[0]; }
      else
      if ( (c1&0x02) != 0 ) {
        pi->c[1] = intersection(pi->c[0],pi->c[1],
                                pf->c[0],pf->c[1],
                                r->sd->c[0]);
        pi->c[0] = r->sd->c[0]; }
        else
        if ( (c1&0x04) != 0 ) {
          pi->c[0] = intersection(pi->c[1],pi->c[0],
                                  pf->c[1],pf->c[0],
                                  r->ig->c[1]);
          pi->c[1] = r->ig->c[1]; }
          else
          if ( (c1&0x08) != 0 ) {
            pi->c[0] = intersection(pi->c[1],pi->c[0],
                                    pf->c[1],pf->c[0],
                                    r->sd->c[1]);
            pi->c[1] = r->sd->c[1]; }
    c1 = code(pi,r); }
  return ( !c1 && !c2);
}