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

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

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

#include "Triangle2D.h"
#include "Position2D.h"
#include "Trace.h"

Triangle2D::Triangle2D(void) {
  p1 = new Position2D();
  p2 = new Position2D();
  p3 = new Position2D();
}

Triangle2D::Triangle2D(Position2D *pt1,
                       Position2D *pt2,
                       Position2D *pt3) {
  p1 = new Position2D(pt1);
  p2 = new Position2D(pt2);
  p3 = new Position2D(pt3);
}

Triangle2D::Triangle2D(Triangle2D *t) {
  p1 = new Position2D(t->p1);
  p2 = new Position2D(t->p2);
  p3 = new Position2D(t->p3);
}

Triangle2D::~Triangle2D(void) {
  delete(p1);
  delete(p2);
  delete(p3);
}

void Triangle2D::print(void) {
  p1->print();
  printf("\n");
  p2->print();
  printf("\n");
  p3->print();
  printf("\n");
}

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

void Triangle2D::trace(void) {
  traceSegment(round(p1->c[0]),round(p1->c[1]),
               round(p2->c[0]),round(p2->c[1]));
  traceSegment(round(p1->c[0]),round(p1->c[1]),
               round(p3->c[0]),round(p3->c[1]));
  traceSegment(round(p3->c[0]),round(p3->c[1]),
               round(p2->c[0]),round(p2->c[1]));
}

static void gereAbscisse(int x,int y,int *xmin,int *xmax) {
  if ( x < xmin[y] )
    xmin[y] = x;
  if ( x > xmax[y] )
    xmax[y] = x;
}

static void traceCote(int xi,int yi,int xf,int yf,
                      int *xmin,int *xmax,int ymin) {
  int i,cumul;
  yi -= ymin;
  yf -= ymin;
  int x = xi;
  int y = yi;
  int dx = xf - xi;
  int dy = yf - yi;
  int xinc = ( dx > 0 ) ? 1 : -1;
  int yinc = ( dy > 0 ) ? 1 : -1;
  dx = abs(dx);
  dy = abs(dy);
  gereAbscisse(x,y,xmin,xmax);
  if ( dx > dy ) {
    cumul = dx / 2;
    for ( i = 1 ; i <= dx ; i++ ) {
      x += xinc;
      cumul += dy;
      if (cumul >= dx) {
        cumul -= dx;
        y += yinc; }
      gereAbscisse(x,y,xmin,xmax); } }
    else {
    cumul = dy / 2;
    for ( i = 1 ; i <= dy ; i++ ) {
      y += yinc;
      cumul += dx;
      if ( cumul >= dy ) {
        cumul -= dy;
        x += xinc; }
      gereAbscisse(x,y,xmin,xmax); } }
}

void Triangle2D::remplit(void) {
  int ymin = round(p1->c[1]);
  int ymax = round(p1->c[1]);
  if ( round(p2->c[1]) < ymin )
    ymin = round(p2->c[1]);
  if ( round(p2->c[1]) > ymax )
    ymax = round(p2->c[1]);
  if ( round(p3->c[1]) < ymin )
    ymin = round(p3->c[1]);
  if ( round(p3->c[1]) > ymax )
    ymax = round(p3->c[1]);
  int dy = ymax-ymin+1;
  int *xmin =(int *) calloc(dy,sizeof(int));
  int *xmax =(int *) calloc(dy,sizeof(int));
  for ( int i = 0 ; i < dy ; i++ ) {
    xmax[i] = -1000000;
    xmin[i] = 1000000; }
  traceCote(round(p1->c[0]),round(p1->c[1]),
            round(p2->c[0]),round(p2->c[1]),
            xmin,xmax,ymin);
  traceCote(round(p1->c[0]),round(p1->c[1]),
            round(p3->c[0]),round(p3->c[1]),
            xmin,xmax,ymin);
  traceCote(round(p3->c[0]),round(p3->c[1]),
            round(p2->c[0]),round(p2->c[1]),
            xmin,xmax,ymin);
  glBegin(GL_POINTS);
  for ( int y = ymin ; y <= ymax ; y++ )
    for ( int x = xmin[y-ymin] ; x <= xmax[y-ymin] ; x++ )
      glVertex2i(x,y);
  glEnd();
  free(xmin);
  free(xmax);
}