/* Auteur: Nicolas JANEY            */
/* nicolas.janey@univ-fcomte.fr     */
/* Novembre 2004                    */
/* Algorithme de Bresenham          */

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

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

#include "ModuleCouleurs.h"
#include "ModuleMenus.h"
#include "ModuleFont.h"
#include "ModuleReshape.h"

struct point {
  int x ;
  int y ; } ;

struct segment {
  point pi ;
  point pf ; } ;

struct rectangle {
  point sg ;
  point id ; } ;

static int aff = 0 ;
static int pt = 0 ;
static segment s[8] = { {  2,10,27,19 },
                        {  5, 9,28, 4 },
                        { 25, 3, 8,16 },
                        { 28,13, 4, 4 },
                        { 12, 3,17,19 },
                        { 13,18,19, 4 },
                        { 18, 3,15,16 },
                        { 18,18,14, 4 } } ;
static int f1;
static int f2;

void pixel(int x,int y,float *c) {
  glColor4fv(c) ;
  glBegin(GL_QUADS) ;
  glVertex2f(x-1.0F,y-1.0F) ;
  glVertex2f(x-1.0F,y) ;
  glVertex2f(x,y) ;
  glVertex2f(x,y-1.0F) ;
  glEnd() ;
}

void line(int xi,int yi,int xf,int yf,float *c) {
  int dx,dy,i,xinc,yinc,cumul,x,y ;
  x = xi ;
  y = yi ;
  dx = xf - xi ;
  dy = yf - yi ;
  xinc = ( dx > 0 ) ? 1 : -1 ;
  yinc = ( dy > 0 ) ? 1 : -1 ;
  dx = abs(dx) ;
  dy = abs(dy) ;
  pixel(x,y,c) ;
  if ( dx > dy ) {
    cumul = dx / 2 ;
    for ( i = 1 ; i <= dx ; i++ ) {
      x += xinc ;
      cumul += dy ;
      if (cumul >= dx) {
        cumul -= dx ;
        y += yinc ; }
      pixel(x,y,c) ; } }
    else {
    cumul = dy / 2 ;
    for ( i = 1 ; i <= dy ; i++ ) {
      y += yinc ;
      cumul += dx ;
      if ( cumul >= dy ) {
        cumul -= dy ;
        x += xinc ; }
      pixel(x,y,c) ; } }
}

void dessineQuadrillage(void) {
  float i;
  glColor4fv(couleurGrisMoyen()) ;
  glBegin(GL_LINES);
  for ( i = 0 ; i <= 30 ; i++ ) {
    glVertex3d(i,0,-10.0);
    glVertex3d(i,20,-10.0); }
  for ( i = 0 ; i <= 20 ; i++ ) {
    glVertex3d(0,i,-10.0);
    glVertex3d(30,i,-10.0); }
  glEnd() ;
}

void dessinSegment(segment *s) {
  pixel(s->pi.x,s->pi.y,couleurRouge());
  pixel(s->pf.x,s->pf.y,couleurVert());
  line(s->pi.x,s->pi.y,s->pf.x,s->pf.y,couleurBleu(0.3));
}

void display1() {
  glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
  glPushMatrix();
  dessineQuadrillage();
  switch (aff) {
    case 0 : 
    case 1 : 
    case 2 : 
    case 3 : 
    case 4 : 
    case 5 : 
    case 6 : 
    case 7 : dessinSegment(&s[aff]);
             break ; }
  glPopMatrix();
  glFlush();
  glutSwapBuffers() ;
}

void affichePosition(segment *s) {
  float pos = 1.0F;
  glColor4fv(couleurNoir());
  placeFontCursor(5.0F,-pos*20.0F,0.0F) ;
  simpleBitmapOutput(1,REGULAR8x13,"PI :%3d %3d",s->pi.x,s->pi.y) ;
  pos += 1.0F;
  placeFontCursor(5.0F,-pos*20.0F,0.0F) ;
  simpleBitmapOutput(1,REGULAR8x13,"PF :%3d %3d",s->pf.x,s->pf.y) ;
}

void display2() {
  glClearColor(0.5F,0.5F,0.5F,1.0F);
  glClear(GL_DEPTH_BUFFER_BIT|GL_COLOR_BUFFER_BIT);
  glPushMatrix();
  switch ( aff) {
    case 0 : 
    case 1 : 
    case 2 : 
    case 3 : 
    case 4 : 
    case 5 : 
    case 6 : 
    case 7 : affichePosition(&s[aff]);
             break ; }
  glPopMatrix();
  glutSwapBuffers();
}

void special(int key,int x,int y) {
  switch ( key ) {
    case GLUT_KEY_RIGHT : if ( pt ) 
                            s[aff].pi.x++;
                            else
                            s[aff].pf.x++;
                          glutPostWindowRedisplay(f1);
                          glutPostWindowRedisplay(f2);
                          break;
    case GLUT_KEY_LEFT : if ( pt ) 
                            s[aff].pi.x--;
                            else
                            s[aff].pf.x--;
                          glutPostWindowRedisplay(f1);
                          glutPostWindowRedisplay(f2);
                          break;
    case GLUT_KEY_UP    : if ( pt ) 
                            s[aff].pi.y++;
                            else
                            s[aff].pf.y++;
                          glutPostWindowRedisplay(f1);
                          glutPostWindowRedisplay(f2);
                          break;
    case GLUT_KEY_DOWN  : if ( pt ) 
                            s[aff].pi.y--;
                            else
                            s[aff].pf.y--;
                          glutPostWindowRedisplay(f1);
                          glutPostWindowRedisplay(f2);
                          break; }
}

void key(unsigned char key,int x,int y) {
  switch ( key ) {
    case 0x20 : pt = !pt;
                break;
    case 0x0D : aff = (aff+1)%8 ;
                glutPostWindowRedisplay(f1);
                glutPostWindowRedisplay(f2);
                break;
    case 0x1B : exit(0);
                break; }
}

void reshape2(int w,int h) {
  glViewport(0,0,w,h);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  glOrtho(0,w,-h,0,-1.0,1.0); 
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

void myinit() {
  glEnable(GL_ALPHA_TEST);
  glEnable(GL_BLEND);
  glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
  glClearColor(0.8F,0.8F,0.8F,1.0F);
}

int main(int argc,char **argv) {
  glutInit(&argc,argv);
  glutInitDisplayMode(GLUT_RGBA|GLUT_DEPTH|GLUT_DOUBLE);
  glutInitWindowSize(250,168); 
  glutInitWindowPosition(50,50); 
  f1 = glutCreateWindow("Bresenham"); 
  myinit(); 
  creationMenuBasique();
  setParametresOrthoBasique(-0.5,20.5,-0.5,20.5,-50.0,50.0);
  glutReshapeFunc(reshapeOrthoBasique);
  glutKeyboardFunc(key);
  glutSpecialFunc(special);
  glutDisplayFunc(display1);
  glutInitWindowSize(120,50);
  glutInitWindowPosition(60,340);
  glutInitDisplayMode(GLUT_RGBA|GLUT_DEPTH|GLUT_DOUBLE);
  f2 = glutCreateWindow("Valeurs");
  creationMenuBasique();
  glutDisplayFunc(display2);
  glutReshapeFunc(reshape2);
  glutKeyboardFunc(key);
  glutSpecialFunc(special);
  glutMainLoop();
  return(0);
}