#include "windows.h"

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

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

/* ************************************************** */

static int w = 0 ;
static int h = 0 ;
static int anim = 0 ;
static int image = 0 ;

/* ************************************************** */

void CALLBACK myReshape(int ww,int hh) {
  w = ww ;
  h = hh ;
  glViewport(0,0,ww,hh);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  glOrtho(-w/60,w/60,-h/120,h/30-h/120,-10.0,10.0);
  glMatrixMode(GL_MODELVIEW);
}
/* -------------------------------------------------- */
/* Fonction d'initialisation.                         */
/*  - Une lumiere blanche                             */
/*  - Matiere diffusante rouge                        */
/*  - Activation de l'elimination des parties cachees */
/* -------------------------------------------------- */
void myinit(void) {
  GLfloat light_ambient[] = { 0.0F,0.0F,0.0F,1.0F };
  GLfloat light_diffuse[] = { 1.0F,1.0F,1.0F,1.0F };
  GLfloat light_specular[] = { 1.0F,1.0F,1.0F,1.0F };
  GLfloat light_position[] = { 1.0F,1.0F,1.0F,0.0F };
  glLightfv(GL_LIGHT0,GL_AMBIENT,light_ambient);
  glLightfv(GL_LIGHT0,GL_DIFFUSE,light_diffuse);
  glLightfv(GL_LIGHT0,GL_SPECULAR,light_specular);
  glLightfv(GL_LIGHT0,GL_POSITION,light_position);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  GLfloat rouge[] = { 1.0F,0.0F,0.0F,0.0F };
  glMaterialfv(GL_FRONT_AND_BACK,GL_DIFFUSE,rouge);
  glDepthFunc(GL_LESS);
  glEnable(GL_DEPTH_TEST);
}
/* -------------------------------------------------- */
/* Dessin d'une image.                                */
/* - Effacement de la fenetre.                        */
/* - Empilement de la transformation courante.        */
/* - Translation selon l'axe y de valeur fonction     */
/*   du numero de l'image.                            */
/* - Dessin de la sphere.                             */
/* - Flush de l'image.                                */
/* - Depilement de la transformation courante.        */
/* -------------------------------------------------- */
void CALLBACK display(void) {
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glPushMatrix();
  if ( image < 100 )
    glTranslatef(0.0F,10.0F-image*image/1000,0.0F) ;
    else
    glTranslatef(0.0F,10.0F-(200-image)*(200-image)/1000,0.0F) ;
  auxSolidSphere(1.0) ;
  glPopMatrix();
  glFlush();
  auxSwapBuffers();
}
/* -------------------------------------------------- */
/* Gestion de l'animation.                            */
/* Si une animation est en cours :                    */
/*   - Le numero de l'image est incremente.           */
/*   - Si le numero de l'image devient superieur      */
/*     a 200, il redevient egal a 0 et l'animation    */
/*     est desactivee.                                */
/*   - Le dessin d'une image est demande.             */
/* -------------------------------------------------- */
void CALLBACK idle(void) {
  if ( anim ) {
    image++ ;
    if ( image > 200 ) {
      image = 0 ;
      anim = 0 ; }
    display() ; }
}
/* -------------------------------------------------- */
/* Activation/Desactivation de l'animation.           */
/* -------------------------------------------------- */
void CALLBACK keyA(void) {
  anim = !anim ;
}
/* -------------------------------------------------- */
void main(void) {
  auxInitDisplayMode(AUX_DOUBLE|AUX_RGB|AUX_DEPTH);
  auxInitPosition(10,10,300,500);
  auxInitWindow("Exercice 2 : La sphere");
  myinit();
  auxIdleFunc(idle);
  auxKeyFunc(AUX_A,keyA);
  auxReshapeFunc(myReshape);
  auxMainLoop(display);
}

/* ************************************************** */