/* Une molecule de benzene : C6H6               */
/*                                              */
/* Auteur: Nicolas JANEY                        */
/* nicolas.janey@univ-fcomte.fr                 */
/* Octobre 2011                                 */

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

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

#include "ModuleAxes.h"

/* Variables et constantes globales             */

static float rx = 0.0F;
static float ry = 0.0F;
static float rz = 0.0F;
static int objet = 0;
static int aff = 1;

/* Fonction executee lors de la frappe          */
/* d'une touche du clavier                      */

void keyboard(unsigned char key,int x,int y) {
  switch ( key ) {
    case 0x20 :
      aff = (aff+1)%2;
      glutPostRedisplay(); 
      break;
    case 0x0D :
      objet = (objet+1)%2;
      glutPostRedisplay(); 
      break;
    case 0x1B :
      exit(0); 
      break; }
}

/* Fonction executee lors de l'appui            */
/* d'une touche de curseur ou d'une touche      */
/* page up ou page down                         */

void special(int key,int x,int y) {
  switch(key) {
    case GLUT_KEY_UP :
      rx++;
      glutPostRedisplay();
      break;
    case GLUT_KEY_DOWN :
      rx--;
      glutPostRedisplay();
      break;
    case GLUT_KEY_LEFT :
      ry++;
      glutPostRedisplay();
      break;
    case GLUT_KEY_RIGHT :
      ry--;
      glutPostRedisplay();
      break;
    case GLUT_KEY_PAGE_UP :
      rz++;
      glutPostRedisplay();
      break;
    case GLUT_KEY_PAGE_DOWN :
      rz--;
      glutPostRedisplay();
      break; }
}

/* Fonction d'initialisation des parametres     */
/* OpenGL ne changeant pas au cours de la vie   */
/* du programme                                 */

void init(void) {
  float noir[] = { 0.0F, 0.0F, 0.0F, 1.0F };
  glLightModelfv(GL_LIGHT_MODEL_AMBIENT,noir);
  glDepthFunc(GL_LESS);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_NORMALIZE);
  glEnable(GL_AUTO_NORMAL);
  glEnable(GL_CULL_FACE);
}

/* Scene dessinee                               */

void mySolidCylinder(double h,double r,int n,int m) {
  glPushMatrix();
  glRotatef(90.0F,1.0F,0.0F,0.0F);
  glTranslatef(0.0F,0.0F,-h/2);
  GLUquadricObj *qobj = gluNewQuadric();
  gluQuadricDrawStyle(qobj,GLU_FILL);
  gluCylinder(qobj,r,r,h,n,m);
  gluDeleteQuadric(qobj);  
  glPopMatrix();
}

void motif(int objet) {
  glPushMatrix();
  glTranslatef(2.0F,0.0F,0.0F);
  glutSolidSphere(0.5,36,36);
  glPushMatrix();
  glRotatef(30.0,0.0F,0.0F,1.0F);
  glTranslatef(0.0F,1.0F,0.0F);
  switch (objet) {
    case 2 :
      mySolidCylinder(2.0,0.15,20,20);
      break;
    case 1 :
      glTranslatef(0.1F,0.0F,0.0F);
      mySolidCylinder(2.0,0.05,20,20);
      glTranslatef(-0.2F,0.0F,0.0F);
      mySolidCylinder(2.0,0.05,20,20);
      break;
    case 0 :
      mySolidCylinder(2.0,0.05,20,20);
      break; }
  glPopMatrix();
  glTranslatef(0.6F,0.0F,0.0F);
  glPushMatrix();
  glRotatef(90.0,0.0F,0.0F,1.0F);
  mySolidCylinder(1.2,0.05,20,20);
  glPopMatrix();
  glTranslatef(0.6F,0.0F,0.0F);
  glutSolidSphere(0.25,36,36);
  glPopMatrix();
}

void scene(void) {
  glPushMatrix();
  for ( int i = 0 ; i < 6 ; i++ ) {
    float angle = i*60.0F;
    glPushMatrix();
    glRotatef(angle,0.0F,0.0F,1.0F);
    motif((objet) ? i%2 : 2);
    glPopMatrix(); }
  glPopMatrix();
}

/* Fonction executee lors d'un rafraichissement */
/* de la fenetre de dessin                      */

void display(void) {
  glClearColor(0.25F,0.25F,0.25F,1.0F);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glPolygonMode(GL_FRONT_AND_BACK,(aff) ? GL_FILL : GL_LINE);
  glPushMatrix();
  dessinAxes();
  glRotatef(rx,1.0F,0.0F,0.0F);
  glRotatef(ry,0.0F,1.0F,0.0F);
  glRotatef(rz,0.0F,0.0F,1.0F);
  scene();
  glPopMatrix();
  glFlush();
  glutSwapBuffers();
  int error = glGetError();
  if ( error != GL_NO_ERROR )
    printf("Erreur OpenGL: %d\n",error);
}

/* Fonction executee lors d'un changement       */
/* de la taille de la fenetre OpenGL            */
/* -> Ajustement de la camera de visualisation  */

void reshape(int x,int y) {
  glViewport(0,0,x,y); 
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(23.0F,(float) x/y,1.0,50.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  gluLookAt(5.0,10.0,15.0,0.0,0.0,0.0,0.0,1.0,0.0);
}

/* Fonction principale                          */

int main(int argc,char **argv) {
  glutInit(&argc,argv);
  glutInitDisplayMode(GLUT_RGBA|GLUT_DEPTH|GLUT_DOUBLE);
  glutInitWindowSize(300,300); 
  glutInitWindowPosition(50,50); 
  glutCreateWindow("Une molecule de benzene non eclairee"); 
  init();
  glutKeyboardFunc(keyboard);
  glutSpecialFunc(special);
  glutReshapeFunc(reshape);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}