/* Gestion de lumieres et de materiaux          */
/*                                              */
/* Auteur: Nicolas JANEY                        */
/* nicolas.janey@univ-fcomte.fr                 */
/* Septembre 2011                               */

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

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

/* Variables et constantes globales             */
/* pour les angles et les couleurs utilises     */

static float rx = 0.0F;
static float ry = 0.0F;
static float rz = 0.0F;
static const float blanc[]       = { 1.0F,1.0F,1.0F,1.0F };
static const float jaune[]       = { 1.0F,1.0F,0.0F,1.0F };
static const float cyan[]        = { 0.0F,1.0F,1.0F,1.0F };
static const float magenta[]     = { 1.0F,0.0F,1.0F,1.0F };
static const float rouge[]       = { 1.0F,0.0F,0.0F,1.0F };
static const float vert[]        = { 0.0F,1.0F,0.0F,1.0F };
static const float bleu[]        = { 0.0F,0.0F,1.0F,1.0F };
static const float noir[]        = { 0.0F,0.0F,0.0F,1.0F };
static const float grisMoyen[]   = { 0.5F,0.5F,0.5F,1.0F };
static const float jauneMoyen[]  = { 0.5F,0.5F,0.0F,1.0F };
static const float defaultDiff[] = { 0.8F,0.8F,0.8F,1.0F };
static const float defaultSpec[] = { 0.0F,0.0F,0.0F,1.0F };
static const float defaultAmbi[] = { 0.2F,0.2F,0.2F,1.0F };

static int scn = 0;
static int n = 18;
static int aff = 1;

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

void init(void) {
  glDepthFunc(GL_LESS);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_NORMALIZE);
  glEnable(GL_AUTO_NORMAL);
}

/* Scene dessinee                               */

void scene(void) {
  glPushMatrix();
  glutSolidTorus(1.0,9.0F,n,n*8);
  glRotatef(90.0F,1.0F,0.0F,0.0F);
  glutSolidTorus(1.0,9.0F,n,n*8);
  glRotatef(90.0F,0.0F,1.0F,0.0F);
  glutSolidTorus(1.0,9.0F,n,n*8);
  glPopMatrix();
}

void configurationLumieresEtMateriaux(void) {
  glEnable(GL_LIGHTING);
  glDisable(GL_LIGHT0);
  glDisable(GL_LIGHT1);
  glDisable(GL_LIGHT2);
  switch (scn) {
    case 0 :
    case 1 :
    case 2 :
      glMaterialfv(GL_FRONT,GL_AMBIENT,noir);
      glMaterialfv(GL_FRONT,GL_SPECULAR,noir);
      glMaterialfv(GL_FRONT,GL_DIFFUSE,defaultDiff);
      break;
    case 3 :
      glMaterialfv(GL_FRONT,GL_AMBIENT,noir);
      glMaterialfv(GL_FRONT,GL_DIFFUSE,defaultDiff);
      glMaterialfv(GL_FRONT,GL_SPECULAR,blanc);
      { const GLfloat shininess[] = { 64.0 };
        glMaterialfv(GL_FRONT,GL_SHININESS,shininess); }
      break;
    case 4 :
      glMaterialfv(GL_FRONT,GL_AMBIENT,defaultAmbi);
      glMaterialfv(GL_FRONT,GL_DIFFUSE,noir);
      glMaterialfv(GL_FRONT,GL_SPECULAR,noir);
      break; }
  const GLfloat light0_position[] = {   0.0, 0.0, 0.0, 1.0 };
  const GLfloat light1_position[] = {   1.0, 0.0, 0.0, 0.0 };
  const GLfloat light2_position[] = { -20.0,20.0,20.0, 1.0 };
  const GLfloat light2_dir[] = { 1.0,-1.0,-1.0 };
  switch (scn) {
    case 0 :
      glEnable(GL_LIGHT0);
      glLightfv(GL_LIGHT0,GL_DIFFUSE,jaune);
      glLightfv(GL_LIGHT0,GL_POSITION,light0_position);
      break;
    case 1 :
      glEnable(GL_LIGHT0);
      glEnable(GL_LIGHT1);
      glLightfv(GL_LIGHT0,GL_DIFFUSE,jaune);
      glLightfv(GL_LIGHT1,GL_DIFFUSE,cyan);
      glLightfv(GL_LIGHT0,GL_POSITION,light0_position);
      glLightfv(GL_LIGHT1,GL_POSITION,light1_position);
      break;
    case 2 :
      glEnable(GL_LIGHT0);
      glEnable(GL_LIGHT1);
      glEnable(GL_LIGHT2);
      glLightfv(GL_LIGHT0,GL_DIFFUSE,jaune);
      glLightfv(GL_LIGHT1,GL_DIFFUSE,cyan);
      glLightfv(GL_LIGHT2,GL_DIFFUSE,magenta);
      glLightfv(GL_LIGHT0,GL_POSITION,light0_position);
      glLightfv(GL_LIGHT1,GL_POSITION,light1_position);
      glLightfv(GL_LIGHT2,GL_POSITION,light2_position);
      glLightfv(GL_LIGHT2,GL_SPOT_DIRECTION,light2_dir);
      glLightf(GL_LIGHT2,GL_SPOT_CUTOFF,10.0F);
      break;
    case 3 :
      glEnable(GL_LIGHT0);
      glEnable(GL_LIGHT1);
      glEnable(GL_LIGHT2);
      glLightfv(GL_LIGHT0,GL_DIFFUSE,jaune);
      glLightfv(GL_LIGHT1,GL_DIFFUSE,cyan);
      glLightfv(GL_LIGHT2,GL_DIFFUSE,magenta);
      glLightfv(GL_LIGHT0,GL_SPECULAR,blanc);
      glLightfv(GL_LIGHT1,GL_SPECULAR,blanc);
      glLightfv(GL_LIGHT2,GL_SPECULAR,blanc);
      glLightfv(GL_LIGHT0,GL_POSITION,light0_position);
      glLightfv(GL_LIGHT1,GL_POSITION,light1_position);
      glLightfv(GL_LIGHT2,GL_POSITION,light2_position);
      glLightfv(GL_LIGHT2,GL_SPOT_DIRECTION,light2_dir);
      glLightf(GL_LIGHT2,GL_SPOT_CUTOFF,10.0F);
      break;
    case 4 :
      glEnable(GL_LIGHT0);
      glLightfv(GL_LIGHT0,GL_DIFFUSE,noir);
      glLightfv(GL_LIGHT0,GL_SPECULAR,noir);
      glLightfv(GL_LIGHT0,GL_AMBIENT,jauneMoyen);
      break; }
}

/* Fonction executee lors d'un changement       */
/* de la taille de la fenetre OpenGL            */

void reshape(int w,int h) {
  glViewport(0,0,w,h); 
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(14.0F,(float) w/h,80.0,120.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  gluLookAt(0.0,0.0,100.0,0.0,0.0,0.0,0.0,1.0,0.0);
}

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

void display(void) {
  glClearColor(0.5F,0.5F,0.5F,1.0F);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  configurationLumieresEtMateriaux();
  glPolygonMode(GL_FRONT_AND_BACK,(aff) ? GL_FILL : GL_LINE);
  glPushMatrix();
  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();
}

/* Fonction executee lorsqu'aucun evenement     */
/* n'est en file d'attente                      */

void idle(void) {
  rx += 0.3355F;
  ry += 0.6117F;
  rz += 0.4174F;
  glutPostRedisplay();
}

/* Fonction executee lors de la frappe          */
/* d'une touche special du clavier:             */
/* - touches de curseur                         */
/* - touches de fonction                        */
/* - ...                                        */

void special(int code,int x,int y) {
  switch ( code ) {
    case GLUT_KEY_UP :
      rx += 1.0F;
      glutPostRedisplay(); 
      break;
    case GLUT_KEY_DOWN :
      rx -= 1.0F;
      glutPostRedisplay(); 
      break;
    case GLUT_KEY_RIGHT :
      ry += 1.0F;
      glutPostRedisplay(); 
      break;
    case GLUT_KEY_LEFT :
      ry -= 1.0F;
      glutPostRedisplay(); 
      break;
    case GLUT_KEY_PAGE_UP :
      rz += 1.0F;
      glutPostRedisplay(); 
      break;
    case GLUT_KEY_PAGE_DOWN :
      rz -= 1.0F;
      glutPostRedisplay(); 
      break; }
}

/* Fonction executee lors de l'appui            */
/* d'une touche alphanumerique du clavier       */

void keyboard(unsigned char key,int x,int y) {
  switch (key) {
    case 'r' :
      rx = 35.0F;
      ry = 10.0F;
      rz = 40.0F;
      glutPostRedisplay();
      break;
    case 43 :
      n++;
      glutPostRedisplay();
      break;
    case 45 :
      n--;
      if ( n == 2 )
        n = 3;
      glutPostRedisplay();
      break;
    case 0x20 :
      scn = (scn+1)%5;
      glutPostRedisplay();
      break;
    case 'm' :
      aff = !aff;
      glutPostRedisplay();
      break;
    case 0x0D :
      { static int anim = 0;
        anim = !anim;
        glutIdleFunc(( anim ) ? idle : NULL); }
      break;
    case 0x1B :
      exit(0);
      break; }
}

/* 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("Lumieres et matériaux"); 
  init();
  glutKeyboardFunc(keyboard);
  glutSpecialFunc(special);
  glutReshapeFunc(reshape);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}