/* Une animation en OpenGL                      */
/*                                              */
/* Auteur: Nicolas JANEY                        */
/* nicolas.janey@univ-fcomte.fr                 */
/* Mars 2021                                    */

#include <stdlib.h>
#include <stdio.h>
#include <math.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 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 int obj = 1;
static int axe = 1;
static int animationSphere = 0;
static int animationCamera = 0;
static float distance = 0.0F;
static float delta = 0.1F;
static float longueur;

/* Affichage des informations relatives         */
/* a OpenGL                                     */

static void informationsOpenGL(void) {
  printf("GL_VENDOR     = %s\n",(const char *) glGetString(GL_VENDOR));
  printf("GL_VERSION    = %s\n",(const char *) glGetString(GL_VERSION));
  printf("GL_RENDERER   = %s\n",(const char *) glGetString(GL_RENDERER));
  printf("GL_EXTENSIONS = %s\n",(const char *) glGetString(GL_EXTENSIONS));
}

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

static void init(void) {
  const GLfloat shininess[] = { 50.0 };
  glMaterialfv(GL_FRONT,GL_SHININESS,shininess);
  glLightfv(GL_LIGHT0,GL_DIFFUSE,rouge);
  glLightfv(GL_LIGHT1,GL_DIFFUSE,jaune);
  glLightfv(GL_LIGHT2,GL_DIFFUSE,bleu);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  glEnable(GL_LIGHT1);
  glEnable(GL_LIGHT2);
  glDepthFunc(GL_LESS);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_NORMALIZE);
  glEnable(GL_AUTO_NORMAL);
}

/* Scene dessinee                               */

#ifndef M_PI
#define M_PI 3.14159265358979323846264338327950288
#endif

static void solidCylindre(double rayon,double hauteur,int nbFTube,int nbFHauteur) {
  GLboolean nm = glIsEnabled(GL_NORMALIZE);
  if ( !nm )
    glEnable(GL_NORMALIZE);
  float normale[4];
  glGetFloatv(GL_CURRENT_NORMAL,normale);
  glPushMatrix();
  for ( int j = 0 ; j < nbFHauteur ; j++ ) {
    float hi = hauteur/2-j*hauteur/nbFHauteur;
    float hf = hi-hauteur/nbFHauteur;
    glBegin(GL_QUAD_STRIP);
    for( int i = 0 ; i <= nbFTube ; i++ ) {
      float a = (2*M_PI*i)/nbFTube;
      float cs = cos(a);
      float sn = -sin(a);
      glNormal3f(cs,0.0F,sn);
      float x = rayon*cs;
      float z = rayon*sn;
      glVertex3f(x,hi,z);
      glVertex3f(x,hf,z); }
    glEnd(); }
  glPopMatrix();
  glNormal3f(normale[0],normale[1],normale[2]);
  if ( !nm )
    glDisable(GL_NORMALIZE);
}

void solidTore(double rayonTube,double rayonTore,double angleI,double angleF,int nbTube,int nbTore) {
  for ( int i = 0 ; i < nbTore ; i++ ) {
    float da = angleF-angleI;
    float alphai = angleI+da*i/nbTore;
    float alphaj = alphai+da/nbTore;
    float cosalphai = cos(alphai);
    float sinalphai = sin(alphai);
    float cosalphaj = cos(alphaj);
    float sinalphaj = sin(alphaj);
    glBegin(GL_QUAD_STRIP);
    for ( int j = 0 ; j <= nbTube ; j++ ) {
      float beta = 2*M_PI*j/nbTube;
      float cosbeta = cos(beta);
      float sinbita = sin(beta);
      float x1 = (rayonTore+rayonTube*cosbeta)*cosalphai;
      float y1 = (rayonTore+rayonTube*cosbeta)*sinalphai;
      float z1 = rayonTube*sinbita;
      glNormal3f(cosbeta*cosalphai,cosbeta*sinalphai,sinbita);
      glVertex3f(x1,y1,z1);
      float x2 = (rayonTore+rayonTube*cosbeta)*cosalphaj;
      float y2 = (rayonTore+rayonTube*cosbeta)*sinalphaj;
      float z2 = rayonTube*sinbita;
      glNormal3f(cosbeta*cosalphaj,cosbeta*sinalphaj,sinbita);
      glVertex3f(x2,y2,z2); }
    glEnd(); }
}

void solidTore(double rayonTube,double rayonTore,int nbFTube,int nbFTore) {
  solidTore(rayonTube,rayonTore,0.0,2*M_PI,nbFTube,nbFTore);
}

static void calculLongueurTunnel(void) {
  if ( obj ) {
    longueur = 4.0F*(10.0F+2.0F*M_PI*5.0F/4.0F); }
    else {
    longueur = 2.0F*2.0F*M_PI*8.0F; }
}

static void scene1(int axe) {
  glPushMatrix();
  // Axe du tunnel
  if ( axe ) {
    glMaterialfv(GL_FRONT,GL_DIFFUSE,vert);
    for ( int i = 0 ; i < 4 ; i++ ) {
      glRotatef(90.0F*i,0.0F,1.0F,0.0F);
      glPushMatrix();
      glTranslatef(-5.0F,0.0F,5.0F);
      glRotatef(90.0F,1.0F,0.0F,0.0F);
      solidTore(0.05F,5.0F,M_PI/2.0,M_PI,18,100);
      glPopMatrix();
      glPushMatrix();
      glTranslatef(-10.0F,0.0F,0.0F);
      glRotatef(90.0F,1.0F,0.0F,0.0F);
      solidCylindre(0.05F,10.0F,18,100);
      glPopMatrix(); } }
  // Tunnel
  glMaterialfv(GL_FRONT,GL_DIFFUSE,blanc);
  for ( int i = 0 ; i < 4 ; i++ ) {
    glRotatef(90.0F*i,0.0F,1.0F,0.0F);
    for ( int i = 1 ; i <= 5 ; i++ ) {
      glPushMatrix();
      glTranslatef(5.0F,0.0F,-5.0F);
      glRotatef(i*180.0F/12,0.0F,1.0F,0.0F);
      glTranslatef(5.0F,0.0F,0.0F);
      solidTore(0.1,2.0,18,72);
      glPopMatrix(); }
    for ( int i = -5 ; i <= 5 ; i++) {
      glPushMatrix();
      glTranslatef(10.0F,0.0F,i);
      solidTore(0.1,2.0,18,72);
      glPopMatrix(); } }
  glPopMatrix();
}

static void scene2(int axe) {
  glPushMatrix();
  // Axe du tunnel
  if ( axe ) {
    glMaterialfv(GL_FRONT,GL_DIFFUSE,vert);
    glPushMatrix();
    glTranslatef(8.0F,0.0F,0.0F);
    glRotatef(90.0F,1.0F,0.0F,0.0F);
    solidTore(0.05,8.0,18,180);
    glPopMatrix();
    glPushMatrix();
    glTranslatef(-8.0F,0.0F,0.0F);
    glRotatef(90.0F,1.0F,0.0F,0.0F);
    solidTore(0.05,8.0,18,180);
    glPopMatrix(); }
  // Tunnel
  glMaterialfv(GL_FRONT,GL_DIFFUSE,blanc);
  for ( int i = 0 ; i <= 36 ; i++ ) {
    glPushMatrix();
    glTranslatef(8.0F,0.0F,0.0F);
    glRotatef(i*180.0F/18,0.0F,1.0F,0.0F);
    glTranslatef(8.0F,0.0F,0.0F);
    solidTore(0.1,2.0,18,72);
    glPopMatrix();
    glPushMatrix();
    glTranslatef(-8.0F,0.0F,0.0F);
    glRotatef(i*180.0F/18,0.0F,1.0F,0.0F);
    glTranslatef(-8.0F,0.0F,0.0F);
    solidTore(0.1,2.0,18,72);
    glPopMatrix(); }
  glPopMatrix();
}

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

static void gestionAnimationSphere(void) {
  if ( obj ) {
    glPushMatrix();
    int n = distance/(longueur/4.0F);
    float p = distance - n*(longueur/4.0F);
    glRotatef(90.0F*n,0.0F,1.0F,0.0F);
    if ( p <= 10.0F ) {
      glTranslatef(10.0F,0.0F,5.0F-p); }
      else {
      glTranslatef(5.0F,0.0F,-5.0F);
      glRotatef(90.0F*(p-10.0F)/(5.0F*2.0F*M_PI/4.0F),0.0F,1.0F,0.0F);
      glTranslatef(5.0F,0.0F,0.0F); }
    glMaterialfv(GL_FRONT,GL_DIFFUSE,bleu);
    glutSolidSphere(1.2,36,36);
    glPopMatrix(); }
    else {
    glPushMatrix();
    int n = distance/(longueur/2.0F);
    float p = distance - n*(longueur/2.0F);
    float angle = 360.0F*p/(longueur/2.0F);
    if ( n == 0 ) {
      glTranslatef(8.0F,0.0F,0.0F);
      glRotatef(angle,0.0F,1.0F,0.0F);
      glTranslatef(-8.0F,0.0F,0.0F); }
      else {
      glTranslatef(-8.0F,0.0F,0.0F);
      glRotatef(-angle,0.0F,1.0F,0.0F);
      glTranslatef(8.0F,0.0F,0.0F); }
    glMaterialfv(GL_FRONT,GL_DIFFUSE,bleu);
    glutSolidSphere(1.2,36,36);
    glPopMatrix(); }
}

static void gestionAnimationCamera(void) {
  if ( obj ) {
    int n = distance/(longueur/4.0F);
    float p = distance - n*(longueur/4.0F);
    float px;
    float pz;
    float aux;
    float angle;
    if ( p <= 10.0F ) {
      angle = 0.0F;
      px = 10.0F;
      pz = 5.0F-p; }
      else {
      angle = M_PI/2.0F*(p-10.0F)/(5.0F*2.0F*M_PI/4.0F);
      px = 5.0F+5.0F*cos(angle);
      pz = -5.0F-5.0F*sin(angle); }
    switch (n) {
      case 1 :
        aux = -px;
        px = pz;
        pz = aux;
        break;
      case 2 :
        px = -px;
        pz = -pz;
        break;
      case 3 :
        aux = px;
        px = -pz;
        pz = aux;
        break; }
    angle += n*M_PI/2.0F;
    gluLookAt(px,0.0,pz,px-sin(angle),0.0,pz-cos(angle),0.0,1.0,0.0);
    glRotatef(rz,0.0F,0.0F,1.0F);
    glRotatef(ry,0.0F,1.0F,0.0F);
    glRotatef(rx,1.0F,0.0F,0.0F); }
    else {
    int n = distance/(longueur/2.0F);
    float p = distance - n*(longueur/2.0F);
    float angle = 2.0*M_PI*p/(longueur/2.0F);
    if ( n == 1 ) {
      angle = -angle; }
    float px;
    float pz;
    if ( n == 0 ) {
      px = 8.0F-8.0F*cos(angle);
      pz = 8.0F*sin(angle); }
      else {
      px = -8.0F+8.0F*cos(angle);
      pz = -8.0F*sin(angle); }
    gluLookAt(px,0.0,pz,px+sin(angle),0.0,pz+cos(angle),0.0,1.0,0.0); }
}

static void display(void) {
  printf("D\n");
  glClearColor(0.5F,0.5F,0.5F,0.5F);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  const GLfloat light0_position[] = { 0.0,0.0,0.0,1.0 };
  const GLfloat light1_position[] = { -1.0,1.0,1.0,0.0 };
  const GLfloat light2_position[] = { 1.0,-1.0,1.0,0.0 };
  glLightfv(GL_LIGHT0,GL_POSITION,light0_position);
  glLightfv(GL_LIGHT1,GL_POSITION,light1_position);
  glLightfv(GL_LIGHT2,GL_POSITION,light2_position);
  glPushMatrix();
  if ( animationCamera ) {
    gestionAnimationCamera(); }
    else {
    gluLookAt(5.0,10.0,20.0,0.0,0.0,0.0,0.0,1.0,0.0); }
  if ( animationSphere ) {
    gestionAnimationSphere(); }
  if ( obj ) {
    scene1(axe); }
    else {
    scene2(axe); }
  glPopMatrix();
  glFlush();
  glutSwapBuffers();
  int error = glGetError();
  if ( error != GL_NO_ERROR )
    printf("Attention erreur %d\n",error);
}

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

static void idle(void) {
  printf("I\n");
  distance += delta;
  while ( distance > longueur ) {
    distance -= longueur; }
  glutPostRedisplay();
}

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

static void reshape(int x,int y) {
  glViewport(0,0,x,y); 
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(70.0F,(float) x/y,0.1,40.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

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

static void special(int key,int x,int y) {
  switch (key) {
    case GLUT_KEY_UP :
      rx += 1.0F;
      glutPostRedisplay();
      break;
    case GLUT_KEY_DOWN :
      rx -= 1.0F;
      glutPostRedisplay();
      break;
    case GLUT_KEY_LEFT :
      ry += 1.0F;
      glutPostRedisplay();
      break;
    case GLUT_KEY_RIGHT :
      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       */

static void keyboard(unsigned char key,int x,int y) {
  switch (key) {
    case 43 :
      distance += delta;
      while ( distance > longueur ) {
        distance -= longueur; }
      glutPostRedisplay();
      break;
    case 45 :
      distance = distance-delta+longueur;
      while ( distance > longueur ) {
        distance -= longueur; }
      glutPostRedisplay();
      break;
    case 'f' :
    case 'F' :
      { static int fullScreen = 0;
        static int tx;
        static int ty;
        static int px;
        static int py;
        fullScreen = !fullScreen;
        if ( fullScreen ) {
          px = glutGet(GLUT_WINDOW_X);
          py = glutGet(GLUT_WINDOW_Y);
          tx = glutGet(GLUT_WINDOW_WIDTH);
          ty = glutGet(GLUT_WINDOW_HEIGHT);
          glutFullScreen(); }
          else
          glutPositionWindow(px,py);
          glutReshapeWindow(tx,ty); }
      break;
    case 0x0D :
      { static int anim = 0;
        anim = !anim;
        glutIdleFunc(( anim ) ? idle : NULL); }
      break;
    case ' ' :
      { informationsOpenGL(); }
      break;
    case 'a' :
    case 'A' :
      axe = !axe;
      glutPostRedisplay();
      break;
    case 's' :
    case 'S' :
      animationSphere = !animationSphere;
      //animationCamera = 0;
      glutPostRedisplay();
      break;
    case 'c' :
    case 'C' :
      animationCamera = !animationCamera;
      //animationSphere = 0;
      glutPostRedisplay();
      break;
    case 'o' :
    case 'O' :
      obj = !obj;
      distance = 0.0F;
      calculLongueurTunnel();
      glutPostRedisplay();
      break;
    case 0x1B :
      exit(0);
      break; }
}

/* Fonction principale                          */

int main(int argc,char **argv) {
  calculLongueurTunnel();
  glutInit(&argc,argv);
  glutInitDisplayMode(GLUT_RGBA|GLUT_DEPTH|GLUT_DOUBLE);
  glutInitWindowSize(480,320);
  glutInitWindowPosition(50,50);
  glutCreateWindow("Un circuit matérialisé par des anneaux");
  init();
  glutKeyboardFunc(keyboard);
  glutReshapeFunc(reshape);
  glutSpecialFunc(special);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}
