/* Lumieres et materiaux                         */
/*                                               */
/* Auteur: Nicolas JANEY                         */
/* nicolas.janey@univ-fcomte.fr                  */
/* Fevrier 2019                                  */

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

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

/* Variables et constantes globales              */

static double px = 0.0;
static double py = 0.0;
static double pz = 10.0;

static float rxs = 0.0;
static float rys = 0.0;
static float rzs = 0.0;

static int n = 100;
static int n1 = 72;
static int n2 = 360;

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,0.0F,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 int affichage = 1;
static int scene = 0;
static int animation = 0;
static int culling = 0;

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

static void init(void) {
  glClearColor(0.0F,0.0F,0.0F,1.0F);
  glDepthFunc(GL_LESS);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_NORMALIZE);
  glLightModelfv(GL_LIGHT_MODEL_AMBIENT,noir);
}

/* Modelisation geometrique d'un parallelogramme */
/* (quadrilatere dont les cotes opposes          */
/* sont paralleles)                              */
/* px, py et pz    : La position du sommet       */
/*                   de reference                */
/* tx1, ty1 et tz1 : Les dimensions du cote 1    */
/* tx2, ty2 et tz2 : Les dimensions du cote 2    */
/* n1 et n2        : Les nombres de facettes     */
/*                   selon les cotes 1 et 2      */

static void mySolidParallelogram(double px,double py,double pz,
                                 double tx1,double ty1,double tz1,
                                 double tx2,double ty2,double tz2,
                                 int n1,int n2) {
  double dx1 = tx1/n1;
  double dy1 = ty1/n1;
  double dz1 = tz1/n1;
  double dx2 = tx2/n2;
  double dy2 = ty2/n2;
  double dz2 = tz2/n2;
  double ds = 1.0/n1;
  double dt = 1.0/n2;
  for ( int i1 = 0 ; i1 < n1 ; i1++ ) {
    glBegin(GL_QUAD_STRIP);
    double x = px+i1*dx1;
    double y = py+i1*dy1;
    double z = pz+i1*dz1;
    double s = i1*ds;
    double t = 0.0;
    for ( int i2 = 0 ; i2 <= n2 ; i2++ ) {
      glTexCoord2d(s,t);
      glVertex3d(x,y,z);
      glTexCoord2d(s+ds,t);
      glVertex3d(x+dx1,y+dy1,z+dz1);
      x += dx2;
      y += dy2;
      z += dz2;
      t += dt; }
    glEnd(); }
}

/* Modelisation geometrique d'un cube            */
/* ct : la taille du cube                        */
/* n  : le nombre de facettes generees           */
/*      selon chaque axe pour le dessin          */
/*      de chacune des faces                     */

static void mySolidCube(double ct,int n) {
  double c = ct/2.0F;
  glNormal3f(0.0F,0.0F,-1.0F);
  mySolidParallelogram(-c,-c,-c,0.0,ct,0.0,ct,0.0,0.0,n,n);
  glNormal3f(0.0F,-1.0F,0.0F);
  mySolidParallelogram(-c,-c,-c,ct,0.0,0.0,0.0,0.0,ct,n,n);
  glNormal3f(-1.0F,0.0F,0.0F);
  mySolidParallelogram(-c,-c,-c,0.0,0.0,ct,0.0,ct,0.0,n,n);
  glNormal3f(0.0F,0.0F,1.0F);
  mySolidParallelogram(c,c,c,-ct,0.0,0.0,0.0,-ct,0.0,n,n);
  glNormal3f(0.0F,1.0F,0.0F);
  mySolidParallelogram(c,c,c,0.0,0.0,-ct,-ct,0.0,0.0,n,n);
  glNormal3f(1.0F,0.0F,0.0F);
  mySolidParallelogram(c,c,c,0.0,-ct,0.0,0.0,0.0,-ct,n,n);
}

/* Scene dessinee 2                              */

static void configurationMaterielCube(void) {
}

static void scene2() {
  glPushMatrix();
  configurationMaterielCube();
  mySolidCube(7.0,n);
  glPopMatrix();
}

/* Scene dessinee 1                              */

static void configurationMaterielTore1(void) {
}

static void configurationMaterielTore2(void) {
}

static void configurationMaterielTore3(void) {
}

static void scene1() {
  glPushMatrix();
  configurationMaterielTore1();
  glutSolidTorus(1.0,5.0,n1,n2);
  glRotatef(90.0F,1.0F,0.0F,0.0F);
  configurationMaterielTore2();
  glutSolidTorus(1.0,5.0,n1,n2);
  glRotatef(90.0F,0.0F,1.0F,0.0F);
  configurationMaterielTore3();
  glutSolidTorus(1.0,5.0,n1,n2);
  glPopMatrix();
}

/* Fonction de configuration des lumieres        */

static void configurationLumieres(void) {
}

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

static void display(void) {
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glPolygonMode(GL_FRONT_AND_BACK,(affichage) ? GL_FILL : GL_LINE);
  if ( culling ) {
    glEnable(GL_CULL_FACE); }
    else {
    glDisable(GL_CULL_FACE); }
  glPushAttrib(GL_LIGHTING_BIT);
  glPushMatrix();
  gluLookAt(px,py,pz,0.0,0.0,0.0,0.0,1.0,0.0);
  configurationLumieres();
  glRotatef(rxs,1.0F,0.0F,0.0F);
  glRotatef(rys,0.0F,1.0F,0.0F);
  glRotatef(rzs,0.0F,0.0F,1.0F);
  switch (scene) {
    case 0 :
      scene1();
      break;
    case 1 :
      scene2();
      break; }
  glPopMatrix();
  glPopAttrib();
  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   */

static void reshape(int tx,int ty) {
  glViewport(0,0,tx,ty); 
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  double ratio =(double) tx/ty;
  if ( ratio >= 1.0 )
    gluPerspective(80.0,ratio,1.0,20.0);
    else
    gluPerspective(80.0/ratio,ratio,1.0,20.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

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

static void special(int key,int x,int y) {
  switch ( key ) {
    case GLUT_KEY_UP :
      py += 0.1;
      glutPostRedisplay(); 
      break;
    case GLUT_KEY_DOWN :
      py -= 0.1;
      glutPostRedisplay(); 
      break;
    case GLUT_KEY_LEFT :
      px -= 0.1;
      glutPostRedisplay(); 
      break;
    case GLUT_KEY_RIGHT :
      px += 0.1;
      glutPostRedisplay(); 
      break;
    case GLUT_KEY_PAGE_UP :
      pz -= 0.1;
      glutPostRedisplay(); 
      break;
    case GLUT_KEY_PAGE_DOWN :
      pz += 0.1;
      glutPostRedisplay(); 
      break;
    case GLUT_KEY_F1 :
      px = 0.0;
      py = 0.0;
      pz = 10.0;
      glutPostRedisplay(); 
      break;
    case GLUT_KEY_F2 :
      rxs = 0.0;
      rys = 0.0;
      rzs = 0.0;
      glutPostRedisplay(); 
      break;
    case GLUT_KEY_F3 :
      rxs = 10.0;
      rys = 60.0;
      rzs = 110.0;
      glutPostRedisplay(); 
      break; }
}

/* Fonction executee en tache de fond            */

static void idle1(void) {
  rxs += 0.7F;
  rys += 0.5F;
  rzs += 0.3F;
  glutPostRedisplay();
}

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

static void keyboard(unsigned char key,int x,int y) {
  switch ( key ) {
    case 'a' :
      animation = (animation+1)%2;
      switch (animation) {
        case 0 :
          glutIdleFunc(NULL);
          break;
        case 1 :
          glutIdleFunc(idle1);
          break; }
      break;
    case 'c' :
      culling = !culling;
      glutPostRedisplay();
      break;
    case 0x20 :
      affichage = !affichage;
      glutPostRedisplay(); 
      break;
    case 's' :
      scene = (scene+1)%2;
      glutPostRedisplay(); 
      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(360,360); 
  glutInitWindowPosition(50,50); 
  glutCreateWindow("Lumieres et matériel"); 
  init();
  glutKeyboardFunc(keyboard);
  glutSpecialFunc(special);
  glutReshapeFunc(reshape);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}