/* Une molecule de benzene : C6H6               */
/*                                              */
/* Auteur: Nicolas JANEY                        */
/* nicolas.janey@univ-fcomte.fr                 */
/* Decembre 2012                                */

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

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

#include "Position3D.h"
#include "Direction3D.h"

/* Variables et constantes globales             */

static const float blanc[] = { 1.0F,1.0F,1.0F,1.0F };
static const float gris[]  = { 0.7F,0.7F,0.7F,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 float rx = 0.0F;
static float ry = 0.0F;
static float rz = 0.0F;
static int aff = 1;
static int niveau = 0;

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

static void keyboard(unsigned char key,int x,int y) {
  switch ( key ) {
    case 43 :
      niveau++;
      glutPostRedisplay(); 
      break;
    case 45 :
      niveau--;
      if ( niveau < 0 )
        niveau = 0;
      glutPostRedisplay(); 
      break;
    case 0x20 :
      aff = (aff+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                         */

static 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                                 */

static void init(void) {
  const GLfloat mat_shininess[] = { 50.0 };
  glMaterialfv(GL_FRONT,GL_SPECULAR,blanc);
  glMaterialfv(GL_FRONT,GL_SHININESS,mat_shininess);
  glLightfv(GL_LIGHT0,GL_DIFFUSE,rouge);
  glLightfv(GL_LIGHT1,GL_DIFFUSE,vert);
  glLightfv(GL_LIGHT2,GL_DIFFUSE,bleu);
  glLightfv(GL_LIGHT0,GL_SPECULAR,blanc);
  glLightfv(GL_LIGHT1,GL_SPECULAR,blanc);
  glLightfv(GL_LIGHT2,GL_SPECULAR,blanc);
  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);
  glEnable(GL_CULL_FACE);
}

//////////////////////////////////////////////////

/* Scene dessinee                               */

static void position3DIntermediaire(Position3D *si,
                                    Position3D *sf,
                                    Position3D *p) {
  p->c[0] = (si->c[0]+sf->c[0])/2.0;
  p->c[1] = (si->c[1]+sf->c[1])/2.0;
  p->c[2] = (si->c[2]+sf->c[2])/2.0;
}

static void decompositionRecursiveFacette(int n,
                                          Position3D *s1,
                                          Position3D *s2,
                                          Position3D *s3) {
  if ( n ) {
    Position3D s12; 
    Position3D s23;
    Position3D s31;
    position3DIntermediaire(s1,s2,&s12);
    position3DIntermediaire(s2,s3,&s23);
    position3DIntermediaire(s3,s1,&s31);
    decompositionRecursiveFacette(n-1,s1,&s12,&s31);
    decompositionRecursiveFacette(n-1,s2,&s23,&s12);
    decompositionRecursiveFacette(n-1,s3,&s31,&s23);
    decompositionRecursiveFacette(n-1,&s31,&s12,&s23); }
    else {
    glVertex3f(s1->c[0],s1->c[1],s1->c[2]);
    glVertex3f(s2->c[0],s2->c[1],s2->c[2]);
    glVertex3f(s3->c[0],s3->c[1],s3->c[2]); }
}

static void affichageFacette(int n,
                             Position3D *s1,
                             Position3D *s2,
                             Position3D *s3) {
  glPushMatrix();
  Direction3D *nm = new Direction3D(s1,s2);
  Direction3D *d = new Direction3D(s1,s3);
  nm->produitVectoriel(d);
  nm->normalisation();
  glNormal3f(nm->c[0],nm->c[1],nm->c[2]);
  delete(d);
  delete(nm);
  glBegin(GL_TRIANGLES);
  decompositionRecursiveFacette(niveau,s1,s2,s3);
  glEnd();
  glPopMatrix();
}

//////////////////////////////////////////////////

static void scene(void) {
  glPushMatrix();
  Position3D *s1 = new Position3D(4.0,4.0,0.5);
  Position3D *s2 = new Position3D(-3.0,-2.0,0.0);
  Position3D *s3 = new Position3D(3.0,-4.0,-0.5);
  affichageFacette(niveau,s1,s2,s3);
  delete(s1);
  delete(s2);
  delete(s3);
  glPopMatrix();
}

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

static void display(void) {
  //glClearColor(0.5F,0.5F,0.5F,1.0F);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  const GLfloat light0_position[] = { 2.5,1.0,1.0,2.0 };
  const GLfloat light1_position[] = { 1.0,0.0,1.0,1.5 };
  const GLfloat light2_position[] = { 2.2,-2.0,1.0,1.0 };
  glLightfv(GL_LIGHT0,GL_POSITION,light0_position);
  glLightfv(GL_LIGHT1,GL_POSITION,light1_position);
  glLightfv(GL_LIGHT2,GL_POSITION,light2_position);
  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();
  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 x,int y) {
  glViewport(0,0,x,y); 
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(25.0F,(float) x/y,1.0,50.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  gluLookAt(0.0,0.0,20.0,0.0,0.0,0.0,0.0,1.0,0.0);
}

/* 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("Decomposition recursive"); 
  init();
  glutKeyboardFunc(keyboard);
  glutSpecialFunc(special);
  glutReshapeFunc(reshape);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}