/* Une sphere illuminee                         */
/*                                              */
/* Auteur: Nicolas JANEY                        */
/* nicolas.janey@univ-fcomte.fr                 */
/* Septembre 2010                               */

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

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

#include "CoordonneesHomogenes.h"
#include "Position3D.h"
#include "Direction3D.h"
#include "FacetteTriangulaire.h"
#include "LumierePonctuelle.h"
#include "Energie.h"
#include "Couleur.h"
#include "Rotation.h"

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

static int lum = 0;
static float rx = 0.0F;
static float ry = 0.0F;
static float rz = 0.0F;
static int n = 36;
static LumierePonctuelle *lp;
static Position3D *obs;

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

void init(void) {
  const GLfloat shininess[] = { 50.0 };
  glDepthFunc(GL_LESS);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_NORMALIZE);
  glEnable(GL_AUTO_NORMAL);
}

/* Scene dessinee                               */

void facette(Position3D *p1,Position3D *p2,Position3D *p3,
             Direction3D *n1,Direction3D *n2,Direction3D *n3) {
  Couleur *kd;
  Couleur *kr;
  switch ( lum ) {
    case 0 :
      kd = new Couleur(1.0,0.0,0.0);
      kr = new Couleur(0.0,0.8,0.8);
      break;
    case 1 :
      kd = new Couleur(1.0,0.0,0.0);
      kr = new Couleur(0.0,0.0,0.0);
      break;
    case 2 :
      kd = new Couleur(0.0,0.0,0.0);
      kr = new Couleur(0.0,0.8,0.8);
      break; }
  Energie *e1 = new Energie();
  Energie *e2 = new Energie();
  Energie *e3 = new Energie();
  { Energie *ed1 = new Energie();
    ed1->calculDiffusion(p1,n1,kd,lp);
    Energie *er1 = new Energie();
    er1->calculReflexionSpeculaire(p1,n1,kr,lp,obs);
    e1->r = ed1->r+er1->r;
    e1->v = ed1->v+er1->v;
    e1->b = ed1->b+er1->b;
    delete(ed1);
    delete(er1); }
  { Energie *ed2 = new Energie();
    ed2->calculDiffusion(p2,n2,kd,lp);
    Energie *er2 = new Energie();
    er2->calculReflexionSpeculaire(p2,n2,kr,lp,obs);
    e2->r = ed2->r+er2->r;
    e2->v = ed2->v+er2->v;
    e2->b = ed2->b+er2->b;
    delete(ed2);
    delete(er2); }
  { Energie *ed3 = new Energie();
    ed3->calculDiffusion(p3,n3,kd,lp);
    Energie *er3 = new Energie();
    er3->calculReflexionSpeculaire(p3,n3,kr,lp,obs);
    e3->r = ed3->r+er3->r;
    e3->v = ed3->v+er3->v;
    e3->b = ed3->b+er3->b;
    delete(ed3);
    delete(er3); }
  glBegin(GL_TRIANGLES);
  glColor3dv((double *) e1);
  glVertex3dv((double *) p1);
  glColor3dv((double *) e2);
  glVertex3dv((double *) p2);
  glColor3dv((double *) e3);
  glVertex3dv((double *) p3);
  glEnd();
  delete(e1);
  delete(e2);
  delete(e3);
  delete(kd);
  delete(kr);
}

#ifndef M_PI
#define M_PI 3.14159
#endif

void sphere(double r,float n,float m) {
  for ( int i = 0 ; i < n ; i++ ) {
    float a1 = -M_PI/2.0F + i*M_PI/n ;
    float a2 = a1 + M_PI/n ;
    float cs1 = cos(a1);
    float cs2 = cos(a2);
    float sn1 = sin(a1);
    float sn2 = sin(a2);
    for ( int j = 0 ; j < m ; j++ ) {
      float a = j*2*M_PI/m;
      float b = (j+1)*2*M_PI/m;
      double csa = cos(a);
      double sna = sin(a);
      double csb = cos(b);
      double snb = sin(b);
      float ax1 = cs1*csa;
      float ay1 = cs1*sna;
      float ax2 = cs2*csa;
      float ay2 = cs2*sna;
      float bx1 = cs1*csb;
      float by1 = cs1*snb;
      float bx2 = cs2*csb;
      float by2 = cs2*snb;
      { Position3D p1(r*bx2,r*by2,r*sn2);
        Position3D p2(r*ax2,r*ay2,r*sn2);
        Position3D p3(r*ax1,r*ay1,r*sn1);
        Direction3D n1(bx2,by2,sn2);
        Direction3D n2(ax2,ay2,sn2);
        Direction3D n3(ax1,ay1,sn1);
        facette(&p1,&p2,&p3,&n1,&n2,&n3); }
      { Position3D p1(r*bx1,r*by1,r*sn1);
        Position3D p2(r*bx2,r*by2,r*sn2);
        Position3D p3(r*ax1,r*ay1,r*sn1);
        Direction3D n1(bx1,by1,sn1);
        Direction3D n2(bx2,by2,sn2);
        Direction3D n3(ax1,ay1,sn1);
        facette(&p1,&p2,&p3,&n1,&n2,&n3); } } }
}

void scene() {
  Rotation *rtx = new Rotation(95.0*sin(rx),1.0,0.0,0.0);
  Rotation *rty = new Rotation(95.0*sin(ry),0.0,1.0,0.0);
  Rotation *rtz = new Rotation(rz,0.0,0.0,1.0);
  TransformationGeometrique *tg = new TransformationGeometrique();
  tg->produit(rtx,rty);
  tg->produit(tg,rtz);
  Position3D *pos = new Position3D(0.0,0.0,10.0);
  tg->transforme(pos);
  Couleur *jaunatre = new Couleur(1.0,1.0,1.0);
  lp = new LumierePonctuelle(pos,70.0,jaunatre);
  obs = new Position3D(0.0,0.0,20.0);
  delete(pos);
  delete(jaunatre);
  delete(tg);
  delete(rtx);
  delete(rty);
  delete(rtz);
  glPushMatrix();
  sphere(3.0,n,n);
  glPopMatrix();
  delete(obs);
  delete(lp);
}

/* 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);
  glPushMatrix();
  scene();
  glPopMatrix();
  glFlush();
  glutSwapBuffers();
  int error = glGetError();
  if ( error != GL_NO_ERROR )
    printf("Erreur OpenGL\n",error);
}

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

void idle(void) {
  rx += 0.00311F ;
  ry += 0.00634F ;
  rz += 0.17174F ;
  glutPostRedisplay() ;
}

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

void reshape(int x,int y) {
  glViewport(0,0,x,y); 
  glMatrixMode(GL_PROJECTION) ;
  glLoadIdentity() ;
  gluPerspective(25.0F,(float) x/y,15.0,35.0) ;
  glMatrixMode(GL_MODELVIEW) ;
  glLoadIdentity() ;
  gluLookAt(0.0,0.0,20.0,0.0,0.0,0.0,0.0,1.0,0.0);
}

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

void keyboard(unsigned char key,int x,int y) {
  switch (key) {
    case 43  :
      n++;
      glutPostRedisplay();
      break;
    case 45  :
      n--;
      if ( n == 2 )
        n = 3;
      glutPostRedisplay();
      break;
    case 'f' :
      { static int face = 1;
        face = !face;
        glPolygonMode(GL_FRONT_AND_BACK,( face ) ? GL_FILL : GL_LINE); }
      glutPostRedisplay();
      break;
    case 0x20 :
      lum = (lum+1)%3;
      glutPostRedisplay();
      break;
    case 0x0D :
      { static int anim = 1;
        anim = !anim;
        glutIdleFunc(( anim ) ? idle : NULL); }
      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 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 sphere illuminee"); 
  init();
  glutKeyboardFunc(keyboard);
  glutSpecialFunc(special);
  glutReshapeFunc(reshape);
  glutIdleFunc(idle);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}