/* Gestion de materiels et de lumieres          */
/* en OpenGL                                    */
/*                                              */
/* Auteur: Nicolas JANEY                        */
/* nicolas.janey@univ-fcomte.fr                 */
/* Octobre 2009                                 */

#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 int lumiere = 0;
static int camera = 0;
static int wx;
static int wy;
static float rx = 0.0F;
static float ry = 0.0F;
static float rz = 0.0F;

/* Scene dessinee                               */

void cylindre(double h,double r,int n,int m) {
  glPushMatrix();
  glRotatef(90.0F,1.0F,0.0F,0.0F);
  glTranslatef(0.0F,0.0F,-h/2);
  GLUquadricObj *qobj = gluNewQuadric();
  gluQuadricDrawStyle(qobj,GLU_FILL);
  gluCylinder(qobj,r,r,h,n,m);
  gluDeleteQuadric(qobj);  
  glPopMatrix();
}

void scene() {
  GLfloat blanc[4] = { 1.0F,1.0F,1.0F,1.0F };
  GLfloat noir[4] = { 0.0F,0.0F,0.0F,1.0F };
  GLfloat rouge[4] = { 1.0F,0.0F,0.0F,1.0F };
  GLfloat vert[4] = { 0.0F,1.0F,0.0F,1.0F };
  GLfloat bleu[4] = { 0.0F,0.0F,1.0F,1.0F };
  GLfloat jaune[4] = { 1.0F,1.0F,0.0F,1.0F };
  glPushMatrix();
  glMaterialfv(GL_FRONT,GL_AMBIENT,noir);
  glMaterialfv(GL_FRONT,GL_SPECULAR,blanc);
  glMaterialf(GL_FRONT,GL_SHININESS,50.0F);
  glPushMatrix();
  glTranslatef(2.0F,2.0F,0.0F);
  glMaterialfv(GL_FRONT,GL_DIFFUSE,rouge);
  glutSolidCube(2.0); 
  glPopMatrix();
  glPushMatrix();
  glTranslatef(2.0F,-2.0F,0.0F);
  glMaterialfv(GL_FRONT,GL_DIFFUSE,vert);
  glutSolidSphere(1.0,72,72); 
  glPopMatrix();
  glPushMatrix();
  glTranslatef(-2.0F,2.0F,0.0F);
  glMaterialfv(GL_FRONT,GL_DIFFUSE,bleu);
  glRotatef(90.0F,-1.0F,0.0F,0.0F);
  glTranslatef(0.0F,0.0F,-1.0F);
  glutSolidCone(1.0,2.0,72,72); 
  glPopMatrix();
  glPushMatrix();
  glMaterialfv(GL_FRONT,GL_DIFFUSE,jaune);
  glTranslatef(-2.0F,-2.0F,0.0F);
  cylindre(2.0,1.0,72,72); 
  glPopMatrix();
  glPopMatrix();
}

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

void display(void) {
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  double cx;
  double cy;
  double cz;
  switch (camera) {
    case 0 :
      cx = 0.0;
      cy = 0.0;
      cz = 10.0;
      break;
    case 1 :
      cx = 10.0;
      cy = 0.0;
      cz = 10.0;
      break;
    case 2 :
      cx = 10.0;
      cy = 10.0;
      cz = 10.0;
      break; }
  double d = sqrt(cx*cx+cy*cy+cz*cz);
  gluPerspective(520.0/d,(float) wx/wy,d-5.0,d+5.0F);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  gluLookAt(cx,cy,cz,0.0,0.0,0.0,0.0,1.0,0.0);
  glRotatef(rx,1.0F,0.0F,0.0F);
  glRotatef(ry,0.0F,1.0F,0.0F);
  glRotatef(rz,0.0F,0.0F,1.0F);
  switch ( lumiere ) {
    case 0 :
      { glEnable(GL_LIGHT0);
        glDisable(GL_LIGHT1);
        glDisable(GL_LIGHT2);
        const GLfloat light0_position[] = { 0.0,0.0,0.0,1.0 };
        glLightfv(GL_LIGHT0,GL_POSITION,light0_position); }
      break;
    case 1 :
      { glDisable(GL_LIGHT0);
        glEnable(GL_LIGHT1);
        glDisable(GL_LIGHT2);
        const GLfloat light1_position[] = { 1.0,0.0,0.0,0.0 };
        glLightfv(GL_LIGHT1,GL_POSITION,light1_position); }
      break;
    case 2 :
      { glDisable(GL_LIGHT0);
        glDisable(GL_LIGHT1);
        glEnable(GL_LIGHT2);
        const GLfloat light2_position[] = { -12.0,0.0,10.0,1.0 };
        const GLfloat light2_direction[] = { 1.0,0.0,-1.0,0.0 };
        glLightfv(GL_LIGHT2,GL_POSITION,light2_position);
        glLightfv(GL_LIGHT2,GL_SPOT_DIRECTION,light2_direction); }
      break;
    case 3 :
      { glEnable(GL_LIGHT0);
        glEnable(GL_LIGHT1);
        glEnable(GL_LIGHT2);
        const GLfloat light0_position[] = { 0.0,0.0,0.0,1.0 };
        glLightfv(GL_LIGHT0,GL_POSITION,light0_position);
        const GLfloat light1_position[] = { 1.0,0.0,0.0,0.0 };
        glLightfv(GL_LIGHT1,GL_POSITION,light1_position);
        const GLfloat light2_position[] = { -12.0,0.0,10.0,1.0 };
        const GLfloat light2_direction[] = { 1.0,0.0,-1.0,0.0 };
        glLightfv(GL_LIGHT2,GL_POSITION,light2_position);
        glLightfv(GL_LIGHT2,GL_SPOT_DIRECTION,light2_direction); }
      break; }
  scene();
  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 += 0.4256F;
  ry += 0.6117F;
  rz += 0.4174F;
  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);
  wx = x;
  wy = y;
}

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

void keyboard(unsigned char key,int x,int y) {
  switch (key) {
    case 'c' :
      camera = (camera+1)%3;
      glutPostRedisplay();
      break;
    case 'l' :
      lumiere = (lumiere+1)%4;
      glutPostRedisplay();
      break;
    case 0x0D :
      { static int anim = 0;
        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 d'initialisation des parametres     */
/* constants d'OpenGL                           */

static void init(void) {
  GLfloat blanc[4] = { 1.0F,1.0F,1.0F,1.0F };
  GLfloat cyan[4] = { 0.0F,1.0F,1.0F,1.0F };
  GLfloat jaune[4] = { 1.0F,1.0F,0.0F,1.0F };
  glEnable(GL_LIGHTING);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_NORMALIZE);
  glLightfv(GL_LIGHT0,GL_DIFFUSE,blanc);
  glLightfv(GL_LIGHT0,GL_SPECULAR,blanc);
  glLightfv(GL_LIGHT1,GL_DIFFUSE,cyan);
  glLightfv(GL_LIGHT1,GL_SPECULAR,cyan);
  glLightf(GL_LIGHT2,GL_SPOT_CUTOFF,8.59F);
  glLightfv(GL_LIGHT2,GL_DIFFUSE,jaune);
  glLightfv(GL_LIGHT2,GL_SPECULAR,jaune);
}

/* 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("Materiels et lumieres OpenGL");
  init();
  glutKeyboardFunc(keyboard);
  glutSpecialFunc(special);
  glutReshapeFunc(reshape);
  //glutIdleFunc(idle);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}