/* Examen de TD n°1 2011-2012                   */
/*                                              */
/* Auteur: Nicolas JANEY                        */
/* nicolas.janey@univ-fcomte.fr                 */
/* Novembre 2011                                */

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

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

/* Variables et constantes globales             */

#ifndef M_PI
#define M_PI 3.14159
#endif

static int aff = 1;

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

void init(void) {
  glDepthFunc(GL_LESS);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_NORMALIZE);
  glEnable(GL_AUTO_NORMAL);
  glEnable(GL_CULL_FACE);
}

/* Scene dessinee                               */

static void materiel(void) {
  GLfloat diff[4] = { 0.6F,0.6F,0.6F,1.0F };
  glMaterialfv(GL_FRONT,GL_DIFFUSE,diff);
  GLfloat spec[4] = { 0.4F,0.4F,0.4F,1.0F };
  glMaterialfv(GL_FRONT,GL_SPECULAR,spec);
  glMaterialf(GL_FRONT,GL_SHININESS,40.0F);
  GLfloat ambi[4] = { 0.0F,0.0F,0.0F,1.0F };
  glMaterialfv(GL_FRONT,GL_AMBIENT,ambi);
}

static void lumieres(void) {
  glEnable(GL_LIGHTING);
  { glEnable(GL_LIGHT0);
    const GLfloat light0_position[] = { -4.0,-2.0,-3.0,1.0 };
    glLightfv(GL_LIGHT0,GL_POSITION,light0_position);
    const GLfloat blanc[] = { 1.0F,1.0F,1.0F,1.0F };
    glLightfv(GL_LIGHT0,GL_DIFFUSE,blanc);
    glLightfv(GL_LIGHT0,GL_SPECULAR,blanc);
    const GLfloat noir[] = { 0.0F,0.0F,0.0F,1.0F };
    glLightfv(GL_LIGHT0,GL_AMBIENT,noir); }
  { glEnable(GL_LIGHT1);
    const GLfloat light1_position[] = { 1.5,-1.0,-1.0,0.0 };
    glLightfv(GL_LIGHT1,GL_POSITION,light1_position);
    const GLfloat jaune[] = { 1.0F,1.0F,0.0F,1.0F };
    glLightfv(GL_LIGHT1,GL_DIFFUSE,jaune);
    glLightfv(GL_LIGHT1,GL_SPECULAR,jaune);
    const GLfloat noir[] = { 0.0F,0.0F,0.0F,1.0F };
    glLightfv(GL_LIGHT1,GL_AMBIENT,noir); }
}

static void spheres(void) {
  const float p[4][3] =
    { { 0.0F, 0.0F, 0.0F },
      { 4.0F, 0.0F, 0.0F },
      { 0.0F, 4.0F, 0.0F },
      { 0.0F, 0.0F, 4.0F } };
  glPushMatrix();
  for ( int i = 0 ; i < 4 ; i++ ) {
    glPushMatrix();
    glTranslatef(p[i][0],p[i][1],p[i][2]);
    glutSolidSphere(1.0,36,36);
    glPopMatrix(); }   
  glPopMatrix();
}

static void tetraedre(void) {
  const float p[4][4] =
    { { 0.0F, 0.0F, 0.0F, 1.0F },
      { 4.0F, 0.0F, 0.0F, 1.0F },
      { 0.0F, 4.0F, 0.0F, 1.0F },
      { 0.0F, 0.0F, 4.0F, 1.0F } };
  glPushMatrix();
  glBegin(GL_TRIANGLES);
  glNormal3f(0.0F,0.0F,-1.0F);
  glVertex3fv(p[2]);
  glVertex3fv(p[1]);
  glVertex3fv(p[0]);
  glNormal3f(0.0F,-1.0F,0.0F);
  glVertex3fv(p[3]);
  glVertex3fv(p[0]);
  glVertex3fv(p[1]);
  glNormal3f(-1.0F,0.0F,0.0F);
  glVertex3fv(p[3]);
  glVertex3fv(p[2]);
  glVertex3fv(p[0]);
  float n =(float) (sqrt(3.0)/3.0);
  glNormal3f(n,n,n);
  glVertex3fv(p[1]);
  glVertex3fv(p[2]);
  glVertex3fv(p[3]);
  glEnd();
  glPopMatrix();
}

void scene() {
  glPushMatrix();
  materiel();
  lumieres();
  spheres();
  tetraedre();
  glPopMatrix();
}

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

void display(void) {
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glPolygonMode(GL_FRONT_AND_BACK,(aff) ? GL_FILL : GL_LINE);
  glPushMatrix();
  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  */

void reshape(int x,int y) {
  glViewport(0,0,x,y); 
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(2*asin(5.0/30.0)*180.0/M_PI,(float) x/y,25.0,35.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  gluLookAt(-19.0,-19.0,-9.0,1.0,1.0,1.0,0.0,1.0,0.0);
}

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

void keyboard(unsigned char key,int x,int y) {
  switch ( key ) {
    case 0x20 :
      aff = (aff+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(300,300); 
  glutInitWindowPosition(50,50); 
  glutCreateWindow("Colle TD"); 
  init();
  glutKeyboardFunc(keyboard);
  glutReshapeFunc(reshape);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}