/* Texturage d'une facette carree               */
/*                                              */
/* Auteur: Nicolas JANEY                        */
/* nicolas.janey@univ-fcomte.fr                 */
/* Novembre 2012                                */

#include <stdlib.h>
#include <stdio.h>
#include <io.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 float rx = 0.0F;
static float ry = 0.0F;
static float rz = 0.0F;
static const float gris[] = { 0.7F,0.7F,0.7F,1.0F };
static const float jaune[] = { 1.0F,1.0F,0.0F,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 int enCouleur = 0;
static int face = 1;
static int lum = 1;
static int tex = 1;

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

static const float noir[] = { 0.0F,0.0F,0.0F,1.0F };
static const float blanc[] = { 1.0F,1.0F,1.0F,1.0F };

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

static int fileSize(char *filename) {
  struct _finddata_t c_file;
  intptr_t hFile;
  if( (hFile = _findfirst(filename,&c_file)) == -1L )
    return(-1);
  int size = c_file.size;
  _findclose(hFile);
  return(size);
}

static unsigned char *loadRawImage(char *filename) {
  int size = fileSize(filename);
  if ( size == -1 )
    return(NULL);
  unsigned char *img =(unsigned char *) malloc(size);
  if ( !img )
    return(NULL);
  FILE *f = fopen(filename,"rb");
  if ( !f ) {
    free(img);
    return(NULL); }
  fread(img,1,size,f);
  fclose(f);
  return(img);
} 

static void init(void) {
  const GLfloat shininess[] = { 50.0 };
  glMaterialfv(GL_FRONT_AND_BACK,GL_AMBIENT,noir);
  glMaterialfv(GL_FRONT_AND_BACK,GL_DIFFUSE,blanc);
  glMaterialfv(GL_FRONT_AND_BACK,GL_SPECULAR,noir);
  glMaterialfv(GL_FRONT_AND_BACK,GL_SHININESS,shininess);
  glLightModeli(GL_LIGHT_MODEL_TWO_SIDE,1);
  glEnable(GL_LIGHT0);
  glEnable(GL_LIGHT1);
  glEnable(GL_LIGHT2);
  glDepthFunc(GL_LESS);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_NORMALIZE);
  glEnable(GL_AUTO_NORMAL);
  glPixelStorei(GL_UNPACK_ALIGNMENT,1); 
  { unsigned char *img = loadRawImage("Image.raw");
    glTexImage2D(GL_TEXTURE_2D,0,3,64,64,0,GL_RGB,GL_UNSIGNED_BYTE,img);
    free(img); }
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT); 
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST); 
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST); 
}

/* Scene affichee                               */

static void scene() {
  glPushMatrix();
  glBegin(GL_QUADS);
  glTexCoord2f(0.0F,0.0F);
  glVertex2f(2.0F,2.0F);
  glTexCoord2f(1.0F,0.0F);
  glVertex2f(-2.0F,2.0F);
  glTexCoord2f(1.0F,1.0F);
  glVertex2f(-2.0F,-2.0F);
  glTexCoord2f(0.0F,1.0F);
  glVertex2f(2.0F,-2.0F);
  glEnd();
  glPopMatrix();
}

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

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

static void display(void) {
  glClearColor(0.75F,0.75F,0.75F,1.0F);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glPushMatrix();
  const GLfloat light0_dir[] = {  0.7, 0.3, 0.7, 0.0 };
  const GLfloat light1_dir[] = { -0.7, 0.0, 0.7, 0.0 };
  const GLfloat light2_dir[] = {  0.7,-0.3, 0.7, 0.0 };
  glLightfv(GL_LIGHT0,GL_POSITION,light0_dir);
  glLightfv(GL_LIGHT1,GL_POSITION,light1_dir);
  glLightfv(GL_LIGHT2,GL_POSITION,light2_dir);
  if ( enCouleur ) {
    glLightfv(GL_LIGHT0,GL_DIFFUSE,rouge);
    glLightfv(GL_LIGHT1,GL_DIFFUSE,vert);
    glLightfv(GL_LIGHT2,GL_DIFFUSE,bleu); }
    else {
    glLightfv(GL_LIGHT0,GL_DIFFUSE,gris);
    glLightfv(GL_LIGHT1,GL_DIFFUSE,gris);
    glLightfv(GL_LIGHT2,GL_DIFFUSE,gris); }
  glPolygonMode(GL_FRONT_AND_BACK,( face ) ? GL_FILL : GL_LINE);
  if ( lum )
    glEnable(GL_LIGHTING);
    else
    glDisable(GL_LIGHTING);
  if ( tex )
    glEnable(GL_TEXTURE_2D);
    else
    glDisable(GL_TEXTURE_2D);
  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 lorsqu'aucun evenement     */
/* n'est en file d'attente                      */

static void idle(void) {
  rx += 0.14256F ;
  ry += 0.18117F ;
  rz += 0.23174F ;
  glutPostRedisplay() ;
}

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

static void reshape(int x,int y) {
  glViewport(0,0,x,y); 
  glMatrixMode(GL_PROJECTION) ;
  glLoadIdentity() ;
  gluPerspective(70.0F,(float) x/y,1.0,40.0) ;
  glMatrixMode(GL_MODELVIEW) ;
  glLoadIdentity() ;
  gluLookAt(0.0,0.0,5.0,0.0,0.0,0.0,0.0,1.0,0.0);
}

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

static void keyboard(unsigned char key,int x,int y) {
  switch (key) {
    case ' ' :
      tex = !tex;
      glutPostRedisplay();
      break;
    case 'c' :
      enCouleur = !enCouleur;
      glutPostRedisplay();
      break;
    case 'l' :
      lum = !lum;
      glutPostRedisplay();
      break;
    case 'f' :
      face = !face;
      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                         */

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 principale                          */

int main(int argc,char **argv) {
  glutInit(&argc,argv);
  glutInitDisplayMode(GLUT_RGBA|GLUT_DEPTH|GLUT_DOUBLE);
  glutInitWindowSize(300,300); 
  glutInitWindowPosition(50,50); 
  glutCreateWindow("Texturage d'une facette carrée"); 
  init();
  glutKeyboardFunc(keyboard);
  glutSpecialFunc(special);
  glutReshapeFunc(reshape);
  glutIdleFunc(idle);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}