Eclairage et matériaux Par Xavier Michelon

Code source

#include <stdio.h>
#include <stdlib.h>
#include <GL/glut.h>
#include <jpeglib.h>
#include <jerror.h>

unsigned char image[256*256*3];
unsigned char texture[256][256][3];
char presse;
int anglex=30,angley=20,x,y,xold,yold;

void affichage();
void clavier(unsigned char touche,int x,int y);
void souris(int boutton, int etat,int x,int y);
void sourismouv(int x,int y);
void redim(int l,int h);
void loadJpegImage(char *fichier);

int main(int argc,char **argv)

{
  /* Chargement de la texture */
  loadJpegImage("texture.jpg");

  /* Creation de la fenetre OpenGL */
  glutInit(&argc,argv);
  glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
  glutInitWindowSize(200,200);
  glutCreateWindow("Texture JPEG");

  /* Initialisation de l'etat d'OpenGL */
  glClearColor(0.0,0.0,0.0,0.0);
  glShadeModel(GL_FLAT);
  glEnable(GL_DEPTH_TEST);

  /* Mise en place de la projection perspective */
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(45.0,1,1.0,5.0);
  glMatrixMode(GL_MODELVIEW);

  /* Parametrage du placage de textures */
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);
  glTexImage2D(GL_TEXTURE_2D,0,GL_RGB,256,256,0,
	       GL_RGB,GL_UNSIGNED_BYTE,texture);
  glEnable(GL_TEXTURE_2D);

  /* Mise en place des fonctions de rappel */
  glutDisplayFunc(affichage);
  glutKeyboardFunc(clavier);
  glutMouseFunc(souris);
  glutMotionFunc(sourismouv);
  glutReshapeFunc(redim);

  /* Entrée dans la boucle principale glut */
  glutMainLoop();
  return 0;
}



void affichage()
{
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  glLoadIdentity();

  gluLookAt(0.0,0.0,2.5,0.0,0.0,0.0,0.0,1.0,0.0);
  glRotatef(angley,1.0,0.0,0.0);
  glRotatef(anglex,0.0,1.0,0.0);

  glBegin(GL_POLYGON);
  glTexCoord2f(0.0,0.0);   glVertex3f(-0.5, 0.5, 0.5);
  glTexCoord2f(0.0,1.0);   glVertex3f(-0.5,-0.5, 0.5);
  glTexCoord2f(1.0,1.0);   glVertex3f( 0.5,-0.5, 0.5);
  glTexCoord2f(1.0,0.0);   glVertex3f( 0.5, 0.5, 0.5);
  glEnd();

  glBegin(GL_POLYGON);  
  glTexCoord2f(0.0,0.0);   glVertex3f( 0.5, 0.5, 0.5);
  glTexCoord2f(0.0,1.0);   glVertex3f( 0.5,-0.5, 0.5);
  glTexCoord2f(1.0,1.0);   glVertex3f( 0.5,-0.5,-0.5);
  glTexCoord2f(1.0,0.0);   glVertex3f( 0.5, 0.5,-0.5);
  glEnd();

  glBegin(GL_POLYGON);
  glTexCoord2f(0.0,0.0);   glVertex3f( 0.5, 0.5,-0.5);
  glTexCoord2f(0.0,1.0);   glVertex3f( 0.5,-0.5,-0.5);
  glTexCoord2f(1.0,1.0);   glVertex3f(-0.5,-0.5,-0.5);
  glTexCoord2f(1.0,0.0);   glVertex3f(-0.5, 0.5,-0.5);
  glEnd();

  glBegin(GL_POLYGON);
  glTexCoord2f(0.0,0.0);   glVertex3f(-0.5, 0.5,-0.5);
  glTexCoord2f(0.0,1.0);   glVertex3f(-0.5,-0.5,-0.5);
  glTexCoord2f(1.0,1.0);   glVertex3f(-0.5,-0.5, 0.5);
  glTexCoord2f(1.0,0.0);   glVertex3f(-0.5, 0.5, 0.5);
  glEnd();

  glBegin(GL_POLYGON);
  glTexCoord2f(0.0,0.0);   glVertex3f(-0.5, 0.5,-0.5);
  glTexCoord2f(0.0,1.0);   glVertex3f(-0.5, 0.5, 0.5);
  glTexCoord2f(1.0,1.0);   glVertex3f( 0.5, 0.5, 0.5);
  glTexCoord2f(1.0,0.0);   glVertex3f( 0.5, 0.5,-0.5);
  glEnd();
  glBegin(GL_POLYGON);
  glTexCoord2f(0.0,0.0);   glVertex3f(-0.5,-0.5,-0.5);
  glTexCoord2f(0.0,1.0);   glVertex3f(-0.5,-0.5, 0.5);
  glTexCoord2f(1.0,1.0);   glVertex3f( 0.5,-0.5, 0.5);
  glTexCoord2f(1.0,0.0);   glVertex3f( 0.5,-0.5,-0.5);
  glEnd();

  glutSwapBuffers();

}



void clavier(unsigned char touche,int x,int y)
{
  switch(touche) {
  case 'l':
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glutPostRedisplay();
    break;
  case 'n':
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);
    glutPostRedisplay();
  break;
  
  case 27: /* touche ESC */
    exit(0);
  default:
  }
}

void souris(int bouton, int etat,int x,int y)
{
  if (bouton == GLUT_LEFT_BUTTON && etat == GLUT_DOWN) 
  {
    presse = 1;
    xold = x; 
    yold=y;
  }
  if (bouton == GLUT_LEFT_BUTTON && etat == GLUT_UP) 
    presse=0; 
}



void sourismouv(int x,int y)
{
  if (presse)
  {
    anglex=anglex+(x-xold); 
    angley=angley+(y-yold);
    glutPostRedisplay();
  }
    
  xold=x; 
  yold=y;
}


void redim(int l,int h)
{
  if (l<h)
    glViewport(0,(h-l)/2,l,l);
  else 
    glViewport((l-h)/2,0,h,h);
}



void loadJpegImage(char *fichier)
{
  struct jpeg_decompress_struct cinfo;
  struct jpeg_error_mgr jerr;
  FILE *file;	
  unsigned char *ligne;
  int i,j;

  cinfo.err = jpeg_std_error(&jerr);
  jpeg_create_decompress(&cinfo);
  if ((file=fopen(fichier,"rb"))==NULL)
    {
      fprintf(stderr,"Erreur : impossible d'ouvrir le fichier texture.jpg\n");
      exit(1);
    }
  jpeg_stdio_src(&cinfo, file);
  jpeg_read_header(&cinfo, TRUE);

  if ((cinfo.image_width!=256)||(cinfo.image_height!=256)) {
    fprintf(stdout,"Erreur : l'image doit etre de taille 256x256\n");
    exit(1);
  }
  if (cinfo.jpeg_color_space==JCS_GRAYSCALE) {
    fprintf(stdout,"Erreur : l'image doit etre de type RGB\n");
    exit(1);
  }

  jpeg_start_decompress(&cinfo);
  ligne=image;
  while (cinfo.output_scanline<cinfo.output_height)
    {
      ligne=image+3*256*cinfo.output_scanline;
      jpeg_read_scanlines(&cinfo,&ligne,1);
    }
  jpeg_finish_decompress(&cinfo);
  jpeg_destroy_decompress(&cinfo);
  
  for (i=0;i<256;i++)
    for (j=0;j<256;j++) {
      texture[i][j][0]=image[i*256*3+j*3];
      texture[i][j][1]=image[i*256*3+j*3+1];
      texture[i][j][2]=image[i*256*3+j*3+2];
    }
}