extern int num_texture;
extern int LoadBitmap(char *filename);

int LoadBitmap(char *filename) 
{

   unsigned char *l_texture;
   int i, j=0;
   FILE *l_file;
   BITMAPFILEHEADER fileheader; 
   BITMAPINFOHEADER infoheader;
   RGBTRIPLE rgb;
   num_texture++;
   if( (l_file = fopen(filename, "rb"))==NULL) return (-1);
   fread(&fileheader, sizeof(fileheader), 1, l_file);
   fseek(l_file, sizeof(fileheader), SEEK_SET);
   fread(&infoheader, sizeof(infoheader), 1, l_file);
   l_texture = (byte *) malloc(infoheader.biWidth * infoheader.biHeight * 4);
   memset(l_texture, 0, infoheader.biWidth * infoheader.biHeight * 4);
   for (i=0; i < infoheader.biWidth*infoheader.biHeight; i++)
   { 
      fread(&rgb, sizeof(rgb), 1, file); 

      l_texture[j+0] = rgb.rgbtRed; // Red component
      l_texture[j+1] = rgb.rgbtRed; // Green component
      l_texture[j+2] = rgb.rgbtBlue; // Blue component
      l_texture[j+3] = 255; // Alpha value
      j += 4; // Go to the next position
   }
   fclose(l_file); // Closes the file stream
   glBindTexture(GL_TEXTURE_2D, num_texture);
   
   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_LINEAR);
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
   glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);

   glTexImage2D(GL_TEXTURE_2D, 0, 4, infoheader.biWidth, infoheader.biHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, l_texture);
   gluBuild2DMipmaps(GL_TEXTURE_2D, 4, infoheader.biWidth, infoheader.biHeight, GL_RGBA, GL_UNSIGNED_BYTE, l_texture);
   free(l_texture);
   return (num_texture);
}