progs/samples/loadppm.c

   1
   2 typedef struct {
   3     size_t sizeX, sizeY;
   4     GLubyte *data;
   5 } PPMImage;
   6
   7 static PPMImage *LoadPPM(const char *filename)
   8 {
   9     char buff[16];
  10     PPMImage *result;
  11     FILE *fp;
  12     int maxval, w, h;
  13
  14     fp = fopen(filename, "rb");
  15     if (!fp)
  16     {
  17         fprintf(stderr, "Unable to open file `%s'\n", filename);
  18         exit(1);
  19     }
  20
  21     if (!fgets(buff, sizeof(buff), fp))
  22     {
  23         perror(filename);
  24         exit(1);
  25     }
  26
  27     if (buff[0] != 'P' || buff[1] != '6')
  28     {
  29         fprintf(stderr, "Invalid image format (must be `P6')\n");
  30         exit(1);
  31     }
  32
  33     result = (PPMImage *) malloc(sizeof(PPMImage));
  34     if (!result)
  35     {
  36         fprintf(stderr, "Unable to allocate memory\n");
  37         exit(1);
  38     }
  39
  40     if (fscanf(fp, "%d %d", &w, &h) != 2)
  41     {
  42         fprintf(stderr, "Error loading image `%s'\n", filename);
  43         exit(1);
  44     }
  45     result->sizeX = w;
  46     result->sizeY = h;
  47
  48     if (fscanf(fp, "%d", &maxval) != 1)
  49     {
  50         fprintf(stderr, "Error loading image `%s'\n", filename);
  51         exit(1);
  52     }
  53
  54     while (fgetc(fp) != '\n')
  55         ;
  56
  57     result->data = (GLubyte *) malloc(3 * result->sizeX * result->sizeY);
  58     if (!result)
  59     {
  60         fprintf(stderr, "Unable to allocate memory\n");
  61         exit(1);
  62     }
  63
  64     if (fread(result->data, 3 * result->sizeX, result->sizeY, fp) != result->sizeY)
  65     {
  66         fprintf(stderr, "Error loading image `%s'\n", filename);
  67         exit(1);
  68     }
  69
  70     fclose(fp);
  71
  72     return result;
  73 }
  74