CODEWITHSUNDEEP
cstb-image
Vitor Hugo
Vitor Hugo

Reputation: 1126

stbi_load() returning empty string ""

I have the following function using stbi_load:

void load_texture_from_file(const char *file, bool alpha, const char *name) {
    Texture *tex;
    tex = malloc(sizeof(Texture));
    tex->name = name;

    int width, height, channels;
    unsigned char *data = stbi_load(file, &width, &height, &channels, 0); 
    generate_texture(width, height, data, tex, alpha); 
    
    stbi_image_free(data);
}

File is coming from:

load_texture_from_file("/home/correct_folder/correct_name.png", true, "sprite");

I get no error using stbi_failure_reason() and when checking the contents of data with gdb I see:

Thread 1 "a" hit Breakpoint 2, load_texture_from_file (file=0x555555579d18 "/home/correct_folder/correct_name.png", 
    alpha=true, name=0x555555579d12 "face") at resource_manager.c:25
25          generate_texture(width, height, data, tex, alpha); 
(gdb) print data
$1 = (unsigned char *) 0x7ffff40c1010 ""

What am I missing?

Upvotes: 0

Views: 963

Answers (1)

yano
yano

Reputation: 5265

To expand on @HolyBlackCat's comment, you may not be doing anything wrong at all in terms of loading the data. You should try examining memory with gdb instead of printing it, which is treating data as as string. You can do so in gdb with the following command:

x/nfu <address>

where

  • x/ is the "examine memory" command
  • n is the number of memory units/elements you want to examine
  • f is the display format ('x' for hex, 'd' for decimal, etc. See link below)
  • u is the unit/element format ('b' for bytes, 'w' for words, etc. See link below)
  • address is the address where you want to begin examining memory

For example, to look at the first 5 bytes of data in hex format, you would enter

x/5xb data

To look at the first ten 4-byte words in hex format, you would enter

x/10xw data

See this page for more information and an exhaustive list of all parameter options.

Upvotes: 1

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