Issue loading BMP image using SDL_image

Question

I am new to SDL_image and I am trying to use it in a C file to load a BMP image. To that end, I have written the following code:

#include "SDL/SDL.h"
#include "SDL_image.h"

SDL_RWops *rwop;
rwop = SDL_RWFromFile("sample.bmp", "rb");

However, for some reason, although rwop after those lines are executed is not NULL anymore, IMG_isBMP(rwop) is 0.

Any idea what could be wrong?

Answer 1

Perhaps better example. This (might) yield more information and perhaps if BMP is supported:

https://www.libsdl.org/projects/SDL_image/docs/SDL_image_32.html

You could also try using IMG_LoadBMP_RW as per example here:

https://www.libsdl.org/projects/SDL_image/docs/SDL_image_16.html#SEC16

#include <stdio.h>

#include "SDL/SDL.h"
#include "SDL/SDL_image.h"

int main(int argc, char *argv[])
{
    const char *fn = "sample.bmp";
    SDL_Surface *surf;

    if (argc > 1)
        fn = argv[1];

    if ((surf = SDL_LoadBMP(fn)) == NULL) {
        printf("SDL_loadBMP failed: %s\n", SDL_GetError());
        SDL_Quit();
        return 1;
    }

    printf("%s is bmp\n", fn);

    SDL_FreeSurface(surf);
    SDL_Quit();

    return 0;
}

---

Old answer:

---

Tested and validated:

#include <stdio.h>

#include "SDL/SDL.h"
#include "SDL/SDL_image.h"

int main(int argc, char *argv[])
{
    const char *fn = "sample.bmp";
    int v;
    SDL_RWops *rwop;

    if (argc > 1)
        fn = argv[1];

    if ((rwop = SDL_RWFromFile(fn, "rb")) == NULL) {
        printf("SDL_RWFromFile failed: %s\n", SDL_GetError());
        SDL_Quit();
        return 1;
    }

    v = IMG_isBMP(rwop);

    printf("%s is bmp = %d\n", fn, v);

    SDL_FreeRW(rwop);
    SDL_Quit();

    return 0;
}

Compiled with:

gcc -Wall -Wextra -pedantic -o sdl sdl.c `sdl-config --libs` -lSDL_image

Yield for BMP images, e.g.:

$ ./sdltest lena.bmp 
lena.bmp is bmp = 1