SDL2 is just not working (bmp not displaying).

SDL Development
1

I’m on ArchLinux (with X11, if that matters), just started learning SDL2. Everything compiles and no errors after running. It’s just that the bmp is not displayed. I literally have no idea why this is not working. This code is derived from Lazy Foo’s SDL2 tutorial. This is my code (c++):

#include <SDL2/SDL.h>
#include <iostream>

#define SCREEN_WIDTH  640
#define SCREEN_HEIGHT 480

SDL_Window *window;
SDL_Surface *surface;

SDL_Surface *bmp;

void init()
{
    if (SDL_Init(SDL_INIT_VIDEO) < 0) {
        std::cerr << "SDL could not start! SDL error: " << SDL_GetError() << "\n";
        exit(EXIT_FAILURE);
    }
    window = SDL_CreateWindow( "SDL Tutorial", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN );
    if (window == NULL) {
        std::cerr << "Window could not be created! SDL_Error: " << SDL_GetError() << "\n";
        exit(EXIT_FAILURE);
    }
    surface = SDL_GetWindowSurface(window);
}
void loadMedia()
{
    bmp = SDL_LoadBMP("helloworld.bmp");
    if (bmp == NULL) {
        std::cerr << "Unable to load image! SDL_Error: " << SDL_GetError() << "\n"; 
        exit(EXIT_FAILURE);
    }
}
void end()
{
    SDL_FreeSurface(bmp);
    bmp = NULL;
    SDL_DestroyWindow(window);
    window = NULL;
    SDL_Quit();
}

int main(void)
{
    init();
    loadMedia();
    SDL_BlitSurface(bmp, NULL, surface, NULL);
    SDL_UpdateWindowSurface(window);
    SDL_Delay(5000);
    end();
    return 0;
}
2

You need to handle events in order for the window to display properly.

3

Yes, it’s an oddity at the OS level–I would guess it’s intended to make sure that anything with a window can respond to kill signals, the little x in the upper right corner of the window, etc. But in any case, there’s no workaround. This means you’ll need to call SDL_PollEvent() in a loop. You can find lots of tutorials for this online. I don’t know if you technically need to do anything with the events you receive for it to display an image, but there’s generally no reason not to, for a windowed application. If nothing else, you should check for SDL_QuitEvent (user clicks the x) and halt execution.

Also note that while lazyfoo is a great tutorial, it is pretty out of date, so there are a few things like this that aren’t accurate anymore.

4

Ok thanks it works now got it working.