SDL: Blit to a non-visible surface

[fatlardo]

I am trying to write a method which returns an SDL_Surface*. The code I am using is:

SDL_Surface* SDLMenu::getSurface() {
	//Create and unlock surface
	SDL_Surface* output = SDL_CreateRGBSurface(SDL_SWSURFACE, 100, 25, 32, 0, 0, 0, 0);
	SDL_UnlockSurface(output);

	SDL_FillRect(output, 0, SDL_MapRGB(output->format, 255, 0, 255));

	SDL_LockSurface(output);

	return output;
}

The problem I have is when I call this function, the output shown is a black screen. Can anyone tell me where I'm going wrong?

	SDLApplication app;

	SDLMenu menu = SDLMenu();
	SDL_BlitSurface(menu.getSurface(), NULL, app.getScreen(), NULL);

	SDL_Flip(app.getScreen());

	SDL_Delay(10000);

	return 0;

Thanks,
Gary

[IllegalCharacter]

Since your masks are all zero, it filters out any colours you're trying to put. Hence why you have black

Try putting this in:

    Uint32 rmask, gmask, bmask, amask;
    rmask = 0x000000ff;
    gmask = 0x0000ff00;
    bmask = 0x00ff0000;
    amask = 0xff000000;
    
    SDL_Surface * output = SDL_CreateRGBSurface(SDL_SWSURFACE, 100, 25, 32,
        rmask, gmask, bmask, amask);