Store an array of SDL_Surface items in a class? - c++

Question

I want to store all my SDL_Surface variables in an array, and to hold that array in a class. The reason is that I want to be able to reload all SDL_Surfaces based on events.
I think it should be something like this, I'm probably wrong though:
class Imgs_Arr{
private:
int pos;
public:
// DECLARE THE ARRAY
Imgs_Arr();
void addItem(char * path);
void changeItem(int pos);
};
Imgs_Arr::Imgs_Arr(){
// CREATE ARRAY
}
void Imgs_Arr::addItem(char * path){ // ADD ITEM IN LAST ARRAY POSITION
vec[pos] = load_image(path);
if( vec[pos] == NULL ) exit(5);
pos++;
}
void Imgs_Arr::changeItem(int p){ // ADD ITEM IN LAST ARRAY POSITION
vec[p] = load_image(path);
if( vec[p] == NULL ) exit(5);
}
I'm looking for an example of how to do it. But any information will be useful. Thanks

Answer 1

Your problem is somewhat specific, since SDL_Surface* is an opaque handle. You must never know the actual SDL_Surface object which it points to. So, you need a dynamic array of opaque handles. For the main array, we just use std::vector, so I'd do it like this:
#include <memory>
#include <vector>
#include <SDL.h>
class Arr_Images
{
using sdl_handle = std::unique_ptr<SDL_Surface, void(*)(SDL_Surface*)>;
sdl_handle wrap_unique_surface(SDL_Surface * s)
{
return sdl_handle(s, SDL_FreeSurface);
}
std::vector<sdl_handle> surfaces;
public:
void addImg(char const * path)
{
if (SDL_Surface * p = load_image(path))
{
surfaces.push_back(wrap_unique_surface(p));
}
else
{
// failed to load
}
}
};