Question

I have this, in my header:

    struct Surface {
        char *objectName;
        int xPos;
        int yPos;
        SDL_Surface *surface;
    };

    struct WorldSurface {
        Surface *surface = new Surface[MAX_SURFACES];
        int counter = 0;
        int current = 0;
    };

    WorldSurface *worldSurface;

I then initialize the worldSurface in the .cpp:

    WorldSurface *worldSurface = new WorldSurface[MAX_LEVELS];

And this function, I can’t get to work no matter what, have tried messing around with = NULL, pointers, the -> instead of .’s… (do have in mind I’m not very savvy of pointer subjects)

    void drawClass::addSurface(char* objectName, char* surfaceFile, int xPos, int yPos, int drawLevel) {
        int cnt = worldSurface[drawLevel].counter;
        worldSurface[drawLevel].surface[cnt].objectName = objectName;
        worldSurface[drawLevel].surface[cnt].surface = load_image(surfaceFile);
        worldSurface[drawLevel].surface[cnt].xPos = xPos;
        worldSurface[drawLevel].surface[cnt].yPos = yPos;
        worldSurface[drawLevel].counter++;
    }

It’s 10 worldSurfaces, each containing 50 surface structs, and I want to acess the struct, which is inside the worldSurface[drawLevel], and the surface struct I want to access is known in the worldSurface, in the .counter variable. But all of the acesses to the underlying surface struct fail with segmentation fault, and I have no clue why…

Thanks for the help!

Answer 1

Your WorldSurface isn’t defined nor initialized properly:

struct WorldSurface {
    Surface *surface = new Surface[MAX_SURFACES];
    int counter = 0;
    int current = 0;
};

You can’t initialize your data in place along with the declaration of the class. You need to do this in a constructor, e.g.:

struct WorldSurface {
    Surface *surface;
    int counter;
    int current;
};
...
WorldSurface::WorldSurface():
    counter(0),current(0),surface(new Surface[MAX_SURFACES]){}