SDL - SigSegV fault

[Labdabeta]

I have made a header file for SDL GUI applications. I was testing the SDLGame::Draw() function when I got a SigSegV fault. The fault occurs in different locations each time I run the program. Also sometimes instead of a SigSegV fault I get a SigTrap fault. Here is the code involved with the SigSegV.
SDLGame class constructor:

SDLGame::SDLGame(int w, int h, int bpp, Uint32 flags)
{
    if (SDL_Init(SDL_INIT_EVERYTHING)==-1)
        exit(-1);
    Window=SDL_SetVideoMode(w, h, bpp, flags);
    if (Window==NULL)
        exit(-2);
}

SDLGame class Draw():

void SDLGame::Draw(Sprite img, int x, int y)
{
    SDL_Rect offset;
    offset.x=x;
    offset.y=y;
    SDL_BlitSurface((SDL_Surface*)img, NULL, Window, &offset);
}

Sprite class constructor (from file):

Sprite::Sprite(char *filename)
{
    SDL_Surface *Temp=IMG_Load(filename);
    if (Temp!=NULL)
    {
        SDL_Surface *Good=SDL_DisplayFormatAlpha(Temp);
        pixels=new Pixel32[Good->w*Good->h];
        w=Good->w;
        h=Good->h;
        pixels=(Pixel32*)Good->pixels;
        SDL_FreeSurface(Temp);
        //SDL_FreeSurface(Good);
    }
    else
    {
        pixels=NULL;
        w=0;
        h=0;
        SDL_FreeSurface(Temp);
    }
}

Sprite class SDL_Surface typecast operator:

Sprite::operator SDL_Surface*()const
{
    SDL_Surface *ret=NULL;
    ret=SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 32, 0x00FF0000, 0x0000FF00, 0x000000FF, 0xFF000000);
    Pixel32 *surface=(Pixel32*)ret->pixels;
    for (int i=0; i<(w*h); i++)
    {
        if (!pixels[i]||!surface[i])
        {
            i=(w*h);
            break;
        }
        surface[i]=pixels[i];
    }
    SDL_Surface *dup=ret;
    ret->refcount++;
    return dup;
}

Pixel32 is essentially typedef'd as Uint32. This is the basis of my main() function (but not it entirely, I think the problem lies in the fact that I draw a surface twice):

int main()
{
SDL_Game TTT(600, 600, 32, SDL_SWSURFACE);
Sprite Board("BOARD.png");
TTT.Draw(Board, 0, 0);
TTT.Step();
TTT.Draw(Board, 0, 0);
TTT.Step();
return 0;
}

If I need to post the whole code I can. I just don't wish to right now. Could anybody solve this problem without more code?

[rxlim]

Do you get the same problem if you debug the application?

[Labdabeta]

Yes, it usually happens at the end of the conversion from Sprite to SDL_Surface *, although occasionally it happens at the Draw function. I think that somehow the Sprite is getting delete[]d after it's pixel surface is blitted, I just can't see why.

[rxlim]

Are you deleting anything in the destructor of Sprite? If so, then you will invalidate the original Sprite object's corresponding pointer, unless you have a copy constructor that takes this into account? You are passing your sprite by value, so if this is your problem, then perhaps you should pass it by reference instead.

[Labdabeta]

THANK YOU! I knew it would be something stupid with the pointers, come to think of it, it fails after the blitting, but that is also the last line, where the sprite goes out of scope! I'm gonna just try deleting the deconstructor, so what if I have some deallocated memory, it will be overwritten later.