[SDL] Segmentation fault in SDL_DisplayFormat{,Alpha}

[charly]

Hi,

I'm starting playing around with SDL. Im using Lazy FOo' 
tutorials(http://lazyfoo.net/SDL_tutorials/index.php) to help me.

The prog here used to work, i don't know what i did to make it crash now. No 
changes were made in the crashing functions.
gdb reports:
#0  0xb7f0d0e3 in SDL_DisplayFormatAlpha () from /usr/lib/libSDL-1.2.so.0
#1  0x08049a74 in load_image (filename=@0xbfe0eb08) at wrappers.cpp:18
#2  0x08049495 in Plane (this=0xbfe0eb44, planeid=0, planetype=0)
    at plane.cpp:22
#3  0x08049ccc in main () at abricots.cpp:46

And here's my load_image function:

SDL_Surface *load_image(std::string filename)
{
    SDL_Surface *loadedImage = NULL;
    SDL_Surface *optimizedImage = NULL;
    loadedImage = IMG_Load( filename.c_str() );
    if( loadedImage != NULL )
    {
        std::cout << "Image loaded!\n";
        Uint32 colorkey = SDL_MapRGB( loadedImage->format, 0xFF, 0, 0xFF );
        optimizedImage = SDL_DisplayFormatAlpha( loadedImage );
        SDL_FreeSurface( loadedImage );
    }
    return optimizedImage;
}

The image being loaded is a simple 24 bits png wich, as i said, loaded fine 
before. SDL_SetVideoMode is called as SDL_SetVideoMode( 800, 600, 24, 
SDL_HWSURFACE );

The last changes made inclued a timer to move the surface smoothly regardless 
of the framerate. Let me know if you want me to join the whole prog (7 
files).

Regards,