Re: [AD] END_OF_MAIN removal patch for msvc

["Stefanos A." <stapostol@xxxxxxxxxx>]

On Tue, 2008-11-18 at 14:48 -0700, Thomas Fjellstrom wrote:
> On November 18, 2008, Peter Wang wrote:
> > On 2008-11-18, Thomas Fjellstrom <tfjellstrom@xxxxxxxxxx> wrote:
> > > Wait, didn't allegro specifically go to an event loop and whatnot to get
> > > around this little problem? al_init() initializes any internal lib state,
> > > and the event loop gives allegro time to "do its thing" when needed
> > > without having an explicit al_update_allegro(); api.
> >
> > No, that's not what the event system was designed for and that's not how
> > it works.
> 
> Probably not.
> 
> So whats the alternative then? Try and be too clever? or just export a simple 
> update function?
> 
> What do you prefer?
> 
> > Peter
> >
> >

If I may make a suggestion, it might actually be better to make the
event system mandatory. I am not up to date with the current A5 API (I'm
only familiar with the old design docs), but in pseudocode this would
look something like:

int main(void)
{
    al_init();

    AL_WINDOW* window = al_open_window(...);
    al_register_event(window, AL_MOUSE_INPUT, [callback]);
    al_register_event(window, AL_WINDOW_RESIZE, [callback]);
    al_register_event(window, AL_WINDOW_CLOSE, [callback]);
    al_register_event(window, AL_WINDOW_IDLE, [callback]);
    al_run_events(window);   // Blocks until al_exit.

    return 0;
}

In this case, the game loop fits perfectly inside the AL_WINDOW_IDLE
event handler:

void idle(Window* window, [callback args])
{
    while (al_is_window_idle(window))
    {
        // Here goes the game loop, which looks like A4.
    }
}

Advantages of this design:
1. The event loop runs alongside the user code just fine - no hacks.
2. Clean and consistent API.
3. Fits modern APIs (e.g. XNA, where Shawn is working now, follows the
exact same model).
4. Fits the way modern operating systems work.

Disadvantages:
1. Paradigm shift from A4.
2. Event-based only.
3. Can only be emulated in older operating systems, e.g. DOS (does
anyone even care anymore?)

I know there have been extensive discussions about the A5 api, so feel
free to disregard any of this. However, my experience from coding a
similar library is that this is the way to go.

(The library is OpenTK, which is pretty much Allegro for Mono/.Net.
Indeed, Allegro has proved a great source of information.)