[Caml-list] Re: Two severe limitations in Graphics module

["Michaël Grünewald" <michael-grunewald@wanadoo.fr>]

Berke Durak <berke@altern.org> writes:

> Hello everyone,
> 
> I was wondering how many hours would coding Tetris using the Graphics
> module require when I noticed that the Graphics module lacks two
> important constructs :
> 
> 1) The Graphics.wait_next_event doesn't allow you to wait for an event
> with a timeout, à la select(). Since in Tetris things might happen
> even if you don't press any key, you can't wait indefinitely.
> 
> Workarounds include :
> 	-- continuously calling wait_next_event [Poll;...]  and doing a
> small delay between each call. I think I will do this. Not very
> efficient, since the delay must be of the order of the screen refresh
> interval.
> 	-- do a horrible hack by getting the X11 file descriptor -- but
> then how will Microsoft-sequestrated people enjoy your delightful
> MLtris ?

1/You may have two threads, the first will watch the keyboard
(wait_next_event), the second will update puzzle tiles positions, both will
send events to your main loop, that will process these events.

2/Why don't use alarm signam or something like ?

> 2) There is no way to get the cursor keys. Sure that's no problem to
> h,j,k,l-people. Might I suggest the following bindings :
> 
> 	-- left : '\002' (Ctrl-b)
> 	-- right : '\006' (Ctrl-f)
> 	-- up : '\011' (Ctrl-k)
> 	-- down : '\010' (Ctrl-j)
> 
> or a supplementary keysym type like
> 
> 	type keysym = Latin1 of char | Left | Right | Up | Down | ...
> 
> 3) It would further be nice to be able to select() another FD plus
> the graphical interface, portably if possible. I know, under UNIX,
> simply adding a function to the Graphics module that returns the
> descriptor of the X11 connection would solve problems 1 and 3.
> That would be non portable.
> 
> Has anyone managed to solve these issues cleanly (i.e. without
> patching the compiler) ?
> --
> Berke
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-- 
Michaël Grünewald <michael-grunewald@wanadoo.fr>  - RSA PGP Key ID: 0x20D90C12
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