Re: [Caml-list] OpenGL and LWT

["Daniel Bünzli" <daniel.buenzli@erratique.ch>]

Le lundi, 17 mars 2014 à 23:50, Richard Neswold a écrit :
> I could have an Lwt thread call Sdl.poll_event and then go to sleep if no events were available, but I'm trying to make this driven by events and not resort to polling, if possible.

There is certainly more than one way to do that, but that's what I do at the moment (with another cooperative threading library). Favor the treatement of the UI events, if there's no UI event run the scheduler for 10ms.  

let rec loop deadline =  
  while Sdl.poll_event e do do_event e done;
  run_scheduler ~timeout:10;  
  loop ()

Regarding Tsdl.Sdl.wait_event, it's not really better than that, if you have a look at its C implementation [1] you'll see it tries to get an event and if none is available it will sleep for 10ms before trying again. This means that any SDL based program using Sdl.wait_event, constantly uses ~1.5% cpu (at least on osx), you should be able to bring that down by writing your own loop as above and augmenting the timeout value when your application is not in the foreground.  

Best,

Daniel

[1] http://hg.libsdl.org/SDL/file/4c01875a4620/src/events/SDL_events.c#l421