How to use multiple event loop togather?

tiye · May 9, 2021, 7:42pm

in my case I have to event loops, one from notify, and the other from a 2d drawing library. I could handle very simple case if both of them use channels like:

loop {
  a.try_recv()
  b.try_recv()

 // sleep for a while
}

but as I looked into winit, piston, sdl2.. I see many of them use iterators, which makes its event loop hard to cooperate with a channel. and winit internally uses a callback on macos which makes it even harder().

I also thought about moving my notify code into the closure of UI event loop, but a lot of variables can not be moved in a simple way. So I don't know if that's viable as well...

thought for a while of turning the iterator into a channel, but how about threads, and the types of channels? still unclear...

is there a clear way of common pattern in solving this? or which 2d library plus window library should I use in such a case?

alice · May 9, 2021, 7:46pm

It sounds like you should probably spawn a thread for each.

alanhkarp · May 10, 2021, 12:10am

You could try crossbeam select!().

tiye · May 10, 2021, 3:56am

finally made it work, but in a dirty solution, based on a breaking(kind of... on macos) API event_loop.run_return(...):

github.com

calcit-lang/calcit-paint/blob/61a7b0ac54e0ded7b9cbc91862f403cb7e620e05/src/main.rs#L94


      
          }
          
          
let cb = ggez::ContextBuilder::new("eventloop", "ggez");
          let (ref mut ctx, mut events_loop) = cb.build()?;
          
          
let mut first_paint = true;
          
          
while ctx.continuing {
            // Handle events. Refer to `winit` docs for more information.
            use winit::platform::run_return::EventLoopExtRunReturn;
            events_loop.run_return(|event, _window_target, control_flow| {
              // println!("Event: {:?}", event);
              ctx.process_event(&event);
              if first_paint {
                if let Err(e) = draw(ctx) {
                  println!("failed first paint: {:?}", e);
                }
                first_paint = false
              }
          
          
    match event {

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How to use multiple event loop togather?

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