main.rs

use winit::{
    event::{Event, WindowEvent},
    event_loop::{ControlFlow},
};
use std::cell::RefCell;

pub struct ExampleBase {
    pub window: winit::window::Window,
    pub event_loop: RefCell<winit::event_loop::EventLoop<()>>,
    pub test: i32,
}

impl ExampleBase {
    pub fn render_loop<F: Fn()>(&self, f: F) {
        // FIXME 1: cannot move out of dereference of `std::cell::RefMut<'_, winit::event_loop::EventLoop<()>>`
        self.event_loop.borrow_mut().run(move |event, _, control_flow| {
            //FIXME 2: the parameter type `F` may not live long enough
            f();
            *control_flow = ControlFlow::Wait;
            match event {
                Event::WindowEvent { event, .. } => {
                    match event {
                        WindowEvent::CloseRequested => {
                            *control_flow = ControlFlow::Exit;
                        }
                        _ => (),
                    }
                }
                _ => (),
            }
        });
    }
    
    pub fn new() -> Self {
        let event_loop = winit::event_loop::EventLoop::new();
        let window = winit::window::WindowBuilder::new()
            .with_title("Example")
            .with_inner_size(winit::dpi::LogicalSize::new( f64::from(800), f64::from(600),))
            .build(&event_loop)
            .unwrap();
        let test = 42;
        ExampleBase {
            event_loop: RefCell::new(event_loop),
            window,
            test
        }
    }
}

fn main() {
    let base = ExampleBase::new();
    base.render_loop(|| {
        println!("test: {:?}", base.test);
    })
}