winit-wgpu-tokio

use tokio::{runtime::Builder, sync::{mpsc}};
use winit::{event::{Event, WindowEvent}, event_loop::{ControlFlow, EventLoop}, window::{Window, WindowBuilder}};


pub struct Gpu {
    pub surface: wgpu::Surface,
    pub device: wgpu::Device,
    pub queue: wgpu::Queue,
    pub sc_desc: wgpu::SwapChainDescriptor,
    pub swap_chain: wgpu::SwapChain,
    pub swapchain_format: wgpu::TextureFormat,
    pub adapter: wgpu::Adapter,
}
impl Gpu {
    pub async fn new(window: &Window) -> Self {
        let size = window.inner_size();
        let swapchain_format = wgpu::TextureFormat::Bgra8UnormSrgb;
        let instance = wgpu::Instance::new(wgpu::BackendBit::PRIMARY);
        let surface = unsafe { instance.create_surface(window) };
        let adapter = instance
            .request_adapter(&wgpu::RequestAdapterOptions {
                power_preference: wgpu::PowerPreference::default(),
                compatible_surface: Some(&surface),
            })
            .await
            .expect("Failed to find an appropiate adapter");

        let (device, queue) = adapter
            .request_device(
                &wgpu::DeviceDescriptor {
                    label: None,
                    features: wgpu::Features::NON_FILL_POLYGON_MODE,
                    limits: wgpu::Limits::default(),
                },
                None,
            )
            .await
            .expect("Failed to create device");

        let sc_desc = wgpu::SwapChainDescriptor {
            usage: wgpu::TextureUsage::RENDER_ATTACHMENT,
            format: swapchain_format,
            width: size.width,
            height: size.height,
            present_mode: wgpu::PresentMode::Immediate,
        };

        let swap_chain = device.create_swap_chain(&surface, &sc_desc);

        Self {
            sc_desc,
            swap_chain,
            device,
            surface,
            queue,
            swapchain_format,
            adapter,
        }
    }
    fn clear(&self) {
        let frame = self.swap_chain
            .get_current_frame()
            .expect("Failed to acquire next swap chain texture")
            .output;
        let mut encoder = self.device.create_command_encoder(&wgpu::CommandEncoderDescriptor { label: None });
        {
            encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                label: None,
                color_attachments: &[wgpu::RenderPassColorAttachment {
                    view: &frame.view,
                    resolve_target: None,
                    ops: wgpu::Operations {
                        load: wgpu::LoadOp::Clear(wgpu::Color::GREEN),
                        store: true,
                    },
                }],
                depth_stencil_attachment: None,
            });
        }

        self.queue.submit(Some(encoder.finish()));
    }
}

fn main() {

    let runtime = Builder::new_multi_thread()
        .enable_all()
        .build()
        .unwrap();

    let (event_tx, mut event_rx) = mpsc::unbounded_channel();

    let event_loop = EventLoop::new();
    let window = WindowBuilder::new().build(&event_loop).unwrap();

    runtime.block_on(async {
        let gpu = Gpu::new(&window).await;

        runtime.spawn(async move {
            loop {
                let event = event_rx.recv().await.unwrap();
                println!("{:?} {:?}", event, std::thread::current().id());
                gpu.clear();
            }
        });
    });

    event_loop.run(move |event, _, control_flow| {
        *control_flow = ControlFlow::Wait;

        match &event {
            Event::WindowEvent { event: WindowEvent::CloseRequested, .. } => *control_flow = ControlFlow::Exit,
            _ => (),
        }
        event_tx.send(event.to_static()).unwrap();
    });
}

Quick note; I ended up moving away from this and just running the game loop on the main thread (like normal) instead, and integrating tokio by just creating a runtime and passing around Handle's to it, which can be used to spawn.

integrating tokio by just creating a runtime and passing around Handle's to it, which can be used to spawn

@FredrikNoren can you elaborate what you mean by this?