Switch over to Tokio and drop web for now

Cargo.toml

@@ -10,10 +10,5 @@ license = "AGPL-3.0-or-later"
 [dependencies]
 legion = "0.2.1"
 rand = "0.7.3"
-rocket = "0.4.4"
-serde = { version = "1.0.111", features = ["derive"] }
+tokio = { version = "0.2", features = ["full"] }
 
-[dependencies.rocket_contrib]
-version = "0.4.5"
-default-features = false
-features = ["tera_templates"]

src/main.rs

@@ -1,39 +1,19 @@
-#![feature(proc_macro_hygiene, decl_macro)]
-
-#[macro_use]
-extern crate rocket;
-extern crate serde;
-
-use std::sync::Arc;
-
-use rocket::State as RocketState;
-use rocket_contrib::templates::Template;
-
 mod simulation;
 mod state;
 
 use simulation::Simulation;
-use state::WrappedState;
 
-#[get("/")]
-fn index(sim: RocketState<WrappedState>) -> Template {
-    let state = sim.lock().unwrap();
-
-    
-    Template::render("stuff", state.clone())
-}
-
-fn main() {
+#[tokio::main]
+async fn main() {
     let mut simulation = Simulation::new();
-    let state = Arc::clone(&simulation.state);
+    let mut state_channel = simulation.state();
     
-    std::thread::spawn(move || {
-        simulation.run();
+    tokio::spawn(async move {
+        simulation.run().await;
     });
 
-    rocket::ignite()
-        .attach(Template::fairing())
-        .manage(state)
-        .mount("/", routes![index])
-        .launch();
+    loop {
+        let state = state_channel.recv().await.unwrap();
+        println!("Iteration {}", state.iteration)
+    }
 }

src/simulation.rs

@@ -1,12 +1,10 @@
-use std::sync::{Arc, Mutex};
-use std::thread;
-use std::time::Duration;
-
+use std::time::{Duration, Instant};
 
 use legion::prelude::*;
 use rand::prelude::*;
+use tokio::{sync::watch, time};
 
-use crate::state::{State, WrappedState, Object};
+use crate::state::{Object, State};
 
 #[derive(Clone, Debug, PartialEq)]
 struct Name {
@@ -27,7 +25,24 @@ struct Velocity {
 
 pub struct Simulation {
     world: World,
-    pub state: WrappedState,
+    iteration: u64,
+    last: Instant,
+    tx: watch::Sender<State>,
+    rx: watch::Receiver<State>,
+}
+
+fn render(world: &mut World) -> Vec<Object> {
+    let mut result = vec![];
+
+    for (name, pos) in <(Read<Name>, Read<Position>)>::query().iter(world) {
+        result.push(Object {
+            name: name.name.clone(),
+            x: pos.x,
+            y: pos.y,
+        });
+    }
+
+    result
 }
 
 impl Simulation {
@@ -40,7 +55,9 @@ impl Simulation {
             (),
             (0..999).map(|n| {
                 (
-                    Name { name: format!("Entity {}", n)},
+                    Name {
+                        name: format!("Entity {}", n),
+                    },
                     Position { x: 0.0, y: 0.0 },
                     Velocity {
                         dx: rng.gen_range(0.0, 1.0),
@@ -50,40 +67,46 @@ impl Simulation {
             }),
         );
 
-        let mut result = Self {world, state: Arc::new(Mutex::new(State {
-            iteration: 0, objects: vec![]
-        }))};
+        let (tx, rx) = watch::channel(State {
+            iteration: 0,
+            objects: render(&mut world),
+        });
         
-        result.render();
-
-        result
+        Self { world, last: Instant::now(), iteration: 0, tx, rx }
     }
 
-    pub fn update(&mut self) {
+    fn update(&mut self) {
         let update_query = <(Write<Position>, Read<Velocity>)>::query();
+        let now = Instant::now();
+        let dt = now.duration_since(self.last);
         for (mut pos, vel) in update_query.iter(&mut self.world) {
-            pos.x += vel.dx;
-            pos.y += vel.dy;
+            pos.x += vel.dx * dt.as_secs_f64();
+            pos.y += vel.dy * dt.as_secs_f64();
         }
-        self.state.lock().unwrap().iteration += 1;
+        self.last = now;
+        self.iteration += 1;
     }
 
-    fn render(&mut self) {
-        let mut state = self.state.lock().unwrap();
-
-        state.objects = vec![];
-
-        for (name, pos) in <(Read<Name>, Read<Position>)>::query().iter(&mut self.world) {
-            state.objects.push(Object{ name: name.name.clone(), x: pos.x, y: pos.y });
+    fn render(&mut self) -> State {
+        State {
+            iteration: self.iteration,
+            objects: render(&mut self.world),
         }
     }
 
-    pub fn run(&mut self) {
+    pub async fn run(&mut self) {
+        let mut interval = time::interval(Duration::from_millis(1000 / 60));
+
         loop {
             self.update();
-            self.render();
+            let state = self.render();
+            self.tx.broadcast(state).unwrap();
 
-            thread::sleep(Duration::from_secs(1))
+            interval.tick().await;
         }
     }
+
+    pub fn state(&mut self) -> watch::Receiver<State> {
+        self.rx.clone()
+    }
 }

src/state.rs

@@ -1,18 +1,12 @@
-use std::sync::{Arc, Mutex};
-
-use serde::Serialize;
-
-#[derive(Clone, Serialize)]
+#[derive(Clone, Debug)]
 pub struct Object {
     pub name: String,
     pub x: f64,
     pub y: f64,
 }
 
-#[derive(Clone, Serialize)]
+#[derive(Clone, Debug)]
 pub struct State {
     pub iteration: u64,
-    pub objects: Vec<Object>
+    pub objects: Vec<Object>,
 }
-
-pub type WrappedState = Arc<Mutex<State>>;