Move the simulation out of the main file

src/main.rs

@@ -3,41 +3,21 @@
 #[macro_use]
 extern crate rocket;
 
+mod simulation;
+
 use std::fmt::Write as FmtWrite;
 use std::sync::{Arc, Mutex};
 use std::thread;
 use std::time::Duration;
 
-use legion::prelude::*;
-use rand::prelude::*;
 use rocket::State;
 
-#[derive(Clone, Debug, PartialEq)]
-struct Name {
-    name: String,
-}
+use simulation::{Object, Simulation};
 
-#[derive(Clone, Copy, Debug, PartialEq)]
-struct Position {
-    x: f64,
-    y: f64,
-}
-
-#[derive(Clone, Copy, Debug, PartialEq)]
-struct Velocity {
-    dx: f64,
-    dy: f64,
-}
-
-struct ObjectOutput {
-    pub name: String,
-    pub x: f64,
-    pub y: f64,
-}
 
 struct SimState {
     pub iteration: u64,
-    pub objects: Vec<ObjectOutput>
+    pub objects: Vec<Object>
 }
 
 type WrappedState = Arc<Mutex<SimState>>;
@@ -59,41 +39,15 @@ fn index(sim: State<WrappedState>) -> String {
 
 fn simulation(s: WrappedState) {
     std::thread::spawn(move || {
-        let universe = Universe::new();
-        let mut world = universe.create_world();
-        let mut rng = thread_rng();
-
-        world.insert(
-            (),
-            (0..999).map(|n| {
-                (
-                    Name { name: format!("Entity {}", n)},
-                    Position { x: 0.0, y: 0.0 },
-                    Velocity {
-                        dx: rng.gen_range(0.0, 1.0),
-                        dy: rng.gen_range(0.0, 1.0),
-                    },
-                )
-            }),
-        );
-
+        let mut simulation = Simulation::new();
 
         loop {
-            let update_query = <(Write<Position>, Read<Velocity>)>::query();
-            for (mut pos, vel) in update_query.iter(&mut world) {
-                pos.x += vel.dx;
-                pos.y += vel.dy;
-            }
-
+            simulation.update();
+            {
                 let mut state = s.lock().unwrap();
                 (*state).iteration += 1;
-            let mut result: Vec<ObjectOutput> = vec![];
-
-            for (name, pos) in <(Read<Name>, Read<Position>)>::query().iter(&mut world) {
-                result.push(ObjectOutput{ name: name.name.clone(), x: pos.x, y: pos.y });
+                (*state).objects = simulation.render();
             }
-            (*state).objects = result;
-
             thread::sleep(Duration::from_secs(1))
         }
     });

src/simulation.rs

@@ -0,0 +1,71 @@
+use legion::prelude::*;
+use rand::prelude::*;
+
+#[derive(Clone, Debug, PartialEq)]
+struct Name {
+    name: String,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+struct Position {
+    x: f64,
+    y: f64,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+struct Velocity {
+    dx: f64,
+    dy: f64,
+}
+
+pub struct Simulation {
+    world: World
+}
+
+pub struct Object {
+    pub name: String,
+    pub x: f64,
+    pub y: f64,
+}
+
+impl Simulation {
+    pub fn new() -> Simulation {
+        let universe = Universe::new();
+        let mut world = universe.create_world();
+        let mut rng = thread_rng();
+    
+        world.insert(
+            (),
+            (0..999).map(|n| {
+                (
+                    Name { name: format!("Entity {}", n)},
+                    Position { x: 0.0, y: 0.0 },
+                    Velocity {
+                        dx: rng.gen_range(0.0, 1.0),
+                        dy: rng.gen_range(0.0, 1.0),
+                    },
+                )
+            }),
+        );
+    
+        Simulation {world}
+    }
+
+    pub fn update(&mut self) {
+        let update_query = <(Write<Position>, Read<Velocity>)>::query();
+        for (mut pos, vel) in update_query.iter(&mut self.world) {
+            pos.x += vel.dx;
+            pos.y += vel.dy;
+        }
+    }
+
+    pub fn render(&mut self) -> Vec<Object> {
+        let mut result: Vec<Object> = vec![];
+
+        for (name, pos) in <(Read<Name>, Read<Position>)>::query().iter(&mut self.world) {
+            result.push(Object{ name: name.name.clone(), x: pos.x, y: pos.y });
+        }
+
+        result
+    }
+}