Removed Thread Jitter from Simulation Thread Lock

simulator/src/main.rs

@@ -2,7 +2,7 @@ use std::cmp::max;
 use std::collections::HashMap;
 use std::sync::{Arc, RwLock};
 use std::thread;
-use std::time::Duration;
+use std::time::{Duration, Instant};
 use cgmath::num_traits::ToPrimitive;
 use cgmath::Rotation3;
 use pollster::FutureExt;
@@ -287,7 +287,7 @@ impl<'a> State<'a> {
             index_count: circle_indices.len() as u32,
         });
 
-        let mut sim = Simulator::new(43200.0);
+        let mut sim = Simulator::new(5000.0);
         sim.add_body(Body {
             name: "Sun".to_string(),
             position: [0.0, 0.0],
@@ -301,21 +301,7 @@ impl<'a> State<'a> {
             mass: 5.972e24,
         });
 
-        let simulator = Arc::new(RwLock::new(sim));
-
-        let sim_clone = simulator.clone();
-        thread::spawn(move || {
-            loop {
-                {
-                    let mut sim = sim_clone.write().unwrap();
-                    sim.step();
-                }
-                thread::sleep(Duration::from_millis(16));
-            }
-        });
-
         let instances = {
-            let sim = simulator.read().unwrap();
             let sun_pos = sim.bodies[0].position;
             sim.bodies.iter().enumerate().map(|(i, b)| RenderInstance {
                 position: cgmath::Vector3::new(
@@ -341,6 +327,24 @@ impl<'a> State<'a> {
             usage: wgpu::BufferUsages::VERTEX | wgpu::BufferUsages::COPY_DST,
         });
 
+        let simulator = Arc::new(RwLock::new(sim));
+        let simulator_clone = simulator.clone();
+        thread::spawn(move || {
+            let mut last = Instant::now();
+            loop {
+                let now = Instant::now();
+                let dt = now.duration_since(last).as_secs_f64();
+                last = now;
+
+                {
+                    let mut sim = simulator_clone.write().unwrap();
+                    sim.step(dt * 50000.0);
+                }
+
+                thread::sleep(Duration::from_millis(1));
+            }
+        });
+
         Self {
             surface,
             device,
@@ -389,8 +393,9 @@ impl<'a> State<'a> {
     }
 
     fn update(&mut self) {
+        let sim = self.simulator.read().unwrap();
+
         let updated_instances: Vec<RenderInstance> = {
-            let sim = self.simulator.read().unwrap();
             sim.bodies.iter().enumerate().map(|(i, b)| RenderInstance {
                 position: cgmath::Vector3::new((b.position[0] / 1.496e11) as f32, (b.position[1] / 1.496e11) as f32, 0.0),
                 rotation: cgmath::Quaternion::from_angle_z(cgmath::Deg(0.0)),

solar_engine/src/simulator.rs

@@ -29,8 +29,7 @@ impl Simulator {
         self.bodies.push(body);
     }
 
-    pub fn step(&mut self) {
-        let dt = self.timestep;
+    pub fn step(&mut self, dt: f64) {
         let n = self.bodies.len();
 
         #[derive(Clone)]