Match loop on the client side: orders go to the server, a confirmed turn steps the world five times, and a checksum of the shared state catches worlds that diverge

src/game.rs

@@ -594,6 +594,8 @@ pub struct Game {
     #[serde(skip)]
     step_acc: f32, // real time not yet paid for with a step
     #[serde(skip)]
+    pub netplay: Option<crate::netplay::Netplay>, // a match: turns come in, the world steps per turn
+    #[serde(skip)]
     pub hints: bool, // show hint messages (setting)
     #[serde(skip, default = "hint_times")]
     hint_t: [f32; 32], // last time each hint slot was shown
@@ -774,6 +776,7 @@ impl Game {
             cmd_seq: 0,
             sim_steps: 0,
             step_acc: 0.0,
+            netplay: None,
             hint_t: hint_times(),
             reserve: 0.0,
             incoming: Vec::new(),
@@ -1176,13 +1179,19 @@ impl Game {
     // ---------------------------------------------------------------- update
 
     pub fn update(&mut self, dt: f32) {
-        self.step_acc = (self.step_acc + dt).min(STEP * MAX_STEPS_PER_FRAME as f32);
         let mut steps = 0usize;
-        while self.step_acc >= STEP {
-            self.step_acc -= STEP;
-            steps += 1;
-        }
-        let cmds = std::mem::take(&mut self.pending);
+        let cmds = if self.netplay.is_some() {
+            // a match runs turn by turn (see netplay.rs): without the next turn the world stands still,
+            // and local orders are not applied here - they travel to the server first
+            Vec::new()
+        } else {
+            self.step_acc = (self.step_acc + dt).min(STEP * MAX_STEPS_PER_FRAME as f32);
+            while self.step_acc >= STEP {
+                self.step_acc -= STEP;
+                steps += 1;
+            }
+            std::mem::take(&mut self.pending)
+        };
         self.apply_turn(&cmds, steps);
         // what only the camera cares about runs in real time: it is not part of the shared state
         self.update_particles(dt);