Optimize instant replay

rust/src/game_manager.rs

@@ -257,6 +257,7 @@ pub struct Game {
     pub goals: HashMap<u8, u16>,
 
     pub replay_recorder: Option<Gd<ReplayRecorder>>,
+    pub current_replay_frame_start: usize,
     pub current_replay_playback: Option<Gd<ReplayPlayback>>,
     pub last_replay_clone: f64,
 
@@ -361,7 +362,10 @@ impl INode for Game {
         {
             self.last_replay_clone += delta;
             if self.last_replay_clone >= 1. {
-                playback.bind_mut().replay = recorder.bind().replay.clone();
+                playback.bind_mut().replay = recorder
+                    .bind()
+                    .replay
+                    .clone_since(self.current_replay_frame_start);
                 self.last_replay_clone = 0.
             }
         }
@@ -404,7 +408,14 @@ impl Game {
     pub fn start_playback(&mut self, time_delta: f64, spectated_id: u16) {
         if let Some(recorder) = &self.replay_recorder {
             let mut playback = ReplayPlayback::new_alloc();
-            playback.bind_mut().replay = recorder.bind().replay.clone();
+
+            let frame = recorder
+                .bind()
+                .replay
+                .find_frame(recorder.bind().time_elapsed + time_delta);
+            self.current_replay_frame_start = frame;
+
+            playback.bind_mut().replay = recorder.bind().replay.clone_since(frame);
             playback.bind_mut().current_map = self.current_map.clone();
             playback.bind_mut().current_time = (recorder.bind().time_elapsed + time_delta).max(0.);
             playback.bind_mut().fast_forwarding = true;

rust/src/replay.rs

@@ -508,6 +508,33 @@ impl Default for Replay {
     }
 }
 
+impl Replay {
+    pub fn find_frame(&self, elapsed: f64) -> usize {
+        self.frames
+            .iter()
+            .enumerate()
+            .skip_while(|(_, f)| f.time < elapsed)
+            .next()
+            .map(|(i, _)| i)
+            .unwrap_or(0)
+    }
+
+    pub fn clone_since(&self, frame_idx: usize) -> Replay {
+        Replay {
+            map_idx: self.map_idx,
+            players: self.players.clone(),
+            teams: self.teams.clone(),
+            goals: self.goals.clone(),
+            frames: self
+                .frames
+                .iter()
+                .skip(frame_idx)
+                .cloned()
+                .collect::<Vec<_>>(),
+        }
+    }
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct ReplayTeam {
     pub name: String,