Fix rtsim NPC respawning

rtsim/src/data/npc.rs

@@ -100,6 +100,8 @@ pub struct Npc {
     pub faction: Option<FactionId>,
     pub riding: Option<Riding>,
 
+    pub is_dead: bool,
+
     /// The [`Report`]s that the NPC is aware of.
     pub known_reports: HashSet<ReportId>,
 
@@ -139,6 +141,7 @@ impl Clone for Npc {
             home: self.home,
             faction: self.faction,
             riding: self.riding.clone(),
+            is_dead: self.is_dead,
             known_reports: self.known_reports.clone(),
             body: self.body,
             personality: self.personality,
@@ -169,6 +172,7 @@ impl Npc {
             home: None,
             faction: None,
             riding: None,
+            is_dead: false,
             known_reports: Default::default(),
             chunk_pos: None,
             current_site: None,

rtsim/src/rule/cleanup.rs

@@ -22,12 +22,27 @@ impl Rule for CleanUp {
 
             // TODO: Use `.into_par_iter()` for these by implementing rayon traits in upstream slotmap.
 
+            // Decay NPC sentiments
             data.npcs
                 .iter_mut()
                 // Only cleanup NPCs every few ticks
                 .filter(|(_, npc)| (npc.seed as u64 + ctx.event.tick) % NPC_SENTIMENT_TICK_SKIP == 0)
                 .for_each(|(_, npc)| npc.sentiments.decay(&mut rng, ctx.event.dt * NPC_SENTIMENT_TICK_SKIP as f32));
 
+            // Remove dead NPCs
+            // TODO: Don't do this every tick, find a sensible way to gradually remove dead NPCs after they've been
+            // forgotten
+            data.npcs
+                .retain(|npc_id, npc| if npc.is_dead {
+                    // Remove NPC from home population
+                    if let Some(home) = npc.home.and_then(|home| data.sites.get_mut(home)) {
+                        home.population.remove(&npc_id);
+                    }
+                    false
+                } else {
+                    true
+                });
+
             // Clean up entities
             data.npcs
                 .iter_mut()

rtsim/src/rule/npc_ai.rs

@@ -215,6 +215,8 @@ impl Rule for NpcAi {
                 let mut data = ctx.state.data_mut();
                 data.npcs
                     .iter_mut()
+                    // Don't run AI for dead NPCs
+                    .filter(|(_, npc)| !npc.is_dead)
                     // Don't run AI for simulated NPCs every tick
                     .filter(|(_, npc)| matches!(npc.mode, SimulationMode::Loaded) || (npc.seed as u64 + ctx.event.tick) % SIMULATED_TICK_SKIP == 0)
                     .map(|(npc_id, npc)| {

rtsim/src/rule/simulate_npcs.rs

@@ -61,7 +61,10 @@ fn on_death(ctx: EventCtx<SimulateNpcs, OnDeath>) {
                         Some(*id) != npc.home
                             && site.faction == npc.faction
                             && site.world_site.map_or(false, |s| {
-                                matches!(ctx.index.sites.get(s).kind, SiteKind::Refactor(_))
+                                matches!(ctx.index.sites.get(s).kind, SiteKind::Refactor(_)
+                | SiteKind::CliffTown(_)
+                | SiteKind::SavannahPit(_)
+                | SiteKind::DesertCity(_))
                             })
                     })
                     .min_by_key(|(_, site)| site.population.len())
@@ -142,6 +145,8 @@ fn on_death(ctx: EventCtx<SimulateNpcs, OnDeath>) {
                 home.population.insert(npc_id);
             }
         }
+    } else {
+        error!("Trying to respawn non-existent NPC");
     }
 }
 
@@ -151,7 +156,7 @@ fn on_tick(ctx: EventCtx<SimulateNpcs, OnTick>) {
         .npcs
         .npcs
         .values_mut()
-        .filter(|npc| matches!(npc.mode, SimulationMode::Simulated))
+        .filter(|npc| matches!(npc.mode, SimulationMode::Simulated) && !npc.is_dead)
     {
         // Simulate NPC movement when riding
         if let Some(riding) = &npc.riding {

rtsim/src/rule/sync_npcs.rs

@@ -34,19 +34,10 @@ fn on_death(ctx: EventCtx<SyncNpcs, OnDeath>) {
     let data = &mut *ctx.state.data_mut();
 
     if let Actor::Npc(npc_id) = ctx.event.actor {
-        // Remove NPC from home population
-        if let Some(home) = data
-            .npcs
-            .get(npc_id)
-            .and_then(|npc| npc.home)
-            .and_then(|home| data.sites.get_mut(home))
-        {
-            home.population.remove(&npc_id);
+        if let Some(npc) = data.npcs.get_mut(npc_id) {
+            // Mark the NPC as dead, allowing us to clear them up later
+            npc.is_dead = true;
         }
-
-        // TODO: Maybe death should be a marker flag instead of outright deleting the
-        // NPC so that we can still query details about them?
-        data.npcs.remove(npc_id);
     }
 }