fix

src/entities/tasks/idle.rs

@@ -31,33 +31,42 @@ pub(super) fn execute_idle(
 
     let entity_pos = (transform.translation / ITILE_SIZE as f32).as_ivec3();
 
+    // Track if target actually changed this tick
+    let mut target_changed = false;
+
     // If reached target or target is no longer standable, pick new target
     if entity_pos == *target || !tilemap.is_standable(*target) {
         if let Some(new_target) = pick_wander_target(origin, *wander_radius, tilemap, rng) {
             *target = new_target;
+            target_changed = true;
         }
     }
 
-    // Set ambulatory target - pathfinding system will compute path
-    ambulatory.target = Some(Vec3::new(
-        target.x as f32,
-        target.y as f32,
-        transform.translation.z,
-    ));
-    ambulatory.current_path = None;
-    ambulatory.path_index = 0;
+    // Only reset path if target changed or no path exists
+    // This avoids forcing pathfinding to recompute every frame
+    if target_changed || ambulatory.current_path.is_none() {
+        ambulatory.target = Some(Vec3::new(
+            target.x as f32,
+            target.y as f32,
+            transform.translation.z,
+        ));
+        ambulatory.current_path = None;
+        ambulatory.path_index = 0;
+    }
+    // Otherwise: keep existing path, let movement system continue along it
 }
 
 /// Pick a random standable tile within wander radius of origin.
+/// Uses reservoir sampling to avoid heap allocation.
 fn pick_wander_target(
     origin: &IVec3,
     radius: i32,
     tilemap: &TileMap,
     rng: &mut WyRand,
 ) -> Option<IVec3> {
-    let mut candidates = smallvec::SmallVec::<[IVec3; 16]>::new();
+    let mut chosen = None;
+    let mut count = 0u32;
 
-    // Collect valid tiles within radius
     for dx in -radius..=radius {
         for dy in -radius..=radius {
             let candidate = IVec3::new(
@@ -66,15 +75,13 @@ fn pick_wander_target(
                 origin.z,
             );
             if tilemap.is_standable(candidate) {
-                candidates.push(candidate);
+                count += 1;
+                // Reservoir sampling: 1/count chance to replace chosen
+                if rng.random_range(0..count) == 0 {
+                    chosen = Some(candidate);
+                }
             }
         }
     }
-
-    if candidates.is_empty() {
-        return None;
-    }
-
-    let idx = rng.random_range(0..candidates.len());
-    Some(candidates[idx])
+    chosen
 }