fix segfault for real

src/Aquarium.cpp

@@ -47,15 +47,18 @@ void Aquarium::ensureEntitiesSorted() {
 
 void Aquarium::redraw() {
   clearCurrentFrame();
-
   ensureBigEntityExists();
 
-  std::vector<std::unique_ptr<Entity>> newEntities;
-  bool entities_modified = false;
+  // Use static vectors to avoid per-frame allocations
+  static std::vector<std::unique_ptr<Entity>> newEntities;
+  static std::vector<size_t> entitiesToRemove;
 
-  // Update and check for removal/replacement
-  for (auto it = entities.begin(); it != entities.end();) {
-    auto &entity = *it;
+  newEntities.clear();
+  entitiesToRemove.clear();
+
+  // Update all entities and collect changes
+  for (size_t i = 0; i < entities.size(); ++i) {
+    auto &entity = entities[i];
     entity->update();
 
     // Handle fish bubble spawning
@@ -69,30 +72,32 @@ void Aquarium::redraw() {
     if (entity->shouldBeRemoved()) {
       auto replacement = entity->createReplacement();
       if (replacement) {
-        *it = std::move(replacement);
-        entities_modified = true;
-        ++it;
+        entity = std::move(replacement); // Replace in-place
+        entities_need_sorting = true;
       } else {
-        it = entities.erase(it);
-        entities_modified = true;
+        entitiesToRemove.push_back(i); // Mark for removal
       }
-    } else {
-      ++it;
     }
   }
 
-  // Add new entities if any
+  // Remove entities in reverse order to maintain indices
+  for (auto it = entitiesToRemove.rbegin(); it != entitiesToRemove.rend();
+       ++it) {
+    entities.erase(entities.begin() + *it);
+    entities_need_sorting = true;
+  }
+
+  // Add new entities (only if we have them)
   if (!newEntities.empty()) {
+    // Reserve space to minimize reallocations
+    entities.reserve(entities.size() + newEntities.size());
+
     for (auto &newEntity : newEntities) {
       entities.emplace_back(std::move(newEntity));
     }
-    entities_modified = true;
-  }
-
-  // Only sort if entities were modified
-  if (entities_modified) {
     entities_need_sorting = true;
   }
+
   ensureEntitiesSorted();
 
   // Draw all entities