cleanup: Game::checkCreatures (#3020)

The loop by iterator has been replaced by erase_if, as it is visually
cleaner and more intuitive. In terms of performance, there was not much
gain, as both use object reallocation, perhaps a slight improvement, as
erase_if uses std::move to reallocate the last object.

A dead code that is never called has also been removed, as this code is
already called by Creature::changeHealth on line 892

src/creatures/creature.hpp

@@ -199,6 +199,11 @@ class Creature : virtual public Thing, public SharedObject {
 	int32_t getHealth() const {
 		return health;
 	}
+
+	bool isAlive() const {
+		return !isDead();
+	}
+
 	virtual int32_t getMaxHealth() const {
 		return healthMax;
 	}

src/game/game.cpp

@@ -6395,28 +6395,17 @@ void Game::checkCreatures() {
 	metrics::method_latency measure(__METHOD_NAME__);
 	static size_t index = 0;
 
-	auto &checkCreatureList = checkCreatureLists[index];
-	size_t it = 0, end = checkCreatureList.size();
-	while (it < end) {
-		auto creature = checkCreatureList[it];
-		if (creature && creature->creatureCheck) {
-			if (creature->getHealth() > 0) {
-				creature->onThink(EVENT_CREATURE_THINK_INTERVAL);
-				creature->onAttacking(EVENT_CREATURE_THINK_INTERVAL);
-				creature->executeConditions(EVENT_CREATURE_THINK_INTERVAL);
-			} else {
-				afterCreatureZoneChange(creature, creature->getZones(), {});
-				creature->onDeath();
-			}
-			++it;
-		} else {
-			creature->inCheckCreaturesVector = false;
-
-			checkCreatureList[it] = checkCreatureList.back();
-			checkCreatureList.pop_back();
-			--end;
+	std::erase_if(checkCreatureLists[index], [this](const std::shared_ptr<Creature> &creature) {
+		if (creature->creatureCheck && creature->isAlive()) {
+			creature->onThink(EVENT_CREATURE_THINK_INTERVAL);
+			creature->onAttacking(EVENT_CREATURE_THINK_INTERVAL);
+			creature->executeConditions(EVENT_CREATURE_THINK_INTERVAL);
+			return false;
 		}
-	}
+
+		creature->inCheckCreaturesVector = false;
+		return true;
+	});
 
 	index = (index + 1) % EVENT_CREATURECOUNT;
 }