[Performance] Improvements to ScanCloseMobs logic (#4534)

* [Performance] Minor improvements to ScanCloseMobs

* Remove timer checks one level up to reduce branching

* Reserve memory in m_close_mobs to avoid frequent re-allocations if not already reserved.

zone/bot.cpp

@@ -1578,7 +1578,10 @@ bool Bot::Process()
 		return false;
 	}
 
-	ScanCloseMobProcess();
+	if (m_scan_close_mobs_timer.Check()) {
+		entity_list.ScanCloseMobs(this);
+	}
+
 	SpellProcess();
 
 	if (tic_timer.Check()) {

zone/client_packet.cpp

@@ -5013,7 +5013,11 @@ void Client::Handle_OP_ClientUpdate(const EQApplicationPacket *app) {
 	SetMoving(!(cy == m_Position.y && cx == m_Position.x));
 
 	CheckClientToNpcAggroTimer();
+
+	if (m_mob_check_moving_timer.Check()) {
 		CheckScanCloseMobsMovingTimer();
+	}
+
 	CheckSendBulkClientPositionUpdate();
 
 	int32 new_animation = ppu->animation;

zone/client_process.cpp

@@ -281,7 +281,9 @@ bool Client::Process() {
 			}
 		}
 
-		ScanCloseMobProcess();
+		if (m_scan_close_mobs_timer.Check()) {
+			entity_list.ScanCloseMobs(this);
+		}
 
 		if (RuleB(Inventory, LazyLoadBank)) {
 			// poll once a second to see if we are close to a banker and we haven't loaded the bank yet

zone/entity.cpp

@@ -2947,6 +2947,12 @@ void EntityList::ScanCloseMobs(Mob *scanning_mob)
 {
 	float scan_range = RuleI(Range, MobCloseScanDistance) * RuleI(Range, MobCloseScanDistance);
 
+	// Reserve memory in m_close_mobs to avoid frequent re-allocations if not already reserved.
+	// Assuming mob_list.size() as an upper bound for reservation.
+	if (scanning_mob->m_close_mobs.bucket_count() < mob_list.size()) {
+		scanning_mob->m_close_mobs.reserve(mob_list.size());
+	}
+
 	scanning_mob->m_close_mobs.clear();
 
 	for (auto &e : mob_list) {
@@ -2957,28 +2963,14 @@ void EntityList::ScanCloseMobs(Mob *scanning_mob)
 
 		float distance = DistanceSquared(scanning_mob->GetPosition(), mob->GetPosition());
 		if (distance <= scan_range || mob->GetAggroRange() >= scan_range) {
-			scanning_mob->m_close_mobs.emplace(std::pair<uint16, Mob *>(mob->GetID(), mob));
+			// add mob to scanning_mob's close list and vice versa
-
+			mob->m_close_mobs[scanning_mob->GetID()] = scanning_mob;
-			// add self to other mobs close list
+			scanning_mob->m_close_mobs[mob->GetID()] = mob;
-			if (scanning_mob->GetID() > 0) {
-				bool has_mob = false;
-
-				for (auto &cm: mob->m_close_mobs) {
-					if (scanning_mob->GetID() == cm.first) {
-						has_mob = true;
-						break;
 		}
 	}
 
-				if (!has_mob) {
+	LogAIScanClose(
-					mob->m_close_mobs.insert(std::pair<uint16, Mob *>(scanning_mob->GetID(), scanning_mob));
+		"[{}] Scanning close list > list_size [{}] moving [{}]",
-				}
-			}
-		}
-	}
-
-	LogAIScanCloseDetail(
-		"[{}] Scanning Close List | list_size [{}] moving [{}]",
 		scanning_mob->GetCleanName(),
 		scanning_mob->m_close_mobs.size(),
 		scanning_mob->IsMoving() ? "true" : "false"

zone/mob.cpp

@@ -8584,6 +8584,7 @@ bool Mob::HasBotAttackFlag(Mob* tar) {
 const uint16 scan_close_mobs_timer_moving = 6000; // 6 seconds
 const uint16 scan_close_mobs_timer_idle   = 60000; // 60 seconds
 
+// If the moving timer triggers, lets see if we are moving or idle to restart the appropriate dynamic timer
 void Mob::CheckScanCloseMobsMovingTimer()
 {
 	LogAIScanCloseDetail(
@@ -8593,9 +8594,6 @@ void Mob::CheckScanCloseMobsMovingTimer()
 		m_scan_close_mobs_timer.GetRemainingTime()
 	);
 
-	// If the moving timer triggers, lets see if we are moving or idle to restart the appropriate
-	// dynamic timer
-	if (m_mob_check_moving_timer.Check()) {
 	// If the mob is still moving, restart the moving timer
 	if (moving) {
 		if (m_scan_close_mobs_timer.GetRemainingTime() > scan_close_mobs_timer_moving) {
@@ -8611,14 +8609,6 @@ void Mob::CheckScanCloseMobsMovingTimer()
 		m_scan_close_mobs_timer.Disable();
 		m_scan_close_mobs_timer.Start(scan_close_mobs_timer_idle);
 	}
-	}
-}
-
-void Mob::ScanCloseMobProcess()
-{
-	if (m_scan_close_mobs_timer.Check()) {
-		entity_list.ScanCloseMobs(this);
-	}
 }
 
 std::unordered_map<uint16, Mob *> &Mob::GetCloseMobList(float distance)

zone/mob.h

@@ -1488,7 +1488,6 @@ public:
 
 	bool IsCloseToBanker();
 
-	void ScanCloseMobProcess();
 	std::unordered_map<uint16, Mob *> &GetCloseMobList(float distance = 0.0f);
 	void CheckScanCloseMobsMovingTimer();
 

zone/npc.cpp

@@ -601,8 +601,13 @@ bool NPC::Process()
 		DepopSwarmPets();
 	}
 
-	ScanCloseMobProcess();
+	if (m_scan_close_mobs_timer.Check()) {
+		entity_list.ScanCloseMobs(this);
+	}
+
+	if (m_mob_check_moving_timer.Check()) {
 		CheckScanCloseMobsMovingTimer();
+	}
 
 	if (hp_regen_per_second > 0 && hp_regen_per_second_timer.Check()) {
 		if (GetHP() < GetMaxHP()) {