Monsters: improve targeting

* Replace DoWithNearestPlayer with bounding box search (avoid iterating through all players in world).
* Do line-of-sight checks from eye-to-eye.
+ Added LOS and LOS lost timer to target lost checks, in addition to distance.

src/Mobs/AggressiveMonster.cpp

@@ -38,11 +38,6 @@ void cAggressiveMonster::InStateChasing(std::chrono::milliseconds a_Dt, cChunk &
 
 void cAggressiveMonster::EventSeePlayer(cPlayer * a_Player, cChunk & a_Chunk)
 {
-	if (!a_Player->CanMobsTarget())
-	{
-		return;
-	}
-
 	Super::EventSeePlayer(a_Player, a_Chunk);
 	m_EMState = CHASING;
 }
@@ -60,27 +55,25 @@ void cAggressiveMonster::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 		return;
 	}
 
+	// Set or clear m_Target depending on rules for this Monster:
 	if (m_EMState == CHASING)
 	{
-		CheckEventLostPlayer();
+		CheckEventLostPlayer(a_Dt);
 	}
 	else
 	{
 		CheckEventSeePlayer(a_Chunk);
 	}
 
-	auto target = GetTarget();
-	if (target == nullptr)
-	{
-		return;
-	}
-
-	// TODO: Currently all mobs see through lava, but only Nether-native mobs should be able to.
-	Vector3d MyHeadPosition = GetPosition() + Vector3d(0, GetHeight(), 0);
-	Vector3d TargetPosition = target->GetPosition() + Vector3d(0, target->GetHeight(), 0);
 	if (
+		(GetTarget() != nullptr) &&
 		TargetIsInRange() &&
-		cLineBlockTracer::LineOfSightTrace(*GetWorld(), MyHeadPosition, TargetPosition, cLineBlockTracer::losAirWaterLava) &&
+		cLineBlockTracer::LineOfSightTrace(
+			*GetWorld(),
+			GetPosition().addedY(GetHeight()),
+			GetTarget()->GetPosition().addedY(GetTarget()->GetHeight()),
+			cLineBlockTracer::losAirWaterLava  // TODO: Currently all mobs see through lava, but only Nether-native mobs should be able to.
+		) &&
 		(GetHealth() > 0.0)
 	)
 	{

src/Mobs/Enderman.cpp

@@ -113,14 +113,8 @@ void cEnderman::CheckEventSeePlayer(cChunk & a_Chunk)
 
 	ASSERT(Callback.GetPlayer() != nullptr);
 
-	if (!Callback.GetPlayer()->CanMobsTarget())
-	{
-		return;
-	}
-
-	// Target the player
-	cMonster::EventSeePlayer(Callback.GetPlayer(), a_Chunk);
-	m_EMState = CHASING;
+	// Target the player:
+	cAggressiveMonster::EventSeePlayer(Callback.GetPlayer(), a_Chunk);
 	m_bIsScreaming = true;
 	GetWorld()->BroadcastEntityMetadata(*this);
 }
@@ -129,16 +123,6 @@ void cEnderman::CheckEventSeePlayer(cChunk & a_Chunk)
 
 
 
-void cEnderman::CheckEventLostPlayer(void)
-{
-	Super::CheckEventLostPlayer();
-	EventLosePlayer();
-}
-
-
-
-
-
 void cEnderman::EventLosePlayer()
 {
 	Super::EventLosePlayer();

src/Mobs/Enderman.h

@@ -20,7 +20,6 @@ public:
 
 	virtual void GetDrops(cItems & a_Drops, cEntity * a_Killer = nullptr) override;
 	virtual void CheckEventSeePlayer(cChunk & a_Chunk) override;
-	virtual void CheckEventLostPlayer(void) override;
 	virtual void EventLosePlayer(void) override;
 	virtual void Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk) override;
 

src/Mobs/Monster.cpp

@@ -2,6 +2,7 @@
 #include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules
 
 #include "IncludeAllMonsters.h"
+#include "LineBlockTracer.h"
 #include "../BlockInfo.h"
 #include "../Root.h"
 #include "../Server.h"
@@ -306,19 +307,6 @@ void cMonster::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 	{
 		++m_TicksSinceLastDamaged;
 	}
-	if ((GetTarget() != nullptr))
-	{
-		ASSERT(GetTarget()->IsTicking());
-
-		if (GetTarget()->IsPlayer())
-		{
-			if (!static_cast<cPlayer *>(GetTarget())->CanMobsTarget())
-			{
-				SetTarget(nullptr);
-				m_EMState = IDLE;
-			}
-		}
-	}
 
 	// Process the undead burning in daylight.
 	HandleDaylightBurning(*Chunk, WouldBurnAt(GetPosition(), *Chunk));
@@ -764,29 +752,94 @@ void cMonster::OnRightClicked(cPlayer & a_Player)
 // monster sez: Do I see the player
 void cMonster::CheckEventSeePlayer(cChunk & a_Chunk)
 {
-	m_World->DoWithNearestPlayer(GetPosition(), static_cast<float>(m_SightDistance), [&](cPlayer & a_Player) -> bool
+	if (GetTarget() != nullptr)
 	{
-		EventSeePlayer(&a_Player, a_Chunk);
-		return true;
-	}, true);
+		return;
+	}
+
+	cPlayer * TargetPlayer = nullptr;
+	double ClosestDistance = m_SightDistance * m_SightDistance;
+	const auto MyHeadPosition = GetPosition().addedY(GetHeight());
+
+	// Enumerate all players within sight:
+	m_World->ForEachEntityInBox({ GetPosition(), m_SightDistance * 2.0 }, [this, &TargetPlayer, &ClosestDistance, MyHeadPosition](cEntity & a_Entity)
+	{
+		if (!a_Entity.IsPlayer())
+		{
+			// Continue iteration:
+			return false;
+		}
+
+		const auto Player = static_cast<cPlayer *>(&a_Entity);
+
+		if (!Player->CanMobsTarget())
+		{
+			return false;
+		}
+
+		const auto TargetHeadPosition = a_Entity.GetPosition().addedY(a_Entity.GetHeight());
+		const auto TargetDistance = (TargetHeadPosition - MyHeadPosition).SqrLength();
+
+		// TODO: Currently all mobs see through lava, but only Nether-native mobs should be able to.
+		if (
+			(TargetDistance < ClosestDistance) &&
+			cLineBlockTracer::LineOfSightTrace(*GetWorld(), MyHeadPosition, TargetHeadPosition, cLineBlockTracer::losAirWaterLava)
+		)
+		{
+			TargetPlayer = Player;
+			ClosestDistance = TargetDistance;
+		}
+
+		return false;
+	});
+
+	// Target him if suitable player found:
+	if (TargetPlayer != nullptr)
+	{
+		EventSeePlayer(TargetPlayer, a_Chunk);
+	}
 }
 
 
 
 
 
-void cMonster::CheckEventLostPlayer(void)
+void cMonster::CheckEventLostPlayer(const std::chrono::milliseconds a_Dt)
 {
-	if (GetTarget() != nullptr)
+	const auto Target = GetTarget();
+
+	if (Target == nullptr)
 	{
-		if ((GetTarget()->GetPosition() - GetPosition()).Length() > m_SightDistance)
+		return;
+	}
+
+	// Check if the player died, is in creative mode, etc:
+	if (Target->IsPlayer() && !static_cast<cPlayer *>(Target)->CanMobsTarget())
+	{
+		EventLosePlayer();
+		return;
+	}
+
+	// Check if the target is too far away:
+	if (!Target->GetBoundingBox().DoesIntersect({ GetPosition(), m_SightDistance * 2.0 }))
+	{
+		EventLosePlayer();
+		return;
+	}
+
+	const auto MyHeadPosition = GetPosition().addedY(GetHeight());
+	const auto TargetHeadPosition = Target->GetPosition().addedY(Target->GetHeight());
+	if (!cLineBlockTracer::LineOfSightTrace(*GetWorld(), MyHeadPosition, TargetHeadPosition, cLineBlockTracer::losAirWaterLava))
+	{
+		if ((m_LoseSightAbandonTargetTimer += a_Dt) > std::chrono::seconds(4))
 		{
 			EventLosePlayer();
 		}
 	}
 	else
 	{
-		EventLosePlayer();
+		// Subtract the amount of time we "handled" instead of setting to zero, so we don't ignore a large a_Dt of say, 8s:
+		m_LoseSightAbandonTargetTimer -= std::min(std::chrono::milliseconds(4000), m_LoseSightAbandonTargetTimer);
 	}
 }
 
@@ -809,7 +862,9 @@ void cMonster::EventSeePlayer(cPlayer * a_SeenPlayer, cChunk & a_Chunk)
 void cMonster::EventLosePlayer(void)
 {
 	SetTarget(nullptr);
+
 	m_EMState = IDLE;
+	m_LoseSightAbandonTargetTimer = std::chrono::seconds::zero();
 }
 
 

src/Mobs/Monster.h

@@ -117,7 +117,7 @@ public:
 	virtual bool IsUndead(void);
 
 	virtual void EventLosePlayer(void);
-	virtual void CheckEventLostPlayer(void);
+	virtual void CheckEventLostPlayer(std::chrono::milliseconds a_Dt);
 
 	virtual void InStateIdle    (std::chrono::milliseconds a_Dt, cChunk & a_Chunk);
 	virtual void InStateChasing (std::chrono::milliseconds a_Dt, cChunk & a_Chunk);
@@ -313,6 +313,7 @@ protected:
 	double m_AttackRange;
 	int m_AttackCoolDownTicksLeft;
 	int m_SightDistance;
+	std::chrono::milliseconds m_LoseSightAbandonTargetTimer;
 
 	float m_DropChanceWeapon;
 	float m_DropChanceHelmet;

src/Mobs/PassiveAggressiveMonster.cpp

@@ -26,7 +26,7 @@ bool cPassiveAggressiveMonster::DoTakeDamage(TakeDamageInfo & a_TDI)
 		return false;
 	}
 
-	if ((GetTarget() != nullptr) && (GetTarget()->IsPlayer()))
+	if ((GetTarget() != nullptr) && GetTarget()->IsPlayer())
 	{
 		if (static_cast<cPlayer *>(GetTarget())->CanMobsTarget())
 		{

src/Mobs/PassiveMonster.cpp

@@ -57,7 +57,7 @@ void cPassiveMonster::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 
 	if (m_EMState == ESCAPING)
 	{
-		CheckEventLostPlayer();
+		CheckEventLostPlayer(a_Dt);
 	}
 
 	cMonster::LoveTick();

src/Mobs/Spider.cpp

@@ -48,10 +48,7 @@ void cSpider::EventSeePlayer(cPlayer * a_Player, cChunk & a_Chunk)
 		return;
 	}
 
-	if (
-		a_Player->CanMobsTarget() &&
-		!((Chunk->GetSkyLightAltered(Rel.x, Rel.y, Rel.z) > 11) || (Chunk->GetBlockLight(Rel.x, Rel.y, Rel.z) > 11))
-	)
+	if ((Chunk->GetSkyLightAltered(Rel.x, Rel.y, Rel.z) <= 11) && (Chunk->GetBlockLight(Rel.x, Rel.y, Rel.z) <= 11))
 	{
 		Super::EventSeePlayer(a_Player, a_Chunk);
 	}