From 0e07e231a219fb810c100e1cd823ef7585f7e2ff Mon Sep 17 00:00:00 2001
From: Mat <mail@mathias.is>
Date: Thu, 19 Mar 2020 19:13:41 +0200
Subject: [PATCH] Improvements to knockback (#4504)

* Improvements to knockback
* SetSpeed for explosions
* Improve code consistency
---
 src/ChunkMap.cpp               |  2 +-
 src/Entities/ArrowEntity.cpp   |  8 ++++++--
 src/Entities/Entity.cpp        | 24 ++++++++++++++++++------
 src/Entities/Player.cpp        |  4 ----
 src/Mobs/AggressiveMonster.cpp |  4 +++-
 5 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/src/ChunkMap.cpp b/src/ChunkMap.cpp
index 32c7d548f..364dfbb3d 100644
--- a/src/ChunkMap.cpp
+++ b/src/ChunkMap.cpp
@@ -1319,7 +1319,7 @@ void cChunkMap::DoExplosionAt(double a_ExplosionSize, double a_BlockX, double a_
 				DistanceFromExplosion.Normalize();
 				DistanceFromExplosion *= Impact;
 
-				a_Entity.AddSpeed(DistanceFromExplosion);
+				a_Entity.SetSpeed(DistanceFromExplosion);
 			}
 
 			return false;
diff --git a/src/Entities/ArrowEntity.cpp b/src/Entities/ArrowEntity.cpp
index 249ff42d0..6fef2c7ee 100644
--- a/src/Entities/ArrowEntity.cpp
+++ b/src/Entities/ArrowEntity.cpp
@@ -115,9 +115,13 @@ void cArrowEntity::OnHitEntity(cEntity & a_EntityHit, Vector3d a_HitPos)
 		Damage += ExtraDamage;
 	}
 
+	double Knockback = 10;
+
 	unsigned int PunchLevel = m_CreatorData.m_Enchantments.GetLevel(cEnchantments::enchPunch);
-	double KnockbackAmount = 11 + 10 * PunchLevel;
-	a_EntityHit.TakeDamage(dtRangedAttack, GetCreatorUniqueID(), Damage, KnockbackAmount);
+	unsigned int PunchLevelMultiplier = 8;
+
+	Knockback += PunchLevelMultiplier * PunchLevel;
+	a_EntityHit.TakeDamage(dtRangedAttack, GetCreatorUniqueID(), Damage, Knockback);
 
 	if (IsOnFire() && !a_EntityHit.IsInWater())
 	{
diff --git a/src/Entities/Entity.cpp b/src/Entities/Entity.cpp
index 206e6af60..f0118104b 100644
--- a/src/Entities/Entity.cpp
+++ b/src/Entities/Entity.cpp
@@ -344,7 +344,17 @@ void cEntity::TakeDamage(eDamageType a_DamageType, cEntity * a_Attacker, int a_R
 		Heading = a_Attacker->GetLookVector();
 	}
 
-	TDI.Knockback = Heading * a_KnockbackAmount;
+	int KnockbackHeight = 3;
+
+	if (IsPlayer())
+	{
+		KnockbackHeight = 8;
+	}
+
+	// Apply slight height to knockback
+	Vector3d FinalKnockback = Vector3d(Heading.x * a_KnockbackAmount, Heading.y + KnockbackHeight, Heading.z * a_KnockbackAmount);
+
+	TDI.Knockback = FinalKnockback;
 	DoTakeDamage(TDI);
 }
 
@@ -535,7 +545,7 @@ bool cEntity::DoTakeDamage(TakeDamageInfo & a_TDI)
 	// Add knockback:
 	if ((IsMob() || IsPlayer()) && (a_TDI.Attacker != nullptr))
 	{
-		AddSpeed(a_TDI.Knockback);
+		SetSpeed(a_TDI.Knockback);
 	}
 
 	m_World->BroadcastEntityStatus(*this, esGenericHurt);
@@ -772,18 +782,20 @@ int cEntity::GetArmorCoverAgainst(const cEntity * a_Attacker, eDamageType a_Dama
 
 double cEntity::GetKnockbackAmountAgainst(const cEntity & a_Receiver)
 {
-	// Returns the knockback amount that the currently equipped items would cause to a_Receiver on a hit
-	double Knockback = 11;
+	// Default knockback for entities
+	double Knockback = 10;
 
 	// If we're sprinting, bump up the knockback
 	if (IsSprinting())
 	{
-		Knockback = 16;
+		Knockback = 15;
 	}
 
 	// Check for knockback enchantments (punch only applies to shot arrows)
 	unsigned int KnockbackLevel = GetEquippedWeapon().m_Enchantments.GetLevel(cEnchantments::enchKnockback);
-	Knockback += 10 * KnockbackLevel;
+	unsigned int KnockbackLevelMultiplier = 8;
+
+	Knockback += KnockbackLevelMultiplier * KnockbackLevel;
 
 	return Knockback;
 }
diff --git a/src/Entities/Player.cpp b/src/Entities/Player.cpp
index 07342bd52..b182629ea 100644
--- a/src/Entities/Player.cpp
+++ b/src/Entities/Player.cpp
@@ -1000,10 +1000,6 @@ void cPlayer::ApplyArmorDamage(int a_DamageBlocked)
 
 bool cPlayer::DoTakeDamage(TakeDamageInfo & a_TDI)
 {
-	SetSpeed(0, 0, 0);
-	// Prevents knocking the player in the wrong direction due to
-	// the speed vector problems, see #2865
-	// In the future, the speed vector should be fixed
 	if ((a_TDI.DamageType != dtInVoid) && (a_TDI.DamageType != dtPlugin))
 	{
 		if (IsGameModeCreative() || IsGameModeSpectator())
diff --git a/src/Mobs/AggressiveMonster.cpp b/src/Mobs/AggressiveMonster.cpp
index 9b13615de..da2b02a6d 100644
--- a/src/Mobs/AggressiveMonster.cpp
+++ b/src/Mobs/AggressiveMonster.cpp
@@ -102,7 +102,9 @@ bool cAggressiveMonster::Attack(std::chrono::milliseconds a_Dt)
 
 	// Setting this higher gives us more wiggle room for attackrate
 	ResetAttackCooldown();
-	GetTarget()->TakeDamage(dtMobAttack, this, m_AttackDamage, 0);
+
+	double KnockbackAmount = 9;
+	GetTarget()->TakeDamage(dtMobAttack, this, m_AttackDamage, KnockbackAmount);
 
 	return true;
 }