From 03a47b82c764e73243aa809f0d033f4dfbaaa793 Mon Sep 17 00:00:00 2001
From: JavidPack <javidpack@gmail.com>
Date: Thu, 25 Jan 2024 12:41:24 -0700
Subject: [PATCH] HitModifiers.DisableKnockback to fix Flat modifier applying
 to knockBackResist==0 NPC

---
 patches/tModLoader/Terraria/NPC.TML.Hit.cs | 9 ++++++++-
 patches/tModLoader/Terraria/NPC.cs.patch   | 4 +++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/patches/tModLoader/Terraria/NPC.TML.Hit.cs b/patches/tModLoader/Terraria/NPC.TML.Hit.cs
index c0c2ef45348..187909ed12b 100644
--- a/patches/tModLoader/Terraria/NPC.TML.Hit.cs
+++ b/patches/tModLoader/Terraria/NPC.TML.Hit.cs
@@ -148,6 +148,13 @@ public struct HitModifiers
 		/// </summary>
 		public void SetCrit() => _critOverride ??= true;
 
+		private bool _knockbackDisabled = false;
+
+		/// <summary>
+		/// Sets the hit to have no knockback, regardless of <see cref="Knockback"/> values. Set automatically for NPC with <see cref="NPC.knockBackResist"/> values of 0 for consistency.
+		/// </summary>
+		public void DisableKnockback() => _knockbackDisabled = true;
+
 		/// <summary>
 		/// Used by <see cref="NPC.onFire2"/> buff (additive) and <see cref="NPC.knockBackResist"/> (multiplicative) <br/>
 		/// <br/>
@@ -223,7 +230,7 @@ public struct HitModifiers
 			return Math.Clamp((int)FinalDamage.ApplyTo(damage), 1, _damageLimit);
 		}
 
-		public readonly float GetKnockback(float baseKnockback) => Math.Max(Knockback.ApplyTo(baseKnockback), 0);
+		public readonly float GetKnockback(float baseKnockback) => _knockbackDisabled ? 0 : Math.Max(Knockback.ApplyTo(baseKnockback), 0);
 
 		public HitInfo ToHitInfo(float baseDamage, bool crit, float baseKnockback, bool damageVariation = false, float luck = 0f)
 		{
diff --git a/patches/tModLoader/Terraria/NPC.cs.patch b/patches/tModLoader/Terraria/NPC.cs.patch
index 4870a385cd5..fd5938ea182 100644
--- a/patches/tModLoader/Terraria/NPC.cs.patch
+++ b/patches/tModLoader/Terraria/NPC.cs.patch
@@ -2115,7 +2115,7 @@
  	public int checkArmorPenetration(int armorPenetration, float armorPenetrationPercent)
  	{
  		if (ichor)
-@@ -64591,26 +_,163 @@
+@@ -64591,26 +_,165 @@
  
  		return armorPenetration / 2;
  	}
@@ -2193,6 +2193,8 @@
 +			modifiers.Knockback += 0.1f;
 +
 +		modifiers.Knockback *= knockBackResist;
++		if (knockBackResist == 0)
++			modifiers.DisableKnockback();
 +
 +		NPCLoader.ModifyIncomingHit(this, ref modifiers);
 +		return modifiers;