From cdd22626b47973f9ad8b2ebfa69fbd0616051b11 Mon Sep 17 00:00:00 2001
From: Eric Robinson <68359262+kphoenix137@users.noreply.github.com>
Date: Sun, 22 Sep 2024 20:46:33 -0400
Subject: [PATCH] Fix Knockback direction (#7093)

---
 Source/missiles.cpp | 6 +++---
 Source/monster.cpp  | 8 ++++----
 Source/monster.h    | 2 +-
 Source/msg.cpp      | 2 +-
 Source/player.cpp   | 2 +-
 5 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/Source/missiles.cpp b/Source/missiles.cpp
index 2d5bc48b6b3..b171138a71c 100644
--- a/Source/missiles.cpp
+++ b/Source/missiles.cpp
@@ -203,7 +203,7 @@ int ProjectileTrapDamage()
 	return currlevel + GenerateRnd(2 * currlevel);
 }
 
-bool MonsterMHit(const Player &player, int monsterId, int mindam, int maxdam, int dist, MissileID t, DamageType damageType, bool shift)
+bool MonsterMHit(const Player &player, int monsterId, int mindam, int maxdam, int dist, MissileID t, WorldTilePosition startPos, DamageType damageType, bool shift)
 {
 	Monster &monster = Monsters[monsterId];
 
@@ -268,7 +268,7 @@ bool MonsterMHit(const Player &player, int monsterId, int mindam, int maxdam, in
 		PlayEffect(monster, MonsterSound::Hit);
 	} else {
 		if (monster.mode != MonsterMode::Petrified && missileData.isArrow() && HasAnyOf(player._pIFlags, ItemSpecialEffect::Knockback))
-			M_GetKnockback(monster);
+			M_GetKnockback(monster, startPos);
 		if (monster.type().type != MT_GOLEM)
 			M_StartHit(monster, player, dam);
 	}
@@ -422,7 +422,7 @@ void CheckMissileCol(Missile &missile, DamageType damageType, int minDamage, int
 			// then the missile can potentially hit this target
 			isMonsterHit = MonsterTrapHit(mid, minDamage, maxDamage, missile._midist, missile._mitype, damageType, isDamageShifted);
 		} else if (IsAnyOf(missile._micaster, TARGET_BOTH, TARGET_MONSTERS)) {
-			isMonsterHit = MonsterMHit(*missile.sourcePlayer(), mid, minDamage, maxDamage, missile._midist, missile._mitype, damageType, isDamageShifted);
+			isMonsterHit = MonsterMHit(*missile.sourcePlayer(), mid, minDamage, maxDamage, missile._midist, missile._mitype, missile.position.start, damageType, isDamageShifted);
 		}
 	}
 
diff --git a/Source/monster.cpp b/Source/monster.cpp
index ab6adf8762d..60e8cfb96bb 100644
--- a/Source/monster.cpp
+++ b/Source/monster.cpp
@@ -3734,9 +3734,9 @@ void M_ClearSquares(const Monster &monster)
 	}
 }
 
-void M_GetKnockback(Monster &monster)
+void M_GetKnockback(Monster &monster, WorldTilePosition attackerStartPos)
 {
-	Direction dir = Opposite(monster.direction);
+	Direction dir = GetDirection(attackerStartPos, monster.position.tile);
 	if (!IsRelativeMoveOK(monster, monster.position.old, dir)) {
 		return;
 	}
@@ -4449,7 +4449,7 @@ void MissToMonst(Missile &missile, Point position)
 
 		if (player->_pmode != PM_GOTHIT && player->_pmode != PM_DEATH)
 			StartPlrHit(*player, 0, true);
-		Point newPosition = oldPosition + monster.direction;
+		Point newPosition = oldPosition + GetDirection(missile.position.start, oldPosition);
 		if (PosOkPlayer(*player, newPosition)) {
 			player->position.tile = newPosition;
 			FixPlayerLocation(*player, player->_pdir);
@@ -4470,7 +4470,7 @@ void MissToMonst(Missile &missile, Point position)
 	if (IsAnyOf(monster.type().type, MT_NSNAKE, MT_RSNAKE, MT_BSNAKE, MT_GSNAKE))
 		return;
 
-	Point newPosition = oldPosition + monster.direction;
+	Point newPosition = oldPosition + GetDirection(missile.position.start, oldPosition);
 	if (IsTileAvailable(*target, newPosition)) {
 		monster.occupyTile(newPosition, false);
 		dMonster[oldPosition.x][oldPosition.y] = 0;
diff --git a/Source/monster.h b/Source/monster.h
index 44d46ed31a5..a4d72243135 100644
--- a/Source/monster.h
+++ b/Source/monster.h
@@ -514,7 +514,7 @@ void ApplyMonsterDamage(DamageType damageType, Monster &monster, int damage);
 bool M_Talker(const Monster &monster);
 void M_StartStand(Monster &monster, Direction md);
 void M_ClearSquares(const Monster &monster);
-void M_GetKnockback(Monster &monster);
+void M_GetKnockback(Monster &monster, WorldTilePosition attackerStartPos);
 void M_StartHit(Monster &monster, int dam);
 void M_StartHit(Monster &monster, const Player &player, int dam);
 void StartMonsterDeath(Monster &monster, const Player &player, bool sendmsg);
diff --git a/Source/msg.cpp b/Source/msg.cpp
index 0a6e2e445bd..cbcfd6bcb31 100644
--- a/Source/msg.cpp
+++ b/Source/msg.cpp
@@ -1659,7 +1659,7 @@ size_t OnKnockback(const TCmd *pCmd, Player &player)
 
 	if (gbBufferMsgs != 1 && player.isOnActiveLevel() && monsterIdx < MaxMonsters) {
 		Monster &monster = Monsters[monsterIdx];
-		M_GetKnockback(monster);
+		M_GetKnockback(monster, player.position.tile);
 		M_StartHit(monster, player, 0);
 	}
 
diff --git a/Source/player.cpp b/Source/player.cpp
index 2489fc473e1..a4e26c81f44 100644
--- a/Source/player.cpp
+++ b/Source/player.cpp
@@ -679,7 +679,7 @@ bool PlrHitMonst(Player &player, Monster &monster, bool adjacentDamage = false)
 		M_StartKill(monster, player);
 	} else {
 		if (monster.mode != MonsterMode::Petrified && HasAnyOf(player._pIFlags, ItemSpecialEffect::Knockback))
-			M_GetKnockback(monster);
+			M_GetKnockback(monster, player.position.tile);
 		M_StartHit(monster, player, dam);
 	}
 	return true;