From ab60afd0b8cf281bd7884bef904f0c458107d93b Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Mon, 13 Jun 2011 10:25:03 +0000
Subject: [PATCH] - added DavifPH's fix for poisoning invulnerable players.

SVN r3231 (trunk)
---
 src/actor.h                    |  1 +
 src/p_interaction.cpp          | 19 +++++++++++++++++++
 src/thingdef/thingdef_data.cpp |  1 +
 3 files changed, 21 insertions(+)

diff --git a/src/actor.h b/src/actor.h
index fecd11a73..a79b584cd 100644
--- a/src/actor.h
+++ b/src/actor.h
@@ -328,6 +328,7 @@ enum
 	MF6_BOSSCUBE		= 0x00800000,	// Actor spawned by A_BrainSpit, flagged for timefreeze reasons.
 	MF6_SEEINVISIBLE	= 0x01000000,	// Monsters can see invisible player.
 	MF6_DONTCORPSE		= 0x02000000,	// [RC] Don't autoset MF_CORPSE upon death and don't force Crash state change.
+	MF6_POISONALWAYS	= 0x04000000,	// Always apply poison, even when target can't take the damage.
 
 // --- mobj.renderflags ---
 
diff --git a/src/p_interaction.cpp b/src/p_interaction.cpp
index c8dca95ec..957fdd2c8 100644
--- a/src/p_interaction.cpp
+++ b/src/p_interaction.cpp
@@ -1373,6 +1373,25 @@ void P_PoisonMobj (AActor *target, AActor *inflictor, AActor *source, int damage
 	int olddamage = target->PoisonDamageReceived;
 	int oldduration = target->PoisonDurationReceived;
 
+	// Check for invulnerability.
+	if (!(inflictor->flags6 & MF6_POISONALWAYS))
+	{
+		if (target->flags2 & MF2_INVULNERABLE)
+		{ // actor is invulnerable
+			if (target->player == NULL)
+			{
+				if (!(inflictor->flags3 & MF3_FOILINVUL))
+				{
+					return;
+				}
+			}
+			else
+			{
+				return;
+			}
+		}
+	}
+
 	target->Poisoner = source;
 
 	if (inflictor->flags6 & MF6_ADDITIVEPOISONDAMAGE)
diff --git a/src/thingdef/thingdef_data.cpp b/src/thingdef/thingdef_data.cpp
index 5d0c274bf..24b0200f9 100644
--- a/src/thingdef/thingdef_data.cpp
+++ b/src/thingdef/thingdef_data.cpp
@@ -231,6 +231,7 @@ static FFlagDef ActorFlags[]=
 	DEFINE_FLAG(MF6, NOMENU, AActor, flags6),
 	DEFINE_FLAG(MF6, SEEINVISIBLE, AActor, flags6),
 	DEFINE_FLAG(MF6, DONTCORPSE, AActor, flags6),
+	DEFINE_FLAG(MF6, POISONALWAYS, AActor, flags6),
 
 	// Effect flags
 	DEFINE_FLAG(FX, VISIBILITYPULSE, AActor, effects),