From d36f656caf78f6bc8a4d4c043aec7038b9efc2d7 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Wed, 29 Mar 2017 20:25:54 +0200
Subject: [PATCH] - added a callback for when damage is drained from a target.

---
 src/p_interaction.cpp           | 6 ++++++
 wadsrc/static/zscript/actor.txt | 5 +++++
 2 files changed, 11 insertions(+)

diff --git a/src/p_interaction.cpp b/src/p_interaction.cpp
index eb1fb46fe..431c637de 100644
--- a/src/p_interaction.cpp
+++ b/src/p_interaction.cpp
@@ -1415,6 +1415,12 @@ static int DamageMobj (AActor *target, AActor *inflictor, AActor *source, int da
 				}
 			}
 
+			IFVIRTUALPTR(source, AActor, OnDrain)
+			{
+				VMValue params[] = { source, target, draindamage, mod.GetIndex() };
+				VMReturn ret(&draindamage);
+				GlobalVMStack.Call(func, params, countof(params), &ret, 1);
+			}
 			if ( P_GiveBody( source, int(draindamage * damage)))
 			{
 				S_Sound(source, CHAN_ITEM, "*drainhealth", 1, ATTN_NORM );
diff --git a/wadsrc/static/zscript/actor.txt b/wadsrc/static/zscript/actor.txt
index daac2f23d..fb883f846 100644
--- a/wadsrc/static/zscript/actor.txt
+++ b/wadsrc/static/zscript/actor.txt
@@ -489,6 +489,11 @@ class Actor : Thinker native
 		return Obituary;
 	}
 	
+	virtual int OnDrain(Actor victim, int damage, Name dmgtype)
+	{
+		return damage;
+	}
+	
 	native virtual bool OkayToSwitchTarget(Actor other);
 	native static class<Actor> GetReplacement(class<Actor> cls);
 	native static class<Actor> GetReplacee(class<Actor> cls);