From 31ca5a1900062e5e5bee074d8b2c4919361cf55b Mon Sep 17 00:00:00 2001
From: Major Cooke <paul.growney22@gmail.com>
Date: Sat, 8 Oct 2016 11:04:12 -0500
Subject: [PATCH] Added OverlayX/Y(int layer)

- Retrieves the X/Y positions of an overlay.
- A_OverlayFlags and A_OverlayOffset now interpret a layer of 0 to mean 'use this calling layer'.
---
 src/p_pspr.cpp                 | 52 ++++++++++++++++++++++++++++++++--
 wadsrc/static/actors/actor.txt |  2 ++
 2 files changed, 51 insertions(+), 3 deletions(-)

diff --git a/src/p_pspr.cpp b/src/p_pspr.cpp
index fab7e38d8d..e5b076acdc 100644
--- a/src/p_pspr.cpp
+++ b/src/p_pspr.cpp
@@ -1006,7 +1006,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_OverlayOffset)
 	PARAM_FLOAT_OPT(wx)		{ wx = 0.; }
 	PARAM_FLOAT_OPT(wy)		{ wy = 32.; }
 	PARAM_INT_OPT(flags)	{ flags = 0; }
-	A_OverlayOffset(self, layer, wx, wy, flags);
+	A_OverlayOffset(self, ((layer != 0) ? layer : stateinfo->mPSPIndex), wx, wy, flags);
 	return 0;
 }
 
@@ -1033,10 +1033,10 @@ DEFINE_ACTION_FUNCTION(AActor, A_OverlayFlags)
 	PARAM_INT(flags);
 	PARAM_BOOL(set);
 
-	if (self->player == nullptr)
+	if (!ACTION_CALL_FROM_PSPRITE())
 		return 0;
 
-	DPSprite *pspr = self->player->FindPSprite(layer);
+	DPSprite *pspr = self->player->FindPSprite(((layer != 0) ? layer : stateinfo->mPSPIndex));
 
 	if (pspr == nullptr)
 		return 0;
@@ -1049,6 +1049,52 @@ DEFINE_ACTION_FUNCTION(AActor, A_OverlayFlags)
 	return 0;
 }
 
+//---------------------------------------------------------------------------
+//
+// PROC OverlayX/Y
+// Action function to return the X/Y of an overlay.
+//---------------------------------------------------------------------------
+
+static double GetOverlayPosition(AActor *self, int layer, bool gety)
+{
+	if (layer)
+	{
+		DPSprite *pspr = self->player->FindPSprite(layer);
+
+		if (pspr != nullptr)
+		{
+			return gety ? (pspr->y) : (pspr->x);
+		}
+	}
+	return 0.;
+}
+
+DEFINE_ACTION_FUNCTION(AActor, OverlayX)
+{
+	PARAM_ACTION_PROLOGUE;
+	PARAM_INT_OPT(layer) { layer = 0; }
+
+	if (ACTION_CALL_FROM_PSPRITE())
+	{
+		double res = GetOverlayPosition(self, ((layer != 0) ? layer : stateinfo->mPSPIndex), false);
+		ACTION_RETURN_FLOAT(res);	
+	}
+	ACTION_RETURN_FLOAT(0.);
+}
+
+DEFINE_ACTION_FUNCTION(AActor, OverlayY)
+{
+	PARAM_ACTION_PROLOGUE;
+	PARAM_INT_OPT(layer) { layer = 0; }
+
+	if (ACTION_CALL_FROM_PSPRITE())
+	{
+		double res = GetOverlayPosition(self, ((layer != 0) ? layer : stateinfo->mPSPIndex), true);
+		ACTION_RETURN_FLOAT(res);
+	}
+	ACTION_RETURN_FLOAT(0.);
+}
+
 //---------------------------------------------------------------------------
 //
 // PROC OverlayID
diff --git a/wadsrc/static/actors/actor.txt b/wadsrc/static/actors/actor.txt
index 44b801f511..fb6b4c832f 100644
--- a/wadsrc/static/actors/actor.txt
+++ b/wadsrc/static/actors/actor.txt
@@ -58,6 +58,8 @@ ACTOR Actor native //: Thinker
 	native float GetSpriteRotation(int ptr = AAPTR_DEFAULT);
 	native int GetMissileDamage(int mask, int add, int ptr = AAPTR_DEFAULT);
 	action native int OverlayID();
+	action native float OverlayX(int layer = 0);
+	action native float OverlayY(int layer = 0);
 
 	// Action functions
 	// Meh, MBF redundant functions. Only for DeHackEd support.