From abd6275f17a19707163f31a3fefd56b7f5e266f9 Mon Sep 17 00:00:00 2001
From: Mitchell Richters <mjr4077au@gmail.com>
Date: Mon, 21 Nov 2022 14:53:52 +1100
Subject: [PATCH] - Add new double `DCoreActor::viewzoffset` set in spawning
 code during level loads.

* Interpolated backup copy isn't needed for Duke, but will be for SW.
---
 source/core/coreactor.h            | 3 +++
 source/core/savegamehelp.cpp       | 9 +++++++--
 source/core/vmexports.cpp          | 1 +
 source/games/duke/src/premap.cpp   | 5 ++++-
 wadsrc/static/zscript/coreactor.zs | 1 +
 5 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/source/core/coreactor.h b/source/core/coreactor.h
index bec88ea60..3c8202ba1 100644
--- a/source/core/coreactor.h
+++ b/source/core/coreactor.h
@@ -44,6 +44,7 @@ public:
 	DVector3 opos;
 	DAngle oang;
 	DVector3 vel;
+	double oviewzoffset, viewzoffset;
 	double clipdist;
 
 	int time;
@@ -113,6 +114,7 @@ public:
 	void backupz()
 	{
 		opos.Z = spr.pos.Z;
+		oviewzoffset = viewzoffset;
 	}
 
 	void backupvec2()
@@ -123,6 +125,7 @@ public:
 	void backuppos()
 	{
 		opos = spr.pos;
+		oviewzoffset = viewzoffset;
 	}
 
 	void backupang()
diff --git a/source/core/savegamehelp.cpp b/source/core/savegamehelp.cpp
index 7bbc48761..96fc6615f 100644
--- a/source/core/savegamehelp.cpp
+++ b/source/core/savegamehelp.cpp
@@ -627,9 +627,14 @@ void DCoreActor::Serialize(FSerializer& arc)
 		("spriteext", sprext)
 		("xvel", vel.X)
 		("yvel", vel.Y)
-		("zvel", vel.Z);
+		("zvel", vel.Z)
+		("viewzoffset", viewzoffset);
 
-	if (arc.isReading()) spsmooth = {};
+	if (arc.isReading())
+	{
+		spsmooth = {};
+		backuppos();
+	}
 }
 
 
diff --git a/source/core/vmexports.cpp b/source/core/vmexports.cpp
index 43ef4f383..67383b5dc 100644
--- a/source/core/vmexports.cpp
+++ b/source/core/vmexports.cpp
@@ -619,6 +619,7 @@ DEFINE_FIELD_NAMED(DCoreActor, time, spawnindex)
 DEFINE_FIELD(DCoreActor, spritesetindex)
 DEFINE_FIELD_NAMED(DCoreActor, spr.angle, angle)
 DEFINE_FIELD(DCoreActor, vel)
+DEFINE_FIELD(DCoreActor, viewzoffset)
 
 void coreactor_setpos(DCoreActor* self, double x, double y, double z, int relink)
 {
diff --git a/source/games/duke/src/premap.cpp b/source/games/duke/src/premap.cpp
index 61dd1a733..1f1df86cd 100644
--- a/source/games/duke/src/premap.cpp
+++ b/source/games/duke/src/premap.cpp
@@ -512,9 +512,12 @@ void resetpspritevars(int g)
 	int aimmode[MAXPLAYERS];
 	STATUSBARTYPE tsbar[MAXPLAYERS];
 
-	CreateActor(ps[0].cursector, ps[0].posGet(),
+	auto newActor = CreateActor(ps[0].cursector, ps[0].posGet(),
 		TILE_APLAYER, 0, DVector2(0, 0), ps[0].angle.ang, 0., 0., nullptr, 10);
 
+	newActor->viewzoffset = -gs.playerheight;
+	newActor->backupz();
+
 	if (ud.recstat != 2) for (i = 0; i < MAXPLAYERS; i++)
 	{
 		aimmode[i] = ps[i].aim_mode;
diff --git a/wadsrc/static/zscript/coreactor.zs b/wadsrc/static/zscript/coreactor.zs
index 6c3216b79..424c1a3eb 100644
--- a/wadsrc/static/zscript/coreactor.zs
+++ b/wadsrc/static/zscript/coreactor.zs
@@ -45,6 +45,7 @@ class CoreActor native
 	native double clipdist;
 	native double angle;
 	native Vector3 vel;
+	native double viewzoffset;
 
 	native readonly int16 spritesetindex;
 	native readonly int spawnindex;