From fac5abf69e92c397cb005cd19bcb34294755c80b Mon Sep 17 00:00:00 2001
From: "James R." <justsomejames2@gmail.com>
Date: Sun, 17 Sep 2023 19:06:55 -0700
Subject: [PATCH] MT_SHADOW: move code to objects/shadow.cpp; copy whiteshadow
 from followed object

---
 src/k_objects.h            |  4 +++
 src/objects/CMakeLists.txt |  1 +
 src/objects/hyudoro.c      | 16 +----------
 src/objects/shadow.cpp     | 59 ++++++++++++++++++++++++++++++++++++++
 src/p_mobj.c               | 12 ++------
 5 files changed, 68 insertions(+), 24 deletions(-)
 create mode 100644 src/objects/shadow.cpp

diff --git a/src/k_objects.h b/src/k_objects.h
index 7050ddff4..1ea1578a3 100644
--- a/src/k_objects.h
+++ b/src/k_objects.h
@@ -214,6 +214,10 @@ void Obj_EmeraldFlareThink(mobj_t *flare);
 void Obj_BeginEmeraldOrbit(mobj_t *emerald, mobj_t *target, fixed_t radius, INT32 revolution_time, tic_t fuse);
 void Obj_GiveEmerald(mobj_t *emerald);
 
+/* Fake Shadow */
+mobj_t *Obj_SpawnFakeShadow(mobj_t *from);
+void Obj_FakeShadowThink(mobj_t *shadow);
+
 /* Checkpoints */
 void Obj_ResetCheckpoints(void);
 void Obj_LinkCheckpoint(mobj_t *end);
diff --git a/src/objects/CMakeLists.txt b/src/objects/CMakeLists.txt
index c3b01f4a0..89d5a17c1 100644
--- a/src/objects/CMakeLists.txt
+++ b/src/objects/CMakeLists.txt
@@ -29,4 +29,5 @@ target_sources(SRB2SDL2 PRIVATE
 	sneaker-panel.c
 	emerald.c
 	checkpoint.cpp
+	shadow.cpp
 )
diff --git a/src/objects/hyudoro.c b/src/objects/hyudoro.c
index 4b104b9d0..b5fa87429 100644
--- a/src/objects/hyudoro.c
+++ b/src/objects/hyudoro.c
@@ -183,20 +183,6 @@ project_hyudoro_hover (mobj_t *hyu)
 	bob_in_place(hyu, 64);
 }
 
-static void
-spawn_hyudoro_shadow (mobj_t *hyu)
-{
-	mobj_t *shadow = P_SpawnMobjFromMobj(
-			hyu, 0, 0, 0, MT_SHADOW);
-
-	shadow->whiteshadow = true;
-
-	shadow->shadowscale = hyu->shadowscale;
-	hyu->shadowscale = 0;
-
-	P_SetTarget(&shadow->tracer, hyu);
-}
-
 static mobj_t *
 find_duel_target (mobj_t *ignore)
 {
@@ -572,7 +558,7 @@ Obj_InitHyudoroCenter (mobj_t * center, mobj_t * master)
 		hyu->renderflags &= ~(K_GetPlayerDontDrawFlag(master->player));
 	}
 
-	spawn_hyudoro_shadow(hyu); // this sucks btw
+	Obj_SpawnFakeShadow(hyu); // this sucks btw
 }
 
 void
diff --git a/src/objects/shadow.cpp b/src/objects/shadow.cpp
new file mode 100644
index 000000000..448f9d4af
--- /dev/null
+++ b/src/objects/shadow.cpp
@@ -0,0 +1,59 @@
+#include "../info.h"
+#include "../k_objects.h"
+#include "../p_local.h"
+#include "../p_mobj.h"
+#include "../p_tick.h"
+#include "../typedef.h"
+
+#define shadow_follow(o) ((o)->tracer)
+
+struct Shadow : mobj_t
+{
+	mobj_t* follow() const { return shadow_follow(this); }
+	void follow(mobj_t* n) { P_SetTarget(&shadow_follow(this), n); }
+
+	static Shadow* spawn(mobj_t* from)
+	{
+		return static_cast<Shadow*>(P_SpawnMobjFromMobj(from, 0, 0, 0, MT_SHADOW))->init(from);
+	}
+
+	bool valid() const { return !P_MobjWasRemoved(this) && !P_MobjWasRemoved(follow()); }
+
+	void destroy() { P_RemoveMobj(this); }
+
+	void move()
+	{
+		whiteshadow = follow()->whiteshadow;
+
+		P_MoveOrigin(this, follow()->x, follow()->y, P_GetMobjFeet(follow()));
+	}
+
+private:
+	Shadow* init(mobj_t* from)
+	{
+		shadowscale = from->shadowscale;
+		from->shadowscale = 0;
+
+		follow(from);
+
+		return this;
+	}
+};
+
+mobj_t* Obj_SpawnFakeShadow(mobj_t* from)
+{
+	return Shadow::spawn(from);
+}
+
+void Obj_FakeShadowThink(mobj_t* shadow)
+{
+	auto x = static_cast<Shadow*>(shadow);
+
+	if (!x->valid())
+	{
+		x->destroy();
+		return;
+	}
+
+	x->move();
+}
diff --git a/src/p_mobj.c b/src/p_mobj.c
index 30179af6c..0cab3eefc 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -5782,16 +5782,10 @@ static void P_MobjSceneryThink(mobj_t *mobj)
 	switch (mobj->type)
 	{
 	case MT_SHADOW:
-		if (mobj->tracer)
+		Obj_FakeShadowThink(mobj);
+
+		if (P_MobjWasRemoved(mobj))
 		{
-			P_MoveOrigin(mobj,
-					mobj->tracer->x,
-					mobj->tracer->y,
-					mobj->tracer->z);
-		}
-		else
-		{
-			P_RemoveMobj(mobj);
 			return;
 		}
 		break;