diff --git a/source/games/duke/src/actors.cpp b/source/games/duke/src/actors.cpp
index 92a23ec24..f8cfbdef6 100644
--- a/source/games/duke/src/actors.cpp
+++ b/source/games/duke/src/actors.cpp
@@ -78,7 +78,7 @@ void deletesprite(DDukeActor *const actor)
 		S_StopSound(actor->s->lotag, actor);
 	else
 		S_RelinkActorSound(actor, nullptr);
-	::deletesprite(actor->GetIndex());
+	::deletesprite(actor->GetSpriteIndex());
 }
 
 //---------------------------------------------------------------------------
diff --git a/source/games/duke/src/actors_d.cpp b/source/games/duke/src/actors_d.cpp
index e49bbe035..a84cefff8 100644
--- a/source/games/duke/src/actors_d.cpp
+++ b/source/games/duke/src/actors_d.cpp
@@ -1561,7 +1561,7 @@ static bool movefireball(DDukeActor* actor)
 			int trail = actor->temp_data[1];
 			auto ball = spawn(actor, FIREBALL);
 			auto spr = ball->s;
-			actor->temp_data[1] = ball->GetIndex();
+			actor->temp_data[1] = ball->GetSpriteIndex();
 			
 			spr->xvel = s->xvel;
 			spr->yvel = s->yvel;
@@ -1585,7 +1585,7 @@ static bool movefireball(DDukeActor* actor)
 
 			FireProj proj = { spr->x, spr->y, spr->z, spr->xvel, spr->yvel, spr->zvel };
 			
-			fire.Insert(ball->GetIndex(), proj);
+			fire.Insert(ball->GetSpriteIndex(), proj);
 			changeactorstat(ball, STAT_PROJECTILE);
 		}
 		actor->temp_data[0]++;
diff --git a/source/games/duke/src/dukeactor.h b/source/games/duke/src/dukeactor.h
index 7c75b6479..d7804b525 100644
--- a/source/games/duke/src/dukeactor.h
+++ b/source/games/duke/src/dukeactor.h
@@ -97,22 +97,22 @@ inline int player_struct::GetPlayerNum()
 // Refactoring helpers/intermediates
 inline void changeactorstat(DDukeActor* a, int newstat)
 {
-	::changespritestat(a->GetIndex(), newstat);
+	::changespritestat(a->GetSpriteIndex(), newstat);
 }
 
 inline void changeactorsect(DDukeActor* a, int newsect)
 {
-	::changespritesect(a->GetIndex(), newsect);
+	::changespritesect(a->GetSpriteIndex(), newsect);
 }
 
 inline int setsprite(DDukeActor* a, int x, int y, int z)
 {
-	return ::setsprite(a->GetIndex(), x, y, z);
+	return ::setsprite(a->GetSpriteIndex(), x, y, z);
 }
 
 inline int setsprite(DDukeActor* a, const vec3_t& pos)
 {
-	return ::setsprite(a->GetIndex(), pos.x, pos.y, pos.z);
+	return ::setsprite(a->GetSpriteIndex(), pos.x, pos.y, pos.z);
 }
 
 // see comment for changespritestat.
@@ -124,7 +124,7 @@ inline int setsprite(int i, int x, int y, int z)
 inline int ActorToScriptIndex(DDukeActor* a)
 {
 	if (!a) return -1;
-	return a->GetIndex();
+	return a->GetSpriteIndex();
 }
 
 inline DDukeActor* ScriptIndexToActor(int index)
@@ -139,7 +139,7 @@ int spawn_r(int j, int pn);
 
 inline DDukeActor* spawn(DDukeActor* spawner, int type)
 {
-	int i = (isRR()? spawn_r : spawn_d)(spawner ? spawner->GetIndex() : -1, type);
+	int i = (isRR()? spawn_r : spawn_d)(spawner ? spawner->GetSpriteIndex() : -1, type);
 	return i == -1 ? nullptr : &hittype[i];
 }
 
diff --git a/source/games/duke/src/gamevar.cpp b/source/games/duke/src/gamevar.cpp
index 68b73a236..29b432626 100644
--- a/source/games/duke/src/gamevar.cpp
+++ b/source/games/duke/src/gamevar.cpp
@@ -286,7 +286,7 @@ int GetGameVarID(int id, DDukeActor* sActor, int sPlayer)
 	}
 	if (id == g_iThisActorID)
 	{
-		return sActor->GetIndex();
+		return sActor->GetSpriteIndex();
 	}
 	if( aGameVars[id].dwFlags & GAMEVAR_FLAG_PERPLAYER )
 	{
@@ -305,7 +305,7 @@ int GetGameVarID(int id, DDukeActor* sActor, int sPlayer)
 		// for the current actor
 		if(sActor != nullptr)
 		{
-			return aGameVars[id].plArray[sActor->GetIndex()];
+			return aGameVars[id].plArray[sActor->GetSpriteIndex()];
 		}
 		else
 		{
@@ -359,7 +359,7 @@ void SetGameVarID(int id, int lValue, DDukeActor* sActor, int sPlayer)
 	else if( aGameVars[id].dwFlags & GAMEVAR_FLAG_PERACTOR )
 	{
 		// for the current actor
-		if (sActor != nullptr) aGameVars[id].plArray[sActor->GetIndex()]=lValue;
+		if (sActor != nullptr) aGameVars[id].plArray[sActor->GetSpriteIndex()]=lValue;
 		else for (auto& i : aGameVars[id].plArray) i = lValue; // -1 sets all actors - was undefined OOB access in WW2GI.
 	}
 	else if( aGameVars[id].dwFlags & GAMEVAR_FLAG_PLONG )
diff --git a/source/games/duke/src/premap.cpp b/source/games/duke/src/premap.cpp
index 0d9781deb..e410615a6 100644
--- a/source/games/duke/src/premap.cpp
+++ b/source/games/duke/src/premap.cpp
@@ -623,7 +623,7 @@ void resetpspritevars(int g)
             else
                 s->pal = ps[j].palookup = ud.user_pals[j];
 
-            ps[j].i = act->GetIndex();
+            ps[j].i = act->GetSpriteIndex();
             ps[j].frag_ps = j;
             act->SetOwner(act);
 
diff --git a/source/games/duke/src/spawn.cpp b/source/games/duke/src/spawn.cpp
index 24a5ef141..1c909aaa7 100644
--- a/source/games/duke/src/spawn.cpp
+++ b/source/games/duke/src/spawn.cpp
@@ -147,7 +147,7 @@ int initspriteforspawn(DDukeActor* actj, int pn, const std::initializer_list<int
 		spawned->picnum = actj->s->picnum;
 		sp = spawned->s;
 		t = spawned->temp_data;
-		i = spawned->GetIndex();
+		i = spawned->GetSpriteIndex();
 	}
 	else
 	{
diff --git a/source/games/duke/src/types.h b/source/games/duke/src/types.h
index 2f506bf6d..9256a53e5 100644
--- a/source/games/duke/src/types.h
+++ b/source/games/duke/src/types.h
@@ -39,7 +39,7 @@ struct DDukeActor
 
 	static DDukeActor* array();	// this is necessary to allow define inline functions referencing the global array inside the definition itself.
 
-	DDukeActor() : s(&sprite[this - array()]) {}			// little trick to initialize the reference automatically. ;)
+	DDukeActor() : s(&sprite[this - array()]) {}
 	DDukeActor(const DDukeActor& other) = delete;				// we also do not want to allow copies.
 	DDukeActor& operator=(const DDukeActor& other) = delete;
 	void clear()
@@ -49,7 +49,7 @@ struct DDukeActor
 		floorz = ceilingz = lastvx = lastvy = aflags = saved_ammo = 0;
 		memset(temp_data, 0, sizeof(temp_data));
 	}
-	int GetIndex() const { return int(this - array()); }
+	int GetSpriteIndex() const { return int(this - array()); }
 
 	// Wrapper around some ugliness. The 'owner' field gets abused by some actors, so better wrap its real use in access functions to keep things in order.
 	inline DDukeActor* GetOwner()
@@ -59,7 +59,7 @@ struct DDukeActor
 
 	inline void SetOwner(DDukeActor* a)
 	{
-		s->owner = a? a->GetIndex() : -1;
+		s->owner = a? a->GetSpriteIndex() : -1;
 	}
 
 	// same for the 'hittype' owner - which is normally the shooter in an attack.
@@ -70,7 +70,7 @@ struct DDukeActor
 
 	inline void SetHitOwner(DDukeActor* a)
 	{
-		owner = a ? a->GetIndex() : -1;
+		owner = a ? a->GetSpriteIndex() : -1;
 	}
 
 	// This used the Owner field - better move this to something more safe.