Updated VisualThinker render linkage

Now uses its own self-managed linked list with its level tracking the head pointer. Allows for VisualThinkers to be moved to any desired stat instead of being stuck in STAT_VISUALTHINKER.

src/g_levellocals.h

@@ -427,11 +427,6 @@ struct FLevelLocals
 	DThinker *CreateThinker(PClass *cls, int statnum = STAT_DEFAULT)
 	{
 		DThinker *thinker = static_cast<DThinker*>(cls->CreateNew());
-		if (thinker->IsKindOf(RUNTIME_CLASS(DVisualThinker)))
-		{
-			statnum = STAT_VISUALTHINKER;
-		}
-
 		assert(thinker->IsKindOf(RUNTIME_CLASS(DThinker)));
 		thinker->ObjectFlags |= OF_JustSpawned;
 		Thinkers.Link(thinker, statnum);
@@ -708,6 +703,7 @@ struct FLevelLocals
 	int			ImpactDecalCount;
 
 	FDynamicLight *lights;
+	DVisualThinker* VisualThinkerHead = nullptr;
 
 	// links to global game objects
 	TArray<TObjPtr<AActor *>> CorpseQueue;

src/p_saveg.cpp

@@ -990,7 +990,8 @@ void FLevelLocals::Serialize(FSerializer &arc, bool hubload)
 		("scrolls", Scrolls)
 		("automap", automap)
 		("interpolator", interpolator)
-		("frozenstate", frozenstate);
+		("frozenstate", frozenstate)
+		("visualthinkerhead", VisualThinkerHead);
 
 
 	// Hub transitions must keep the current total time

src/playsim/dthinker.cpp

@@ -810,11 +810,7 @@ DEFINE_ACTION_FUNCTION_NATIVE(DThinker, ChangeStatNum, ChangeStatNum)
 	PARAM_SELF_PROLOGUE(DThinker);
 	PARAM_INT(stat);
 
-	// do not allow ZScript to reposition thinkers in or out of particle ticking.
-	if (stat != STAT_VISUALTHINKER && !dynamic_cast<DVisualThinker*>(self))
-	{
-		ChangeStatNum(self, stat);
-	}
+	ChangeStatNum(self, stat);
 	return 0;
 }
 

src/playsim/p_effect.cpp

@@ -214,15 +214,13 @@ void P_FindParticleSubsectors (FLevelLocals *Level)
 	{
 		Level->subsectors[i].sprites.Clear();
 	}
-	// [MC] Not too happy about using an iterator for this but I can't think of another way to handle it.
-	// At least it's on its own statnum for maximum efficiency.
-	auto it = Level->GetThinkerIterator<DVisualThinker>(NAME_None, STAT_VISUALTHINKER);
-	DVisualThinker* sp;
-	while (sp = it.Next())
+	auto sp = Level->VisualThinkerHead;
+	while (sp != nullptr)
 	{
 		if (!sp->PT.subsector) sp->PT.subsector = Level->PointInRenderSubsector(sp->PT.Pos);
 
 		sp->PT.subsector->sprites.Push(sp);
+		sp = sp->GetNext();
 	}
 	// End VisualThinker hitching. Now onto the particles. 
 	if (Level->ParticlesInSubsec.Size() < Level->subsectors.Size())
@@ -1007,35 +1005,52 @@ void DVisualThinker::Construct()
 	cursector = nullptr;
 	PT.color = 0xffffff;
 	AnimatedTexture.SetNull();
-}
 
-DVisualThinker::DVisualThinker()
-{
-	Construct();
+	_prev = _next = nullptr;
+	if (Level->VisualThinkerHead != nullptr)
+	{
+		Level->VisualThinkerHead->_prev = this;
+		_next = Level->VisualThinkerHead;
+	}
+	Level->VisualThinkerHead = this;
 }
 
 void DVisualThinker::OnDestroy()
 {
+	if (_prev != nullptr)
+		_prev->_next = _next;
+	if (_next != nullptr)
+		_next->_prev = _prev;
+	if (Level->VisualThinkerHead == this)
+		Level->VisualThinkerHead = _next;
+
 	PT.alpha = 0.0; // stops all rendering.
 	Super::OnDestroy();
 }
 
+DVisualThinker* DVisualThinker::GetNext() const
+{
+	return _next;
+}
+
 DVisualThinker* DVisualThinker::NewVisualThinker(FLevelLocals* Level, PClass* type)
 {
 	if (type == nullptr)
-		return nullptr;
-	else if (type->bAbstract)
 	{
-		Printf("Attempt to spawn an instance of abstract VisualThinker class %s\n", type->TypeName.GetChars());
 		return nullptr;
 	}
 	else if (!type->IsDescendantOf(RUNTIME_CLASS(DVisualThinker)))
 	{
 		Printf("Attempt to spawn class not inherent to VisualThinker: %s\n", type->TypeName.GetChars());
 		return nullptr;
 	}
+	else if (type->bAbstract)
+	{
+		Printf("Attempt to spawn an instance of abstract VisualThinker class %s\n", type->TypeName.GetChars());
+		return nullptr;
+	}
 
-	DVisualThinker *zs = static_cast<DVisualThinker*>(Level->CreateThinker(type, STAT_VISUALTHINKER));
+	auto zs = static_cast<DVisualThinker*>(Level->CreateThinker(type, DVisualThinker::DEFAULT_STAT));
 	zs->Construct();
 	return zs;
 }
@@ -1284,7 +1299,7 @@ void DVisualThinker::Serialize(FSerializer& arc)
 {
 	Super::Serialize(arc);
 
-	arc ("pos", PT.Pos)
+	arc("pos", PT.Pos)
 		("vel", PT.Vel)
 		("prev", Prev)
 		("scale", Scale)
@@ -1300,7 +1315,9 @@ void DVisualThinker::Serialize(FSerializer& arc)
 		("lightlevel", LightLevel)
 		("animData", PT.animData)
 		("flags", PT.flags)
-		("visualThinkerFlags", flags);
+		("visualThinkerFlags", flags)
+		("next", _next)
+		("prev", _prev);
 
     if(arc.isReading())
     {

src/playsim/p_visualthinker.h

@@ -26,7 +26,11 @@ class DVisualThinker : public DThinker
 {
 	DECLARE_CLASS(DVisualThinker, DThinker);
 	void UpdateSector(subsector_t * newSubsector);
+
+	DVisualThinker* _next, * _prev;
 public:
+	static const int DEFAULT_STAT = STAT_VISUALTHINKER;
+
 	DVector3		Prev;
 	DVector2		Scale,
 					Offset;
@@ -41,9 +45,9 @@ class DVisualThinker : public DThinker
 	// internal only variables
 	particle_t		PT;
 
-	DVisualThinker();
 	void Construct();
 	void OnDestroy() override;
+	DVisualThinker* GetNext() const;
 
 	static DVisualThinker* NewVisualThinker(FLevelLocals* Level, PClass* type);
 	void SetTranslation(FName trname);

wadsrc/static/zscript/visualthinker.zs

@@ -33,7 +33,7 @@ Class VisualThinker : Thinker native
 	native protected void UpdateSector(); // needs to be called if the thinker is set to a non-ticking statnum and the position is modified (or if Tick is overriden and doesn't call Super.Tick())
 	native protected void UpdateSpriteInfo(); // needs to be called every time the texture is updated if the thinker uses SPF_LOCAL_ANIM and is set to a non-ticking statnum (or if Tick is overriden and doesn't call Super.Tick())
 
-	static VisualThinker Spawn(Class<VisualThinker> type, TextureID tex, Vector3 pos, Vector3 vel, double alpha = 1.0, int flags = 0,
+	static VisualThinker Spawn(Class<VisualThinker> type, TextureID tex, Vector3 pos, Vector3 vel = (0,0,0), double alpha = 1.0, int flags = 0,
 						  double roll = 0.0, Vector2 scale = (1,1), Vector2 offset = (0,0), int style = STYLE_Normal, TranslationID trans = 0, int VisualThinkerFlags = 0)
 	{
 		if (!Level)	return null;