- properly un-count faded out decals without involving the Destroy method.

src/g_shared/a_decalfx.cpp

@@ -76,6 +76,7 @@ void DDecalFader::Tick ()
 		}
 		else if (Level->maptime >= TimeToEndDecay)
 		{
+			TheDecal->Expired();		// for impact decal bookkeeping.
 			TheDecal->Destroy ();		// remove the decal
 			Destroy ();					// remove myself
 			return;

src/g_shared/a_decals.cpp

@@ -666,6 +666,8 @@ DBaseDecal *DBaseDecal::CloneSelf (const FDecalTemplate *tpl, double ix, double
 
 void DImpactDecal::CheckMax ()
 {
+	static int SpawnCounter;
+
 	if (++Level->ImpactDecalCount >= cl_maxdecals)
 	{
 		DThinker *thinker = Level->FirstThinker (STAT_AUTODECAL);
@@ -683,6 +685,17 @@ void DImpactDecal::CheckMax ()
 //
 //----------------------------------------------------------------------------
 
+void DImpactDecal::Expired()
+{
+	Level->ImpactDecalCount--;
+}
+
+//----------------------------------------------------------------------------
+//
+//
+//
+//----------------------------------------------------------------------------
+
 DImpactDecal *DImpactDecal::StaticCreate (FLevelLocals *Level, const char *name, const DVector3 &pos, side_t *wall, F3DFloor * ffloor, PalEntry color)
 {
 	if (cl_maxdecals > 0)

src/g_shared/a_sharedglobal.h

@@ -26,6 +26,7 @@ public:
 
 	void Serialize(FSerializer &arc);
 	void OnDestroy() override;
+	virtual void Expired() {}	// For thinkers that can remove their decal. For impact decal bookkeeping.
 	FTextureID StickToWall(side_t *wall, double x, double y, F3DFloor * ffloor);
 	double GetRealZ (const side_t *wall) const;
 	void SetShade (uint32_t rgb);
@@ -71,6 +72,7 @@ public:
 	static DImpactDecal *StaticCreate(FLevelLocals *Level, const FDecalTemplate *tpl, const DVector3 &pos, side_t *wall, F3DFloor * ffloor, PalEntry color = 0);
 
 	void BeginPlay ();
+	void Expired() override;
 
 protected:
 	DBaseDecal *CloneSelf(const FDecalTemplate *tpl, double x, double y, double z, side_t *wall, F3DFloor * ffloor) const;