Revert "- removed Interp_Sprite_Z."

Sadly, SW's sprite interpolation is too screwed up to do a better fix on short notice.
It's the same with interpolating sprites attached to SOP's, it is only needed because generally interpolating sprites in SW is problematic.

source/core/interpolate.cpp

@@ -32,11 +32,12 @@ struct Interpolation
 	double old, bak;
 	int index;
 	int type;
+	DCoreActor* actor;
 };
 
 static TArray<Interpolation> interpolations;
 
-double Get(int index, int type)
+double Get(int index, DCoreActor* actor, int type)
 {
 	switch(type)
 	{
@@ -54,11 +55,12 @@ double Get(int index, int type)
 	case Interp_Wall_PanX:				return wall[index].xpan_;
 	case Interp_Wall_PanY:				return wall[index].ypan_;
 
+	case Interp_Sprite_Z:				return actor->spr.pos.Z;
 	default: return 0;
 	}
 }
 
-void Set(int index, int type, double val)
+void Set(int index, DCoreActor* actor, int type, double val)
 {
 	int old;
 	switch(type)
@@ -76,6 +78,8 @@ void Set(int index, int type, double val)
 	case Interp_Wall_Y:                 old = wall[index].pos.Y; wall[index].pos.Y = xs_CRoundToInt(val); if (wall[index].pos.Y != old) wall[index].moved(); break;
 	case Interp_Wall_PanX:              wall[index].xpan_ = float(val);  break;
 	case Interp_Wall_PanY:              wall[index].ypan_ = float(val);  break;
+                                        
+	case Interp_Sprite_Z:               actor->spr.pos.Z = xs_CRoundToInt(val); break;
 	}
 }
 
@@ -89,8 +93,9 @@ void StartInterpolation(int index, int type)
 	int n = interpolations.Reserve(1);
 
     interpolations[n].index = index;
+	interpolations[n].actor = nullptr;
     interpolations[n].type = type;
-    interpolations[n].old = Get(index, type);
+    interpolations[n].old = Get(index, nullptr, type);
 }
 
 void StopInterpolation(int index, int type)
@@ -106,11 +111,41 @@ void StopInterpolation(int index, int type)
     }
 }
 
+void StartInterpolation(DCoreActor* actor, int type)
+{
+	assert(type = Interp_Sprite_Z);
+	for (unsigned i = 0; i < interpolations.Size(); i++)
+	{
+		if (interpolations[i].actor == actor && interpolations[i].type == type)
+			return;
+	}
+	int n = interpolations.Reserve(1);
+
+	interpolations[n].index = -1;
+	interpolations[n].actor = actor;
+	interpolations[n].type = type;
+	interpolations[n].old = Get(-1, actor, type);
+}
+
+void StopInterpolation(DCoreActor* actor, int type)
+{
+	assert(type = Interp_Sprite_Z);
+	for (unsigned i = 0; i < interpolations.Size(); i++)
+	{
+		if (interpolations[i].actor == actor && interpolations[i].type == type)
+		{
+			interpolations[i] = interpolations.Last();
+			interpolations.Pop();
+			return;
+		}
+	}
+}
+
 void UpdateInterpolations()
 {
     for (unsigned i = 0; i < interpolations.Size(); i++)
     {
-		interpolations[i].old = Get(interpolations[i].index, interpolations[i].type);
+		interpolations[i].old = Get(interpolations[i].index, interpolations[i].actor, interpolations[i].type);
 	}		
 }
 
@@ -120,11 +155,11 @@ void DoInterpolations(double smoothratio)
     for (unsigned i = 0; i < interpolations.Size(); i++)
     {
 		double bak;
-		interpolations[i].bak = bak = Get(interpolations[i].index, interpolations[i].type);
+		interpolations[i].bak = bak = Get(interpolations[i].index, interpolations[i].actor, interpolations[i].type);
 		double old = interpolations[i].old;
 		if (interpolations[i].type < Interp_Pan_First || fabs(bak-old) < 128.)
 		{
-			Set(interpolations[i].index, interpolations[i].type, old + (bak - old) * smoothratio);
+			Set(interpolations[i].index, interpolations[i].actor, interpolations[i].type, old + (bak - old) * smoothratio);
 		}
 		else
 		{
@@ -133,7 +168,7 @@ void DoInterpolations(double smoothratio)
 			else old += 256;
 			double cur = old + (bak - old) * smoothratio;
 			if (cur >= 256.) cur -= 256.;
-			Set(interpolations[i].index, interpolations[i].type, cur);
+			Set(interpolations[i].index, interpolations[i].actor, interpolations[i].type, cur);
 		}
 	}
 }
@@ -143,7 +178,7 @@ void RestoreInterpolations()
 	if (!cl_interpolate) return;
 	for (unsigned i = 0; i < interpolations.Size(); i++)
     {
-		Set(interpolations[i].index, interpolations[i].type, interpolations[i].bak);
+		Set(interpolations[i].index, interpolations[i].actor, interpolations[i].type, interpolations[i].bak);
 	}		
 }
 
@@ -212,12 +247,13 @@ FSerializer& Serialize(FSerializer& arc, const char* keyname, Interpolation& w,
     if (arc.BeginObject(keyname))
     {
         arc ("index", w.index)
+			("actor", w.actor)
             ("type", w.type)
             .EndObject();
     }
 	if (arc.isReading())
 	{
-		w.old = Get(w.index, w.type);
+		w.old = Get(w.index, w.actor, w.type);
 	}
     return arc;
 }

source/core/interpolate.h

@@ -13,6 +13,8 @@ enum EInterpolationType
 	Interp_Wall_X,
 	Interp_Wall_Y,
 
+	Interp_Sprite_Z,
+
 	Interp_Pan_First,
 	// order of the following 4 flags must match the corresponding sector flags.
 	Interp_Sect_FloorPanX = Interp_Pan_First,
@@ -25,6 +27,8 @@ enum EInterpolationType
 
 void StartInterpolation(int index, int type);
 void StopInterpolation(int index, int type);
+void StartInterpolation(DCoreActor* actor, int type);
+void StopInterpolation(DCoreActor* actor, int type);
 void UpdateInterpolations();
 void ClearInterpolations();
 void ClearMovementInterpolations();

source/games/sw/src/sprite.cpp

@@ -637,6 +637,7 @@ void KillActor(DSWActor* actor)
         // any Anims attached
         AnimDelete(ANIM_Userz, 0, actor);
         AnimDelete(ANIM_Spritez, 0, actor);
+        StopInterpolation(actor, Interp_Sprite_Z);
 
         // adjust sprites attached to sector objects
         if (actor->user.Flags & (SPR_SO_ATTACHED))

source/games/sw/src/vator.cpp

@@ -254,6 +254,11 @@ void InterpSectorSprites(sectortype* sect, bool state)
             if (actor->user.Flags & (SPR_SKIP2) && actor->spr.statnum <= STAT_SKIP2_INTERP_END)
                 continue;
         }
+
+        if (state)
+            StartInterpolation(actor, Interp_Sprite_Z);
+        else
+            StopInterpolation(actor, Interp_Sprite_Z);
     }
 }