* A direct tag-to-tag relationship can now be established between two things, which allows event lines to be properly setup between them. This is intended for interpolation and patrol specials which are linked via a shared tag, instead of an argument. A POSITIVE value represents the parent thing, where a NEGATIVE value represents the child thing.

* Added interpolation and patrol point specials to the persistent event line processing

Source/Core/Config/ThingTypeInfo.cs

@@ -85,6 +85,7 @@ namespace CodeImp.DoomBuilder.Config
         private string angletext;
         private string flagsvaluetext;
         private string parametertext;
+		private int thinglink;
 
         //mxd. GLOOME rendering settings
         private Thing.SpriteRenderMode rendermode;
@@ -137,7 +138,8 @@ namespace CodeImp.DoomBuilder.Config
         public string AngleText { get { return angletext; } }
         public string FlagsValueText { get { return flagsvaluetext; } }
         public string ParameterText { get { return parametertext; } }
-        #endregion
+		public int ThingLink { get { return thinglink; } }
+		#endregion
 
         #region ================== Constructor / Disposer
 
@@ -180,9 +182,10 @@ namespace CodeImp.DoomBuilder.Config
             this.angletext = "Angle";
             this.flagsvaluetext = "Flags value";
             this.parametertext = "Parameter";
-
+			this.thinglink = 0;
-            // We have no destructor
+			
-            GC.SuppressFinalize(this);
+			// We have no destructor
+			GC.SuppressFinalize(this);
 		}
 
 		// Constructor
@@ -227,6 +230,7 @@ namespace CodeImp.DoomBuilder.Config
             this.angletext = cfg.ReadSetting("thingtypes." + cat.Name + "." + key + ".angletext", cat.AngleText);
             this.flagsvaluetext = cfg.ReadSetting("thingtypes." + cat.Name + "." + key + ".flagsvaluetext", cat.FlagsValueText);
             this.parametertext = cfg.ReadSetting("thingtypes." + cat.Name + "." + key + ".parametertext", cat.ParameterText);
+			this.thinglink = cfg.ReadSetting("thingtypes." + cat.Name + "." + key + ".thinglink", 0);
 
             // Read the args
             for (int i = 0; i < Linedef.NUM_ARGS; i++)

Source/Core/GZBuilder/Data/LinksCollector.cs

@@ -12,7 +12,9 @@ namespace CodeImp.DoomBuilder.GZBuilder.Data
 		private class SpecialThings 
 		{
 			public readonly Dictionary<int, List<Thing>> PatrolPoints; // PatrolPoint tag, list of PatrolPoints
+			public readonly List<Thing> PatrolSpecials;
 			public readonly Dictionary<int, List<PathNode>> InterpolationPoints; // InterpolationPoint tag, list of InterpolationPoints
+			public readonly List<Thing> InterpolationSpecials;
 			public readonly List<Thing> ThingsWithGoal;
 			public readonly List<Thing> Cameras;
 			public readonly Dictionary<int, List<Thing>> ActorMovers; // ActorMover target tag, list of ActorMovers
@@ -23,7 +25,9 @@ namespace CodeImp.DoomBuilder.GZBuilder.Data
 			public SpecialThings()
 			{
 				PatrolPoints = new Dictionary<int, List<Thing>>();
+				PatrolSpecials = new List<Thing>();
 				InterpolationPoints = new Dictionary<int, List<PathNode>>();
+				InterpolationSpecials = new List<Thing>();
 				ThingsWithGoal = new List<Thing>();
 				Cameras = new List<Thing>();
 				ActorMovers = new Dictionary<int, List<Thing>>();
@@ -97,6 +101,10 @@ namespace CodeImp.DoomBuilder.GZBuilder.Data
 						}
 						break;
 
+					case "patrolspecial":
+						result.PatrolSpecials.Add(t);
+						break;
+
 					case "$polyanchor":
 						if(!result.PolyobjectAnchors.ContainsKey(t.AngleDoom)) result.PolyobjectAnchors[t.AngleDoom] = new List<Thing>();
 						result.PolyobjectAnchors[t.AngleDoom].Add(t);
@@ -133,6 +141,10 @@ namespace CodeImp.DoomBuilder.GZBuilder.Data
 						result.InterpolationPoints[t.Tag].Add(new PathNode(t, blockmap, bsp, useblockmap));
 						break;
 
+					case "interpolationspecial":
+						result.InterpolationSpecials.Add(t);
+						break;
+
 					case "movingcamera":
 						if(t.Args[0] != 0 || t.Args[1] != 0) result.Cameras.Add(t);
 						break;
@@ -208,6 +220,23 @@ namespace CodeImp.DoomBuilder.GZBuilder.Data
 				}
 			}
 
+			// Process patrol specials
+			foreach (Thing t in result.PatrolSpecials)
+			{
+				if (!result.PatrolPoints.ContainsKey(t.Tag)) continue;
+
+				start = t.Position;
+				start.z += GetCorrectHeight(t, blockmap, true);
+
+				foreach (Thing tt in result.PatrolPoints[t.Tag])
+				{
+					end = tt.Position;
+					end.z += GetCorrectHeight(tt, blockmap, true);
+
+					lines.Add(new Line3D(start, end, General.Colors.Selection));
+				}
+			}
+
 			// Process cameras [CAN USE INTERPOLATION]
 			foreach(Thing t in result.Cameras)
 			{
@@ -321,6 +350,24 @@ namespace CodeImp.DoomBuilder.GZBuilder.Data
 				foreach(PathNode node in group.Value) node.PropagateCurvedFlag();
 			}
 
+			// Process interpolation specials
+			foreach (Thing t in result.InterpolationSpecials)
+			{
+				int targettag = t.Tag;
+				if (targettag == 0 || !result.InterpolationPoints.ContainsKey(targettag)) continue; //no target / target doesn't exist
+
+				start = t.Position;
+				start.z += GetCorrectHeight(t, blockmap, true);
+
+				foreach (PathNode node in result.InterpolationPoints[targettag])
+				{
+					//Do not connect specials to the first or last node of a curved path, since those are used as spline control points only
+					if (node.IsCurved && (node.PreviousNodes.Count == 0 || node.NextNodes.Count == 0))
+						continue;
+					lines.Add(new Line3D(start, node.Position, General.Colors.Selection));
+				}
+			}
+
 			// 3. Make lines
 			HashSet<int> processedindices = new HashSet<int>();
 			foreach(KeyValuePair<int, List<PathNode>> group in result.InterpolationPoints)

Source/Plugins/BuilderModes/ClassicModes/ThingsMode.cs

@@ -57,6 +57,7 @@ namespace CodeImp.DoomBuilder.BuilderModes
 		// Highlighted item
 		private Thing highlighted;
 		private readonly Association[] association = new Association[Thing.NUM_ARGS];
+		private readonly Association directasso = new Association();
 		private readonly Association highlightasso = new Association();
 
 		// Interface
@@ -90,6 +91,7 @@ namespace CodeImp.DoomBuilder.BuilderModes
 		{
 			//mxd. Associations now requre initializing...
 			for(int i = 0; i < association.Length; i++) association[i] = new Association();
+			directasso = new Association();
 		}
 
 		//mxd
@@ -253,6 +255,7 @@ namespace CodeImp.DoomBuilder.BuilderModes
 				renderer.RenderThingSet(General.Map.ThingsFilter.VisibleThings, alpha);
 				renderer.RenderNiGHTSPath();
 				for (int i = 0; i < Thing.NUM_ARGS; i++) BuilderPlug.RenderAssociations(renderer, association[i], eventlines);
+				BuilderPlug.RenderAssociations(renderer, directasso, eventlines);
 				
 				if((highlighted != null) && !highlighted.IsDisposed)
 				{
@@ -353,8 +356,14 @@ namespace CodeImp.DoomBuilder.BuilderModes
 				//mxd. Update label color?
 				if(labels.ContainsKey(t)) labels[t].Color = General.Colors.Selection;
 
+				//check if this thing directly links to another type of thing
+				ThingTypeInfo ti = General.Map.Data.GetThingInfoEx(t.Type);
+				int linktype = 0;
+				if (ti != null)
+					linktype = ti.ThingLink;
+
 				// New association highlights something?
-				if(t.Tag != 0) highlightasso.Set(t.Position, t.Tag, UniversalType.ThingTag);
+				if(t.Tag != 0) highlightasso.Set(t.Position, t.Tag, UniversalType.ThingTag, linktype);
 			}
 			else
 			{
@@ -382,6 +391,11 @@ namespace CodeImp.DoomBuilder.BuilderModes
 					LinedefActionInfo action = General.Map.Config.LinedefActions[t.Action];
 					for(int i = 0; i < Thing.NUM_ARGS; i++)
 						association[i].Set(t.Position, t.Args[i], action.Args[i].Type);
+
+					//Some things, such as Patrol and Interpolation specials, are associated via a shared tag rather than an argument
+					ThingTypeInfo ti = General.Map.Data.GetThingInfoEx(t.Type);
+					if (ti != null && ti.ThingLink < 0) 
+						directasso.Set(t.Position, t.Tag, (int)UniversalType.ThingTag);
 				}
 				//mxd. Check if we can use thing arguments
 				else if(t.Action == 0)
@@ -398,7 +412,11 @@ namespace CodeImp.DoomBuilder.BuilderModes
 
 			// mxd. Clear associations?
 			if(clearassociations)
-				for(int i = 0; i < Thing.NUM_ARGS; i++) association[i].Set(new Vector2D(), 0, 0);
+			{
+				for (int i = 0; i < Thing.NUM_ARGS; i++)
+					association[i].Set(new Vector2D(), 0, 0);
+				directasso.Set(new Vector2D(), 0, 0);
+			}
 			
 			// Set new highlight and redraw display
 			highlighted = t;

Source/Plugins/BuilderModes/General/Association.cs

@@ -29,10 +29,12 @@ namespace CodeImp.DoomBuilder.BuilderModes
 		private HashSet<int> tags;
 		private Vector2D center;
 		private UniversalType type;
+		private int directlinktype;
 
 		public HashSet<int> Tags { get { return tags; } }
 		public Vector2D Center { get { return center; } }
 		public UniversalType Type { get { return type; } }
+		public int DirectLinkType { get { return directlinktype; } }
 
 		//mxd. This sets up the association
 		public Association()
@@ -74,34 +76,51 @@ namespace CodeImp.DoomBuilder.BuilderModes
 
 		// This sets up the association
 		public void Set(Vector2D center, int tag, int type)
+		{
+			this.Set(center, tag, type, 0);
+		}
+
+		public void Set(Vector2D center, int tag, int type, int directlinktype)
 		{
 			this.tags = new HashSet<int> { tag }; //mxd
 			this.type = (UniversalType)type;
 			this.center = center;
+			this.directlinktype = directlinktype;
 		}
 
 		// This sets up the association
 		public void Set(Vector2D center, int tag, UniversalType type)
+		{
+			this.Set(center, tag, type, 0);
+		}
+
+		public void Set(Vector2D center, int tag, UniversalType type, int directlinktype)
 		{
 			this.tags = new HashSet<int> { tag }; //mxd
 			this.type = type;
 			this.center = center;
+			this.directlinktype = directlinktype;
 		}
 
 		//mxd. This also sets up the association
 		public void Set(Vector2D center, IEnumerable<int> tags, int type)
 		{
-			this.tags = new HashSet<int>(tags); //mxd
+			this.Set(center, tags, (UniversalType)type, 0);
-			this.type = (UniversalType)type;
-			this.center = center;
 		}
 
 		//mxd. This also sets up the association
 		public void Set(Vector2D center, IEnumerable<int> tags, UniversalType type)
+		{
+			this.Set(center, tags, type, 0);
+		}
+
+		//mxd. This also sets up the association
+		public void Set(Vector2D center, IEnumerable<int> tags, UniversalType type, int directlinktype)
 		{
 			this.tags = new HashSet<int>(tags); //mxd
 			this.type = type;
 			this.center = center;
+			this.directlinktype = directlinktype;
 		}
 
 		// This compares an association

Source/Plugins/BuilderModes/General/BuilderPlug.cs

@@ -746,6 +746,12 @@ namespace CodeImp.DoomBuilder.BuilderModes
 					foreach(Thing t in General.Map.Map.Things)
 					{
 						if(!asso.Tags.Contains(t.Tag)) continue;
+
+						//Do not draw the association if the user is hovering over a child link
+						ThingTypeInfo ti = General.Map.Data.GetThingInfoEx(t.Type);
+						if (ti != null && ti.ThingLink < 0)
+							continue;
+
 						renderer.RenderThing(t, General.Colors.Indication, General.Settings.ActiveThingsAlpha);
 						if(General.Settings.GZShowEventLines) eventlines.Add(new Line3D(asso.Center, t.Position)); //mxd
 					}
@@ -813,9 +819,17 @@ namespace CodeImp.DoomBuilder.BuilderModes
 			// Things
 			foreach(Thing t in General.Map.Map.Things)
 			{
+				// Get the thing type info
+				ThingTypeInfo ti = General.Map.Data.GetThingInfoEx(t.Type);
+
 				// Known action on this thing?
 				if((t.Action > 0) && General.Map.Config.LinedefActions.ContainsKey(t.Action))
 				{
+					//Do not draw the association if this is a child link.
+					//  This prevents a reverse link to a thing via an argument, when it should be a direct tag-to-tag link instead.
+					if(ti != null && asso.DirectLinkType < 0 && asso.DirectLinkType != -t.Type)
+						continue;
+
 					LinedefActionInfo action = General.Map.Config.LinedefActions[t.Action];
 					if(  ((action.Args[0].Type == (int)asso.Type) && (asso.Tags.Contains(t.Args[0]))) ||
 						 ((action.Args[1].Type == (int)asso.Type) && (asso.Tags.Contains(t.Args[1]))) ||
@@ -826,12 +840,20 @@ namespace CodeImp.DoomBuilder.BuilderModes
 						renderer.RenderThing(t, General.Colors.Indication, General.Settings.ActiveThingsAlpha);
 						if(General.Settings.GZShowEventLines) eventlines.Add(new Line3D(t.Position, asso.Center)); //mxd
 					}
+
+					//If there is a link setup on this thing, and it matches the association, then draw a direct link to any matching tag
+					if(ti != null && asso.DirectLinkType == t.Type && asso.Tags.Contains(t.Tag))
+					{
+						renderer.RenderThing(t, General.Colors.Indication, General.Settings.ActiveThingsAlpha);
+						if (General.Settings.GZShowEventLines) eventlines.Add(new Line3D(t.Position, asso.Center));
+					}
 				}
 				//mxd. Thing action on this thing?
 				else if(t.Action == 0)
 				{
-					ThingTypeInfo ti = General.Map.Data.GetThingInfoEx(t.Type);
+					//Draw the association, unless it is a child link.
-					if(ti != null)
+					//  This prevents a reverse link to a thing via an argument, when it should be a direct tag-to-tag link instead.
+					if(ti != null && asso.DirectLinkType >= 0 && Math.Abs(asso.DirectLinkType) != t.Type)
 					{
 						if(  ((ti.Args[0].Type == (int)asso.Type) && (asso.Tags.Contains(t.Args[0]))) ||
 						     ((ti.Args[1].Type == (int)asso.Type) && (asso.Tags.Contains(t.Args[1]))) ||