Core/Movement: Correct the allowed distance to target before a repositioning is necessary.

Port From (https://github.com/TrinityCore/TrinityCore/commit/0ce1e9d6522974e3186e8b5cf75b7c653a075862)

Source/Framework/Constants/SharedConst.cs

@@ -1603,7 +1603,6 @@ namespace Framework.Constants
         RateRestOfflineInWilderness,
         RateSkillDiscovery,
         RateTalent,
-        RateTargetPosRecalculationRange,
         RateXpExplore,
         RateXpGuildModifier,
         RateXpKill,

Source/Game/Movement/Generators/TargetMovement.cs

@@ -31,6 +31,8 @@ namespace Game.Movement
 
     public abstract class TargetedMovementGenerator<T> : MovementGeneratorMedium<T>, ITargetedMovementGeneratorBase where T : Unit
     {
+        protected static float MOVE_FOLLOW_REPOSITIONING_DISTANCE = 1.5f;
+
         protected TargetedMovementGenerator(Unit target, float offset = 0, float angle = 0)
         {
             _target = new FollowerReference();
@@ -71,9 +73,10 @@ namespace Game.Movement
             {
                 _timer.Reset(100);
 
-                float distance = owner.GetCombatReach() + WorldConfig.GetFloatValue(WorldCfg.RateTargetPosRecalculationRange);
+                // the allowed distance between target and mover before the mover needs to reposition in order to keep attacking
+                float distance = GetMaxDistanceBeforeRepositioning(owner);
                 if (owner.IsPet() && (owner.GetCharmerOrOwnerGUID() == GetTarget().GetGUID()))
-                    distance = 1.0f; // pet following owner
+                    distance = 1.0f + GetTarget().GetCombatReach(); // pet following owner
 
                 Vector3 destination = owner.MoveSpline.FinalDestination();
                 if (owner.MoveSpline.onTransport)
@@ -85,10 +88,10 @@ namespace Game.Movement
                 }
 
                 // First check distance
-                if (owner.IsTypeId(TypeId.Unit) && owner.ToCreature().CanFly())
-                    targetMoved = !GetTarget().IsWithinDist3d(destination.X, destination.Y, destination.Z, distance);
+                if (owner.IsCreature() && owner.ToCreature().CanFly())
+                    targetMoved = !GetTarget().IsInDist(destination.X, destination.Y, destination.Z, distance);
                 else
-                    targetMoved = !GetTarget().IsWithinDist2d(destination.X, destination.Y, distance);
+                    targetMoved = !GetTarget().IsInDist2d(destination.X, destination.Y, distance);
 
 
                 // then, if the target is in range, check also Line of Sight.
@@ -228,7 +231,8 @@ namespace Game.Movement
         public abstract void ReachTarget(T owner);
         public virtual bool EnableWalking() { return false; }
         public abstract void MovementInform(T owner);
-        
+        public virtual float GetMaxDistanceBeforeRepositioning(T owner) { return 0.0f; }
+
         public void StopFollowing() { }
 
         public bool IsTargetValid() { return _target.IsValid(); }
@@ -302,6 +306,14 @@ namespace Game.Movement
                 owner.ToCreature().SetCannotReachTarget(false);
         }
 
+        public override float GetMaxDistanceBeforeRepositioning(T owner)
+        {
+            // the notion of melee range and melee attack is clearly separated from the notion of the movement.
+            // As a seperation of concern refactoring, this value should be passed into parameter by the caller (during creation of ChaseMoveGen) instead of defining it
+            // here (or a callback should be used since this value depends on dynamic fields (combat reach).
+            return owner.GetMeleeRange(base.GetTarget());
+        }
+
         public override void MovementInform(T owner)
         {
             if (owner.IsTypeId(TypeId.Unit))
@@ -362,6 +374,11 @@ namespace Game.Movement
                 return IsTargetValid() && GetTarget().IsWalking();
         }
 
+        public override float GetMaxDistanceBeforeRepositioning(T owner)
+        {
+            return owner.GetCombatReach() + base.GetTarget().GetCombatReach() + MOVE_FOLLOW_REPOSITIONING_DISTANCE;
+        }
+
         public override void MovementInform(T owner)
         {
             if (owner.IsTypeId(TypeId.Player))

Source/Game/Server/WorldConfig.cs

@@ -134,19 +134,6 @@ namespace Game
 
             Values[WorldCfg.RateCorpseDecayLooted] = GetDefaultValue("Rate.Corpse.Decay.Looted", 0.5f);
 
-            Values[WorldCfg.RateTargetPosRecalculationRange] = GetDefaultValue("TargetPosRecalculateRange", 1.5f);
-            if ((float)Values[WorldCfg.RateTargetPosRecalculationRange] < SharedConst.ContactDistance)
-            {
-                Log.outError(LogFilter.ServerLoading, "TargetPosRecalculateRange ({0}) must be >= {1}. Using {1} instead.", Values[WorldCfg.RateTargetPosRecalculationRange], SharedConst.ContactDistance);
-                Values[WorldCfg.RateTargetPosRecalculationRange] = SharedConst.ContactDistance;
-            }
-            else if ((float)Values[WorldCfg.RateTargetPosRecalculationRange] > SharedConst.NominalMeleeRange)
-            {
-                Log.outError(LogFilter.ServerLoading, "TargetPosRecalculateRange ({0}) must be <= {1}. Using {1} instead.",
-                    Values[WorldCfg.RateTargetPosRecalculationRange], SharedConst.NominalMeleeRange);
-                Values[WorldCfg.RateTargetPosRecalculationRange] = SharedConst.NominalMeleeRange;
-            }
-
             Values[WorldCfg.RateDurabilityLossOnDeath] = GetDefaultValue("DurabilityLoss.OnDeath", 10.0f);
             if ((float)Values[WorldCfg.RateDurabilityLossOnDeath] < 0.0f)
             {

Source/WorldServer/WorldServer.conf.dist

@@ -428,17 +428,6 @@ DetectPosCollision = 1
 
 CheckGameObjectLoS = 1
 
-#
-#    TargetPosRecalculateRange
-#        Description: Max distance from movement target point (+moving unit size) and targeted
-#                     object (+size) after that new target movement point calculated.
-#        Range:       0.5-5.0
-#        Default:     1.5
-#                     0.5 - (Minimum, Contact Range, More sensitive reaction to target movement)
-#                     5.0 - (Maximum, Melee attack range, Less CPU usage)
-
-TargetPosRecalculateRange = 1.5
-
 #
 #    UpdateUptimeInterval
 #        Description: Update realm uptime period (in minutes).