Merge pull request #8753 from MrSmite/Pet_SpeedFix

Fix pets lagging behind and despawning

src/server/game/AI/CoreAI/PetAI.cpp

@@ -251,6 +251,12 @@ void PetAI::UpdateAI(const uint32 diff)
         for (TargetSpellList::const_iterator itr = targetSpellStore.begin(); itr != targetSpellStore.end(); ++itr)
             delete itr->second;
     }
+
+    // Update speed as needed to prevent dropping too far behind and despawning
+    me->UpdateSpeed(MOVE_RUN, true);
+    me->UpdateSpeed(MOVE_WALK, true);
+    me->UpdateSpeed(MOVE_FLIGHT, true);
+    
 }
 
 void PetAI::UpdateAllies()

src/server/game/Entities/Unit/Unit.cpp

@@ -12712,9 +12712,27 @@ void Unit::UpdateSpeed(UnitMoveType mtype, bool forced)
         case MOVE_SWIM:
         case MOVE_FLIGHT:
         {
-            // Set creature speed rate from CreatureInfo
+            // Set creature speed rate
             if (GetTypeId() == TYPEID_UNIT)
-                speed *= ToCreature()->GetCreatureTemplate()->speed_run;    // at this point, MOVE_WALK is never reached
+            {
+                Unit* pOwner = GetCharmerOrOwner();
+                if (isPet() && !isInCombat() && pOwner) // Must check for owner or crash on "Tame Beast"
+                {
+                    // For every yard over 5, increase speed by 0.01
+                    //  to help prevent pet from lagging behind and despawning
+                    float dist = GetDistance(pOwner);
+                    float base_rate = 1.00f; // base speed is 100% of owner speed
+                    
+                    if (dist < 5)
+                        dist = 5;
+
+                    float mult = base_rate + ((dist - 5) * 0.01f);
+
+                    speed *= pOwner->GetSpeedRate(mtype) * mult; // pets derive speed from owner when not in combat
+                }
+                else
+                    speed *= ToCreature()->GetCreatureTemplate()->speed_run;    // at this point, MOVE_WALK is never reached
+            }
 
             // Normalize speed by 191 aura SPELL_AURA_USE_NORMAL_MOVEMENT_SPEED if need
             // TODO: possible affect only on MOVE_RUN