Core/Movement: Prevent pet animation stuttering during movement (#1142)

* fix vanity pet distance and angle
* fix vanity pet distance to player
* put size calculation for normal pets into the if-statement for vanity pets
* change pet speed algorithm
* change distance calculation
* another change to the distance calculation; differentiate between player running or flying

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

@@ -178,6 +178,7 @@ i_motionMaster(new MotionMaster(this)), m_regenTimer(0), m_ThreatManager(this),
     m_rootTimes = 0;
 
     m_state = 0;
+    m_petCatchUp = false;
     m_deathState = ALIVE;
 
     for (uint8 i = 0; i < CURRENT_MAX_SPELL; ++i)
@@ -13093,8 +13094,40 @@ void Unit::UpdateSpeed(UnitMoveType mtype, bool forced)
                 Unit* pOwner = GetCharmerOrOwner();
                 if (pOwner && !IsInCombat() && !IsVehicle() && !HasFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_PLAYER_CONTROLLED) && (IsPet() || IsGuardian() || GetGUID() == pOwner->GetCritterGUID() || GetCharmerGUID() == pOwner->GetGUID()))
                 {
-                    if (speed < pOwner->GetSpeedRate(mtype)+0.1f)
+                    if (pOwner->GetTypeId() != TYPEID_PLAYER)
-                        speed = pOwner->GetSpeedRate(mtype)+0.1f; // pets derive speed from owner when not in combat
+                    {
+                        if (speed < pOwner->GetSpeedRate(mtype)+0.1f)
+                            speed = pOwner->GetSpeedRate(mtype)+0.1f; // pets derive speed from owner when not in combat
+                    }
+                    else
+                    {
+                        // special treatment for player pets in order to avoid stuttering
+                        float ownerSpeed = pOwner->GetSpeedRate(mtype);
+                        float distOwner = GetDistance(pOwner);
+                        float minDist = 2.5f;
+
+                        if (ToCreature()->GetCreatureType() == CREATURE_TYPE_NON_COMBAT_PET)
+                        {
+                            // different minimum distance for vanity pets
+                            minDist = 5.0f;
+
+                            if (mtype == MOVE_FLIGHT)
+                                mtype = MOVE_RUN; // vanity pets use run speed for flight
+                        }
+
+                        float maxDist = ownerSpeed >= 1.0f ? minDist * ownerSpeed * 1.5f : minDist * 1.5f;
+
+                        if (distOwner < minDist && m_petCatchUp)
+                            m_petCatchUp = false;
+
+                        if (distOwner > maxDist && !m_petCatchUp)
+                            m_petCatchUp = true;
+
+                        if (m_petCatchUp)
+                            speed = ownerSpeed * 1.05f;
+                        else
+                            speed = ownerSpeed * 0.95f;
+                    }
                 }
                 else
                     speed *= ToCreature()->GetCreatureTemplate()->speed_run;    // at this point, MOVE_WALK is never reached

src/server/game/Entities/Unit/Unit.h

@@ -2561,6 +2561,7 @@ class Unit : public WorldObject
         bool m_duringRemoveFromWorld; // lock made to not add stuff after begining removing from world
 
         uint32 _oldFactionId;           ///< faction before charm
+        bool m_petCatchUp;
 };
 
 namespace Trinity

src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.cpp

@@ -98,8 +98,17 @@ void TargetedMovementGeneratorMedium<T,D>::_setTargetLocation(T* owner, bool ini
         if ((!initial || (owner->movespline->Finalized() && this->GetMovementGeneratorType() == CHASE_MOTION_TYPE)) && i_target->IsWithinDistInMap(owner, dist) && i_target->IsWithinLOS(owner->GetPositionX(), owner->GetPositionY(), owner->GetPositionZ()))
             return;
 
-        // Xinef: Fix follow angle for hostile units
         float angle = i_angle;
+
+        if (i_target->GetTypeId() == TYPEID_PLAYER && owner->ToCreature()->GetCreatureType() == CREATURE_TYPE_NON_COMBAT_PET)
+        {
+            // fix distance and angle for vanity pets
+            dist = 0.3f;
+            angle = PET_FOLLOW_ANGLE + M_PI * 0.2f;
+            size = i_target->GetCombatReach() - i_target->GetObjectSize();
+        }
+
+        // Xinef: Fix follow angle for hostile units
         if (angle == 0.0f && owner->GetVictim() && owner->GetVictim()->GetGUID() == i_target->GetGUID())
             angle = MapManager::NormalizeOrientation(i_target->GetAngle(owner)-i_target->GetOrientation());
         // to at i_offset distance from target and i_angle from target facing
@@ -298,6 +307,18 @@ bool TargetedMovementGeneratorMedium<T,D>::DoUpdate(T* owner, uint32 time_diff)
         if (i_recalculateTravel)
             _setTargetLocation(owner, false);
     }
+
+    Unit* pOwner = owner->GetCharmerOrOwner();
+
+    if (pOwner && pOwner->GetTypeId() == TYPEID_PLAYER)
+    {
+        // Update pet speed for players in order to avoid stuttering
+        if (pOwner->IsFlying())
+            owner->UpdateSpeed(MOVE_FLIGHT, true);
+        else
+            owner->UpdateSpeed(MOVE_RUN, true);
+    }
+
     return true;
 }