Core/Movement: Delay creating MoveSplineInit objects used by GenericMovementGenerator to spline launch time

* This fixes inconsistent transport state detection for players exiting vehicles that are on transport (ICC gunship battle), fixes players being telerpoted to middle of nowhere on that fight

(cherry picked from commit b1a94bf94c500b64a5c4ae92642a95d048d9f392)

8 files changed, 143 insertions, 123 deletions

diff --git a/src/server/game/Entities/Unit/Unit.cpp b/src/server/game/Entities/Unit/Unit.cpp
index b78cfb76e25..07a5fb86fe6 100644
--- a/src/server/game/Entities/Unit/Unit.cpp
+++ b/src/server/game/Entities/Unit/Unit.cpp
@@ -525,10 +525,12 @@ bool Unit::haveOffhandWeapon() const
 
 void Unit::MonsterMoveWithSpeed(float x, float y, float z, float speed, bool generatePath, bool forceDestination)
 {
-    Movement::MoveSplineInit init(this);
-    init.MoveTo(x, y, z, generatePath, forceDestination);
-    init.SetVelocity(speed);
-    GetMotionMaster()->LaunchMoveSpline(std::move(init), 0, MOTION_PRIORITY_NORMAL, POINT_MOTION_TYPE);
+    std::function<void(Movement::MoveSplineInit&)> initializer = [=](Movement::MoveSplineInit& init)
+    {
+        init.MoveTo(x, y, z, generatePath, forceDestination);
+        init.SetVelocity(speed);
+    };
+    GetMotionMaster()->LaunchMoveSpline(std::move(initializer), 0, MOTION_PRIORITY_NORMAL, POINT_MOTION_TYPE);
 }
 
 void Unit::UpdateSplineMovement(uint32 t_diff)
@@ -12179,18 +12181,19 @@ void Unit::_ExitVehicle(Position const* exitPosition)
         }
     }
 
-    float height = pos.GetPositionZ() + vehicle->GetBase()->GetCollisionHeight();
-
-    Movement::MoveSplineInit init(this);
+    std::function<void(Movement::MoveSplineInit&)> initializer = [=](Movement::MoveSplineInit& init)
+    {
+        float height = pos.GetPositionZ() + vehicle->GetBase()->GetCollisionHeight();
 
-    // Creatures without inhabit type air should begin falling after exiting the vehicle
-    if (GetTypeId() == TYPEID_UNIT && !CanFly() && height > GetMap()->GetWaterOrGroundLevel(GetPhaseShift(), pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ() + vehicle->GetBase()->GetCollisionHeight(), &height))
-        init.SetFall();
+        // Creatures without inhabit type air should begin falling after exiting the vehicle
+        if (GetTypeId() == TYPEID_UNIT && !CanFly() && height > GetMap()->GetWaterOrGroundLevel(GetPhaseShift(), pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ() + vehicle->GetBase()->GetCollisionHeight(), &height))
+            init.SetFall();
 
-    init.MoveTo(pos.GetPositionX(), pos.GetPositionY(), height, false);
-    init.SetFacing(pos.GetOrientation());
-    init.SetTransportExit();
-    GetMotionMaster()->LaunchMoveSpline(std::move(init), EVENT_VEHICLE_EXIT, MOTION_PRIORITY_HIGHEST);
+        init.MoveTo(pos.GetPositionX(), pos.GetPositionY(), height, false);
+        init.SetFacing(pos.GetOrientation());
+        init.SetTransportExit();
+    };
+    GetMotionMaster()->LaunchMoveSpline(std::move(initializer), EVENT_VEHICLE_EXIT, MOTION_PRIORITY_HIGHEST);
 
     if (player)
         player->ResummonPetTemporaryUnSummonedIfAny();
diff --git a/src/server/game/Entities/Vehicle/Vehicle.cpp b/src/server/game/Entities/Vehicle/Vehicle.cpp
index cab96560c1d..a111a07ba71 100644
--- a/src/server/game/Entities/Vehicle/Vehicle.cpp
+++ b/src/server/game/Entities/Vehicle/Vehicle.cpp
@@ -884,12 +884,14 @@ bool VehicleJoinEvent::Execute(uint64, uint32)
     Passenger->SetControlled(true, UNIT_STATE_ROOT);         // SMSG_FORCE_ROOT - In some cases we send SMSG_SPLINE_MOVE_ROOT here (for creatures)
     // also adds MOVEMENTFLAG_ROOT
 
-    Movement::MoveSplineInit init(Passenger);
-    init.DisableTransportPathTransformations();
-    init.MoveTo(x, y, z, false, true);
-    init.SetFacing(o);
-    init.SetTransportEnter();
-    Passenger->GetMotionMaster()->LaunchMoveSpline(std::move(init), EVENT_VEHICLE_BOARD, MOTION_PRIORITY_HIGHEST);
+    std::function<void(Movement::MoveSplineInit&)> initializer = [=](Movement::MoveSplineInit& init)
+    {
+        init.DisableTransportPathTransformations();
+        init.MoveTo(x, y, z, false, true);
+        init.SetFacing(o);
+        init.SetTransportEnter();
+    };
+    Passenger->GetMotionMaster()->LaunchMoveSpline(std::move(initializer), EVENT_VEHICLE_BOARD, MOTION_PRIORITY_HIGHEST);
 
     for (auto const& [guid, threatRef] : Passenger->GetThreatManager().GetThreatenedByMeList())
         threatRef->GetOwner()->GetThreatManager().AddThreat(Target->GetBase(), threatRef->GetThreat(), nullptr, true, true);
diff --git a/src/server/game/Handlers/MovementHandler.cpp b/src/server/game/Handlers/MovementHandler.cpp
index 2c8f70db994..a8cd953abb7 100644
--- a/src/server/game/Handlers/MovementHandler.cpp
+++ b/src/server/game/Handlers/MovementHandler.cpp
@@ -320,10 +320,7 @@ void WorldSession::HandleMovementOpcode(OpcodeClient opcode, MovementInfo& movem
     }
 
     if (!movementInfo.pos.IsPositionValid())
-    {
-        TC_LOG_ERROR("network", "HandleMovementOpcodes: Invalid Position");
         return;
-    }
 
     if (!mover->movespline->Finalized())
         return;
@@ -342,15 +339,11 @@ void WorldSession::HandleMovementOpcode(OpcodeClient opcode, MovementInfo& movem
         // transports size limited
         // (also received at zeppelin leave by some reason with t_* as absolute in continent coordinates, can be safely skipped)
         if (fabs(movementInfo.transport.pos.GetPositionX()) > 75.0f || fabs(movementInfo.transport.pos.GetPositionY()) > 75.0f || fabs(movementInfo.transport.pos.GetPositionZ()) > 75.0f)
-        {
             return;
-        }
 
         if (!Trinity::IsValidMapCoord(movementInfo.pos.GetPositionX() + movementInfo.transport.pos.GetPositionX(), movementInfo.pos.GetPositionY() + movementInfo.transport.pos.GetPositionY(),
             movementInfo.pos.GetPositionZ() + movementInfo.transport.pos.GetPositionZ(), movementInfo.pos.GetOrientation() + movementInfo.transport.pos.GetOrientation()))
-        {
             return;
-        }
 
         // if we boarded a transport, add us to it
         if (plrMover)
diff --git a/src/server/game/Movement/MotionMaster.cpp b/src/server/game/Movement/MotionMaster.cpp
index b0a8aa1fa70..e7dc9d6f632 100644
--- a/src/server/game/Movement/MotionMaster.cpp
+++ b/src/server/game/Movement/MotionMaster.cpp
@@ -27,6 +27,7 @@
 #include "Map.h"
 #include "MoveSpline.h"
 #include "MoveSplineInit.h"
+#include "ObjectAccessor.h"
 #include "PathGenerator.h"
 #include "PetDefines.h"
 #include "Player.h"
@@ -687,10 +688,13 @@ void MotionMaster::MoveCloserAndStop(uint32 id, Unit* target, float distance)
     else
     {
         // We are already close enough. We just need to turn toward the target without changing position.
-        Movement::MoveSplineInit init(_owner);
-        init.MoveTo(_owner->GetPositionX(), _owner->GetPositionY(), _owner->GetPositionZ());
-        init.SetFacing(target);
-        Add(new GenericMovementGenerator(std::move(init), EFFECT_MOTION_TYPE, id));
+        std::function<void(Movement::MoveSplineInit&)> initializer = [=, target = target->GetGUID()](Movement::MoveSplineInit& init)
+        {
+            init.MoveTo(_owner->GetPositionX(), _owner->GetPositionY(), _owner->GetPositionZ());
+            if (Unit const* refreshedTarget = ObjectAccessor::GetUnit(*_owner, target))
+                init.SetFacing(refreshedTarget);
+        };
+        Add(new GenericMovementGenerator(std::move(initializer), EFFECT_MOTION_TYPE, id));
     }
 }
 
@@ -698,24 +702,28 @@ void MotionMaster::MoveLand(uint32 id, Position const& pos, Optional<float> velo
 {
     TC_LOG_DEBUG("movement.motionmaster", "MotionMaster::MoveLand: '%s', landing point Id: %u (X: %f, Y: %f, Z: %f)", _owner->GetGUID().ToString().c_str(), id, pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ());
 
-    Movement::MoveSplineInit init(_owner);
-    init.MoveTo(PositionToVector3(pos), false);
-    init.SetAnimation(AnimTier::Ground);
-    if (velocity)
-        init.SetVelocity(*velocity);
-    Add(new GenericMovementGenerator(std::move(init), EFFECT_MOTION_TYPE, id));
+    std::function<void(Movement::MoveSplineInit&)> initializer = [=](Movement::MoveSplineInit& init)
+    {
+        init.MoveTo(PositionToVector3(pos), false);
+        init.SetAnimation(AnimTier::Ground);
+        if (velocity)
+            init.SetVelocity(*velocity);
+    };
+    Add(new GenericMovementGenerator(std::move(initializer), EFFECT_MOTION_TYPE, id));
 }
 
 void MotionMaster::MoveTakeoff(uint32 id, Position const& pos, Optional<float> velocity /*= {}*/)
 {
     TC_LOG_DEBUG("movement.motionmaster", "MotionMaster::MoveTakeoff: '%s', landing point Id: %u (X: %f, Y: %f, Z: %f)", _owner->GetGUID().ToString().c_str(), id, pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ());
 
-    Movement::MoveSplineInit init(_owner);
-    init.MoveTo(PositionToVector3(pos), false);
-    init.SetAnimation(AnimTier::Hover);
-    if (velocity)
-        init.SetVelocity(*velocity);
-    Add(new GenericMovementGenerator(std::move(init), EFFECT_MOTION_TYPE, id));
+    std::function<void(Movement::MoveSplineInit&)> initializer = [=](Movement::MoveSplineInit& init)
+    {
+        init.MoveTo(PositionToVector3(pos), false);
+        init.SetAnimation(AnimTier::Hover);
+        if (velocity)
+            init.SetVelocity(*velocity);
+    };
+    Add(new GenericMovementGenerator(std::move(initializer), EFFECT_MOTION_TYPE, id));
 }
 
 void MotionMaster::MoveCharge(float x, float y, float z, float speed /*= SPEED_CHARGE*/, uint32 id /*= EVENT_CHARGE*/, bool generatePath /*= false*/,
@@ -778,15 +786,17 @@ void MotionMaster::MoveKnockbackFrom(Position const& origin, float speedXY, floa
     // Use a mmap raycast to get a valid destination.
     _owner->MovePositionToFirstCollision(dest, dist, _owner->GetRelativeAngle(origin) + float(M_PI));
 
-    Movement::MoveSplineInit init(_owner);
-    init.MoveTo(dest.GetPositionX(), dest.GetPositionY(), dest.GetPositionZ(), false);
-    init.SetParabolic(max_height, 0);
-    init.SetOrientationFixed(true);
-    init.SetVelocity(speedXY);
-    if (spellEffectExtraData)
-        init.SetSpellEffectExtraData(*spellEffectExtraData);
+    std::function<void(Movement::MoveSplineInit&)> initializer = [=, effect = (spellEffectExtraData ? Optional<Movement::SpellEffectExtraData>(*spellEffectExtraData) : Optional<Movement::SpellEffectExtraData>())](Movement::MoveSplineInit& init)
+    {
+        init.MoveTo(dest.GetPositionX(), dest.GetPositionY(), dest.GetPositionZ(), false);
+        init.SetParabolic(max_height, 0);
+        init.SetOrientationFixed(true);
+        init.SetVelocity(speedXY);
+        if (effect)
+            init.SetSpellEffectExtraData(*effect);
+    };
 
-    GenericMovementGenerator* movement = new GenericMovementGenerator(std::move(init), EFFECT_MOTION_TYPE, 0);
+    GenericMovementGenerator* movement = new GenericMovementGenerator(std::move(initializer), EFFECT_MOTION_TYPE, 0);
     movement->Priority = MOTION_PRIORITY_HIGHEST;
     movement->AddFlag(MOVEMENTGENERATOR_FLAG_PERSIST_ON_DEATH);
     Add(movement);
@@ -825,14 +835,16 @@ void MotionMaster::MoveJump(float x, float y, float z, float o, float speedXY, f
     float moveTimeHalf = speedZ / Movement::gravity;
     float max_height = -Movement::computeFallElevation(moveTimeHalf, false, -speedZ);
 
-    Movement::MoveSplineInit init(_owner);
-    init.MoveTo(x, y, z, false);
-    init.SetParabolic(max_height, 0);
-    init.SetVelocity(speedXY);
-    if (hasOrientation)
-        init.SetFacing(o);
-    if (spellEffectExtraData)
-        init.SetSpellEffectExtraData(*spellEffectExtraData);
+    std::function<void(Movement::MoveSplineInit&)> initializer = [=, effect = (spellEffectExtraData ? Optional<Movement::SpellEffectExtraData>(*spellEffectExtraData) : Optional<Movement::SpellEffectExtraData>())](Movement::MoveSplineInit& init)
+    {
+        init.MoveTo(x, y, z, false);
+        init.SetParabolic(max_height, 0);
+        init.SetVelocity(speedXY);
+        if (hasOrientation)
+            init.SetFacing(o);
+        if (effect)
+            init.SetSpellEffectExtraData(*effect);
+    };
 
     uint32 arrivalSpellId = 0;
     ObjectGuid arrivalSpellTargetGuid;
@@ -842,7 +854,7 @@ void MotionMaster::MoveJump(float x, float y, float z, float o, float speedXY, f
         arrivalSpellTargetGuid = arrivalCast->Target;
     }
 
-    GenericMovementGenerator* movement = new GenericMovementGenerator(std::move(init), EFFECT_MOTION_TYPE, id, arrivalSpellId, arrivalSpellTargetGuid);
+    GenericMovementGenerator* movement = new GenericMovementGenerator(std::move(initializer), EFFECT_MOTION_TYPE, id, arrivalSpellId, arrivalSpellTargetGuid);
     movement->Priority = MOTION_PRIORITY_HIGHEST;
     movement->BaseUnitState = UNIT_STATE_JUMPING;
     Add(movement);
@@ -855,15 +867,17 @@ void MotionMaster::MoveJumpWithGravity(Position const& pos, float speedXY, float
     if (speedXY < 0.01f)
         return;
 
-    Movement::MoveSplineInit init(_owner);
-    init.MoveTo(pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ(), false);
-    init.SetParabolicVerticalAcceleration(gravity, 0);
-    init.SetUncompressed();
-    init.SetVelocity(speedXY);
-    if (hasOrientation)
-        init.SetFacing(pos.GetOrientation());
-    if (spellEffectExtraData)
-        init.SetSpellEffectExtraData(*spellEffectExtraData);
+    std::function<void(Movement::MoveSplineInit&)> initializer = [=, effect = (spellEffectExtraData ? Optional<Movement::SpellEffectExtraData>(*spellEffectExtraData) : Optional<Movement::SpellEffectExtraData>())](Movement::MoveSplineInit& init)
+    {
+        init.MoveTo(pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ(), false);
+        init.SetParabolicVerticalAcceleration(gravity, 0);
+        init.SetUncompressed();
+        init.SetVelocity(speedXY);
+        if (hasOrientation)
+            init.SetFacing(pos.GetOrientation());
+        if (effect)
+            init.SetSpellEffectExtraData(*effect);
+    };
 
     uint32 arrivalSpellId = 0;
     ObjectGuid arrivalSpellTargetGuid;
@@ -873,7 +887,7 @@ void MotionMaster::MoveJumpWithGravity(Position const& pos, float speedXY, float
         arrivalSpellTargetGuid = arrivalCast->Target;
     }
 
-    GenericMovementGenerator* movement = new GenericMovementGenerator(std::move(init), EFFECT_MOTION_TYPE, id, arrivalSpellId, arrivalSpellTargetGuid);
+    GenericMovementGenerator* movement = new GenericMovementGenerator(std::move(initializer), EFFECT_MOTION_TYPE, id, arrivalSpellId, arrivalSpellTargetGuid);
     movement->Priority = MOTION_PRIORITY_HIGHEST;
     movement->BaseUnitState = UNIT_STATE_JUMPING;
     movement->AddFlag(MOVEMENTGENERATOR_FLAG_PERSIST_ON_DEATH);
@@ -882,67 +896,69 @@ void MotionMaster::MoveJumpWithGravity(Position const& pos, float speedXY, float
 
 void MotionMaster::MoveCirclePath(float x, float y, float z, float radius, bool clockwise, uint8 stepCount)
 {
-    float step = 2 * float(M_PI) / stepCount * (clockwise ? -1.0f : 1.0f);
-    Position const& pos = { x, y, z, 0.0f };
-    float angle = pos.GetAbsoluteAngle(_owner->GetPositionX(), _owner->GetPositionY());
+    std::function<void(Movement::MoveSplineInit&)> initializer = [=](Movement::MoveSplineInit& init)
+    {
+        float step = 2 * float(M_PI) / stepCount * (clockwise ? -1.0f : 1.0f);
+        Position const& pos = { x, y, z, 0.0f };
+        float angle = pos.GetAbsoluteAngle(_owner->GetPositionX(), _owner->GetPositionY());
 
-    Movement::MoveSplineInit init(_owner);
+        // add the owner's current position as starting point as it gets removed after entering the cycle
+        init.Path().push_back(G3D::Vector3(_owner->GetPositionX(), _owner->GetPositionY(), _owner->GetPositionZ()));
 
-    // add the owner's current position as starting point as it gets removed after entering the cycle
-    init.Path().push_back(G3D::Vector3(_owner->GetPositionX(), _owner->GetPositionY(), _owner->GetPositionZ()));
+        for (uint8 i = 0; i < stepCount; angle += step, ++i)
+        {
+            G3D::Vector3 point;
+            point.x = x + radius * cosf(angle);
+            point.y = y + radius * sinf(angle);
 
-    for (uint8 i = 0; i < stepCount; angle += step, ++i)
-    {
-        G3D::Vector3 point;
-        point.x = x + radius * cosf(angle);
-        point.y = y + radius * sinf(angle);
+            if (_owner->IsFlying())
+                point.z = z;
+            else
+                point.z = _owner->GetMapHeight(point.x, point.y, z) + _owner->GetHoverOffset();
+
+            init.Path().push_back(point);
+        }
 
         if (_owner->IsFlying())
-            point.z = z;
+        {
+            init.SetFly();
+            init.SetCyclic();
+            init.SetAnimation(AnimTier::Hover);
+        }
         else
-            point.z = _owner->GetMapHeight(point.x, point.y, z) + _owner->GetHoverOffset();
-
-        init.Path().push_back(point);
-    }
-
-    if (_owner->IsFlying())
-    {
-        init.SetFly();
-        init.SetCyclic();
-        init.SetAnimation(AnimTier::Hover);
-    }
-    else
-    {
-        init.SetWalk(true);
-        init.SetCyclic();
-    }
+        {
+            init.SetWalk(true);
+            init.SetCyclic();
+        }
+    };
 
-    Add(new GenericMovementGenerator(std::move(init), EFFECT_MOTION_TYPE, 0));
+    Add(new GenericMovementGenerator(std::move(initializer), EFFECT_MOTION_TYPE, 0));
 }
 
 void MotionMaster::MoveSmoothPath(uint32 pointId, Position const* pathPoints, size_t pathSize, bool walk, bool fly)
 {
-    Movement::MoveSplineInit init(_owner);
-    if (fly)
-    {
-        init.SetFly();
-        init.SetUncompressed();
-        init.SetSmooth();
-    }
-
     Movement::PointsArray path;
     path.reserve(pathSize);
     std::transform(pathPoints, pathPoints + pathSize, std::back_inserter(path), [](Position const& point)
     {
         return G3D::Vector3(point.GetPositionX(), point.GetPositionY(), point.GetPositionZ());
     });
-    init.MovebyPath(path);
-    init.SetWalk(walk);
+    std::function<void(Movement::MoveSplineInit&)> initializer = [=](Movement::MoveSplineInit& init)
+    {
+        init.MovebyPath(path);
+        init.SetWalk(walk);
+        if (fly)
+        {
+            init.SetFly();
+            init.SetUncompressed();
+            init.SetSmooth();
+        }
+    };
 
     // This code is not correct
     // GenericMovementGenerator does not affect UNIT_STATE_ROAMING_MOVE
     // need to call PointMovementGenerator with various pointIds
-    Add(new GenericMovementGenerator(std::move(init), EFFECT_MOTION_TYPE, pointId));
+    Add(new GenericMovementGenerator(std::move(initializer), EFFECT_MOTION_TYPE, pointId));
 }
 
 void MotionMaster::MoveAlongSplineChain(uint32 pointId, uint16 dbChainId, bool walk)
@@ -1005,11 +1021,13 @@ void MotionMaster::MoveFall(uint32 id/* = 0*/)
         return;
     }
 
-    Movement::MoveSplineInit init(_owner);
-    init.MoveTo(_owner->GetPositionX(), _owner->GetPositionY(), tz + _owner->GetHoverOffset(), false);
-    init.SetFall();
+    std::function<void(Movement::MoveSplineInit&)> initializer = [=](Movement::MoveSplineInit& init)
+    {
+        init.MoveTo(_owner->GetPositionX(), _owner->GetPositionY(), tz + _owner->GetHoverOffset(), false);
+        init.SetFall();
+    };
 
-    GenericMovementGenerator* movement = new GenericMovementGenerator(std::move(init), EFFECT_MOTION_TYPE, id);
+    GenericMovementGenerator* movement = new GenericMovementGenerator(std::move(initializer), EFFECT_MOTION_TYPE, id);
     movement->Priority = MOTION_PRIORITY_HIGHEST;
     Add(movement);
 }
@@ -1106,7 +1124,7 @@ void MotionMaster::MoveFormation(Unit* leader, float range, float angle, uint32
     }
 }
 
-void MotionMaster::LaunchMoveSpline(Movement::MoveSplineInit&& init, uint32 id/*= 0*/, MovementGeneratorPriority priority/* = MOTION_PRIORITY_NORMAL*/, MovementGeneratorType type/*= EFFECT_MOTION_TYPE*/)
+void MotionMaster::LaunchMoveSpline(std::function<void(Movement::MoveSplineInit& init)>&& initializer, uint32 id/*= 0*/, MovementGeneratorPriority priority/* = MOTION_PRIORITY_NORMAL*/, MovementGeneratorType type/*= EFFECT_MOTION_TYPE*/)
 {
     if (IsInvalidMovementGeneratorType(type))
     {
@@ -1116,7 +1134,7 @@ void MotionMaster::LaunchMoveSpline(Movement::MoveSplineInit&& init, uint32 id/*
 
     TC_LOG_DEBUG("movement.motionmaster", "MotionMaster::LaunchMoveSpline: '%s', initiates spline Id: %u (Type: %u, Priority: %u)", _owner->GetGUID().ToString().c_str(), id, type, priority);
 
-    GenericMovementGenerator* movement = new GenericMovementGenerator(std::move(init), type, id);
+    GenericMovementGenerator* movement = new GenericMovementGenerator(std::move(initializer), type, id);
     movement->Priority = priority;
     Add(movement);
 }
diff --git a/src/server/game/Movement/MotionMaster.h b/src/server/game/Movement/MotionMaster.h
index 1b558df44d5..01b1bf125a6 100644
--- a/src/server/game/Movement/MotionMaster.h
+++ b/src/server/game/Movement/MotionMaster.h
@@ -195,7 +195,7 @@ class TC_GAME_API MotionMaster
         void MoveRotate(uint32 id, uint32 time, RotateDirection direction);
         void MoveFormation(Unit* leader, float range, float angle, uint32 point1, uint32 point2);
 
-        void LaunchMoveSpline(Movement::MoveSplineInit&& init, uint32 id = 0, MovementGeneratorPriority priority = MOTION_PRIORITY_NORMAL, MovementGeneratorType type = EFFECT_MOTION_TYPE);
+        void LaunchMoveSpline(std::function<void(Movement::MoveSplineInit& init)>&& initializer, uint32 id = 0, MovementGeneratorPriority priority = MOTION_PRIORITY_NORMAL, MovementGeneratorType type = EFFECT_MOTION_TYPE);
     private:
         typedef std::unique_ptr<MovementGenerator, MovementGeneratorDeleter> MovementGeneratorPointer;
         typedef std::multiset<MovementGenerator*, MovementGeneratorComparator> MotionMasterContainer;
diff --git a/src/server/game/Movement/MovementGenerators/GenericMovementGenerator.cpp b/src/server/game/Movement/MovementGenerators/GenericMovementGenerator.cpp
index f8a494522c4..ba61e180432 100644
--- a/src/server/game/Movement/MovementGenerators/GenericMovementGenerator.cpp
+++ b/src/server/game/Movement/MovementGenerators/GenericMovementGenerator.cpp
@@ -23,9 +23,9 @@
 #include "ObjectAccessor.h"
 #include "Unit.h"
 
-GenericMovementGenerator::GenericMovementGenerator(Movement::MoveSplineInit&& splineInit, MovementGeneratorType type, uint32 id,
+GenericMovementGenerator::GenericMovementGenerator(std::function<void(Movement::MoveSplineInit& init)>&& initializer, MovementGeneratorType type, uint32 id,
     uint32 arrivalSpellId /*= 0*/, ObjectGuid const& arrivalSpellTargetGuid /*= ObjectGuid::Empty*/)
-    : _splineInit(std::move(splineInit)), _type(type), _pointId(id), _duration(0),
+    : _splineInit(std::move(initializer)), _type(type), _pointId(id), _duration(0),
     _arrivalSpellId(arrivalSpellId), _arrivalSpellTargetGuid(arrivalSpellTargetGuid)
 {
     Mode = MOTION_MODE_DEFAULT;
@@ -34,7 +34,7 @@ GenericMovementGenerator::GenericMovementGenerator(Movement::MoveSplineInit&& sp
     BaseUnitState = UNIT_STATE_ROAMING;
 }
 
-void GenericMovementGenerator::Initialize(Unit* /*owner*/)
+void GenericMovementGenerator::Initialize(Unit* owner)
 {
     if (HasFlag(MOVEMENTGENERATOR_FLAG_DEACTIVATED) && !HasFlag(MOVEMENTGENERATOR_FLAG_INITIALIZATION_PENDING)) // Resume spline is not supported
     {
@@ -46,7 +46,9 @@ void GenericMovementGenerator::Initialize(Unit* /*owner*/)
     RemoveFlag(MOVEMENTGENERATOR_FLAG_INITIALIZATION_PENDING | MOVEMENTGENERATOR_FLAG_DEACTIVATED);
     AddFlag(MOVEMENTGENERATOR_FLAG_INITIALIZED);
 
-    _duration.Reset(_splineInit.Launch());
+    Movement::MoveSplineInit init(owner);
+    _splineInit(init);
+    _duration.Reset(init.Launch());
 }
 
 void GenericMovementGenerator::Reset(Unit* owner)
diff --git a/src/server/game/Movement/MovementGenerators/GenericMovementGenerator.h b/src/server/game/Movement/MovementGenerators/GenericMovementGenerator.h
index 6655cd693a7..6b3b984c468 100644
--- a/src/server/game/Movement/MovementGenerators/GenericMovementGenerator.h
+++ b/src/server/game/Movement/MovementGenerators/GenericMovementGenerator.h
@@ -21,6 +21,7 @@
 #include "MovementGenerator.h"
 #include "MoveSplineInit.h"
 #include "Timer.h"
+#include <functional>
 
 class Unit;
 
@@ -29,7 +30,7 @@ enum MovementGeneratorType : uint8;
 class GenericMovementGenerator : public MovementGenerator
 {
     public:
-        explicit GenericMovementGenerator(Movement::MoveSplineInit&& splineInit, MovementGeneratorType type, uint32 id,
+        explicit GenericMovementGenerator(std::function<void(Movement::MoveSplineInit& init)>&& initializer, MovementGeneratorType type, uint32 id,
             uint32 arrivalSpellId = 0, ObjectGuid const& arrivalSpellTargetGuid = ObjectGuid::Empty);
 
         void Initialize(Unit*) override;
@@ -42,7 +43,7 @@ class GenericMovementGenerator : public MovementGenerator
     private:
         void MovementInform(Unit*);
 
-        Movement::MoveSplineInit _splineInit;
+        std::function<void(Movement::MoveSplineInit& init)> _splineInit;
         MovementGeneratorType _type;
         uint32 _pointId;
         TimeTracker _duration;
diff --git a/src/server/game/Movement/Spline/MoveSplineInit.h b/src/server/game/Movement/Spline/MoveSplineInit.h
index bec9b55959f..5e5a7ec0da1 100644
--- a/src/server/game/Movement/Spline/MoveSplineInit.h
+++ b/src/server/game/Movement/Spline/MoveSplineInit.h
@@ -20,6 +20,7 @@
 
 #include "MoveSplineInitArgs.h"
 
+class ObjectGuid;
 class Unit;
 
 enum class AnimTier : uint8;