Core/Movement: Implemented cyclic waypoint movement (#29923)

Co-authored-by: Shauren <shauren.trinity@gmail.com>
(cherry picked from commit 222a80a6d62410eae6fa46dbdc60309f1728653a)

4 files changed, 58 insertions, 11 deletions

diff --git a/src/server/game/Movement/MovementGenerators/WaypointMovementGenerator.cpp b/src/server/game/Movement/MovementGenerators/WaypointMovementGenerator.cpp
index 84a1871a5c1..232ad771b16 100644
--- a/src/server/game/Movement/MovementGenerators/WaypointMovementGenerator.cpp
+++ b/src/server/game/Movement/MovementGenerators/WaypointMovementGenerator.cpp
@@ -41,7 +41,7 @@ WaypointMovementGenerator<Creature>::WaypointMovementGenerator(uint32 pathId, bo
     : PathMovementBase(PathType(std::in_place_type<WaypointPath const*>)), _pathId(pathId), _speed(speed), _speedSelectionMode(speedSelectionMode),
     _waitTimeRangeAtPathEnd(std::move(waitTimeRangeAtPathEnd)), _wanderDistanceAtPathEnds(wanderDistanceAtPathEnds),
     _followPathBackwardsFromEndToStart(followPathBackwardsFromEndToStart), _exactSplinePath(exactSplinePath), _repeating(repeating), _generatePath(generatePath),
-    _moveTimer(0), _nextMoveTime(0), _isReturningToStart(false)
+    _moveTimer(0), _nextMoveTime(0), _waypointTransitionSplinePointsIndex(0), _isReturningToStart(false)
 {
     Mode = MOTION_MODE_DEFAULT;
     Priority = MOTION_PRIORITY_NORMAL;
@@ -59,7 +59,7 @@ WaypointMovementGenerator<Creature>::WaypointMovementGenerator(WaypointPath cons
     : PathMovementBase(std::make_unique<WaypointPath>(path)), _pathId(0), _speed(speed), _speedSelectionMode(speedSelectionMode),
     _waitTimeRangeAtPathEnd(std::move(waitTimeRangeAtPathEnd)), _wanderDistanceAtPathEnds(wanderDistanceAtPathEnds),
     _followPathBackwardsFromEndToStart(followPathBackwardsFromEndToStart), _exactSplinePath(exactSplinePath), _repeating(repeating), _generatePath(generatePath),
-    _moveTimer(0), _nextMoveTime(0), _isReturningToStart(false)
+    _moveTimer(0), _nextMoveTime(0), _waypointTransitionSplinePointsIndex(0), _isReturningToStart(false)
 {
     Mode = MOTION_MODE_DEFAULT;
     Priority = MOTION_PRIORITY_NORMAL;
@@ -218,7 +218,7 @@ bool WaypointMovementGenerator<Creature>::DoUpdate(Creature* owner, uint32 diff)
     }
 
     // if it's moving
-    if (!UpdateMoveTimer(diff))
+    if (!UpdateMoveTimer(diff) && !owner->movespline->Finalized())
     {
         // set home position at place (every MotionMaster::UpdateMotion)
         if (owner->GetTransGUID().IsEmpty())
@@ -227,10 +227,11 @@ bool WaypointMovementGenerator<Creature>::DoUpdate(Creature* owner, uint32 diff)
         // handle switching points in continuous segments
         if (IsExactSplinePath())
         {
-            if (_waypointTransitionSplinePoints.size() > 1 && owner->movespline->currentPathIdx() >= _waypointTransitionSplinePoints.front())
+            if (_waypointTransitionSplinePointsIndex < _waypointTransitionSplinePoints.size()
+                && owner->movespline->currentPathIdx() >= _waypointTransitionSplinePoints[_waypointTransitionSplinePointsIndex])
             {
                 OnArrived(owner);
-                _waypointTransitionSplinePoints.erase(_waypointTransitionSplinePoints.begin());
+                ++_waypointTransitionSplinePointsIndex;
                 if (ComputeNextNode())
                     if (CreatureAI* ai = owner->AI())
                         ai->WaypointStarted(path->Nodes[_currentNode].Id, path->Id);
@@ -363,13 +364,14 @@ void CreateSingularPointPath(Unit const* owner, WaypointPath const* path, uint32
     waypointTransitionSplinePoints->push_back(points->size() - 1);
 }
 
-void CreateMergedPath(Unit const* owner, WaypointPath const* path, uint32 previousNode, uint32 currentNode, bool isReturningToStart, bool generatePath,
+void CreateMergedPath(Unit const* owner, WaypointPath const* path, uint32 previousNode, uint32 currentNode,
+    bool isReturningToStart, bool generatePath, bool isCyclic,
     Movement::PointsArray* points, std::vector<int32>* waypointTransitionSplinePoints, WaypointNode const** lastWaypointOnPath)
 {
     std::span<WaypointNode const> segment = [&]
     {
         // find the continuous segment that our destination waypoint is on
-        auto segmentItr = std::ranges::find_if(path->ContinuousSegments, [&](std::pair<std::size_t, std::size_t> segmentRange)
+        auto segmentItr = std::ranges::find_if(path->ContinuousSegments, [&](std::pair<std::size_t, std::size_t> const& segmentRange)
         {
             auto isInSegmentRange = [&](uint32 node) { return node >= segmentRange.first && node < segmentRange.first + segmentRange.second; };
             return isInSegmentRange(currentNode) && isInSegmentRange(previousNode);
@@ -423,6 +425,15 @@ void CreateMergedPath(Unit const* owner, WaypointPath const* path, uint32 previo
         }
     };
 
+    if (isCyclic)
+    {
+        // create new cyclic path starting at current node
+        std::vector<WaypointNode> cyclicPath = path->Nodes;
+        std::rotate(cyclicPath.begin(), cyclicPath.begin() + currentNode, cyclicPath.end());
+        fillPath(cyclicPath.begin(), cyclicPath.end());
+        return;
+    }
+
     if (!isReturningToStart)
         fillPath(segment.begin(), segment.end());
     else
@@ -503,18 +514,35 @@ void WaypointMovementGenerator<Creature>::StartMove(Creature* owner, bool relaun
     ASSERT(_currentNode < path->Nodes.size(), "WaypointMovementGenerator::StartMove: tried to reference a node id (%u) which is not included in path (%u)", _currentNode, path->Id);
     WaypointNode const* lastWaypointForSegment = &path->Nodes[_currentNode];
 
+    bool isCyclic = IsCyclic();
     Movement::PointsArray points;
 
     if (IsExactSplinePath())
-        CreateMergedPath(owner, path, previousNode, _currentNode, _isReturningToStart, false,
+        CreateMergedPath(owner, path, previousNode, _currentNode, _isReturningToStart, false, isCyclic,
             &points, &_waypointTransitionSplinePoints, &lastWaypointForSegment);
     else
         CreateSingularPointPath(owner, path, _currentNode, _generatePath, &points, &_waypointTransitionSplinePoints);
 
+    _waypointTransitionSplinePointsIndex = 0;
+
     RemoveFlag(MOVEMENTGENERATOR_FLAG_TRANSITORY | MOVEMENTGENERATOR_FLAG_INFORM_ENABLED | MOVEMENTGENERATOR_FLAG_TIMED_PAUSED);
 
     owner->AddUnitState(UNIT_STATE_ROAMING_MOVE);
 
+    if (isCyclic)
+    {
+        bool isFirstCycle = relaunch || owner->movespline->Finalized() || !owner->movespline->isCyclic();
+        if (!isFirstCycle)
+        {
+            for (int32& point : _waypointTransitionSplinePoints)
+                --point;
+
+            // cyclic paths are using identical duration to first cycle with EnterCycle
+            _moveTimer.Reset(Milliseconds(owner->movespline->Duration()));
+            return;
+        }
+    }
+
     Movement::MoveSplineInit init(owner);
 
     //! If creature is on transport, we assume waypoints set in DB are already transport offsets
@@ -567,7 +595,10 @@ void WaypointMovementGenerator<Creature>::StartMove(Creature* owner, bool relaun
     if (_speed)
         init.SetVelocity(*_speed);
 
-    if (IsExactSplinePath() && points.size() > 2 && owner->CanFly())
+    if (isCyclic)
+        init.SetCyclic();
+
+    if (IsExactSplinePath() && (points.size() > 2 && owner->CanFly()))
         init.SetSmooth();
 
     Milliseconds duration(init.Launch());
@@ -633,6 +664,14 @@ bool WaypointMovementGenerator<Creature>::IsExactSplinePath() const
     return GetPath()->Flags.HasFlag(WaypointPathFlags::ExactSplinePath);
 }
 
+bool WaypointMovementGenerator<Creature>::IsCyclic() const
+{
+    return !IsFollowingPathBackwardsFromEndToStart()
+        && IsExactSplinePath()
+        && _repeating
+        && GetPath()->ContinuousSegments.size() == 1;
+}
+
 std::string WaypointMovementGenerator<Creature>::GetDebugInfo() const
 {
     return Trinity::StringFormat("{}\n{}",
diff --git a/src/server/game/Movement/MovementGenerators/WaypointMovementGenerator.h b/src/server/game/Movement/MovementGenerators/WaypointMovementGenerator.h
index a214734db83..fb981f400cd 100755
--- a/src/server/game/Movement/MovementGenerators/WaypointMovementGenerator.h
+++ b/src/server/game/Movement/MovementGenerators/WaypointMovementGenerator.h
@@ -84,6 +84,7 @@ class WaypointMovementGenerator<Creature> : public MovementGeneratorMedium<Creat
 
         bool IsFollowingPathBackwardsFromEndToStart() const;
         bool IsExactSplinePath() const;
+        bool IsCyclic() const;
 
         bool IsLoadedFromDB() const { return std::holds_alternative<WaypointPath const*>(_path); }
 
@@ -101,6 +102,7 @@ class WaypointMovementGenerator<Creature> : public MovementGeneratorMedium<Creat
         TimeTracker _moveTimer;
         TimeTracker _nextMoveTime;
         std::vector<int32> _waypointTransitionSplinePoints;
+        uint32 _waypointTransitionSplinePointsIndex;
         bool _isReturningToStart;
 };
 
diff --git a/src/server/game/Movement/Spline/MoveSplineFlag.h b/src/server/game/Movement/Spline/MoveSplineFlag.h
index 7a8317aa04d..c33711c951c 100644
--- a/src/server/game/Movement/Spline/MoveSplineFlag.h
+++ b/src/server/game/Movement/Spline/MoveSplineFlag.h
@@ -65,7 +65,7 @@ namespace Movement
         // flags that shouldn't be appended into SMSG_MONSTER_MOVE\SMSG_MONSTER_MOVE_TRANSPORT packet, should be more probably
         Mask_No_Monster_Move = Done, // SKIP
         // Unused, not suported flags
-        Mask_Unused         = No_Spline | Enter_Cycle | Frozen | Unknown_0x100 | Unknown_0x20000 | Unknown_0x40000
+        Mask_Unused         = No_Spline | Frozen | Unknown_0x100 | Unknown_0x20000 | Unknown_0x40000
                             | Unknown_0x800000 | FadeObject | UnlimitedSpeed | Unknown_0x40000000 | Unknown_0x80000000 // SKIP
     };
 
diff --git a/src/server/game/Server/Packets/MovementPackets.cpp b/src/server/game/Server/Packets/MovementPackets.cpp
index 7020519bffa..c9f9338cbc8 100644
--- a/src/server/game/Server/Packets/MovementPackets.cpp
+++ b/src/server/game/Server/Packets/MovementPackets.cpp
@@ -356,7 +356,13 @@ void WorldPackets::Movement::CommonMovement::WriteCreateObjectSplineDataBlock(::
     if (!moveSpline.isCyclic())                                                 // Destination
         dest = moveSpline.FinalDestination();
     else
-        dest = G3D::Vector3::zero();
+    {
+        ::Movement::MoveSpline::MySpline const& spline = moveSpline._Spline();
+        if (spline.getPointCount() <= 1)
+            dest = G3D::Vector3::zero();
+        else
+            dest = spline.getPoint(spline.last() - 1);
+    }
 
     data << dest.x << dest.y << dest.z;