Core/Movement: Properly resume chase/follow movement if it was paused by a spell cast. Closes #21900.

4 files changed, 11 insertions, 8 deletions

diff --git a/src/server/game/Movement/MovementGenerators/ChaseMovementGenerator.cpp b/src/server/game/Movement/MovementGenerators/ChaseMovementGenerator.cpp
index f83c7e8b16a..28928cdeacb 100644
--- a/src/server/game/Movement/MovementGenerators/ChaseMovementGenerator.cpp
+++ b/src/server/game/Movement/MovementGenerators/ChaseMovementGenerator.cpp
@@ -73,7 +73,7 @@ void ChaseMovementGenerator::Initialize(Unit* owner)
 
     owner->SetWalk(false);
     _path = nullptr;
-    _lastTargetPosition.Relocate(0.0f, 0.0f, 0.0f);
+    _lastTargetPosition.reset();
 }
 
 void ChaseMovementGenerator::Reset(Unit* owner)
@@ -102,6 +102,7 @@ bool ChaseMovementGenerator::Update(Unit* owner, uint32 diff)
     if (owner->HasUnitState(UNIT_STATE_NOT_MOVE) || owner->IsMovementPreventedByCasting())
     {
         owner->StopMoving();
+        _lastTargetPosition.reset();
         return true;
     }
 
@@ -142,7 +143,7 @@ bool ChaseMovementGenerator::Update(Unit* owner, uint32 diff)
     }
 
     // if the target moved, we have to consider whether to adjust
-    if (_lastTargetPosition != target->GetPosition() || mutualChase != _mutualChase)
+    if (!_lastTargetPosition || target->GetPosition() != _lastTargetPosition.get() || mutualChase != _mutualChase)
     {
         _lastTargetPosition = target->GetPosition();
         _mutualChase = mutualChase;
diff --git a/src/server/game/Movement/MovementGenerators/ChaseMovementGenerator.h b/src/server/game/Movement/MovementGenerators/ChaseMovementGenerator.h
index 48d828b7602..33252de524e 100644
--- a/src/server/game/Movement/MovementGenerators/ChaseMovementGenerator.h
+++ b/src/server/game/Movement/MovementGenerators/ChaseMovementGenerator.h
@@ -40,7 +40,7 @@ class ChaseMovementGenerator : public MovementGenerator, public AbstractFollower
         void Finalize(Unit*, bool, bool) override;
         MovementGeneratorType GetMovementGeneratorType() const override { return CHASE_MOTION_TYPE; }
 
-        void UnitSpeedChanged() override { _lastTargetPosition.Relocate(0.0f, 0.0f, 0.0f); }
+        void UnitSpeedChanged() override { _lastTargetPosition.reset(); }
 
     private:
         static constexpr uint32 RANGE_CHECK_INTERVAL = 100; // time (ms) until we attempt to recalculate
@@ -49,7 +49,7 @@ class ChaseMovementGenerator : public MovementGenerator, public AbstractFollower
         Optional<ChaseAngle> const _angle;
 
         std::unique_ptr<PathGenerator> _path;
-        Position _lastTargetPosition;
+        Optional<Position> _lastTargetPosition;
         uint32 _rangeCheckTimer = RANGE_CHECK_INTERVAL;
         bool _movingTowards = true;
         bool _mutualChase = true;
diff --git a/src/server/game/Movement/MovementGenerators/FollowMovementGenerator.cpp b/src/server/game/Movement/MovementGenerators/FollowMovementGenerator.cpp
index 817401da6ad..e4b7fc78832 100644
--- a/src/server/game/Movement/MovementGenerators/FollowMovementGenerator.cpp
+++ b/src/server/game/Movement/MovementGenerators/FollowMovementGenerator.cpp
@@ -61,7 +61,7 @@ void FollowMovementGenerator::Initialize(Unit* owner)
     owner->StopMoving();
     UpdatePetSpeed(owner);
     _path = nullptr;
-    _lastTargetPosition.Relocate(0.0f, 0.0f, 0.0f);
+    _lastTargetPosition.reset();
 }
 
 void FollowMovementGenerator::Reset(Unit* owner)
@@ -85,6 +85,7 @@ bool FollowMovementGenerator::Update(Unit* owner, uint32 diff)
     if (owner->HasUnitState(UNIT_STATE_NOT_MOVE) || owner->IsMovementPreventedByCasting())
     {
         owner->StopMoving();
+        _lastTargetPosition.reset();
         return true;
     }
 
@@ -112,7 +113,7 @@ bool FollowMovementGenerator::Update(Unit* owner, uint32 diff)
         DoMovementInform(owner, target);
     }
 
-    if (_lastTargetPosition.GetExactDistSq(target->GetPosition()) > 0.0f)
+    if (!_lastTargetPosition || _lastTargetPosition->GetExactDistSq(target->GetPosition()) > 0.0f)
     {
         _lastTargetPosition = target->GetPosition();
         if (owner->HasUnitState(UNIT_STATE_FOLLOW_MOVE) || !PositionOkay(owner, target, _range + FOLLOW_RANGE_TOLERANCE))
diff --git a/src/server/game/Movement/MovementGenerators/FollowMovementGenerator.h b/src/server/game/Movement/MovementGenerators/FollowMovementGenerator.h
index 91d99bb8fb5..0dd2a434cd0 100644
--- a/src/server/game/Movement/MovementGenerators/FollowMovementGenerator.h
+++ b/src/server/game/Movement/MovementGenerators/FollowMovementGenerator.h
@@ -21,6 +21,7 @@
 #include "AbstractFollower.h"
 #include "MovementDefines.h"
 #include "MovementGenerator.h"
+#include "Optional.h"
 #include "Position.h"
 
 class PathGenerator;
@@ -41,7 +42,7 @@ class FollowMovementGenerator : public MovementGenerator, public AbstractFollowe
         void Finalize(Unit*, bool, bool) override;
         MovementGeneratorType GetMovementGeneratorType() const override { return FOLLOW_MOTION_TYPE; }
 
-        void UnitSpeedChanged() override { _lastTargetPosition.Relocate(0.0f, 0.0f, 0.0f); }
+        void UnitSpeedChanged() override { _lastTargetPosition.reset(); }
 
     private:
         static constexpr uint32 CHECK_INTERVAL = 500;
@@ -53,7 +54,7 @@ class FollowMovementGenerator : public MovementGenerator, public AbstractFollowe
 
         uint32 _checkTimer = CHECK_INTERVAL;
         std::unique_ptr<PathGenerator> _path;
-        Position _lastTargetPosition;
+        Optional<Position> _lastTargetPosition;
 };
 
 #endif