Core/Objects: implement internal heartbeat timer for WorldObjects (#29941)

This is the first step of porting the functionality of #25822 by cutting each change into a nicely self-contained commit

---------

Co-authored-by: Mykhailo Redko <ovitnez@gmail.com>

2 files changed, 13 insertions, 1 deletions

diff --git a/src/server/game/Entities/Object/Object.cpp b/src/server/game/Entities/Object/Object.cpp
index 6a7075cfe4d..70588e275ef 100644
--- a/src/server/game/Entities/Object/Object.cpp
+++ b/src/server/game/Entities/Object/Object.cpp
@@ -880,7 +880,7 @@ void MovementInfo::OutDebug()
 WorldObject::WorldObject(bool isWorldObject) : Object(), WorldLocation(), LastUsedScriptID(0),
 m_movementInfo(), m_name(), m_isActive(false), m_isFarVisible(false), m_isStoredInWorldObjectGridContainer(isWorldObject), m_zoneScript(nullptr),
 m_transport(nullptr), m_zoneId(0), m_areaId(0), m_staticFloorZ(VMAP_INVALID_HEIGHT), m_outdoors(false), m_liquidStatus(LIQUID_MAP_NO_WATER),
-m_currMap(nullptr), m_InstanceId(0), _dbPhase(0), m_notifyflags(0)
+m_currMap(nullptr), m_InstanceId(0), _dbPhase(0), m_notifyflags(0), _heartbeatTimer(HEARTBEAT_INTERVAL)
 {
     m_serverSideVisibility.SetValue(SERVERSIDE_VISIBILITY_GHOST, GHOST_VISIBILITY_ALIVE | GHOST_VISIBILITY_GHOST);
     m_serverSideVisibilityDetect.SetValue(SERVERSIDE_VISIBILITY_GHOST, GHOST_VISIBILITY_ALIVE);
@@ -904,6 +904,13 @@ WorldObject::~WorldObject()
 void WorldObject::Update(uint32 diff)
 {
     m_Events.Update(diff);
+
+    _heartbeatTimer -= Milliseconds(diff);
+    while (_heartbeatTimer <= 0ms)
+    {
+        _heartbeatTimer += HEARTBEAT_INTERVAL;
+        Heartbeat();
+    }
 }
 
 void WorldObject::SetIsStoredInWorldObjectGridContainer(bool on)
diff --git a/src/server/game/Entities/Object/Object.h b/src/server/game/Entities/Object/Object.h
index 720cd54d516..3183ff1939e 100644
--- a/src/server/game/Entities/Object/Object.h
+++ b/src/server/game/Entities/Object/Object.h
@@ -145,6 +145,7 @@ namespace UF
 }
 
 float const DEFAULT_COLLISION_HEIGHT = 2.03128f; // Most common value in dbc
+static constexpr Milliseconds const HEARTBEAT_INTERVAL = 5s + 200ms;
 
 class TC_GAME_API Object
 {
@@ -823,6 +824,8 @@ class TC_GAME_API WorldObject : public Object, public WorldLocation
         virtual bool IsInvisibleDueToDespawn([[maybe_unused]] WorldObject const* seer) const { return false; }
         //difference from IsAlwaysVisibleFor: 1. after distance check; 2. use owner or charmer as seer
         virtual bool IsAlwaysDetectableFor([[maybe_unused]] WorldObject const* seer) const { return false; }
+
+        virtual void Heartbeat() { }
     private:
         Map* m_currMap;                                   // current object's Map location
 
@@ -837,6 +840,8 @@ class TC_GAME_API WorldObject : public Object, public WorldLocation
 
         std::unique_ptr<SmoothPhasing> _smoothPhasing;
 
+        Milliseconds _heartbeatTimer;
+
         virtual bool _IsWithinDist(WorldObject const* obj, float dist2compare, bool is3D, bool incOwnRadius = true, bool incTargetRadius = true) const;
 
         bool CanDetect(WorldObject const* obj, bool ignoreStealth, bool checkAlert = false) const;