Core/Movement: Port Ascent r1637 http://sourceforge.net/p/ascentemubackup/code/1637/ to TrinityCore

Port some movement packet fixes, taking into account client/server connection lag.
Credits to original author, check http://sourceforge.net/p/ascentemubackup/code/1637/ for more details.
MOVEMENT_PACKET_TIME_DELAY default value is currently set to 0, feel free to set it to different values and report feedback.

src/server/game/Handlers/MovementHandler.cpp

@@ -31,6 +31,8 @@
 #include "InstanceSaveMgr.h"
 #include "ObjectMgr.h"
 
+#define MOVEMENT_PACKET_TIME_DELAY 0
+
 void WorldSession::HandleMoveWorldportAckOpcode(WorldPacket & /*recvData*/)
 {
     TC_LOG_DEBUG(LOG_FILTER_NETWORKIO, "WORLD: got MSG_MOVE_WORLDPORT_ACK.");
@@ -359,11 +361,15 @@ void WorldSession::HandleMovementOpcodes(WorldPacket& recvData)
         plrMover->SetInWater(!plrMover->IsInWater() || plrMover->GetBaseMap()->IsUnderWater(movementInfo.pos.GetPositionX(), movementInfo.pos.GetPositionY(), movementInfo.pos.GetPositionZ()));
     }
 
+    uint32 mstime = getMSTime();
     /*----------------------*/
+    if(m_clientTimeDelay == 0)
+        m_clientTimeDelay = mstime - movementInfo.time;
 
     /* process position-change */
     WorldPacket data(opcode, recvData.size());
-    movementInfo.time = getMSTime();
+    movementInfo.time = movementInfo.time + m_clientTimeDelay + MOVEMENT_PACKET_TIME_DELAY;
+
     movementInfo.guid = mover->GetGUID();
     WriteMovementInfo(&data, &movementInfo);
     mover->SendMessageToSet(&data, _player);

src/server/game/Server/WorldSession.cpp

@@ -115,6 +115,7 @@ WorldSession::WorldSession(uint32 id, WorldSocket* sock, AccountTypes sec, uint8
     m_sessionDbcLocale(sWorld->GetAvailableDbcLocale(locale)),
     m_sessionDbLocaleIndex(locale),
     m_latency(0),
+    m_clientTimeDelay(0),
     m_TutorialsChanged(false),
     recruiterId(recruiter),
     isRecruiter(isARecruiter),

src/server/game/Server/WorldSession.h

@@ -352,6 +352,7 @@ class WorldSession
 
         uint32 GetLatency() const { return m_latency; }
         void SetLatency(uint32 latency) { m_latency = latency; }
+        void ResetClientTimeDelay() { m_clientTimeDelay = 0; }
         uint32 getDialogStatus(Player* player, Object* questgiver, uint32 defstatus);
 
         time_t m_timeOutTime;
@@ -987,6 +988,7 @@ class WorldSession
         LocaleConstant m_sessionDbcLocale;
         LocaleConstant m_sessionDbLocaleIndex;
         uint32 m_latency;
+        uint32 m_clientTimeDelay;
         AccountData m_accountData[NUM_ACCOUNT_DATA_TYPES];
         uint32 m_Tutorials[MAX_ACCOUNT_TUTORIAL_VALUES];
         bool   m_TutorialsChanged;

src/server/game/Server/WorldSocket.cpp

@@ -1004,7 +1004,10 @@ int WorldSocket::HandlePing (WorldPacket& recvPacket)
         ACE_GUARD_RETURN (LockType, Guard, m_SessionLock, -1);
 
         if (m_Session)
+        {
             m_Session->SetLatency (latency);
+            m_Session->ResetClientTimeDelay();
+        }
         else
         {
             TC_LOG_ERROR(LOG_FILTER_NETWORKIO, "WorldSocket::HandlePing: peer sent CMSG_PING, "