Make player references cross exterior cells only when called by server

Previously, clientside representations of players were able to move to a new exterior cell once during their movement tick and then again when sending a cell change packet to the server. Besides causing crashes in CellRef because of a messy cell-changing record, this also led to major desyncs.

Clientside representations of players can now only change their cells when a server-sent cell change packet specifically allows it.

apps/openmw/mwmp/DedicatedPlayer.cpp

@@ -242,6 +242,10 @@ void DedicatedPlayer::UpdatePtr(MWWorld::Ptr newPtr)
     ptr.mCell = newPtr.mCell;
     ptr.mRef = newPtr.mRef;
     ptr.mContainerStore = newPtr.mContainerStore;
+
+    // Disallow this player's reference from moving across cells until
+    // the correct packet is sent by the player
+    ptr.getBase()->canChangeCell = false;
 }
 
 
@@ -400,5 +404,9 @@ void DedicatedPlayer::updateCell()
         cellStore = world->getExterior(cell.mCellId.mIndex.mX, cell.mCellId.mIndex.mY);
     else
         cellStore = world->getInterior(cell.mName);
+
+    // Allow this player's reference to move across a cell now that
+    // a manual cell update has been called
+    ptr.getBase()->canChangeCell = true;
     UpdatePtr(world->moveObject(ptr, cellStore, pos.pos[0], pos.pos[1], pos.pos[2]));
 }

apps/openmw/mwworld/livecellref.cpp

@@ -14,6 +14,7 @@
 MWWorld::LiveCellRefBase::LiveCellRefBase(const std::string& type, const ESM::CellRef &cref)
   : mClass(&Class::get(type)), mRef(cref), mData(cref)
 {
+    canChangeCell = true;
 }
 
 void MWWorld::LiveCellRefBase::loadImp (const ESM::ObjectState& state)

apps/openmw/mwworld/livecellref.hpp

@@ -27,6 +27,11 @@ namespace MWWorld
          * and individual type-dependent data.
          */
         MWWorld::CellRef mRef;
+    
+        /* Added by TES3MP to prevent dedicated players' references from automatically
+         * and unpredictably moving across exterior cell boundaries on clients
+         */
+        bool canChangeCell;
 
         /** runtime-data */
         RefData mData;

apps/openmw/mwworld/worldimp.cpp

@@ -1141,7 +1141,7 @@ namespace MWWorld
         bool haveToMove = isPlayer || (currCell && mWorldScene->isCellActive(*currCell));
         MWWorld::Ptr newPtr = ptr;
 
-        if (currCell != newCell)
+        if (currCell != newCell && ptr.getBase()->canChangeCell)
         {
             removeContainerScripts(ptr);