IFilterEntityManager work

Signed-off-by: AMZN-Olex <5432499+AMZN-Olex@users.noreply.github.com>

Gems/Multiplayer/Code/Include/Multiplayer/IMultiplayer.h

@@ -10,6 +10,7 @@
 #include <AzCore/RTTI/RTTI.h>
 #include <AzNetworking/ConnectionLayer/IConnection.h>
 #include <AzNetworking/DataStructures/ByteBuffer.h>
+#include <Multiplayer/NetworkEntity/IFilterEntityManager.h>
 #include <Multiplayer/Components/MultiplayerComponentRegistry.h>
 #include <Multiplayer/NetworkEntity/INetworkEntityManager.h>
 #include <Multiplayer/NetworkTime/INetworkTime.h>
@@ -128,6 +129,15 @@ namespace Multiplayer
         //! @return pointer to the network entity manager instance bound to this multiplayer instance
         virtual INetworkEntityManager* GetNetworkEntityManager() = 0;
 
+        //! Sets user-defined filtering manager for entities.
+        //! This allows selectively choosing which entities to replicate on a per client connection.
+        //! See IFilterEntityManager for details.
+        //! @param entityFilter non-owning pointer, the caller is responsible for memory management.
+        virtual void SetFilterEntityManager(IFilterEntityManager* entityFilter) = 0;
+
+        //! @return pointer to the user-defined filtering manager of entities. By default, this isn't set and returns nullptr.
+        virtual IFilterEntityManager* GetFilterEntityManager() = 0;
+
         //! Retrieve the stats object bound to this multiplayer instance.
         //! @return the stats object bound to this multiplayer instance
         MultiplayerStats& GetStats() { return m_stats; }

Gems/Multiplayer/Code/Include/Multiplayer/NetworkEntity/IFilterEntityManager.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) Contributors to the Open 3D Engine Project
+ *
+ * SPDX-License-Identifier: Apache-2.0 OR MIT
+ *
+ */
+
+#pragma once
+
+#include <AzNetworking/ConnectionLayer/IConnection.h>
+#include <Multiplayer/NetworkEntity/NetworkEntityHandle.h>
+
+namespace Multiplayer
+{
+    //! @class IFilterEntityManager
+    //! @brief IFilterEntityManager provides an interface for filtering entities out from replication down to clients.
+    //!
+    //! By default, all entities with NetBindComponent on them are replicated to all clients.
+    //! (There is a built-in distance filtering, where only entities within vicinity of a player are sent to that player.
+    //! This is controlled by sv_ClientAwarenessRadius AZ_CVAR variable.)
+    //!
+    //! There are use cases where you want to limit the entities sent to a client, for example "fog of war" or
+    //! "out of line of sight" anti-cheating mechanic by omitting information clients should not have access to.
+    //!
+    //! By implementing IFilterEntityManager interface and setting it on GetMultiplayer()->SetFilterEntityManager()
+    //! entities can be filtered by IsEntityFiltered(...) returning true.
+    //!
+    //! Note: one cannot filter out entities in Level prefab (spawned by LoadLevel console command). Level prefabs are fully
+    //! spawned on each client. Filtering of entities is applied to dynamically spawned prefabs, and specifically
+    //! entities must have NetBindComponent on them.
+    class IFilterEntityManager
+    {
+    public:
+        AZ_RTTI(IFilterEntityManager, "{91F879F2-3DAF-43B8-B474-B312D26C0F48}");
+
+        virtual ~IFilterEntityManager() = default;
+
+        //! Return true if a given entity should be filtered out, false otherwise.
+        //! Important: this method is a hot code path, it will be called over all entities around each player frequently.
+        //! Ideally, this method should be implemented as a quick look up.
+        //!
+        //! @param entity the entity to be considered for filtering
+        //! @param controllerEntity player's entity for the associated connection
+        //! @param connectionId the affected connection should the entity be filtered out.
+        //! @return if false the given entity will be not be replicated to the connection
+        virtual bool IsEntityFiltered(AZ::Entity* entity, ConstNetworkEntityHandle controllerEntity, AzNetworking::ConnectionId connectionId) = 0;
+    };
+}