8 files changed, 65 insertions, 9 deletions
diff --git a/source/game/StarNetPackets.cpp b/source/game/StarNetPackets.cpp
index fd127a2..3cbb3ad 100644
--- a/source/game/StarNetPackets.cpp
+++ b/source/game/StarNetPackets.cpp
@@ -924,15 +924,26 @@ void WorldStartAcknowledgePacket::write(DataStream& ds) const {
 }
 
 PingPacket::PingPacket() {}
+PingPacket::PingPacket(int64_t time) : time(time) {}
 
-void PingPacket::read(DataStream& ds) {
+void PingPacket::readLegacy(DataStream& ds) {
   // Packets can't be empty, read the trash data
   ds.read<bool>();
+  time = 0;
 }
 
-void PingPacket::write(DataStream& ds) const {
+void PingPacket::read(DataStream& ds) {
+  ds.readVlqI(time);
+}
+
+
+void PingPacket::writeLegacy(DataStream& ds) const {
   // Packets can't be empty, write some trash data
-  ds.write(false);
+  ds.write<bool>(false);
+}
+
+void PingPacket::write(DataStream& ds) const {
+  ds.writeVlqI(time);
 }
 
 EntityCreatePacket::EntityCreatePacket(EntityType entityType, ByteArray storeData, ByteArray firstNetState, EntityId entityId)
@@ -1234,17 +1245,27 @@ void FindUniqueEntityResponsePacket::write(DataStream& ds) const {
 }
 
 PongPacket::PongPacket() {}
+PongPacket::PongPacket(int64_t time) : time(time) {}
 
-void PongPacket::read(DataStream& ds) {
+void PongPacket::readLegacy(DataStream& ds) {
   // Packets can't be empty, read the trash data
   ds.read<bool>();
+  time = 0;
 }
 
-void PongPacket::write(DataStream& ds) const {
+void PongPacket::read(DataStream& ds) {
+  ds.readVlqI(time);
+}
+
+void PongPacket::writeLegacy(DataStream& ds) const {
   // Packets can't be empty, write some trash data
   ds.write<bool>(false);
 }
 
+void PongPacket::write(DataStream& ds) const {
+  ds.writeVlqI(time);
+}
+
 StepUpdatePacket::StepUpdatePacket() : remoteTime(0.0) {}
 
 StepUpdatePacket::StepUpdatePacket(double remoteTime) : remoteTime(remoteTime) {}
diff --git a/source/game/StarNetPackets.hpp b/source/game/StarNetPackets.hpp
index 71ab09f..475f57a 100644
--- a/source/game/StarNetPackets.hpp
+++ b/source/game/StarNetPackets.hpp
@@ -603,9 +603,14 @@ struct FindUniqueEntityResponsePacket : PacketBase<PacketType::FindUniqueEntityR
 
 struct PongPacket : PacketBase<PacketType::Pong> {
   PongPacket();
+  PongPacket(int64_t time);
 
+  void readLegacy(DataStream& ds) override;
   void read(DataStream& ds) override;
+  void writeLegacy(DataStream& ds) const override;
   void write(DataStream& ds) const override;
+
+  int64_t time = 0;
 };
 
 struct ModifyTileListPacket : PacketBase<PacketType::ModifyTileList> {
@@ -717,9 +722,14 @@ struct WorldStartAcknowledgePacket : PacketBase<PacketType::WorldStartAcknowledg
   
 struct PingPacket : PacketBase<PacketType::Ping> {
   PingPacket();
+  PingPacket(int64_t time);
 
+  void readLegacy(DataStream& ds) override;
   void read(DataStream& ds) override;
+  void writeLegacy(DataStream& ds) const override;
   void write(DataStream& ds) const override;
+
+  int64_t time = 0;
 };
 
 struct EntityCreatePacket : PacketBase<PacketType::EntityCreate> {
diff --git a/source/game/StarUniverseClient.cpp b/source/game/StarUniverseClient.cpp
index 752d081..adc6bef 100644
--- a/source/game/StarUniverseClient.cpp
+++ b/source/game/StarUniverseClient.cpp
@@ -123,6 +123,7 @@ Maybe<String> UniverseClient::connect(UniverseConnection connection, bool allowA
     m_mainPlayer->setClientContext(m_clientContext);
     m_mainPlayer->setStatistics(m_statistics);
     m_worldClient = make_shared<WorldClient>(m_mainPlayer);
+    m_worldClient->clientState().setLegacy(m_legacyServer);
     m_worldClient->setAsyncLighting(true);
     for (auto& pair : m_luaCallbacks)
       m_worldClient->setLuaCallbacks(pair.first, pair.second);
diff --git a/source/game/StarWorldClient.cpp b/source/game/StarWorldClient.cpp
index b1ad698..3b8f1a3 100644
--- a/source/game/StarWorldClient.cpp
+++ b/source/game/StarWorldClient.cpp
@@ -403,6 +403,10 @@ RectI WorldClient::clientWindow() const {
   return m_clientState.window();
 }
 
+WorldClientState& WorldClient::clientState() {
+  return m_clientState;
+}
+
 void WorldClient::render(WorldRenderData& renderData, unsigned bufferTiles) {
   if (!m_lightingThread && m_asyncLighting)
     m_lightingThread = Thread::invoke("WorldClient::lightingMain", mem_fn(&WorldClient::lightingMain), this);
@@ -1038,7 +1042,9 @@ void WorldClient::handleIncomingPackets(List<PacketPtr> const& packets) {
       m_worldTemplate->setWorldParameters(netLoadVisitableWorldParameters(worldParametersUpdate->parametersData));
 
     } else if (auto pongPacket = as<PongPacket>(packet)) {
-      if (m_pingTime) 
+      if (pongPacket->time)
+        m_latency = Time::monotonicMilliseconds() - pongPacket->time;
+      else if (m_pingTime) 
         m_latency = Time::monotonicMilliseconds() - m_pingTime.take();
 
     } else {
@@ -1203,10 +1209,11 @@ void WorldClient::update(float dt) {
 
   queueUpdatePackets(m_entityUpdateTimer.wrapTick(dt));
 
-  if (m_pingTime.isNothing()) {
+  if ((!m_clientState.legacy() && m_currentStep % 3 == 0) || m_pingTime.isNothing()) {
     m_pingTime = Time::monotonicMilliseconds();
-    m_outgoingPackets.append(make_shared<PingPacket>());
+    m_outgoingPackets.append(make_shared<PingPacket>(*m_pingTime));
   }
+
   LogMap::set("client_ping", m_latency);
 
   // Remove active sectors that are outside of the current monitoring region
diff --git a/source/game/StarWorldClient.hpp b/source/game/StarWorldClient.hpp
index 6f40b63..e00a3b8 100644
--- a/source/game/StarWorldClient.hpp
+++ b/source/game/StarWorldClient.hpp
@@ -143,6 +143,7 @@ public:
   void centerClientWindowOnPlayer(Vec2U const& windowSize);
   void centerClientWindowOnPlayer();
   RectI clientWindow() const;
+  WorldClientState& clientState();
 
   void update(float dt);
   // borderTiles here should extend the client window for border tile
diff --git a/source/game/StarWorldClientState.cpp b/source/game/StarWorldClientState.cpp
index 5dc6b12..21552cd 100644
--- a/source/game/StarWorldClientState.cpp
+++ b/source/game/StarWorldClientState.cpp
@@ -22,6 +22,8 @@ WorldClientState::WorldClientState() {
 
   m_netGroup.addNetElement(&m_playerId);
   m_netGroup.addNetElement(&m_clientPresenceEntities);
+
+  m_legacy = false;
 }
 
 RectI WorldClientState::window() const {
@@ -87,6 +89,14 @@ void WorldClientState::readDelta(ByteArray delta) {
   m_netGroup.readNetState(std::move(delta));
 }
 
+void WorldClientState::setLegacy(bool legacy) {
+  m_legacy = legacy;
+}
+
+bool WorldClientState::legacy() const {
+  return m_legacy;
+}
+
 void WorldClientState::reset() {
   m_netVersion = 0;
 }
diff --git a/source/game/StarWorldClientState.hpp b/source/game/StarWorldClientState.hpp
index 31ff52f..920fef4 100644
--- a/source/game/StarWorldClientState.hpp
+++ b/source/game/StarWorldClientState.hpp
@@ -36,6 +36,10 @@ public:
   ByteArray writeDelta();
   void readDelta(ByteArray delta);
 
+  // Whether the client is connected to a legacy server.
+  void setLegacy(bool legacy);
+  bool legacy() const;
+
   void reset();
 
 private:
@@ -52,6 +56,8 @@ private:
 
   NetElementInt m_playerId;
   NetElementData<List<EntityId>> m_clientPresenceEntities;
+
+  bool m_legacy;
 };
 
 }
diff --git a/source/game/StarWorldServer.cpp b/source/game/StarWorldServer.cpp
index ec144da..1b4041f 100644
--- a/source/game/StarWorldServer.cpp
+++ b/source/game/StarWorldServer.cpp
@@ -520,7 +520,7 @@ void WorldServer::handleIncomingPackets(ConnectionId clientId, List<PacketPtr> c
           response.get<RpcPromiseKeeper<Json>>().fail(entityMessageResponsePacket->response.left());
       }
     } else if (auto pingPacket = as<PingPacket>(packet)) {
-      clientInfo->outgoingPackets.append(make_shared<PongPacket>());
+      clientInfo->outgoingPackets.append(make_shared<PongPacket>(pingPacket->time));
 
     } else if (auto updateWorldProperties = as<UpdateWorldPropertiesPacket>(packet)) {
       // Kae: Properties set to null (nil from Lua) should be erased instead of lingering around