Increase MP Command delay to 4 turns, decrease MP turns to 200ms.

To hide network latency, MP turns send commands not for the next turn
but N turns after that (introduced in c684c211a2).
Further, MP turn length was increased to 500ms compared to 200ms SP
turns (introduced in 6a15b78c98).
Unfortunately, increasing MP turn length has negative consequences:
- makes pathfinding/unit motion much worse & unit behaviour worse in
general.
- makes the game more 'lag-spikey', since computations are done less
often, but thus then can take more time.

This diff essentially reverts 6a15b78c98, instead increasing
COMMAND_DELAY from 2 to 4 in MP. This:
- Reduces the 'inherent command lag' in MP from 1000ms to 800ms
- Increases the lag range at which MP will run smoothtly from 500ms to
600ms
- makes SP and MP turns behave identically again, removing the
hindrances described above.

As a side effect, single-player was not actually using COMMAND_DELAY,
this is now done (can be used to simulate MP command lag).

Refs #3752

Differential Revision: https://code.wildfiregames.com/D3275
This was SVN commit r25001.

source/network/NetClient.cpp

@@ -40,6 +40,14 @@
 #include "simulation2/Simulation2.h"
 #include "network/StunClient.h"
 
+/**
+ * Once ping goes above turn length * command delay,
+ * the game will start 'freezing' for other clients while we catch up.
+ * Since commands are sent client -> server -> client, divide by 2.
+ * (duplicated in NetServer.cpp to avoid having to fetch the constants in a header file)
+ */
+constexpr u32 NETWORK_BAD_PING = DEFAULT_TURN_LENGTH * COMMAND_DELAY_MP / 2;
+
 CNetClient *g_NetClient = NULL;
 
 /**
@@ -334,9 +342,9 @@ void CNetClient::CheckServerConnection()
 		return;
 	}
 
-	// Report if we have a bad ping to the server
+	// Report if we have a bad ping to the server.
 	u32 meanRTT = m_Session->GetMeanRTT();
-	if (meanRTT > DEFAULT_TURN_LENGTH_MP)
+	if (meanRTT > NETWORK_BAD_PING)
 	{
 		PushGuiMessage(
 			"type", "netwarn",
@@ -857,7 +865,7 @@ bool CNetClient::OnClientPerformance(void *context, CFsmEvent* event)
 	// Display warnings for other clients with bad ping
 	for (size_t i = 0; i < message->m_Clients.size(); ++i)
 	{
-		if (message->m_Clients[i].m_MeanRTT < DEFAULT_TURN_LENGTH_MP || message->m_Clients[i].m_GUID == client->m_GUID)
+		if (message->m_Clients[i].m_MeanRTT < NETWORK_BAD_PING || message->m_Clients[i].m_GUID == client->m_GUID)
 			continue;
 
 		client->PushGuiMessage(

source/network/NetClientTurnManager.cpp

@@ -36,7 +36,7 @@
 extern CStrW g_UniqueLogPostfix;
 
 CNetClientTurnManager::CNetClientTurnManager(CSimulation2& simulation, CNetClient& client, int clientId, IReplayLogger& replay)
-	: CTurnManager(simulation, DEFAULT_TURN_LENGTH_MP, clientId, replay), m_NetClient(client)
+	: CTurnManager(simulation, DEFAULT_TURN_LENGTH, COMMAND_DELAY_MP, clientId, replay), m_NetClient(client)
 {
 }
 
@@ -45,11 +45,11 @@ void CNetClientTurnManager::PostCommand(JS::HandleValue data)
 	NETCLIENTTURN_LOG("PostCommand()\n");
 
 	// Transmit command to server
-	CSimulationMessage msg(m_Simulation2.GetScriptInterface(), m_ClientId, m_PlayerId, m_CurrentTurn + COMMAND_DELAY, data);
+	CSimulationMessage msg(m_Simulation2.GetScriptInterface(), m_ClientId, m_PlayerId, m_CurrentTurn + m_CommandDelay, data);
 	m_NetClient.SendMessage(&msg);
 
 	// Add to our local queue
-	//AddCommand(m_ClientId, m_PlayerId, data, m_CurrentTurn + COMMAND_DELAY);
+	//AddCommand(m_ClientId, m_PlayerId, data, m_CurrentTurn + m_CommandDelay);
 	// TODO: we should do this when the server stops sending our commands back to us
 }
 
@@ -98,7 +98,7 @@ void CNetClientTurnManager::OnDestroyConnection()
 	// Attempt to flush messages before leaving.
 	// Notice the sending is not reliable and rarely makes it to the Server.
 	if (m_NetClient.GetCurrState() == NCS_INGAME)
-		NotifyFinishedOwnCommands(m_CurrentTurn + COMMAND_DELAY);
+		NotifyFinishedOwnCommands(m_CurrentTurn + m_CommandDelay);
 }
 
 void CNetClientTurnManager::OnSimulationMessage(CSimulationMessage* msg)

source/network/NetServer.cpp

@@ -67,6 +67,14 @@ constexpr int FAILED_PASSWORD_TRIES_BEFORE_BAN = 3;
  */
 static const int HOST_SERVICE_TIMEOUT = 50;
 
+/**
+ * Once ping goes above turn length * command delay,
+ * the game will start 'freezing' for other clients while we catch up.
+ * Since commands are sent client -> server -> client, divide by 2.
+ * (duplicated in NetServer.cpp to avoid having to fetch the constants in a header file)
+ */
+constexpr u32 NETWORK_BAD_PING = DEFAULT_TURN_LENGTH * COMMAND_DELAY_MP / 2;
+
 CNetServer* g_NetServer = NULL;
 
 static CStr DebugName(CNetServerSession* session)
@@ -604,7 +612,7 @@ void CNetServerWorker::CheckClientConnections()
 			message = msg;
 		}
 		// Report if the client has bad ping
-		else if (meanRTT > DEFAULT_TURN_LENGTH_MP)
+		else if (meanRTT > NETWORK_BAD_PING)
 		{
 			CClientPerformanceMessage* msg = new CClientPerformanceMessage();
 			CClientPerformanceMessage::S_m_Clients client;

source/network/NetServerTurnManager.cpp

@@ -27,19 +27,21 @@
 #include "simulation2/system/TurnManager.h"
 
 #if 0
+#include "ps/Util.h"
 #define NETSERVERTURN_LOG(...) debug_printf(__VA_ARGS__)
 #else
 #define NETSERVERTURN_LOG(...)
 #endif
 
 CNetServerTurnManager::CNetServerTurnManager(CNetServerWorker& server)
-	: m_NetServer(server), m_ReadyTurn(1), m_TurnLength(DEFAULT_TURN_LENGTH_MP), m_HasSyncError(false)
+	: m_NetServer(server), m_ReadyTurn(COMMAND_DELAY_MP - 1), m_TurnLength(DEFAULT_TURN_LENGTH), m_HasSyncError(false)
 {
 	// Turn 0 is not actually executed, store a dummy value.
 	m_SavedTurnLengths.push_back(0);
-	// Turn 1 is special: all clients run it without waiting on a server command batch.
-	// Because of this, it is always run with the default MP turn length.
-	m_SavedTurnLengths.push_back(m_TurnLength);
+	// Turns [1..COMMAND_DELAY - 1] are special: all clients run them without waiting on a server command batch.
+	// Because of this, they are always run with the default MP turn length.
+	for (u32 i = 1; i < COMMAND_DELAY_MP; ++i)
+		m_SavedTurnLengths.push_back(m_TurnLength);
 }
 
 void CNetServerTurnManager::NotifyFinishedClientCommands(CNetServerSession& session, u32 turn)
@@ -139,7 +141,7 @@ void CNetServerTurnManager::NotifyFinishedClientUpdate(CNetServerSession& sessio
 		std::vector<CStrW> OOSPlayerNames;
 		for (const std::pair<const int, std::string>& hashPair : clientStateHash.second)
 		{
-			NETSERVERTURN_LOG("sync check %d: %d = %hs\n", it->first, cit->first, Hexify(cit->second).c_str());
+			NETSERVERTURN_LOG("sync check %d: %d = %hs\n", clientStateHash.first, hashPair.first, Hexify(hashPair.second).c_str());
 			if (hashPair.second != expected)
 			{
 				// Oh no, out of sync
@@ -174,7 +176,7 @@ void CNetServerTurnManager::InitialiseClient(int client, u32 turn)
 	NETSERVERTURN_LOG("InitialiseClient(client=%d, turn=%d)\n", client, turn);
 
 	ENSURE(m_ClientsReady.find(client) == m_ClientsReady.end());
-	m_ClientsReady[client] = turn + 1;
+	m_ClientsReady[client] = turn + COMMAND_DELAY_MP - 1;
 	m_ClientsSimulated[client] = turn;
 }