Allow client to re send past inputs to the server

src/engine/client/client.cpp

@@ -275,6 +275,13 @@ void CClient::SendInput()
 			Msg.AddInt(m_aPredTick[g_Config.m_ClDummy]);
 			Msg.AddInt(Size);
 
+			// copy to sent inputs
+			int SendIndex = m_aPredTick[g_Config.m_ClDummy] % 200;
+			m_aSentInputs[i][SendIndex].m_AckGameTick = m_aAckGameTick[i];
+			m_aSentInputs[i][SendIndex].m_PredTick = m_aPredTick[g_Config.m_ClDummy];
+			m_aSentInputs[i][SendIndex].Size = Size;
+			mem_copy(m_aSentInputs[i][SendIndex].m_aData, m_aInputs[i][m_aCurrentInput[i]].m_aData, sizeof(m_aSentInputs[i][SendIndex].m_aData));
+
 			m_aInputs[i][m_aCurrentInput[i]].m_Tick = m_aPredTick[g_Config.m_ClDummy];
 			m_aInputs[i][m_aCurrentInput[i]].m_PredictedTime = m_PredictedTime.Get(Now);
 			m_aInputs[i][m_aCurrentInput[i]].m_PredictionMargin = PredictionMargin() * time_freq() / 1000;
@@ -295,6 +302,53 @@ void CClient::SendInput()
 				Force = true;
 		}
 	}
+	if(g_Config.m_ClResendInputs && m_ServerCapabilities.m_SortInputs)
+	{
+		// for each 20ms of prediction margin (1 tick duration) we can usefully send 1 extra input to the server
+		// incase the previous attempt was dropped
+		int ResendTicks = PredictionMargin() / (1000 / GameTickSpeed());
+		for(int Dummy = 0; Dummy < NUM_DUMMIES; Dummy++)
+		{
+			if(!m_DummyConnected && Dummy != 0)
+			{
+				break;
+			}
+			int i = g_Config.m_ClDummy ^ Dummy;
+
+			int FlushTick = 0;
+
+			// figure out which tick will be the last one so we can flush the network
+			for(int Tick = 0; Tick < ResendTicks; Tick++)
+			{
+				int TargetTick = m_aPredTick[g_Config.m_ClDummy] - Tick;
+				int SendIndex = TargetTick % 200;
+				if(m_aSentInputs[i][SendIndex].m_PredTick == TargetTick)
+					FlushTick = Tick;
+			}
+
+			for(int Tick = 0; Tick < ResendTicks; Tick++)
+			{
+				int TargetTick = m_aPredTick[g_Config.m_ClDummy] - Tick;
+				int SendIndex = TargetTick % 200;
+
+				// we only want to send inputs that we already sent the server normally
+				if(m_aSentInputs[i][SendIndex].m_PredTick == TargetTick)
+				{
+					CMsgPacker Msg(NETMSG_INPUT, true);
+					Msg.AddInt(m_aSentInputs[i][SendIndex].m_AckGameTick);
+					Msg.AddInt(m_aSentInputs[i][SendIndex].m_PredTick);
+					Msg.AddInt(m_aSentInputs[i][SendIndex].Size);
+					for(int k = 0; k < m_aSentInputs[i][SendIndex].Size / 4; k++)
+						Msg.AddInt(m_aSentInputs[i][SendIndex].m_aData[k]);
+
+					if(Tick == FlushTick || Tick == ResendTicks - 1)
+						SendMsg(i, &Msg, MSGFLAG_FLUSH);
+					else
+						SendMsg(i, &Msg, 0);
+				}
+			}
+		}
+	}
 }
 
 const char *CClient::LatestVersion() const
@@ -1311,6 +1365,10 @@ static CServerCapabilities GetServerCapabilities(int Version, int Flags)
 	{
 		Result.m_SyncWeaponInput = Flags & SERVERCAPFLAG_SYNCWEAPONINPUT;
 	}
+	if(Version >= 6)
+	{
+		Result.m_SortInputs = Flags & SERVERCAPFLAG_SORTINPUTS;
+	}
 	return Result;
 }
 

src/engine/client/client.h

@@ -55,6 +55,7 @@ class CServerCapabilities
 	bool m_PingEx = false;
 	bool m_AllowDummy = false;
 	bool m_SyncWeaponInput = false;
+	bool m_SortInputs = false;
 };
 
 class CClient : public IClient, public CDemoPlayer::IListener
@@ -175,6 +176,15 @@ class CClient : public IClient, public CDemoPlayer::IListener
 		int64_t m_Time;
 	} m_aInputs[NUM_DUMMIES][200];
 
+	struct CSentInput
+	{
+		int m_AckGameTick;
+		int m_PredTick;
+		int Size;
+		int m_aData[MAX_INPUT_SIZE];
+	};
+	CSentInput m_aSentInputs[NUM_DUMMIES][200];
+
 	int m_aCurrentInput[NUM_DUMMIES] = {0, 0};
 	bool m_LastDummy = false;
 	bool m_DummySendConnInfo = false;

src/engine/server/server.cpp

@@ -1199,7 +1199,7 @@ void CServer::SendCapabilities(int ClientId)
 {
 	CMsgPacker Msg(NETMSG_CAPABILITIES, true);
 	Msg.AddInt(SERVERCAP_CURVERSION); // version
-	Msg.AddInt(SERVERCAPFLAG_DDNET | SERVERCAPFLAG_CHATTIMEOUTCODE | SERVERCAPFLAG_ANYPLAYERFLAG | SERVERCAPFLAG_PINGEX | SERVERCAPFLAG_ALLOWDUMMY | SERVERCAPFLAG_SYNCWEAPONINPUT); // flags
+	Msg.AddInt(SERVERCAPFLAG_DDNET | SERVERCAPFLAG_CHATTIMEOUTCODE | SERVERCAPFLAG_ANYPLAYERFLAG | SERVERCAPFLAG_PINGEX | SERVERCAPFLAG_ALLOWDUMMY | SERVERCAPFLAG_SYNCWEAPONINPUT | SERVERCAPFLAG_SORTINPUTS); // flags
 	SendMsg(&Msg, MSGFLAG_VITAL, ClientId);
 }
 

src/engine/shared/config_variables.h

@@ -22,6 +22,7 @@ MACRO_CONFIG_INT(ClAntiPingSmooth, cl_antiping_smooth, 0, 0, 1, CFGFLAG_CLIENT |
 MACRO_CONFIG_INT(ClAntiPingGunfire, cl_antiping_gunfire, 1, 0, 1, CFGFLAG_CLIENT | CFGFLAG_SAVE, "Predict gunfire and show predicted weapon physics (with cl_antiping_grenade 1 and cl_antiping_weapons 1)")
 MACRO_CONFIG_INT(ClPredictionMargin, cl_prediction_margin, 10, 1, 300, CFGFLAG_CLIENT | CFGFLAG_SAVE, "Prediction margin in ms (adds latency, can reduce lag from ping jumps)")
 MACRO_CONFIG_INT(ClSubTickAiming, cl_sub_tick_aiming, 0, 0, 1, CFGFLAG_CLIENT | CFGFLAG_SAVE, "Send aiming data at sub-tick accuracy")
+MACRO_CONFIG_INT(ClResendInputs, cl_resend_inputs, 1, 0, 1, CFGFLAG_CLIENT | CFGFLAG_SAVE, "Send Inputs to server multiple times when prediction margin is high enough")
 
 MACRO_CONFIG_INT(ClNameplates, cl_nameplates, 1, 0, 1, CFGFLAG_CLIENT | CFGFLAG_SAVE, "Show name plates")
 MACRO_CONFIG_INT(ClAfkEmote, cl_afk_emote, 1, 0, 1, CFGFLAG_CLIENT | CFGFLAG_SAVE, "Show zzz emote next to afk players")

src/engine/shared/protocol_ex.h

@@ -23,13 +23,14 @@ enum
 	UNPACKMESSAGE_OK,
 	UNPACKMESSAGE_ANSWER,
 
-	SERVERCAP_CURVERSION = 5,
+	SERVERCAP_CURVERSION = 6,
 	SERVERCAPFLAG_DDNET = 1 << 0,
 	SERVERCAPFLAG_CHATTIMEOUTCODE = 1 << 1,
 	SERVERCAPFLAG_ANYPLAYERFLAG = 1 << 2,
 	SERVERCAPFLAG_PINGEX = 1 << 3,
 	SERVERCAPFLAG_ALLOWDUMMY = 1 << 4,
 	SERVERCAPFLAG_SYNCWEAPONINPUT = 1 << 5,
+	SERVERCAPFLAG_SORTINPUTS = 1 << 6,
 };
 
 void RegisterUuids(CUuidManager *pManager);

src/game/client/components/controls.cpp

@@ -201,6 +201,8 @@ void CControls::OnMessage(int Msg, void *pRawMsg)
 int CControls::SnapInput(int *pData)
 {
 	static int64_t LastSendTime = 0;
+	static int HotSendCount = 0;
+
 	bool Send = false;
 
 	// update player state
@@ -339,10 +341,19 @@ int CControls::SnapInput(int *pData)
 		else if(m_aInputData[g_Config.m_ClDummy].m_PrevWeapon != m_aLastData[g_Config.m_ClDummy].m_PrevWeapon)
 			Send = true;
 
+		HotSendCount = std::max(0, HotSendCount - 1);
+
+		if(Send)
+			HotSendCount = 5;
+
 		// send at at least 10hz
 		if(time_get() > LastSendTime + time_freq() / 25)
 			Send = true;
 
+		// always send for 5 ticks in a row when a new input happens
+		if(HotSendCount > 0)
+			Send = true;
+
 		if(m_pClient->m_Snap.m_pLocalCharacter && m_pClient->m_Snap.m_pLocalCharacter->m_Weapon == WEAPON_NINJA && (m_aInputData[g_Config.m_ClDummy].m_Direction || m_aInputData[g_Config.m_ClDummy].m_Jump || m_aInputData[g_Config.m_ClDummy].m_Hook))
 			Send = true;
 	}