- misc fixes to client server handshaking and playsim ticking

src/d_main.cpp

@@ -986,11 +986,6 @@ public:
 		return LastTic;
 	}
 
-	int BaseMakeTic() const
-	{
-		return LastTic + 1;
-	}
-
 private:
 	int LastTic = 0;
 	int CurrentTic = 0;
@@ -1038,7 +1033,7 @@ public:
 
 		for (int i = 0; i < tics; i++)
 		{
-			network->SetCurrentTic(gametime.BaseGameTic() + i, gametime.BaseMakeTic() + i);
+			network->SetCurrentTic(gametime.BaseGameTic() + i);
 			network->WriteLocalInput(G_BuildTiccmd());
 
 			if (advancedemo)
@@ -1095,6 +1090,8 @@ void D_DoomLoop()
 
 			if (wantToRestart)
 			{
+				P_UnPredictPlayer();
+
 				wantToRestart = false;
 				return;
 			}

src/network/i_net.cpp

@@ -228,45 +228,31 @@ int DoomComImpl::FindNode(const sockaddr_in *address)
 
 void DoomComImpl::PacketSend(const NetPacket &packet)
 {
-	int c;
-
-	// FIXME: Catch this before we've overflown the buffer. With long chat
-	// text and lots of backup tics, it could conceivably happen. (Though
-	// apparently it hasn't yet, which is good.)
-	if (packet.size > MAX_MSGLEN)
-	{
-		I_FatalError("Netbuffer overflow!");
-	}
 	assert(!(packet.data[0] & NCMD_COMPRESSED));
 
-	uLong size = TRANSMIT_SIZE - 1;
 	if (packet.size >= 10)
 	{
 		mTransmitBuffer[0] = packet.data[0] | NCMD_COMPRESSED;
-		c = compress2(mTransmitBuffer + 1, &size, packet.data + 1, packet.size - 1, 9);
+
+		uLong size = TRANSMIT_SIZE - 1;
+		int c = compress2(mTransmitBuffer + 1, &size, packet.data + 1, packet.size - 1, 9);
 		size += 1;
+
+		if (c == Z_OK && size < (uLong)packet.size)
+		{
+			sendto(mSocket, (char *)mTransmitBuffer, size, 0, (sockaddr *)&mNodeEndpoints[packet.node], sizeof(mNodeEndpoints[packet.node]));
+			return;
+		}
+	}
+
+	if (packet.size <= TRANSMIT_SIZE)
+	{
+		sendto(mSocket, (char *)packet.data, packet.size, 0, (sockaddr *)&mNodeEndpoints[packet.node], sizeof(mNodeEndpoints[packet.node]));
 	}
 	else
 	{
-		c = -1;	// Just some random error code to avoid sending the compressed buffer.
+		I_Error("NetPacket is too large to be transmitted");
 	}
-	if (c == Z_OK && size < (uLong)packet.size)
-	{
-		c = sendto(mSocket, (char *)mTransmitBuffer, size, 0, (sockaddr *)&mNodeEndpoints[packet.node], sizeof(mNodeEndpoints[packet.node]));
-	}
-	else
-	{
-		if (packet.size > TRANSMIT_SIZE)
-		{
-			I_Error("Net compression failed (zlib error %d)", c);
-		}
-		else
-		{
-			c = sendto(mSocket, (char *)packet.data, packet.size, 0, (sockaddr *)&mNodeEndpoints[packet.node], sizeof(mNodeEndpoints[packet.node]));
-		}
-	}
-	//	if (c == -1)
-	//			I_Error ("SendPacket error: %s",strerror(errno));
 }
 
 void DoomComImpl::PacketGet(NetPacket &packet)
@@ -303,7 +289,8 @@ void DoomComImpl::PacketGet(NetPacket &packet)
 				Close(node);
 				packet.node = node;
 				packet.size = 0;
-				packet.stream.pbStreamEnd = packet.stream.pbStream;
+				packet.stream.pbStream = packet.data;
+				packet.stream.pbStreamEnd = packet.data + packet.size;
 				return;
 			}
 			else if (err != WSAEWOULDBLOCK)
@@ -314,7 +301,8 @@ void DoomComImpl::PacketGet(NetPacket &packet)
 			{
 				packet.node = -1;
 				packet.size = 0;
-				packet.stream.pbStreamEnd = packet.stream.pbStream;
+				packet.stream.pbStream = packet.data;
+				packet.stream.pbStreamEnd = packet.data + packet.size;
 				return;
 			}
 		}
@@ -325,7 +313,7 @@ void DoomComImpl::PacketGet(NetPacket &packet)
 				continue;
 
 			packet.data[0] = mTransmitBuffer[0] & ~NCMD_COMPRESSED;
-			if (mTransmitBuffer[0] & NCMD_COMPRESSED)
+			if ((mTransmitBuffer[0] & NCMD_COMPRESSED) && size > 1)
 			{
 				uLongf msgsize = MAX_MSGLEN - 1;
 				int err = uncompress(packet.data + 1, &msgsize, mTransmitBuffer + 1, size - 1);
@@ -343,7 +331,8 @@ void DoomComImpl::PacketGet(NetPacket &packet)
 
 			packet.node = node;
 			packet.size = (short)size;
-			packet.stream.pbStreamEnd = packet.stream.pbStream + packet.size;
+			packet.stream.pbStream = packet.data;
+			packet.stream.pbStreamEnd = packet.data + packet.size;
 			return;
 		}
 	}

src/network/i_net.h

@@ -31,6 +31,9 @@ struct NetPacket
 	const uint8_t &operator[](int i) const { return data[i]; }
 
 	BYTESTREAM_s stream;
+
+	NetPacket(const NetPacket &) = delete;
+	NetPacket &operator=(const NetPacket &) = delete;
 };
 
 // Network packet data.

src/network/net.h

@@ -63,8 +63,8 @@ public:
 	// Check for incoming packets
 	virtual void Update() = 0;
 
-	// Set current tic for reading and writing
+	// Set current tic time
-	virtual void SetCurrentTic(int receivetic, int sendtic) = 0;
+	virtual void SetCurrentTic(int localtic) = 0;
 
 	// Send any pending outgoing data
 	virtual void EndCurrentTic() = 0;

src/network/netclient.cpp

@@ -82,6 +82,7 @@ NetClient::NetClient(FString server)
 	packet.node = mServerNode;
 
 	NetCommand cmd ( NetPacketType::ConnectRequest );
+	cmd.addString("ZDoom Connect Request");
 	cmd.writeCommandToPacket ( packet );
 
 	mComm->PacketSend(packet);
@@ -149,26 +150,62 @@ void NetClient::Update()
 	}
 }
 
-void NetClient::SetCurrentTic(int receivetic, int sendtic)
+void NetClient::SetCurrentTic(int tictime)
 {
-	gametic = receivetic;
+	gametic = tictime;
-	mSendTic = sendtic;
+	mSendTic = gametic + 10;
+
+	int jitter = 2;
+	if (mLastReceivedTic == -1)
+	{
+		mServerTic = 0;
+	}
+	else
+	{
+		if (mServerTicDelta == -1 || std::abs(gametic + mServerTicDelta - mLastReceivedTic) > jitter)
+		{
+			//Printf("netcable icon! ;)\n");
+			mServerTicDelta = mLastReceivedTic - gametic - jitter;
+		}
+
+		mServerTic = MAX(gametic + mServerTicDelta, 0);
+	}
+
+	mCurrentInput[consoleplayer] = mSentInput[gametic % BACKUPTICS];
 }
 
 void NetClient::EndCurrentTic()
 {
+	mCurrentCommands = mSendCommands;
+	mSendCommands.Clear();
+
+	if (mStatus != NodeStatus::InGame)
+		return;
+
+	int targettic = (mSendTic + mServerTicDelta);
+
 	NetPacket packet;
 	packet.node = mServerNode;
 
 	NetCommand cmd ( NetPacketType::Tic );
-	cmd.addByte ( 0 ); // target gametic
+	cmd.addByte (targettic); // target gametic
-	cmd.addBuffer ( &mCurrentInput[consoleplayer].ucmd, sizeof(usercmd_t) );
+	cmd.addBuffer ( &mSentInput[(mSendTic - 1) % BACKUPTICS].ucmd, sizeof(usercmd_t) );
 	cmd.writeCommandToPacket ( packet );
 
 	mComm->PacketSend(packet);
 
-	mCurrentCommands = mSendCommands;
+	TicUpdate &update = mTicUpdates[mServerTic % BACKUPTICS];
-	mSendCommands.Clear();
+	if (update.received)
+	{
+		if (playeringame[consoleplayer] && players[consoleplayer].mo)
+		{
+			players[consoleplayer].mo->SetXYZ(update.x, update.y, update.z);
+			players[consoleplayer].mo->Angles.Yaw = update.yaw;
+			players[consoleplayer].mo->Angles.Pitch = update.pitch;
+		}
+
+		update.received = false;
+	}
 }
 
 int NetClient::GetSendTick() const
@@ -196,8 +233,7 @@ void NetClient::RunCommands(int player)
 
 void NetClient::WriteLocalInput(ticcmd_t cmd)
 {
-	mCurrentInput[consoleplayer] = cmd;
+	mSentInput[(mSendTic - 1) % BACKUPTICS] = cmd;
-	mSentInput[gametic % BACKUPTICS] = cmd;
 }
 
 void NetClient::WriteBotInput(int player, const ticcmd_t &cmd)
@@ -284,25 +320,42 @@ void NetClient::OnDisconnect(const NetPacket &packet)
 	mStatus = NodeStatus::Closed;
 }
 
+void NetClient::UpdateLastReceivedTic(int tic)
+{
+	if (mLastReceivedTic != -1)
+	{
+		int delta = tic - (mLastReceivedTic & 0xff);
+		if (delta > 128) delta -= 256;
+		else if (delta < -128) delta += 256;
+		mLastReceivedTic += delta;
+	}
+	else
+	{
+		mLastReceivedTic = tic;
+	}
+	mLastReceivedTic = MAX(mLastReceivedTic, 0);
+}
+
 void NetClient::OnTic(NetPacket &packet)
 {
-	int tic = packet.stream.ReadByte();
+	UpdateLastReceivedTic(packet.stream.ReadByte());
-	float x = packet.stream.ReadFloat();
-	float y = packet.stream.ReadFloat();
-	float z = packet.stream.ReadFloat();
-	float yaw = packet.stream.ReadFloat();
-	float pitch = packet.stream.ReadFloat();
 
-	if (playeringame[consoleplayer] && players[consoleplayer].mo)
+	TicUpdate update;
-	{
+	update.received = true;
-		players[consoleplayer].mo->SetXYZ(x, y, z);
+	update.x = packet.stream.ReadFloat();
-		players[consoleplayer].mo->Angles.Yaw = yaw;
+	update.y = packet.stream.ReadFloat();
-		players[consoleplayer].mo->Angles.Pitch = pitch;
+	update.z = packet.stream.ReadFloat();
-	}
+	update.yaw = packet.stream.ReadFloat();
+	update.pitch = packet.stream.ReadFloat();
+
+	mTicUpdates[mLastReceivedTic % BACKUPTICS] = update;
 }
 
 void NetClient::OnSpawnPlayer(NetPacket &packet)
 {
+	// To do: this needs a tic and should be inserted in mTicUpdates.
+	// Otherwise it might not arrive at the intended moment in time.
+
 	int player = packet.stream.ReadByte();
 	const float x = packet.stream.ReadFloat();
 	const float y = packet.stream.ReadFloat();
@@ -320,7 +373,7 @@ void NetClient::OnSpawnPlayer(NetPacket &packet)
 
 	// This player is now in the game.
 	playeringame[player] = true;
-	player_t p = players[player];
+	player_t &p = players[player];
 
 	if ( cl_showspawnnames )
 		Printf ( "Spawning player %d at %f,%f,%f (id %d)\n", player, x, y, z, netID );

src/network/netclient.h

@@ -30,7 +30,7 @@ public:
 
 	void Update() override;
 
-	void SetCurrentTic(int receivetic, int sendtic) override;
+	void SetCurrentTic(int tictime) override;
 	void EndCurrentTic() override;
 
 	int GetSendTick() const override;
@@ -56,11 +56,28 @@ private:
 	void OnTic(NetPacket &packet);
 	void OnSpawnPlayer(NetPacket &packet);
 
+	void UpdateLastReceivedTic(int tic);
+
 	std::unique_ptr<doomcom_t> mComm;
 	int mServerNode = -1;
 	int mPlayer = -1;
 	NodeStatus mStatus = NodeStatus::Closed;
+
 	int mSendTic = 0;
+	int mServerTic = 0;
+	int mServerTicDelta = -1;
+	int mLastReceivedTic = -1;
+
+	struct TicUpdate
+	{
+		bool received = false;
+		float x;
+		float y;
+		float z;
+		float yaw;
+		float pitch;
+	};
+	TicUpdate mTicUpdates[BACKUPTICS];
 
 	ticcmd_t mCurrentInput[MAXPLAYERS];
 	ticcmd_t mSentInput[BACKUPTICS];

src/network/netserver.cpp

@@ -76,16 +76,17 @@ NetServer::NetServer()
 
 void NetServer::Update()
 {
+	// Read all packets currently available from clients
 	while (true)
 	{
 		NetPacket packet;
 		mComm->PacketGet(packet);
 		if (packet.node == -1)
-			break;
+			break; // No more packets. We are done.
 
 		NetNode &node = mNodes[packet.node];
 
-		if (packet.size == 0)
+		if (packet.size == 0) // Connection to node closed (timed out)
 		{
 			OnClose(node, packet);
 		}
@@ -108,15 +109,27 @@ void NetServer::Update()
 				case NetPacketType::Tic: OnTic(node, packet); break;
 				}
 			}
-			break;
 		}
 	}
 }
 
-void NetServer::SetCurrentTic(int receivetic, int sendtic)
+void NetServer::SetCurrentTic(int tictime)
 {
-	gametic = receivetic;
+	gametic = tictime;
-	mSendTic = sendtic;
+
+	for (int i = 0; i < MAXNETNODES; i++)
+	{
+		NetNode &node = mNodes[i];
+		if (node.Status == NodeStatus::InGame && node.Player != -1)
+		{
+			NetNode::TicUpdate &update = node.TicUpdates[gametic % BACKUPTICS];
+			if (update.received)
+			{
+				mCurrentInput[node.Player].ucmd = update.input;
+				update.received = false;
+			}
+		}
+	}
 }
 
 void NetServer::EndCurrentTic()
@@ -160,7 +173,7 @@ void NetServer::EndCurrentTic()
 
 int NetServer::GetSendTick() const
 {
-	return mSendTic;
+	return gametic;
 }
 
 ticcmd_t NetServer::GetPlayerInput(int player) const
@@ -223,7 +236,7 @@ void NetServer::OnClose(NetNode &node, const NetPacket &packet)
 {
 	if (node.Status == NodeStatus::InGame)
 	{
-		Printf("Player %d left the server", node.Player);
+		Printf("Player %d left the server\n", node.Player);
 
 		playeringame[node.Player] = false;
 		players[node.Player].settings_controller = false;
@@ -234,29 +247,49 @@ void NetServer::OnClose(NetNode &node, const NetPacket &packet)
 	mComm->Close(packet.node);
 }
 
-void NetServer::OnConnectRequest(NetNode &node, const NetPacket &packet)
+void NetServer::OnConnectRequest(NetNode &node, NetPacket &packet)
 {
-	// Search for a spot in the player list
+	// Make the initial connect packet a bit more complex than a bunch of zeros..
-	if (node.Status != NodeStatus::InGame)
+	if (strcmp(packet.stream.ReadString(), "ZDoom Connect Request") != 0)
 	{
-		for (int i = 0; i < MAXPLAYERS; i++)
+		if (node.Status == NodeStatus::InGame)
 		{
-			if (!playeringame[i])
+			Printf("Junk data received from a joined player\n");
-			{
+		}
-				node.Player = i;
+		else
-				playeringame[i] = true;
+		{
-				players[i].settings_controller = false;
+			node.Status = NodeStatus::Closed;
-				break;
+			mComm->Close(packet.node);
-			}
+			return;
+		}
+	}
+
+	if (node.Status == NodeStatus::InGame)
+		return;
+
+	// Search for a spot in the player list
+	for (int i = 0; i < MAXPLAYERS; i++)
+	{
+		if (!playeringame[i])
+		{
+			node.Player = i;
+			break;
 		}
 	}
 
 	if (node.Player != -1) // Join accepted.
 	{
-		Printf("Player %d joined the server", node.Player);
+		Printf("Player %d joined the server\n", node.Player);
 
+		for (int i = 0; i < BACKUPTICS; i++)
+			node.TicUpdates[i].received = false;
+
+		node.Status = NodeStatus::InGame;
 		mNodeForPlayer[node.Player] = packet.node;
 
+		playeringame[node.Player] = true;
+		players[node.Player].settings_controller = false;
+
 		NetPacket response;
 		response.node = packet.node;
 
@@ -267,8 +300,6 @@ void NetServer::OnConnectRequest(NetNode &node, const NetPacket &packet)
 
 		mComm->PacketSend(response);
 
-		node.Status = NodeStatus::InGame;
-
 		FullUpdate ( node );
 	}
 	else // Server is full.
@@ -294,7 +325,7 @@ void NetServer::OnDisconnect(NetNode &node, const NetPacket &packet)
 {
 	if (node.Status == NodeStatus::InGame)
 	{
-		Printf("Player %d left the server", node.Player);
+		Printf("Player %d left the server\n", node.Player);
 
 		playeringame[node.Player] = false;
 		players[node.Player].settings_controller = false;
@@ -307,16 +338,29 @@ void NetServer::OnDisconnect(NetNode &node, const NetPacket &packet)
 
 void NetServer::OnTic(NetNode &node, NetPacket &packet)
 {
-	if (node.Status == NodeStatus::InGame)
+	if (node.Status != NodeStatus::InGame)
+		return;
+
+	int tic = packet.stream.ReadByte();
+
+	int delta = tic - (gametic & 0xff);
+	if (delta > 128) delta -= 256;
+	else if (delta < -128) delta += 256;
+	tic = gametic + delta;
+
+	if (tic <= gametic)
 	{
-		/* gametic */ packet.stream.ReadByte();
+		// Packet arrived too late.
-		packet.stream.ReadBuffer ( &mCurrentInput[node.Player].ucmd, sizeof(usercmd_t));
+		tic = gametic + 1;
-	}
+
-	else
+		if (tic < 0 || node.TicUpdates[tic % BACKUPTICS].received)
-	{
+			return; // We already received the proper packet.
-		node.Status = NodeStatus::Closed;
-		mComm->Close(packet.node);
 	}
+
+	NetNode::TicUpdate update;
+	update.received = true;
+	packet.stream.ReadBuffer(&update.input, sizeof(usercmd_t));
+	node.TicUpdates[tic % BACKUPTICS] = update;
 }
 
 void NetServer::CmdSpawnPlayer(NetNode &node, int player)

src/network/netserver.h

@@ -38,7 +38,13 @@ struct NetNode
 	int Gametic = 0;
 	int Player = -1;
 
-	ticcmd_t PlayerMovement;
+	struct TicUpdate
+	{
+		bool received = false;
+		usercmd_t input;
+	};
+	TicUpdate TicUpdates[BACKUPTICS];
+
 	FDynamicBuffer Commands; // "NetSpecs"
 };
 
@@ -49,7 +55,7 @@ public:
 
 	void Update() override;
 
-	void SetCurrentTic(int receivetic, int sendtic) override;
+	void SetCurrentTic(int tictime) override;
 	void EndCurrentTic() override;
 
 	int GetSendTick() const override;
@@ -70,7 +76,7 @@ public:
 
 private:
 	void OnClose(NetNode &node, const NetPacket &packet);
-	void OnConnectRequest(NetNode &node, const NetPacket &packet);
+	void OnConnectRequest(NetNode &node, NetPacket &packet);
 	void OnDisconnect(NetNode &node, const NetPacket &packet);
 	void OnTic(NetNode &node, NetPacket &packet);
 
@@ -80,7 +86,6 @@ private:
 	std::unique_ptr<doomcom_t> mComm;
 	NetNode mNodes[MAXNETNODES];
 	int mNodeForPlayer[MAXPLAYERS];
-	int mSendTic = 0;
 
 	ticcmd_t mCurrentInput[MAXPLAYERS];
 	FDynamicBuffer mCurrentCommands;

src/network/netsingle.cpp

@@ -82,10 +82,9 @@ void NetSinglePlayer::Update()
 {
 }
 
-void NetSinglePlayer::SetCurrentTic(int receivetic, int sendtic)
+void NetSinglePlayer::SetCurrentTic(int tictime)
 {
-	gametic = receivetic;
+	gametic = tictime;
-	mSendTic = sendtic;
 }
 
 void NetSinglePlayer::EndCurrentTic()
@@ -96,7 +95,7 @@ void NetSinglePlayer::EndCurrentTic()
 
 int NetSinglePlayer::GetSendTick() const
 {
-	return mSendTic;
+	return gametic;
 }
 
 ticcmd_t NetSinglePlayer::GetPlayerInput(int player) const

src/network/netsingle.h

@@ -30,7 +30,7 @@ public:
 
 	void Update() override;
 
-	void SetCurrentTic(int receivetic, int sendtic) override;
+	void SetCurrentTic(int tictime) override;
 	void EndCurrentTic() override;
 
 	int GetSendTick() const override;
@@ -53,6 +53,5 @@ private:
 	ticcmd_t mCurrentInput[MAXPLAYERS];
 	FDynamicBuffer mCurrentCommands;
 
-	int mSendTic = 0;
 	FDynamicBuffer mSendCommands;
 };