Unique network transmission handling of flares

This patch addresses issues concerning a1796ed71f:

Allow for a more elegant implementation of observer flares.
And still display flares even if the sender is lagging behind:
Split off flares from simulation commands.
Remove the new, problematic 'observer commands' entirely.
Provide an engine function 'SendNetworkFlare' to the JS interface.
-> which sets off the (pretty ordinary) transmission process.
Add a new type of net messages exclusively for flares
-> contains the flare's position and its sender's GUID.

binaries/data/mods/public/gui/session/input.js

@@ -1271,14 +1271,9 @@ function triggerFlareAction(position)
 
 	g_LastFlareTime = now;
 
-	const guid = Engine.GetPlayerGUID();
-	displayFlare(position, guid);
-	Engine.PlayUISound(g_FlareSound, false);
-	Engine.PostNetworkCommand({
-		"type": "map-flare",
-		"position": position,
-		"guid": guid
-	});
+	renderAndPlayFlare(position, Engine.GetPlayerGUID());
+	if (Engine.HasNetClient())
+		Engine.SendNetworkFlare(position);
 }
 
 function handleUnitAction(position, action)

binaries/data/mods/public/gui/session/messages.js

@@ -96,6 +96,9 @@ var g_NetMessageTypes = {
 			"text": msg.text
 		});
 	},
+	"flare": msg => {
+		handleFlare(msg);
+	},
 	"gamesetup": msg => {}, // Needed for autostart
 	"start": msg => {}
 };
@@ -287,29 +290,6 @@ var g_NotificationsTypes =
 		}
 
 		global.music.setLocked(notification.lock);
-	},
-	"map-flare": function(notification, player)
-	{
-		const shouldSeeFlare = g_IsObserver || g_Players[player]?.isMutualAlly[Engine.GetPlayerID()];
-
-		// Don't display for the player that did the flare because they will see it immediately.
-		if (!shouldSeeFlare || notification.guid == Engine.GetPlayerGUID())
-			return;
-
-		let now = Date.now();
-		if (g_FlareRateLimitLastTimes.length)
-		{
-			g_FlareRateLimitLastTimes = g_FlareRateLimitLastTimes.filter(t => now - t < g_FlareRateLimitScope * 1000);
-			if (g_FlareRateLimitLastTimes.length >= g_FlareRateLimitMaximumFlares)
-			{
-				warn("Received too many flares. Dropping a flare request by '" + g_Players[player].name + "'.");
-				return;
-			}
-		}
-		g_FlareRateLimitLastTimes.push(now);
-
-		displayFlare(notification.position, notification.guid);
-		Engine.PlayUISound(g_FlareSound, false);
 	}
 };
 
@@ -524,6 +504,30 @@ function clearChatMessages()
 	g_Chat.ChatOverlay.clearChatMessages();
 }
 
+function handleFlare(data)
+{
+	const playerID = g_PlayerAssignments[data.guid].player;
+	const shouldSeeFlare = g_IsObserver || g_Players[playerID]?.isMutualAlly[Engine.GetPlayerID()];
+
+	// Don't display for the player that sent the flare because they will see it immediately.
+	if (!shouldSeeFlare || data.guid == Engine.GetPlayerGUID())
+		return;
+
+	let now = Date.now();
+	if (g_FlareRateLimitLastTimes.length)
+	{
+		g_FlareRateLimitLastTimes = g_FlareRateLimitLastTimes.filter(t => now - t < g_FlareRateLimitScope * 1000);
+		if (g_FlareRateLimitLastTimes.length >= g_FlareRateLimitMaximumFlares)
+		{
+			warn("Received too many flares. Dropping a flare request by '" + g_PlayerAssignments[data.guid].name + "'.");
+			return;
+		}
+	}
+	g_FlareRateLimitLastTimes.push(now);
+
+	renderAndPlayFlare(data.position, data.guid);
+}
+
 /**
  * This function is used for AIs, whose names don't exist in g_PlayerAssignments.
  */

binaries/data/mods/public/gui/session/unit_actions.js

@@ -1937,7 +1937,7 @@ function DrawTargetMarker(position)
 	});
 }
 
-function displayFlare(position, playerGUID)
+function renderAndPlayFlare(position, playerGUID)
 {
 	const playerID = g_PlayerAssignments[playerGUID].player;
 	Engine.GuiInterfaceCall("AddTargetMarker", {
@@ -1948,6 +1948,7 @@ function displayFlare(position, playerGUID)
 		"owner": playerID != -1 ? playerID : 0
 	});
 	g_MiniMapPanel.flare(position, playerID);
+	Engine.PlayUISound(g_FlareSound, false);
 	addChatMessage({
 		"type": "flare",
 		"guid": playerGUID,

binaries/data/mods/public/simulation/helpers/Commands.js

@@ -4,13 +4,6 @@ var g_DebugCommands = false;
 
 function ProcessCommand(player, cmd)
 {
-	if (player == -1)
-	{
-		if (g_ObserverCommands[cmd.type])
-			g_ObserverCommands[cmd.type](player, cmd, {});
-		return;
-	}
-
 	let cmpPlayer = QueryPlayerIDInterface(player);
 	if (!cmpPlayer)
 		return;
@@ -882,17 +875,6 @@ var g_Commands = {
 		}
 	},
 
-	"map-flare": function(player, cmd, data)
-	{
-		let cmpGuiInterface = Engine.QueryInterface(SYSTEM_ENTITY, IID_GuiInterface);
-		cmpGuiInterface.PushNotification({
-			"type": "map-flare",
-			"players": [player],
-			"guid": cmd.guid,
-			"position": cmd.position
-		});
-	},
-
 	"autoqueue-on": function(player, cmd, data)
 	{
 		for (let ent of data.entities)
@@ -915,10 +897,6 @@ var g_Commands = {
 
 };
 
-var g_ObserverCommands = {
-	"map-flare": g_Commands["map-flare"]
-};
-
 /**
  * Sends a GUI notification about unit(s) that failed to ungarrison.
  */

source/network/NetClient.cpp

@@ -116,6 +116,7 @@ CNetClient::CNetClient(CGame* game) :
 	AddTransition(NCS_INGAME, (uint)NMT_GAME_SETUP, NCS_INGAME, &OnGameSetup, this);
 	AddTransition(NCS_INGAME, (uint)NMT_PLAYER_ASSIGNMENT, NCS_INGAME, &OnPlayerAssignment, this);
 	AddTransition(NCS_INGAME, (uint)NMT_SIMULATION_COMMAND, NCS_INGAME, &OnInGame, this);
+	AddTransition(NCS_INGAME, (uint)NMT_FLARE, NCS_INGAME, &OnFlare, this);
 	AddTransition(NCS_INGAME, (uint)NMT_SYNC_ERROR, NCS_INGAME, &OnInGame, this);
 	AddTransition(NCS_INGAME, (uint)NMT_END_COMMAND_BATCH, NCS_INGAME, &OnInGame, this);
 
@@ -489,6 +490,15 @@ void CNetClient::SendStartGameMessage(const CStr& initAttribs)
 	SendMessage(&gameStart);
 }
 
+void CNetClient::SendFlareMessage(const CStr& positionX, const CStr& positionY, const CStr& positionZ)
+{
+	CFlareMessage flare;
+	flare.m_PositionX = positionX;
+	flare.m_PositionY = positionY;
+	flare.m_PositionZ = positionZ;
+	SendMessage(&flare);
+}
+
 void CNetClient::SendRejoinedMessage()
 {
 	CRejoinedMessage rejoinedMessage;
@@ -963,3 +973,28 @@ bool CNetClient::OnInGame(CNetClient* client, CFsmEvent* event)
 
 	return true;
 }
+
+bool CNetClient::OnFlare(CNetClient* client, CFsmEvent* event)
+{
+	ENSURE(event->GetType() == static_cast<uint>(NMT_FLARE));
+
+	CFlareMessage* message = static_cast<CFlareMessage*>(event->GetParamRef());
+
+	const ScriptInterface& scriptInterface = client->m_Game->GetSimulation2()->GetScriptInterface();
+	ScriptRequest rq(scriptInterface);
+	JS::RootedValue position(rq.cx);
+	Script::CreateObject(
+		rq, &position,
+		// The coordinates are transmitted as strings (because because direct (de)serialisation of floating point numbers is not supported).
+		"x", message->m_PositionX.ToDouble(),
+		"y", message->m_PositionY.ToDouble(),
+		"z", message->m_PositionZ.ToDouble()
+	);
+
+	client->PushGuiMessage(
+		"type", "flare",
+		"guid", message->m_GUID,
+		"position", position);
+
+	return true;
+}

source/network/NetClient.h

@@ -18,6 +18,7 @@
 #ifndef NETCLIENT_H
 #define NETCLIENT_H
 
+
 #include "network/FSM.h"
 #include "network/NetFileTransfer.h"
 #include "network/NetHost.h"
@@ -236,6 +237,11 @@ public:
 
 	void SendStartGameMessage(const CStr& initAttribs);
 
+	/**
+	 * Call when the client (player or observer) has sent a flare.
+	 */
+	void SendFlareMessage(const CStr& positionX, const CStr& positionY, const CStr& positionZ);
+
 	/**
 	 * Call when the client has rejoined a running match and finished
 	 * the loading screen.
@@ -279,6 +285,7 @@ private:
 	static bool OnGameStart(CNetClient* client, CFsmEvent* event);
 	static bool OnJoinSyncStart(CNetClient* client, CFsmEvent* event);
 	static bool OnJoinSyncEndCommandBatch(CNetClient* client, CFsmEvent* event);
+	static bool OnFlare(CNetClient* client, CFsmEvent* event);
 	static bool OnRejoined(CNetClient* client, CFsmEvent* event);
 	static bool OnKicked(CNetClient* client, CFsmEvent* event);
 	static bool OnClientTimeout(CNetClient* client, CFsmEvent* event);

source/network/NetMessage.cpp

@@ -207,6 +207,10 @@ CNetMessage* CNetMessageFactory::CreateMessage(const void* pData,
 		pNewMessage = new CSimulationMessage(scriptInterface);
 		break;
 
+	case NMT_FLARE:
+		pNewMessage = new CFlareMessage;
+		break;
+
 	case NMT_CLEAR_ALL_READY:
 		pNewMessage = new CClearAllReadyMessage;
 		break;

source/network/NetMessages.h

@@ -80,7 +80,8 @@ enum NetMessageType
 	NMT_SYNC_CHECK,	// OOS-detection hash checking
 	NMT_SYNC_ERROR,	// OOS-detection error
 
-	NMT_SIMULATION_COMMAND
+	NMT_SIMULATION_COMMAND,
+	NMT_FLARE
 };
 
 // Authentication result codes
@@ -177,6 +178,13 @@ START_NMT_CLASS_(JoinSyncStart, NMT_JOIN_SYNC_START)
 	NMT_FIELD(CStr, m_InitAttributes)
 END_NMT_CLASS()
 
+START_NMT_CLASS_(Flare, NMT_FLARE)
+	NMT_FIELD(CStr, m_GUID) // ignored when client->server, valid when server->client
+	NMT_FIELD(CStr, m_PositionX)
+	NMT_FIELD(CStr, m_PositionY)
+	NMT_FIELD(CStr, m_PositionZ)
+END_NMT_CLASS()
+
 START_NMT_CLASS_(Rejoined, NMT_REJOINED)
 	NMT_FIELD(CStr, m_GUID)
 END_NMT_CLASS()

source/network/NetServer.cpp

@@ -673,6 +673,7 @@ void CNetServerWorker::SetupSession(CNetServerSession* session)
 	session->AddTransition(NSS_INGAME, (uint)NMT_CONNECTION_LOST, NSS_UNCONNECTED, &OnDisconnect, session);
 	session->AddTransition(NSS_INGAME, (uint)NMT_CHAT, NSS_INGAME, &OnChat, session);
 	session->AddTransition(NSS_INGAME, (uint)NMT_SIMULATION_COMMAND, NSS_INGAME, &OnSimulationCommand, session);
+	session->AddTransition(NSS_INGAME, (uint)NMT_FLARE, NSS_INGAME, &OnFlare, session);
 	session->AddTransition(NSS_INGAME, (uint)NMT_SYNC_CHECK, NSS_INGAME, &OnSyncCheck, session);
 	session->AddTransition(NSS_INGAME, (uint)NMT_END_COMMAND_BATCH, NSS_INGAME, &OnEndCommandBatch, session);
 
@@ -1194,6 +1195,18 @@ bool CNetServerWorker::OnSimulationCommand(CNetServerSession* session, CFsmEvent
 	return true;
 }
 
+bool CNetServerWorker::OnFlare(CNetServerSession* session, CFsmEvent* event)
+{
+	ENSURE(event->GetType() == (uint)NMT_FLARE);
+
+	CNetServerWorker& server = session->GetServer();
+	CFlareMessage* message = (CFlareMessage*)event->GetParamRef();
+	message->m_GUID = session->GetGUID();
+	server.Broadcast(message, { NSS_INGAME });
+
+	return true;
+}
+
 bool CNetServerWorker::OnSyncCheck(CNetServerSession* session, CFsmEvent* event)
 {
 	ENSURE(event->GetType() == (uint)NMT_SYNC_CHECK);

source/network/NetServer.h

@@ -297,6 +297,7 @@ private:
 	static bool OnClientHandshake(CNetServerSession* session, CFsmEvent* event);
 	static bool OnAuthenticate(CNetServerSession* session, CFsmEvent* event);
 	static bool OnSimulationCommand(CNetServerSession* session, CFsmEvent* event);
+	static bool OnFlare(CNetServerSession* session, CFsmEvent* event);
 	static bool OnSyncCheck(CNetServerSession* session, CFsmEvent* event);
 	static bool OnEndCommandBatch(CNetServerSession* session, CFsmEvent* event);
 	static bool OnChat(CNetServerSession* session, CFsmEvent* event);

source/network/scripting/JSInterface_Network.cpp

@@ -274,6 +274,29 @@ void SetTurnLength(int length)
 		LOGERROR("Only network host can change turn length");
 }
 
+void SendNetworkFlare(JS::HandleValue position)
+{
+	ENSURE(g_NetClient);
+
+	ScriptRequest rq(g_NetClient->GetScriptInterface());
+	ENSURE(position.isObject());
+	JS::RootedObject positionObj(rq.cx, &position.toObject());
+	JS::RootedValue positionX(rq.cx);
+	JS::RootedValue positionY(rq.cx);
+	JS::RootedValue positionZ(rq.cx);
+	ENSURE(JS_GetProperty(rq.cx, positionObj, "x", &positionX));
+	ENSURE(JS_GetProperty(rq.cx, positionObj, "y", &positionY));
+	ENSURE(JS_GetProperty(rq.cx, positionObj, "z", &positionZ));
+
+	// (TODO?): Converting the doubles into strings here is a workaround because direct (de)serialisation of floating point numbers is not supported.
+	// It causes somewhat awkward message handling, but the resulting efficiency losses are negligible.
+	g_NetClient->SendFlareMessage(
+		CStr::FromDouble(positionX.toNumber()),
+		CStr::FromDouble(positionY.toNumber()),
+		CStr::FromDouble(positionZ.toNumber())
+	);
+}
+
 void RegisterScriptFunctions(const ScriptRequest& rq)
 {
 	ScriptFunction::Register<&GetDefaultPort>(rq, "GetDefaultPort");
@@ -294,5 +317,6 @@ void RegisterScriptFunctions(const ScriptRequest& rq)
 	ScriptFunction::Register<&ClearAllPlayerReady>(rq, "ClearAllPlayerReady");
 	ScriptFunction::Register<&StartNetworkGame>(rq, "StartNetworkGame");
 	ScriptFunction::Register<&SetTurnLength>(rq, "SetTurnLength");
+	ScriptFunction::Register<&SendNetworkFlare>(rq, "SendNetworkFlare");
 }
 }