Detecting city founding

[Thalassicus]

What's the simplest way to detect when a city is founded?

To detect new units and prevent repeats I gave them a "new unit" promotion... but I don't know of a comparable way to mark new cities.

 

[Androrc the Orc]

With this function:

city:getGameTurnFounded()

 

[Thalassicus]

I mean an event which runs the moment someone founds a city, not checking the turn an existing city was founded.

 

[Spatzimaus]

I've always just used SerialEventCityCreated. I've never had a problem with it; it's not like SerialEventUnitCreated, which also triggers on embark/disembark actions and therefore requires a Rookie promotion to mark it, and unlike the SerialEventImprovementCreated function it does work for AI cities you can't see.

 

[Thalassicus]

SerialEventCityCreated triggers for all cities each time a save is loaded. Since they use Lua mainly for graphics, I suspect those "created" events are when the graphical object is created, not the internal object.

After thinking this over I figured out a straightforward solution. When the event runs, set a flag saying it's run. I don't know why I didn't think of this before...

if not MapModData.VEM.CityFounded then
  MapModData.VEM.CityFounded = {}
  for playerID, player in pairs(Players) do
    MapModData.VEM.CityFounded[playerID] = {}
    for city in player:Cities() do
      MapModData.VEM.CityFounded[playerID][city:GetID()] = true
    end
  end
end

function OnNewCity(hexPos, playerID, cityID, cultureType, eraType, continent, populationSize, size, fowState)
  local player = Players[playerID]
    if not player or not player:IsAlive() then
    return
  end

  local city = Players[playerID]:GetCityByID(cityID)
  if (city == nil
      or MapModData.VEM.CityFounded[playerID][cityID]
      or city:GetGameTurnFounded() < Game.GetGameTurn()
    ) then
    return
  end
  
  MapModData.VEM.CityFounded[playerID][cityID] = true
  LuaEvents.CityFounded(hexPos, playerID, cityID, cultureType, eraType, continent, populationSize, size, fowState)
end

Replace "city" with "unit" and most of this also applies to units.

 

[Pazyryk]

I just have this:

function OnEnterGame()   --Runs when Begin or Countinue Your Journey pressed
	print("Player entering game ...")
	RegisterOnSaveCallback()
	EA_GAME_INITIALIZED = true
end
Events.LoadScreenClose.Add(OnEnterGame)

then test EA_GAME_INITIALIZED in your SerialEventCityCreated function (and other event functions that try to run before the game actually starts).

 

[Thalassicus]

Good idea, thanks! What's the role of RegisterOnSaveCallback?

So basically like this:

function OnEnterGame()
  MapModData.VEM.Initialized = true
end
Events.LoadScreenClose.Add(OnEnterGame)

LuaEvents.CityFounded = LuaEvents.CityFounded or function(hexPos, playerID, cityID, cultureType, eraType, continent, populationSize, size, fowState) end
function OnNewCity(...)
  if MapModData.VEM.Initialized then
    LuaEvents.CityFounded(arg)
  end
end
Events.SerialEventCityCreated.Add(OnNewCity)

--------------------------------------------------

if not MapModData.VEM.UnitCreated then
  MapModData.VEM.UnitCreated = {}
  for playerID, player in pairs(Players) do
    MapModData.VEM.UnitCreated[playerID] = {}
    for unit in player:Units() do
      MapModData.VEM.UnitCreated[playerID][unit:GetID()] = true
    end
  end
end

LuaEvents.UnitSpawned = LuaEvents.UnitSpawned or function(playerID, unitID, hexVec, unitType, cultureType, civID, primaryColor, secondaryColor, unitFlagIndex, fogState, selected, military, notInvisible) end
function OnNewUnit(playerID, unitID, ...)
  if MapModData.VEM.Initialized then
    local unit = Players[playerID]:GetUnitByID(unitID)
    if not MapModData.VEM.UnitCreated[playerID][unitID] then
      MapModData.VEM.UnitCreated[playerID][unitID] = true
      LuaEvents.UnitSpawned(playerID, unitID, arg)
    end
  end
end
Events.SerialEventUnitCreated.Add(OnNewUnit)

_

SerialEventUnitCreated runs both when the game starts and when a unit embarks/disembarks/upgrades, so I think that one still needs a table storing which ones are new. I'm not sure how else the unit version could be simplified...

 

[Pazyryk]

Sorry, the RegisterOnSaveCallback() line is unrelated to the question at hand. Didn't notice as I copied/pasted.

That's how I do SerialEventCityCreate anyway. Except I always use a bunch of

if <something> then return end

lines at the top of my functions, rather than nesting deeper and deeper in if blocks. But that's just personal preference.