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Project Tango

Introduction

Project Tango (name to change later) is an experimental Cities Skylines multiplayer mod. The mod will provide an experience where everything is synced between players (using the client-server model). Players will share money, costs, roads, resources etc. In the future it would be nice to add the ability to players to control individual cities, but this is a HUGE if.

I'm currently developing this in my free-free time (most of my time being spent studying/working and developing SoundByte) so I'd love help! The following information aims to help understand how this mod works and will work in the future, how to set it up, how to use it and how to help develop it.

Installation

Setting up the mod is very easy. You will need to have Visual Studio 2017 installed (free version works), have not tested on older versions.

1. Create a new folder in your cities skylines mod directory (%LOCALAPPDATA%\Colossal Order\Cities_Skylines\Addons\Mods) called Tango.
2. Change your project config to Release and Any CPU.
3. Right-click the Tango Project and select build. Building the project should automatically copy the required files to the newly created Tango folder in AppData.
4. If the build did not automatically copy the required files, copy Tango.dll from bin\Release into this new folder.
5. Copy Lidgren.Network.dll from the Assemblies folder into the Tango folder.
6. Run cities skylines and enable the mod.

Usage

1. Create a new game / open an existing game.
2. Click the Show Multiplayer Menu button in the top-left of your screen.
3. To host a game click on Host Game.
4. To join a game click on Join Game and enter the required information.

Client-Server Model

This mod uses the client-server model. A user will setup their game as a server and transmit information like currency, roads, needs etc. to all connected clients. Clients will connect to the server and retrieve currency, roads, needs etc. from the server, updating the client UI.

This is all done by running a UDP server alongside Cities Skylines. This UDP server will interact with the extension methods in the ICities DLL. It is important that we extend and override the base methods for these extensions (as we override some values).

ICities.dll Extensions

Here is a list of extensions that can be used in the ICities.dll (not much documentation elsewhere).

AreasExtensionBase

We can use these extension methods to sync which areas have been bought.

Method	Return
OnCanUnlockArea(int x, int z, bool originalResult)	originalResult
OnGetAreaPrice(uint ore, uint oil, uint forest, uint fertility, uint water, bool road, bool train, bool ship, bool plane, float landFlatness, int originalPrice)	originalPrice
OnUnlockArea(int x, int z)	VOID

BuildingExtensionBase

We can use this to find out where builds are. Looks like it may be quite complicated. Guess we will see.

Method	Return
SpawnData OnCalculateSpawn(Vector3 location, SpawnData spawn)	spawn
OnBuildingCreated(ushort id)	VOID
OnBuildingRelocated(ushort id)	VOID
OnBuildingReleased(ushort id)	VOID

ChirperExtensionBase

This really is not that important, (I personally don't really like the "Twitter" like feature), but it can still be implemented. On Server we send the new chirper message to the clients on OnNewMessage event. Client side we ignore these chirpers.

Method	Return
OnNewMessage(IChirperMessage message)	VOID

DemandExtensionBase

This extension will allow us to synchronize demand across all connected clients. More research is required, but from what I understand, we need to override the OnCalculate*Demmand methods to grab the calculated demand from the server. On the server we will access the demand manager to get the current demand. The OnUpdateDemand method will also be used for server-client syncing.

Method	Return
OnCalculateResidentialDemand(int originalDemand)	originalDemand
OnCalculateCommercialDemand(int originalDemand)	originalDemand
OnCalculateWorkplaceDemand(int originalDemand)	originalDemand
OnUpdateDemand(int lastDemand, int nextDemand, int targetDemand)	nextDemand

EconomyExtensionBase

Currently looking at implementing OnUpdateMoneyAmount to sync money between clients. Some basic testing showed that this was only updating the UI? Need to look further into it.

Method	Return
OnAddResource(EconomyResource resource, int amount, Service service, SubService subService, Level level)	amount
OnFetchResource(EconomyResource resource, int amount, Service service, SubService subService, Level level)	amount
OnPeekResource(EconomyResource resource, int amount)	amount
OnGetConstructionCost(int originalConstructionCost, Service service, SubService subService, Level level)	amount
OnGetMaintenanceCost(int originalMaintenanceCost, Service service, SubService subService, Level level)	amount
OnGetRelocationCost(int constructionCost, int relocationCost, Service service, SubService subService, Level level)	amount
OnGetRefundAmount(int constructionCost, int refundAmount, Service service, SubService subService, Level level)	amount
OnUpdateMoneyAmount(long internalMoneyAmount)	internalMoneyAmount

IDisasterBase

This has a different naming scheme for some reason? This would be used for syncing disasters (going to be interesting to setup)

Method	Return
OnDisasterCreated(ushort disasterID)	VOID
OnDisasterStarted(ushort disasterID)	VOID
OnDisasterDetected(ushort disasterID)	VOID
OnDisasterActivated(ushort disasterID)	VOID
OnDisasterDeactivated(ushort disasterID)	VOID
OnDisasterFinished(ushort disasterID)	VOID

LevelUpExtensionBase

todo

LoadingExtensionBase

todo

MilestonesExtensionBase

todo

ResourceExtensionBase

todo

SerializableDataExtensionBase

todo

TerrainExtensionBase

todo

ThreadingExtensionBase

todo