Show HN: Unity MMORPG Boilerplate – Multiplayer in Unity Made Easy

https://github.com/valkyrienyanko/Unity-MMORPG-Boilerplate

131 79 6 years ago

The purpose of this boilerplate is to make multiplayer in Unity a piece of cake, specifically for MMORPGs. The boilerplate consists of a launcher, a web server, a game server and a client. The idea is the user loads up the launcher, updates the client, launches the client, logs in to an account through the web server and then connects to the game server.

NanoWar• 6 years ago

Looks like a Dektop only version. Any plans for mobile?

valkyrienyanko4• 6 years ago

From what I've seen Unity (the client) can be ported to any device.

The launcher uses (Avalonia) which is cross-platform (Windows-Linux-MacOS), not sure about mobile though. Now that I think about it, I suppose there could be different ways to go about mobile and just avoid the launcher entirely.

kevingadd2• 6 years ago

Since the "Massive" in MMORPG implies large scale, some things worth considering, plus some general thoughts:

* You checked in your .vs folder, my understanding is that it is the .suo equivalent and shouldn't be checked in.

* Pulling updates from the GitHub releases page will probably get your repository rate-limited if not taken down, you need to think carefully about how to scale that up.

* While the readme says it pulls updates from GitHub, I can't find any code that actually does it. As far as I can tell the Launcher folder is completely empty boilerplate.

* Using XAML for the launcher UI seems like it would negatively impact portability unless you're pairing it with something that supports Mac and Linux (I couldn't tell if you are). It would make a lot more sense to implement your launcher in Unity (as a separate executable) since the end-user already is using Unity.

* You appear to have checked in local copies of NuGet packages, which is a bad idea. You should gitignore that folder so developers' msbuild can restore the packages locally.

* It looks like you also checked in third-party Unity asset files? I'm not sure you should do that either.

* You appear to not be making use of indexes for many of your queries, for example:

var user = db.Users.ToList().Find(x => x.Name.Equals(name));

This will stop scaling almost instantly.

fxtentacle4• 6 years ago

For unity users, "massive" means something like 64+ concurrent players. Because that's the limit for (custom engine) triple-A productions like Battlefield.

deathgrips2• 6 years ago

Today I learned that Runescape is where the real men write backend game servers.

shultays4• 6 years ago

That sounds a very unimpressive amount to be called massive.

PudgePacket2• 6 years ago

* Pulling updates from the GitHub releases page will probably get your repository rate-limited if not taken down, you need to think carefully about how to scale that up.

This is the default mechanism for electron apps to auto update, and I haven't heard any issues from it to do with rate limiting.

atraac• 6 years ago

var user = db.Users.ToList().Find(x => x.Name.Equals(name));

It's even worse. This will literally retrieve all Users into memory and then iterate over it. Every time you want to find this single one. Looks like the person who wrote it never actually wrote a single backend server using Entity Framework. It also does so synchronously, while async method is available. This means that this thread will be locked until it finishes this IO and won't be able to process anything else.

kevindeasis• 6 years ago

How do you usually handle game state for online multiplayer games to avoid cheating? My background isn't on making games, but knowing more about this domain is something I'm curious about

I'm guessing you can use timestamp by having PlayerA and PlayerB send udp packets, but wouldn't that cause latency, even if you put the instance region zones close enough to both players? How about direct socket connection between PlayerA and PlayerB and sending some results to the backend, but how do you prevent cheating on the client side then?

nightowl_games• 6 years ago

You run the real simulation on the server, and clients merely predict what they think the server will do.

hombre_fatal2• 6 years ago

I remember in World of Warcraft, your internet connection could drop completely and you wouldn't notice until you realized you hadn't seen mobs or another player for a while.

bigfoot675• 6 years ago

Any sensitive data (i.e. things you can cheat with) is generally server-authoritative. There are lots of tricks you can use for predicting/interpolating data to make up for the latency created by going from client -> server -> client

Edit: As cheschire said, it entirely depends on the type of game and what kind of actions the player is performing

HenryBemis2• 6 years ago

Like with any Risk, the actions are: Prevent, Detect, Correct (and least used Transfer).

Rule of thumb that is used in banking, 'sanity check'. Cheap and effective way to see if the gains-number (e.g. xp/coin gain) is making sense. If a top player can make 100k per hour and you get a newbie making 500k/h, you better start reading logs/snooping. The value of equip when a player saves & exits would not be x100000 from the previous time he/she saved and exited (and other similar metrics).

It is an ongoing process to make and maintain a useful dashboard. Also (I've seen it happening in some MUDs), you start snooping random players at times (preferably ones with massive gains) and see what is what.

Imho the cheapest way is to detect and correct, not prevent cheating. Unless you have an army of devs scouring the internet looking for cheating solutions that can work out preventative methods.

cheschire• 6 years ago

This is a deep topic, and people write entire thesis papers on this topic. This is/was a major performance issue in Star Citizen for years.

Because cheating tends to be an outlier activity, some companies choose to invest more in identifying cheaters after the fact using pattern recognition and machine learning tools rather than outright prevention. Depends on if your game inherently resets between game loops (i.e. battle royale, deathmatch, MOBA, etc), or if you have a continuous persistent state that has to be kept stable (i.e. MMORPG).

Full security means validating every activity with a fully trusted server before broadcasting to other players. Full performance basically means full client trust, whatever the implementation ends up looking like.

There's a whole spectrum of solutions somewhere in the middle for most games.

henrikschroder• 6 years ago

It also completely depends on what kind of multiplayer game it is. If you're doing a simple turn-based card game, obviously you can run the entire game on the server, and have the clients just do input and display of the game state. If you're doing a fast-paced first-person-shooter, you need to run more logic on each game client and trust them more. Add a real-time physics engine and it gets even trickier, because now you need to make sure it's deterministic regardless of client hardware.

If you can solve the latter problem in a general way, you can easily build a company around it. There's already a bunch that do nothing but this. It's just a fundamentally hard problem because the speed of light is what it is, the distribution of computing hardware is what it is, and the distribution of players is what it is.

ggambetta• 6 years ago

I've written a bit about that here: https://gabrielgambetta.com/client-server-game-architecture....

meritt• 6 years ago

https://github.com/MFatihMAR/Game-Networking-Resources is solid compilation of resources on this topic.

shultays4• 6 years ago

Depends on the game/cheat we are talking about really.

Some cheaters try to fool server/other clients. For example in a game of chess, a client can try to move his pawn like a queen. In this case a server would run the "game simulation" it self and would detect that the client is making an illegal move and a cheater. But this is not always possible/feasible. In an mmo for example it may not be feasible to run physics simulations on server and maybe a server can trust clients when they say "I moved from my old point A to new point B" but in reality there may be a wall in between point A and B

Not all cheats are about fooling the server. Some runs on entirely on cheater's side. A board game example would be battleships. A cheater can decide to "look" other side of the board and cheat by looking at opponent's ships. This kind of cheats are solved by only sharing necessary information with clients. For battleships, this would be server only responding the bombing coordinates a client sends and the answer would be a simple "hit/miss". Again, this is not always practical. In a game like counter strike, ideally you would share enemy positions only when they should be visible on someone's screen. But due to lag or not being able to detect this visibility information, a server can choose to always share this information and clients can cheat by presenting that information

A harder to catch cheat would be aim hack. In this case a cheater neither fooling the server or benefiting of an information it doesn't have. They usually catch these by checking programs that does this or via player reports or automated systems that catches players that are too good to be legit.

hnick3• 6 years ago

You might find this article about fighting game netcode interesting.

https://arstechnica.com/gaming/2019/10/explaining-how-fighti...

While it's mostly about ensuring both clients have a smooth experience and how to achieve that (prediction, rollback, etc) many of the same techniques apply to cheat prevention - have the client "echo" or predict what it thinks will happen, but have the source of truth be the server. "Desync" is a common term for what happens when they disagree, the server keeps its version of events and kills the client connection. In peer-to-peer or direct connection games, one player is the server and this does present a problem, but keeping it random will reveal statistical irregularities.

In general, how it works depends on the cheat. You cannot stop someone running a program to automatically aim and shoot at enemies. The enemy data is in memory so pinpoint accuracy is simple to achieve. Usually, statistical analysis, recording, allowing an admin to view their screen, and other methods can be used. Often, anti-cheat software is installed to scan for known cheats or by using heuristics (much like anti-virus software). This is a bit of a hot topic right now as a recent game tried to install such a program in Ring 0 (lowest level device driver) in Windows, which runs at startup even if the game isn't running, and won't automatically uninstall. Some people reported it stopped their PC booting.

For informational cheats (such as seeing players through walls) that data is also in memory and is harder to detect if the player doesn't make any illogical plays taking advantage of it. You might ask why the client has player position data for people you can't see? That again depends, but IIRC in at least one case a game tried to suppress the information until just before they became visible but the cheaters realised that the game had to generate sound (footsteps) for the players and reverse engineered the directional sound back into positions.

In other cases, passing network data through a proxy defeats local anti-cheat. Packet scanning and direct injection can be used for superhuman speed (such as claiming unique monsters in an MMO before anyone else can).

In general, stopping cheats is largely impossible, it's more about how to catch them and policies to handle the fallout e.g. If I cheat and earn a bunch of ingame money then trade it to you, should you lose it? How do we know you're not an accomplice?

There is also a MMO called Pwn Adventure where cheating is intended for you to progress. Live Overflow did a series on it at https://www.youtube.com/watch?v=RDZnlcnmPUA

Mirioron6• 6 years ago

The important two points are that the client must react immediately to a user's input, but at the same time the server has to have the authoritative game state.

One way of doing that is that the server runs the authoritative simulation and the clients send input to the server, but the clients also run their own simulations. In some games the client will try to predict what the server will do. If there's a conflict with what the client simulates compared to the server then the client gets rolled back to the server's state. This usually happens when there's a second player that interferes in some way.

Here is a talk by Timothy Ford about Overwatch's netcode (it's really fascinating): https://www.youtube.com/watch?v=W3aieHjyNvw

fxtentacle4• 6 years ago

I wonder if there really is that many people using Unity to build MMORPGs. Especially now that Unity has deprecated their only networking stack in favor of a (not yet existing) future replacement. But the Unity asset store is also full with MMORPG related things.

BorisTheBrave• 6 years ago

There's a lot of new gamedevs who decide they want to build an MMO. They never succeed, but this would be useful to them.

makkesk8• 6 years ago

There's an open source replacement [1] for UNET that's been improved.

[1] https://github.com/vis2k/Mirror

valkyrienyanko4• 6 years ago

Mirror does not support UDP and does not go well with headless servers iirc

moksly• 6 years ago

Albion Online is build with unity. It’s basically Eve Online in a fantasy more newbie friendly setting with league of lengends styles combat, ARPG styles solo PVE, 20 man raids, and, mining that’s actually fun.

Works pretty well, even in massive fights with hundreds of people involved. Frankly handles the MMO part of things better than most MMOs.

dukodk• 6 years ago

A good video of it from 2016 https://youtu.be/x_4Y2-B-THo

golergka4• 6 years ago

Yes, professionally I see a lot of commercial MMO projects targeting Unity as a client. It's network stack was never intended for MMOs anyway, it was always targeted for client-hosted session-based games with very limited scope.

valkyrienyanko4• 6 years ago

The boilerplate uses ENet for the game server, I tried using Unity's networking solutions earlier but found out the hard way that those were really only mean't for P2P and LAN (imo).

ENet provides a middle line between reliable and unreliable packets making it perfect for MMORPGs. You want to send a packet that a player shot a bullet? Use reliable. You want to send position updates? Use unreliable.

HenryBemis2• 6 years ago

Staying on the "making games" domain, can anyone suggest some other simple way to create a game? I have done coding before, but never got engaged into making a game, I would accept any ideas for nature of games, anything between Shilla.org, flash games, anything that can be made and maintained by one person.

Jakob• 6 years ago

I enjoyed the articles on https://www.redblobgames.com/ a lot in the past. They are nice starting points for making a game.

frenchie14• 6 years ago

The best "easy to learn, hard to master" that I know of is PICO-8. You can get up and running with a simple game incredibly fast. The entire IDE/Engine is a single program. You write all code, draw all sprites/maps, compose all music/SFX, and play in one place. You will be surprised with what people who have mastered it can create.

https://www.lexaloffle.com/pico-8.php

hombre_fatal2• 6 years ago

Such a great way to test out some simple game mechanic ideas.

I'd been "planning on building a game" for probably a decade. Pico-8 got me to finally "finish" a few. The integrated graphics and audio system is super useful for cobbling something together.

deathgrips2• 6 years ago

Unity and Unreal Engine are the only realistic options for 99% of indie developers. Yes, you can technically program your own game engine, but if you are asking advice for simple ways to make games, that is not the best option for you right now. There is a lot of really good education content for those two game engines. Most importantly, people use them to make and sell games.

More important than any particular route you take is merely sticking with it. The choice of game engine doesn't matter that much as long as you make and finish games with that engine. Everything else is secondary and mostly procrastination.

TheChaplain• 6 years ago

There is the gamedev subreddit that contains plenty of helpful information and people.

Using a game engine like Unity you can create something pretty advances in a short time. There are tons of tutorials on YT. If you prefer a free game engine, check out Godot.

If you're looking at doing it "from scratch", you should really consider starting out small with something like Pong or Tetris. The best resource I know is Handmade Hero for that, tons of YT videos and huge community.

PudgePacket2• 6 years ago

Try GameMaker or Construct. They are the more intro level tools that will let you get things done without having to learn too much.

After there is the big engines, Unity, Unreal, and Godot. They all have their ups and downs, but are the next level of complexity up from the previously mentioned tools.

If you're into specific niches there are sometimes purpose built engines for it, like RPG Maker. They are usually much less complex, albeit limited to specific kinds of games.

Mirioron6• 6 years ago

Unity. Go download it and watch some tutorials on YouTube. I recommend someone like Brackeys. Pick a game making series and follow along. You'll very quickly get an understanding of how to do things and can go from there.

This is a popular enough way of doing it that it exists for most of the popular engines. Unity just tends to have the most.

You can start here: https://www.youtube.com/watch?v=j48LtUkZRjU&list=PLPV2KyIb3j...

terrycody• 6 years ago

Guys, don't forget Godot, you can choose unity or Godot for 2D games, Godot is the 3rd popular engine today, and will become more popular in the future.

namelosw2• 6 years ago

I'm a web developer but I tried to understand how to build an MMORPG similar to World of Warcraft sometimes ago.

It turns out to build a solid solution that is largely overwhelming to individuals, and I yet to found an open-source framework that tackles these issues in a straightforward way.

To my shallow understanding, it's less about Unity, the game client, despite there are many protocol related works. Here are something I found really hard for me:

1. The first step is basically rebuilding all the game logic in the server-side, or you'll be facing endless cheating. The combat, the inventory, especially the map - you're going to model a huge 3D world on the server-side without existing client-side GUI helpers.

2. The most difficult thing is most of the states need to spread across the whole cluster like a distributed database, and keep sync because there might be interactions between those states (eg. shoot a fireball through the edge of the map to another map then hit someone), this usually done by modeling a quadtree across the cluster.

3. Players can randomly fight each other in an open world, and those combat needs to be dynamically grouped and disbanded. Players should only receive the state update they care about, instead of receiving every information of the world(area of interest), and everyone's interest might be different.

4. Of course, there are global clock and synchronization.

5. Many operations would require transactions, or players can trade and duplicate items when they cross the border of maps or directly disconnect.

moonchild2• 6 years ago

rebuilding all the game logic in the server-side

Start with the server side. This doesn't actually have to be a server application with no gui, but start with the simulation of an entire world. Then 'rebuild' the logic on the client side. This lets you be a little bit sloppy—though not too sloppy, obviously—because it's ok if the server 'cheats', since it has no ulterior motives (except for yours) and there's only one of it.

golergka4• 6 years ago

Real client-side verification and prediction is usually more complicated than just replicating game logic, you have to be able to restore the world to a correct condition after a wrong prediction in an elegant and unoffending way.

dogma1138• 6 years ago

This isn’t just for MMO’s all multiplayer games today run everything on the server side the server side basically runs a client that is the single source of truth.

To improve the experience and compensate for lag player clients run a simulation and can update their state based on their player actions directly before the action is registered or acknowledged by the server client then they only get a confirmation from the server or they get a forced update if the action they performed wasn’t in agreement with the server.

As for other things like give mentioned you don’t usually have to run a full model on the server side of your world, you however hold a representation of it in the form of maps, these are usually huge arrays of coordinates with various properties they basically transform the 3D game world into a board game board.

For MMO’s specifically while there aren’t many good open source frameworks there is something quite good and that is private server clients for popular MMO’s like Mangos https://github.com/mangoszero/server/blob/master/README.md

k__• 6 years ago

As far as I know, MMO creators gave up and used static instances, which degrades most MMOs to multiple regular/non-massive multiplayer games stitched together.

boardwaalk• 6 years ago

Sadly true. There have been games with large, seamless, 3D worlds combined with multiplayer for a long time (late 90s at latest), but almost all new games use some combination zones (e.g. shared spaces, but broken up), or instances (spaces shared only with a small group), or phasing (spaces shared only when you're in a similar game state), or the Destiny-style "we'll have people show up whenever we feel like it" tech. That last one seems hugely popular these days, to the point it's showing up from the other direction -- other people showing up in your single player game.

I think it's because of a combination of technical difficulty and game design reasons dealing with overcrowding and camping and other bad behavior.

And I also think it's a total cop out and decimates any sense of "place" in these games, which I think is so important in games like these.

If anyone has examples of modern games that don't do most of these these things, I'd love to hear it. I'm not up on all of em, particularly the ones in the primarily Asian market.

ReD_CoDE• 6 years ago

What about these two? [1] https://github.com/ketoo/NoahGameFrame [2] https://github.com/ocornut/imgui , https://github.com/ocornut/imgui/issues/3075

Why almost all links are about years ago? Are not there any new technologies/methodologies for MMOGs that support 90fps, or even more? Something hybrid which supports both server and client sides? And mostly has developed for Unreal Engine or other well-known game engines?

nallo• 6 years ago

Started working on a text-based MMO a couple of weeks ago https://github.com/johlits/rpg

I do authentication from another service and send encrypted commands to the server which carries them out and encrypts the responses back.

Even for a text based game it is tough but I keep it simple as long as I can!

Show HN: Unity MMORPG Boilerplate – Multiplayer in Unity Made Easy

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