difference between single and multiplayer games

hey guys,
Can someone tell me where the difference between single and multiplayer developing is?
Are they big differences in coding? The coding process should be the same? but what is with all the network options?

I have to be fast about to leave but really the difference comes down to just two things usually, Replication and Security.

Replication being probably the most involved item, IE the ability to have the environment mirrored or not mirrored on each networked device. When your making SP games it doesn’t matter what you see is what you get. It MP it does matter but not everything needs to be replicated you can get away with some things not being replicated. It also depends on the game but that’s the jist of it. It mean another layer of testing and code or blueprints to be added.

Because its a MP Game usually the next issue to worry about is hacking and that is usually handled with the server / client architecture and or by the guys making the engine.

Look they just released some really good video tutorials about replication, I would watch them and it should fill in the rest of the blanks.

As somebody who had a pretty good working game system up and running for single player then wanted to make it Multiplayer:
If you want to make a multiplayer game, Make it Multiplayer from the very start! I’ve basically had to rewrite almost the entire game logic. Everything from player movement to scorekeeping is affected by multiplayer. Once you get the hang of it it’s not much more difficult than single player authoring, but it’s definitely different and you can’t just make something that works in singleplayer work in multiplayer by changing a setting.

The Blueprint networking videos are a fantastic intro to replication and the client-server model used by UE4. Even if you’re planning on doing your game in C++, they really clarify the whole system and really gave me a head start.

You can also check out my thread where I’ve been learning how to make a multiplayer game in blueprints. It’s got source code and lots of insight on hwo to get various games up and running.

Tom, that is from a networking point of view - what about a local-coop point of view? Would it still applies?

I haven’t built a local co-op game, however some of it would apply, and I think my main advice would still be applicable (Decide what kind of multiplayer you want and make your game work that way from the very start). However since both players are running in the same instance, it should be much more simple as you don’t have to deal with the replication of variables or the possibility of one player gaining an advantage over the other (cheating).

Many thax for the answers!
But i have one more question, when starting UE4, you can choose for example TP First person, TP Third Person etc… is there any presetup for network games?
Because of security etc… i guess all this points have to be implemented by the developer / coder ? or there also any presetup in UE4 ?

Some of them kinda work. At the very least, the players visually replicate between clients. You should definitely watch the tutorial videos posted by Epic: Introduction to Blueprint Networking - YouTube

If you want a more fleshed out example, the ShooterGame content example from the Marketplace is where to go. It demonstrates most everything you need to know to get the core gameplay working in Multiplayer.

If you have the capability of adding another player character to the world, things necessarily become more complex. It’s much easier to quickly prototype something single-player only - you can use code that works in one way for single player, but has unintended side-effects once replicated, and ensuring consistency for each and every action, for each and every player, becomes the priority. If you approach the game as early as possible with MP in mind, you can save yourself a lot of time, as going back in to try and make something replicate properly can be annoying!

A good way of putting it in perspective: single player game is a dialogue between you and the player. A multiplayer game is a couple different conversations going on at once.

You need to to call on individual players, keep track of them, and make sure that nothing sneaky is happening. MP should never be tacked on, it’s harder than it might seem initially.