Stormgate Becomes First RTS To Implement Rollback Netcode

The developers of Stormgate - currently in its closed alpha testing phase - have announced they have enabled rollback netcode on their test realms! This will be the first RTS to use the powerful feature, the advantages of which we explain below:

• Rollback netcode is an important modern feature more and more games with multiplayer are implementing.
• It is a technology that greatly reduces latency in online play - this means less lag between your actions, the opponent's actions, and the server processing all of it.
• Rollback netcode initially treats both players' inputs as 'local' - as in, offline.
• Instead of waiting for the input data to 'arrive' on the server, the local install of the game will attempt to calculate what the player's next move will be.
• If the calculation / prediction is correct, you get very smooth gameplay.
• If the prediction is incorrect, the gameplay adjusts to the correct state (what the player actually did).
• Thus, if the prediction algorithm is strong enough, latency between players will be perceived locally as less than it actually is.

Here's a simple example: You're playing Pong (I hope you remember Pong!). Your opponent's connection is not great, but thankfully rollback netcode is implemented! Say you just hit the ball back toward your opponent, to the top of the screen. Rollback netcode will attempt to predict your opponent's next move (where the rectangle will move next), and considering the trajectory of the ball, the answer is likely to be up.

Meanwhile, on the other end, your opponent is just now seeing you hit that ball back. On your screen, the opponent is already starting to move the rectangle up. On the opponent's screen, the decision has just now been made to move the rectangle up, but because the rollback netcode guessed the move correctly, you are not seeing the opponent's move happening with a delay (or with a janky teleport).

I feel this simple example was not so simple at all, so I'll just say this: Rollback netcode is another layer of code that reduces lag by trying to predict the players' moves before they make them. Kind of like how big data knows what you'll buy before you're shown the ad, you know? You might not click on the ad, but the prediction was still made. Next time, it may 'predict' an ad you'll actually click on!

We don't know the extent of Stormgate's rollback netcode depth, but considering how complex RTS games can get, with their absurd APM (actions per minute), I wouldn't be surprised if their rollback netcode doesn't have some sort of machine learning bits and pieces strewn around to learn how each player uniquely interacts with the game, and thus provide better predictions.

If you want to learn more about Stormgate, you can read (and watch!) all about it in our Stormgate Gameplay Preview - Warcraft Meets Starcraft article from a while back. To close things off, here's the game's cinematic trailer: