Implementing Lag Compensation

Welcome to one of the most anticipated chapters in the book. Here, we will dive into the core of online multiplayer game optimization. In the world of online gaming, where players from across the globe unite to embark on epic adventures, two formidable adversaries lurk in the shadows; they are lag and latency. These foes can transform a thrilling gaming experience into a frustrating trial. In this chapter, we’ll confront these challenges head-on, arming you with the knowledge and tools to mitigate their impact and create an engaging online gaming environment.

In this chapter, we will use Remote Procedure Calls (RPCs) to implement lag compensation techniques, in order to make the Player node’s Spaceship node maintain its position and rotation, synced throughout the game instances across the network. For that, we will understand the core issues regarding packet loss and latency, something common when we use unreliable packets, as we do when...

Technical requirements

As mentioned in Chapter 10, Debugging and Profiling the Network, Part 3, Optimizing the Online Experience, of this book focuses on the final version of the project made in Chapter 9, Creating an Online Adventure Prototype, so it’s fundamental to read, exercise, and implement the concepts presented there. You can get the files necessary to start this chapter at the following link: https://github.com/PacktPublishing/The-Essential-Guide-to-Creating-Multiplayer-Games-with-Godot-4.0/tree/12.prediction-and-interpolation. They contain the progress we’ve made for optimizations in Chapter 11, Optimizing Data Requests.

It’s also necessary that you have read and understood the concepts and tools presented in Chapter 11, Optimizing Data Requests, so that we can continue with the assumption that you already know what they are and how to use them properly.

Introducing lag issues

Addressing lag and unreliable packets involves three techniques – interpolation, prediction, and extrapolation. These techniques smoothen player movements, maintain responsiveness, and anticipate object movements. The Godot Engine’s physics simulation and RPC method are crucial in these techniques, aiding in realistic object movement and data synchronization, despite network issues.

Lag and latency are the archenemies of any online multiplayer game. Lag, often used interchangeably with latency, refers to the delay between a player’s action and its corresponding effect in the game. It’s the momentary pause between pulling the trigger and seeing the enemy fall. Latency, on the other hand, represents the time it takes for data to travel from a player’s device to the game server and back. Together, these factors can disrupt the fluidity of gameplay, leaving players frustrated and disconnected from the virtual world.

Within...

Dealing with unreliable packets

One of the top concerns that developers grapple with when creating online multiplayer games is the reliability of data packets. In this section, we’ll see the complexities surrounding unreliable packets, shedding light on the issues they bring to the forefront of online multiplayer games. As you’ve already gleaned from our discussions, understanding these challenges is core to crafting a smooth and immersive multiplayer gaming experience.

Unreliable packets, as the name suggests, are data packets sent over a network without any guarantee of arrival or order. They’re like letters in the wind, reaching their destination only if the conditions are favorable. These packets are used to transmit non-critical data in online games, such as character positions, because they offer lower latency compared to reliable packets, which come with built-in delivery assurances at the expense of potential lag.

One of the primary issues associated...

Common compensation techniques

Welcome to the most anticipated section in our journey through the realm of online multiplayer game development. In the previous sections, we unraveled the complexities of networking, synchronization, and the intricacies of dealing with unreliable packets. Now, we stand at a crucial juncture, ready to explore the fascinating world of interpolation, prediction, and extrapolation, a trio of techniques that hold the key to creating seamless and responsive online gaming experiences, or at least to get as close as we can to this Holy Grail.

Picture this – you’re in the heat of an intense multiplayer battle, and the stakes couldn’t be higher. In the world of online gaming, every second counts, and every move must be precise. But what happens when network latency rears its head, causing a slight delay in transmitting data between players? This is where interpolation, prediction, and extrapolation come to the rescue.

One of the cornerstones...

Summary

In this chapter, we learned about the issues caused by lag, latency, and packet loss. Then, we saw how to fix them by implementing lag compensation techniques. We explored the concepts of interpolation, prediction, synchronization, and extrapolation to ensure smooth and responsive gameplay, even in the face of network delays.

First, we delved into interpolation, which is the core technique regarding lag compensation. Interpolation helps to fix some drawbacks of latency and sparse data updates by animating between two known values, while actual updates don’t arrive. This ensures that the Spaceship node won’t idling, waiting for new updates from the network. It will smoothly move toward new data, instead of abruptly teleporting to it.

Then, we discussed prediction, which involves making informed guesses about an object’s future position, based on its past behavior. By using Newtonian physics calculations, we were able to calculate the spaceship’...