One of the biggest benefits of all that power is giving developers the ability to make games that are Xbox Series X|S Optimized. This means that they’ve taken full advantage of the unique capabilities of Xbox Series X|S, both for new titles built natively using the Xbox Series X|S development environment as well as previously released titles that have been rebuilt specifically for the console. In our Inside Xbox Series X|S Optimized series, these creators will share the behind-the-scenes accounts of how they’re optimizing their titles for Xbox Series X|S and what that means for the future of gaming. Today, we’ll be chatting with Ben Woodhouse, Lead Console Programmer at Epic Games, about optimizing Fortnite for Xbox Series X|S.
Q: What excites you most about developing and bringing Fortnite to life on next-generation hardware?
A: The new generation of hardware brings huge improvements in CPU, GPU and I/O performance.
The team was clear from the start that we wanted to use the extra horsepower to make the game feel more alive, not just to increase the graphics settings and resolution. To do that, we had to use the power of the hardware in more creative ways.
We added features like volumetric clouds, GPU simulated physics fields and fluid simulations, as well as a host of custom-authored effects, all designed to make the game feel more dynamic.
From a technical standpoint, new hardware is always fun for developers to get their teeth into and we’ve enjoyed the process of optimizing Unreal Engine for the hardware, improving the performance of shaders, reducing CPU bottlenecks and optimizing loading from the SSD. All this work has been pushed back into Unreal Engine for the benefit of licensees.
Q: In addition to benefiting from the power and performance of Xbox Series X|S for quicker load times etc. what Xbox Series X|S features were you most excited to explore leveraging in the development of Fortnite?
A: A lot has been said about the GPU power of Xbox Series X|S and the Velocity Architecture, and Fortnite makes full use of these, but one of the things we’ve been most impressed with is the CPU. We’re seeing a huge uplift in terms of instructions per clock relative to the previous generation. This unlocks experiences that were not possible with the previous generation of hardware.
Q: How will these enhancements impact a player’s experience with Fortnite?
A: Last-gen consoles couldn’t handle running split-screen or Save the World mode at 60fps. We had the GPU power, but even on the Xbox One X, we were bottlenecked by the CPU. On Xbox Series X|S, the additional CPU headroom removes these constraints. With a little tuning, we’re able to get both these machines running at a solid 60fps in both modes.
Similarly on last-gen, Battle Royale mode ran at 60fps but with occasional hitches and dropped frames during heavy scenes due to the CPU being pushed to the limit. On Xbox Series X|S, these issues are much rarer. We’re seeing an order of magnitude fewer dropped frames on this generation, and gameplay feels smoother as a result.
The extra CPU headroom, combined with blazing fast loading performance has allowed us to increase streaming distances dramatically, greatly improving the detail in the distance. This is especially noticeable in 4K.
Q: Why did your development team choose to focus on dynamic visuals and physics as enhancement areas for Fortnite?
A: It goes without saying that we run at 4K and 60fps on Xbox Series X, and we’ve ramped up all the quality settings. But we wanted to go beyond the obvious visual upgrades and use some of the extra power to make the world feel more dynamic and alive.
We added GPU fluid simulations for explosions and smoke and fire effects. These look great in motion and make the effects feel much more natural. We’re also using GPU compute power to simulate physics fields. This allows us to generate shockwaves from grenade and rocket explosions, adding realistic motion to nearby grass and foliage and enhancing the gameplay.
We added raymarched volumetric clouds that have real depth. These look beautiful under different dynamic lighting conditions, especially when you’re skydiving through them. The artists have made full use of the freedom the new hardware gives them. There’s a host of new effects, for fire, elimination animations, and the storm.
We’re very happy to say that we managed to enable the vast majority of these features on Xbox Series S too. A few quality settings are lower than the Xbox Series X, but the main difference was simply resolution (Series S targets 1080p, whereas Series X outputs 4K).
On Xbox Series X|S, we use dynamic resolution and a new bleeding-edge temporal antialiasing algorithm (TAA2) to provide high-quality 4K output at 60fps, regardless of the GPU load. TAA2 will be a new feature in Unreal Engine 4.26.
Q: How do you expect fans of Fortnite will respond to playing it on Xbox Series X|S with these enhancements?
A: Fortnite looks fantastic on Xbox Series X|S. With smooth 60fps gameplay in all modes and super-fast loading, it’s a great experience that we think fans are really going to enjoy. We’re excited to finally get the Xbox Series X|S version of the game in the hands of players so we can hear what they think.
Fortnite is a constantly evolving game that never stands still, and we’ll be adding more enhancements to the Xbox Series X|S version in upcoming releases. Feedback from players will definitely be a factor in deciding what features to add next.
Q: What is it like developing on Xbox Series X|S?
A: Microsoft made the transition very easy for us. The development tools have been great to work with, and many of them are very familiar to us from Xbox One.
As with any new platform, there have been rough edges during development around stability and performance, but we had great support from Microsoft’s hardware team when these issues arose. They’ve turned around fixes very quickly, sometimes within 24 hours.
Another thing that helped our development process was the new Game Development Kit, which allows us to share common code across generations of consoles. This shared codebase will make supporting both generations much easier as players transition over to the new hardware.
Q: Which enhancement were you most excited about to explore leveraging for Fortnite on Xbox Series X|S?
A: We were particularly excited about the Velocity Architecture and making the most of the additional I/O bandwidth on Xbox Series X and S to reduce loading times and improve level streaming performance. This actually came with a number of challenges. As soon as raw disk bandwidth stops being an issue, the CPU can quickly become a bottleneck in loading. To really make the most of the hardware, we had to reduce the CPU overhead significantly.
The engine team spent a lot of time over the past year rewriting the loader in UE4 and optimizing the engine initialization code to reduce these bottlenecks. On the Fortnite side, quite a lot of the load time is spent waiting for servers, so we reordered the work to allow parallel execution. We’re pretty happy with where our loading times ended up at launch, but this is an ongoing area of improvement. Expect further optimizations for future releases.
Aside from load times, the added I/O performance has allowed much faster streaming of assets. Textures, meshes and levels take a lot less time to load in, and the faster streaming also allowed us to increase level streaming distances, increasing visual fidelity in the distance.
Q: What does Xbox Series X|S next-generation development enable in current or future projects that you could not have achieved with the previous generation of consoles?
A: Fortnite is a constantly updated title and players can expect more next-gen enhancements over the coming months. There’s definitely more we want to do with the Xbox Series X|S hardware, both in terms of visuals and reducing latency – we may also look at supporting a 120fps mode in future releases.
This current version is Fortnite on Unreal Engine 4. In the next year, we will start moving Fortnite over to Unreal Engine 5 and are very excited to see what we can do with that change. We’re also very curious to see what Unreal Engine licensees throughout the world can do on next-generation hardware with both Unreal Engine 4 and Unreal Engine 5.