Studio Engineering Director Andrew Sabri on the Exciting Tech in Stormgate

If you thought that launching a kickstarter (with over $1,000,000 in backing as of publishing), beginning the first wave of closed beta, booking a full week of twitch streams, and releasing a new gameplay trailer wasn’t quite enough for one week, Frost Giant’s Studio Engineering Director Andrew Sabri sat down with Digital Foundry to give us some fascinating insight into the technical side of the game.

Snowplay

There are two major components Stormgate’s game engine: Unreal Engine 5, and Snowplay. Snowplay was purpose built by Frost Giant to handle all the pathing and unit interactions at very high unit counts (well beyond what UE5 is capable of), and UE5 is responsible for rendering those units to the screen. It’s also responsible for the UI layer and non-deterministic physics (think particle effects and explosions).

Based on all the testing so far, Snowplay is performing incredibly well. One fundamental requirement of an RTS engine is determinism; each game client has to simulate the game in exactly the same way based on the player’s inputs. Snowplay has been so solid that the team hasn’t witnessed a single de-sync in testing up until the rollback test (more on that in a minute).

When asked about multithreading, Sabri said that Snowplay itself is actually single threaded. The overhead and complexity of multithreading didn’t appear to be worthwhile, and there are benefits to keeping things in a thread-local cache.

Unreal Engine 5

On the Unreal side of things, we got an interesting look at which technologies are (and aren’t) being used in Stormgate.

First, the team has made heavy use of Niagra, a visual effects system in UE5 that allows for sophisticated visual effects to be built by an artist, without the need for a programmer.

The team tried implementing Lumen, a sophisticated illumination system, but unfortunately it didn’t work well with the abrupt camera jumps that are frequent in an RTS. There is some hope that the Unreal team might be able to improve the tech, but for now it’s a no-go.

For map creation, UE5’s terrain editor won’t work either, because getting map creation tools into the community’s hands is a high priority. So all the terrain and trigger editing software has to be built in house so it can be accessible to players and map makers.

Cinematics are going to be in-engine, which is exciting for anyone not wanting tens of gigabytes of videos they’ll only see once sitting on their hard drive (Starcraft II, cough cough). UE5’s fidelity really shines here, and you can get an idea of the quality to expect from the cinematic announcement trailer released last year, which was done entirely in Unreal.

One big win is that, because the role of UE5 and Snowplay are so distinct, the team hasn’t had to do much modification of UE5 itself. So updates have been relatively painless, and the engine likely won’t be stuck on a particular version like games often are.

Rollback

Of all the cool tech going into Stormgate, rollback has to be the most exciting. Rollback is a type of netcode that allows a player’s PC to simulate the game before getting inputs from the opponent. If it turns out that the opponents inputs cause a change in the game state, the game engine will rewind the game, re-run the simulation, and “snap” the game to the correct game state. This almost always happens without the players being able to tell, and it makes the game feel far more responsive than the typical method, which is to delay the game until inputs are received over the network. Stormgate is the first RTS ever to use it.

Up until the second alpha test, rollback was considered quite experimental by the team. There was a lot of apprehension about whether or not it could handle real games under real network conditions. The test, however, went better than anyone had hoped. The plan was to test for a few hours, but it performed so well and the player response was so overwhelmingly positive that the team decided to extend the test to several days. Several pro players, PartinG in particular, reported a solid gameplay improvement, and some players even said that the rollback test was the first time they were ever able to play RTS with a good experience.

There is still more work to be done though. Snowplay had a few de-syncs during the rollback test, and there were some small issues like stuck projectiles.

Interestingly, Frost Giant has been designing it’s rollback code as a standalone library that is agnostic to the game engine. While it’s not in the immediate plans, it’s entirely possible that we’ll see them licensing out their rollback implementation to other games.

Minimum Specs and Settings

When asked about what minimum PC specs the game is targeting, Sabri stressed that the game is still developing, and there is still optimization to be done. But they do have a rough target for players to start thinking about: When asked about what minimum PC specs the game is targeting, Sabri stressed that the game is still developing, and there is still optimization to be done. They do, however, have a rough target for players to start thinking about:

• CPU speed of 2.3ghz
• Windows 10 or later
• 6 CPU cores
• A GTX 1060 (or something in that performance neighborhood)
• 16GB RAM (Unreal is quite memory hungry)

CPU speed is particularly important for rollback, as it determines how many frames can be re-simulated.

On the graphics setting front, the game is mostly limited to broad categories (low, medium, high, ultra, etc.), but individual settings should be broken out over time. DLSS has been implemented (NVIDIA’s frame interpolator and upscaler), and we may see others (like AMD’s FSR) in the future.

How to Get Involved

As always, if you want to engage with the Frost Giant developers and get information from them as they post it, you should sign up for their newsletter, head on over to /r/Stormgate on reddit, and sign up for the beta and wishlist the game on steam!