Lead engineer Trevor Blom on how the studio brought the dead to virtual life in shooter Arizona Sunshine

Vertigo talks VR’s arcade heritage, reinventing the reload and not asking too much of players

Why bring a wave-based zombie arcade-shooter to VR? What about the genre of game made it a good fit for the medium?

When you pick up motion controllers you instantly get the feeling of an arcade. Our first test was to create a gun and see how that would work – some of the controllers even feel like an arcade gun. And shooting in VR is just a lot of fun.

Could you provide some insight into the overall creation process for Arizona Sunshine?

We created Arizona Sunshine in Unity.

Over time we have developed a modular system for VR and utilities to use between our three VR games. If we were to create a new VR game, we simply have to drag in the system and it is VR-enabled for all our supported devices. We have gone through dozens of iterations over the last year(s).

We have been developing since the early versions of the VR headsets, so everything has been changed multiple times. Now the VR systems are hitting their launch targets we are working with stable releases of the SDKs.

"When you pick up motion controllers you instantly get the feeling of an arcade."

Trevor Blom, Vertigo Games

Arizona Sunshine involves staying aware of the enemies around you at all times – meaning a look of listening and looking around. How did you design the visual and audio cues to keep the player informed of their surroundings?

3D audio already proves to be magical in VR. Even though we as humans aren’t able to pinpoint the audio source on degree accurately, it is still exact enough to at least point in the general direction of the source.

Luckily, we are working with zombies, so we can have them make random moans to let the player know where they are.

Also, we design the game in such a way that the player does not have to rotate around often, this also to avoid getting webbed in the headset cords.

We have been working with more advanced audio spatialisation techniques, however they proved to be a bit too computationally demanding in the early stages of development as we also have to hit 90fps. We will explore this more in the future.

With players looking around so quickly, did you ever have worries of inducing nausea? How did you avoid this in the final game?

It is necessary to run games on 90fps when we make the players look around quickly. The tension of the game makes the players look around very abruptly, but the updating of the headset can keep up with this framerate. If it drops below 90fps, however, you notice it instantly. Is it therefore one of our main requirements for new builds that the game is a stable 90 in every situation – preferably with some margin.

Arizona Sunshine is clearly inspired by classic arcade titles such as House of the Dead and Time Crisis. Did you look at the design of such games when developing Arizona Sunshine?

They are certainly inspirations of the design of Arizona. Their mechanics are easily translated to VR. However, they are also quite basic so that everyone can play it with a minimum amount of tutorials.

We design our demos to be easily playable by new players. But our full game will also provide a more in-depth experience.

Players can dual-wield two guns, which require increasing levels of accuracy to quickly take out enemies. From a technical perspective, how did you ensure aiming with the Vive motion controllers felt accurate and ‘fair’ for players?

Initially we did not provide any aim assistant – back then, aiming down the sights would make aiming work accurately, so we achieved a result which is close to real world physics.

However, this also meant some players couldn’t hit anything.

Therefore, we have decided to add a pointer in our demos to assist the aiming. We do not add any other artificial adjustments – the accuracy perceived is simply the accuracy of the VR system combined with our bullet physics. 

Arizona Sunshine utilises a unique reloading mechanic, requiring players to raise their guns to a moveable ammo belt on their chest. Why did you decide on this method of reloading in VR?

Initially, we were looking for a fully manual reloading mechanic, where the player had to eject the magazine from the gun manually, and then insert it manually as well.

We liked this motion, but it were a few too many interactions, so we decided to tone it down a bit while still maintaining that manual reloading feel.

The next step was to eject guns by a button press, and then have the gun reload when it collides with a magazine. These magazines would be placed around on the map, and could also be picked up by the players off-hand. We were happy with this mechanic and later expanded that to the ammo-belt in preparation for more advanced ammo management.

Over time there have been some iterations on the size of the interaction radii, and the cooldown on interactions, but not much else.

"Our main struggle with VR at the moment is to provide feedback to the player when he is interacting with the world, specifically feedback that we would like to solve with haptics."

Trevor Blom, Vertigo Games

Arizona Sunshine is available on both Oculus Rift and HTC Vive. What was it like developing for both platforms?

Luckily for us, there are a lot of similarities between the two platforms. They both provide the same input mechanism and the 360 tracking. We have been in contact with the development teams of both platforms for rapid feedback from both sides. We have the pleasure of discussing current and future hardware with them, and they also provide us valuable feedback on our new builds.

The one main difference is that the Vive development team has always been pushing room-scale with motion controllers as their initial launch product, while the Rift will ship with this later. 

What development challenges remain for VR? How can these be overcome?

This is a huge question; there are a lot of development challenges for VR. Not only on the hardware side, but also the software side.

We are still in the very early stages of modern VR and the coming years will deliver a lot more immersion.

Our main struggle at the moment is to provide feedback to the player when he is interacting with the world, specifically feedback that we would like to solve with haptics. For example, feedback on hits with melee weapons, blocking objects and getting hit by enemies. We are prototyping different ways of solving these, but they all don’t feel as natural as ranged weapons. 

Also, movement; there are three common ways among the current VR titles. The first one is the free movement – nausea… – the second one is no movement outside of the room’s scale and, thirdly, there is the teleportation way where you teleport to where you ‘shoot’.

What’s next for Vertigo Games and Arizona Sunshine?

At GDC we were demoing our first version of the multiplayer experience.

This is already a fun experience that we wanted to share, but we are working on a lot more features for this and other ideas that we would like to explore in the future.

Otherwise we are still fine-tuning our vertical slice and working on additional content based on these art, tech and design benchmarks.

This article is part of our month-long Virtual Reality Special.You can find more VR content here.

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