Moving an existing game into virtual reality is a tough challenge. There are a lot of challenges involved and not every game can make the switch successfully. Radiant Crusade is an example of a game that underwent a significant transformation to turn it into a VR game. Eric Provencher from Radiance Games shared their experience.

Radiant Crusade screen capture and a photo of their team

A look at Radiant Crusade in action and their team!

Radiant Crusade itself was (and still is) a wave defence-style game that had pre-existing game mechanics and features all based around a desktop playing environment. It has a pretty neat concept for a game:

“Radiant Crusade is cockpit-based wave defense game with an RPG-like skill-tree, set in an ocean of darkness, where the player is actually the antagonist, helping the tower consume the world’s light.” — Eric Provencher

Often, games that get ported into VR aren’t thought through very much. They take a first person shooter, for example, and switch the camera out to be a VR one. Change the guns to aim with VR controllers and you’re done… Relatively at least. Those aren’t the best VR games out there, there is a lot more to it than that and Eric and his team worked to do something that was quite well thought out. Their challenge was that the game wasn’t a typical first person shooter… it used a third person camera like so:

A screenshot from the original game pre-VR

Radiant Crusade’s original game

Eric explains,

“As our initial prototype was built with a third person camera in mind, we brainstormed a few ways to make the game play nicely in VR, and settled on a first person perspective, which required rethinking a lot of our mechanics. For starters, the original version, as you can see in the video below, featured a jump mechanic, which as it turns out, served no purpose in the gameplay, but was a lot fun to mess around with. Unfortunately, that mechanic was an enormous source of nausea, so it just made sense to strip it out.”

“We spent a lot of time prototyping interaction systems for the game, and ultimately settled on a gaze-based targeting system, which felt the most natural given the headtracking HMDs provide, along with the fast paced nature of a driving experience.” — Eric Provencher

Porting things across

The existing camera wasn’t the only thing that needed adjusting, the whole way the game displayed its interface for the player wasn’t appropriate in virtual reality. There are a whole lot of interface design considerations which a lot of developers don’t anticipate going into it:

“I think the most unexpected thing in bringing the game into VR, was designing an interface that was both readable to the player, while being thematically sound in the context of the world we were creating.” — Eric Provencher

“The original game, as you can see from the video above, didn’t go out of its way to design an interface that was any more than functional, and we wanted to push this front forward with a sort of futuristic interface that was a part the car the player was driving.”

They also found it required a bit more work and reverse engineering to get a VR game running in Unity:

“I was surprised to find out how little Unity did to help get VR interfaces working. While traditional games have a full input management system to work from, building our gaze-based interaction systems involved reverse-engineering the VR samples Unity ships with, and fixing bugs they came with, while adding functionality specific to our title.”

Get your VR project in front of new people as early as you can!

It is something we’ve heard time and time again from VR developers — it’s crucial to get your VR projects out there and try them out on people who’ve never tried them before. The results almost always will surprise you and you’ll be glad you did. Doug North Cook from Decoder VR wished they’d gotten more hardcore VR gamers to test their game prior to launch, VirZoom changed the design of their VR exercise bike after user tests and Katie Goode from Triangular Pixels highly recommended you find playtesters and “look for their reactions, not just what they say“. Eric had a very similar lesson to share as their most important thing:

“In terms of VR oriented learning, I think the most important thing the team learned was the importance of getting the game into the hands of people who’d never played it. For the first few months, it was just me and a few of the team members that had played it, and then at one point I brought it to be played by people who didn’t know anything about it, and they just tore it to shreds, which was amazing.” (PatCat: emphasis my own here!)

“We thought we were just about ready to ship, but realized the bulk of the work was ahead, as we had to redesign some core mechanics, while improving things as subtle as color contrast to improve the game’s readability. Seriously, getting a fresh perspective is SO important.” — Eric Provencher on getting your VR game into the hands of new people to test

Optimise, optimise, optimise

One huge component of creating a VR application is optimisation. This is a hugely common issue for developers and often takes a lot more time and effort than they expect. Eric points out that “the worst part of making this game was the optimization I had to do right before shipping it”. It’s important to note, they hadn’t put off optimisation or forgotten it — there was just even more optimisation than they’d expected to get the game to where it needed to be:

“We had done a whole lot to profile and optimize every little part of the experience, and thought we were in the green to hit the 90fps target, but then when we had sent to Oculus for review, we got 2 rejections before I realized just how much I’d have to do to make the game run well on the minimum spec.”

“I had to redesign the lighting system, strip out image effects, and put nearly every piece of eye candy behind the high-preset in the settings, all while trying to preserve the game’s visual style and crazy particle effects. Do not underestimate the pains of optimization!” — Eric Provencher

Got a game you want to port over? Strip it down to its essence

Sketches and 3D models of the characters

Some pretty neat looking designs of their character models!

Eric’s words of advice for developers looking to bring their games into VR? He says “you should strip down the game to its essence to find out what’s absolutely necessary to make the game work without compromising what it’s about”. Eric says that doing so is important and will help you see “what VR can bring to the experience, rather than focusing on how the experience can work in VR”. Just porting a game across usually isn’t going to make it truly good or engaging for the player. Stripping it down, as Eric suggests, is a good starting point to really see how you can reshape it while keeping the essence of the game. Eric says, “It’s often not that interesting to simply port a game into VR, as the movement mechanics will likely cause nausea, while not leveraging all the interaction tools VR brings.”

There is a lot involved in changing up how you display information for the player in VR, compared to other game formats. Eric outlines how they had to adjust the way they delivered information to the player,

“In terms of technical aspects, flatgames rely a lot on something called screenspace, which sits on top of the game world, and is usually used to render a HUD. This is completely unavailable in VR, and everything needs to be in world space, as a part of the game world. This brings legibility issues with text aliasing as you have less pixels available to render the same thing, along with interaction issues because you need to find creative ways of putting information in front the player, with no guarantees they’ll actually see it, given that players can look wherever they want.”

Why not feed it back into your original game?

The absolute coolest thing from this interview was when I discovered they were actually taking their lessons from the VR port of the game and bringing those into the original game as an update! How fantastic is that? The whole process of bringing it to VR ultimately will result in even the original game improving! I love that. He points out,

“Given that we have a core experience that originally worked without VR, we’re actually making an update to the game that will bring it back into the realm of the flatgame!” The update will have the game “running in third person, with all the cool new UI elements and game mechanics we built for the VR version. It’s still a work in progress, but I’d say it’s actually easier to go back to the flat world from VR than the other way around. This update should be out some time in early June.”

We’ve got a screenshot of that new interface for the original game below!

Their VR-inspired update

A fancy new VR-inspired design

Thanks to Eric for taking the time to delve into his experiences with porting Radiant Crusade into VR! There were some gems of insight in there which I’m so glad he shared! If you want to check out their work and have a play of Radiant Crusade, head to the Radiant Crusade website for all the links you’ll need!

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