“I briefly considered making an actual presentation for this, but I figured I’ve made it this far without ever using a PowerPoint, so I’m just going to wing it again.”

Oculus CTO John Carmack opened his mobile VR lecture today with a joke about his legacy of performing off-the-cuff presentations during his time at id Software. But while Carmack made his name in PC game development, his GDC 2015 presentation was aimed squarely at getting game developers to appreciate mobile.

“The first thing I get asked a lot is…why mobile VR at all?” said Carmack. “Why aren’t I working on PC, with all the latest and greatest stuff? Why am I spending almost all of my time working almost exclusively on this?”

The answer, it seems, is the appeal of potentially reaching anyone with a smartphone. Carmack says PC game design is still Oculus’ core focus, but he hopes to go beyond that.

“I honestly do see a world with a billion people using virtual reality headsets,” said Carmack. “We have a billion smartphones, we’re heading towards a billion tablets…it’s amazing to think we’re addressing a sizable portion of the world’s population.”

For developers, the question is when that market will become viable — as it stands, Oculus’ mobile VR marketplace doesn’t support payments, so you basically have to release your Gear VR games for free. Today, Carmack told his audience of developers that this support is “coming soon,” but encourage everyone to make mobile VR games now to capitalize on an expected influx of VR users. 

“People may come to VR for different things, but they’ll find games there as the platform evolves,” said Carmack. Because of that, “I do believe VR is worth you spending time and resources to make games for.”

On the state of the mobile VR market

The veteran programmer’s interest in mobile VR development started when Samsung and Oculus first began collaborating on what would become the Gear VR. 

“I looked at the software and said ‘okay, this is not very good, but I can do something with this,’” said Carmack. “That literally was the thing that made me come on full-time at Oculus: this opportunity to make mobile VR happen.”

Carmack says he spent his first six months at Oculus pretty much just writing mobile VR software; in fact, he shared some of the lessons learned about mobile VR development in an interview with Gamasutra last year, alongside some complaints about the challenges of working with Android.

But now the Gear VR Innovator Edition is out in stores, and while Carmack spoke ruefully about Samsung’s decision to sell it as an “Innovator Edition” instead of labeling it a developer kit (“Because Samsung doesn’t do ‘developer kits’”) he pitched it to developers as a boon for expanding the VR user base.

“Cell phone stores are full of lots of boring stuff,” said Carmack, so having the Gear VR out on store shelves alongside racks of nondescript smartphones should help developers by drumming up a lot of consumer interest in mobile VR experiences — and games. 

But Carmack also cautioned developers to be careful when releasing VR games, as Oculus is afraid that a few bad experiences might yet undermine the entire platform.

“At Oculus there’s a lot of concern about ‘poisoning the well.’” said Carmack, with a rueful smile. “There’s this fear that if a really bad VR product goes out, it could set the industry back to the ‘90s.” 

But for now, it continues moving forward. Just this week, Samsung announced the Galaxy S6 and an updated version of the Gear VR for it. Carmack says this “Gear VR 2” isn’t “significantly different” from the Gear VR Innovator Edition, but there are a few changes developers should appreciate, including a notifications system that plays nicer with the phone when it’s in VR mode.

“I expect Google will pick up some of the things we’ve done with Gear VR and make it Android standard,” said Carmack.

However, with the impending rollout of a new Gear VR headset, new mobile hardware and some time to go before it becomes possible for mobile VR game makers to start charging for their work, it seems likely that early Gear VR dev adopters will be waiting some time to see significant returns. 

“I want to personally apologize to some developers, some early NDA developers, that I may have enthused about all of this to,” said Carmack. “The early developers that went and built products…there’s just not going to be that much opportunity to move a whole lot of units.”

Carmack says it wasn’t what he expected to happen, but that’s how it went — Samsung wanted to launch Gear VR last year and Oculus wasn’t comfortable bringing its mobile VR marketplace fully online. Instead, they launched the limited no-payment version and are “scrambling” to build it out.

“We needed more time, but we’ve got a plan now,” said Carmack. “We’ve got a date: Oculus is going for it as hard as we can, broad consumer to try and sell as many units as possible, with the next Gear VR.”

He suggested that when Oculus decides it’s ready it will retroactively unlock the ability to sell and promote VR products on its platforms, and Oculus has a vested interest in seeing VR developers do well. 

“I’m braced for a year of crunch on this,” said Carmack.  “We are going to hang ourselves out there to be judged, and I’m going to do my damnedest to make sure we’re judged well.” Come from Soccer 13 pools and matches

How Facebook is helping out

Part of that crunch involves making the platform ready to support over a billion users internationally, and it’s there that Carmack says the Facebook money and expertise comes in handy.

“Being acquired by Facebook is going to turn out to be a really, really good thing for Oculus from a platform standpoint,” said Carmack. “I was one of the really big boosters of the acquisition from the beginning,” because he believes Facebook knows “infrastructure stuff” better than anyone else in the world.

“We are aiming for extremely broad usage,” said Carmack. “I want to see a billion people in VR. Zuck wants to see a billion people in VR.”

In terms of making Gear VR games, Carmack encourages developers to “plan on shipping on PC as well.” He claims that if you’re working on a Gear VR project, ti’s worth your time to anticipate what it might look like if you could bring it to the PC at some point — and don’t worry too much about having to change your game to accommodate the new Gear VR hardware. 

“For the next Gear VR, don’t expect anything radically different,” said Carmack. “What we are working on is better optics, and better ergonomics,” as well as a minor performance boost, but it will otherwise be “essentially the same thing.”

So if you already have a Gear VR, it’s still a reasonable target platform to make games for.

Tips on making a better mobile VR game

As far as practical VR game design advice goes, Carmack recommends developers consider tweaking an established type of game with a new VR-friendly camera system. “I tell people that fundamentally, Wolfenstein and Doom — the first first-person shooters — were just Gauntlet changed into a different perspective.”

The veteran developer suggests it may be a good idea to avoid the temptation of building fully-navigable 3D worlds in your early VR games, because the risk of discomfitting new players is still so high. Carmack says he's excited to see game makers explore experiences with "limited, tuned navigation capabilities"

“There is a lot that can be done with the design aesthetic of earlier 3D games,” said Carmack. “I tell people, just because everyone needs a number, to try to stay at 50,000 polygons drawn in a scene.” However, that’s just a safe baseline — experienced graphics programmers can reasonably expect to successfully push the limits of the hardware.

“If you’re kind of an old-school graphics programmer, you can make [console-like experiences] run on Gear VR,” said Oculus. But many contemporary VR developers aren’t hardcore graphics programmers; they’re developers who are more comfortable working in toolsets like Unity. Carmack says Oculus recognizes this fact, and is developing its technology accordingly.

And getting console-quality games running on Gear VR may not be the best way to make an attractive VR game.

“Fancy shaders and specular bump mapping…it’s probably not a good idea,” said Carmack. “Staying out of the things that alias. Think GameCube — don’t do super high-density, and for god’s sake mipmap all of your textures.” Otherwise, you’ll tank both your game’s visuals and its performance on the Gear VR.

“One of the things I notice most is terrible aliasing,” said Carmack. Especially in UI elements, which makes everything really hard to read. “I see a lot of room for improvement there.”

Narrow tunnels are also not a good idea, says Carmack, "because you get a lot of parallax problems" and some players can feel claustrophobic. And while it’s a very good idea to make sure your VR game can maintain 60 frames per second, it you should be okay if it drops occasionally because the headset can make that less nausea-inducing with rendering techniques like asynchronous time warp.

It's worth noting that if you want to make uncomfortable experiences — like, say, a fast-moving first-person shooter — Oculus will accept them into its marketplace, but it will label them accordingly so “people don’t stumble into the worst-case experiences.”

But if you want to make a game for people with “cast-iron stomachs”, you should still be able to distribute it on Oculus’ storefront — and it's in Oculus' best interest to woo developers to its platform.

“I want to convince everyone here that this is a legitimate opportunity,” said Carmack. “There will be customers there who will be evaluating your work…I can sincerely say I think this is an important opportunity for people to make a mark, a mark you can’t necessarily make in saturated places elsewhere.”