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Wednesday, February 26, 2014

Valve VR. I want to believe.

Premise: Spoiler alert, I guess. Albeit it might not matter, it's worth noting that if you're going to experience either Valve's or Rift's Crystal Cove demo anytime soon (GDC perhaps) you could want to consider approaching it without any preconceived notion that this or other articles might give. Also, lengthy as usual.

Introduction
Valve fanboy, I am not. In fact I might say I still hold a grudge against it, I want Valve to make games, not stickers to slap on PCs in a marketing stunt with the hope of moving some units of a platform in general decline. I understand that Steam makes money, but on a personal level I can't really care...

So this morning, after waking up way too early for my habits I arrive at Valve's building I can't help muttering "so cheap" as I look for the street number and make sure that I'm in the right place. Of course it's silly of me as money is not the reason why they didn't bother to put a logo on the facade nor the name on the directory, but anyhow I digress... The "I" in the titular "I want to believe" here refers not to my faith, but to how my brain reacted to the system.

Now, it's hard to put in words an experience, especially something novel as this is, as there aren't easy analogies to make and frames of reference in most people's experiences to anchor to. I'll try my best to explain how it works, or how I think it works.

Visuals are a tricky beast. Rendering engineers are often deeply embedded in very technical concerns, but at the end of the day, what really matters is psychology. What happens, when stars align and things go right (because, mind you, we're really far from making this a science and the little science there is most of the times is still very far from mingling with entertainment) is that we create a visual experience that somehow tickles the right neurons in our brain to "evoke" a given atmosphere, sensations, feelings that we learned in real life and are "replayed" by these stimuli. 
Mostly for me that happened with environments, I guess because we're really discriminating when it comes to characters: Call of Duty, Red Dead Redemption, Kentucky Route Zero are all great examples.

When we try to achieve this via photorealism we hope that by simulating what's perceptually important, what we can notice in a scene, the light, the materials, the shapes and so on, we reach a point where our brain accepts the image we generated as a reproduction of reality, like a photo. And we hope that our artists can use this tool that gets us close to reality to more easily be able to fool our brains into producing emotions, because we're nearer to the paths that normally fire when we experience things in the real world.

Inside Virtual Reality
A good VR experience completely sidesteps all this, Abrash says it right, when things align in VR you get presence and it's an infinitely more powerful tool. Presence is the sensation that you are there; That virtual wall is at ten meters from you. And it is really unquestionable. Realism doesn't matter anymore.
The VR prototype suffered from all kinds of defects: it's clearly "low resolution", a lot of demos didn't have lighting, most did do only lightmaps or diffuse, not specular, most had no textures, I could see banding and even some aliasing, I could spot errors in the lightmaps, even quite clearly the ghosts from the OLEDs and so on and on. A nightmare for a rendering engineer, on a 2d screen you would have said the worst visuals ever.
Yet you were fooled into thinking you were there, not through realism but through the immersion that is possible with the low-latency, full head tracking (rotation AND position) stereo sauce Valve has implemented. I suspect there are a million things to get just right, we discussed how OLEDs provided enough dynamic range that you didn't question the scene much for example and they have a catalog of things that are crucial and things you can ignore.

The most succinct way to describe this is that in all medias before this, at best you had the impression of looking at a greatly detailed, technologically advanced reproduction of reality (think of the best immersive stereo projection movie you've ever seen for example). Here even when you're looking at really basic renderings you think you are in some sort of weird, wrong alternate world, similar if you wish to certain installations, rooms that play with light and shapes to create some very unusual experiences.

The demo environments Valve created (or actually I should say, I witnessed) were quite tame. Clearly they didn't want to push it to avoid certain people reacting negatively to the experience. Most of the time the scene was static, not in the sense of devoid of animation but as in a fixed room you could move in but that wasn't moving relative to you. Things never got scary and I didn't interact in any way with the simulation (even if I, in numerous times, instinctively went reaching with my hands to objects and avoided objects getting to near me), yet there were some intense moments.

I guess a few people now described a scene where you're in the simplest room possible, no shading, no lighting, yet you start on a small ledge and you can't avoid feeling vertigo and have to actively force yourself to step into the "void". You know it's not real, at an intellectual level. You have all the possible visual hints saying it's not real, yet your brain tells you otherwise.
Another, switching for the first time to a scene with some animated robots, at the moment of the switch I had a second of high alertness, as your primitive brain steps in and rushes to prepare for a suspicious activity.
The weirdest sensation was at the end, flying (very slowly, as apparently motion creates quite easily discomfort) through CDAK. There the visuals were distorted enough (see the youtube video linked) that I didn't feel as much presence (so there are some extreme cases where visuals can break it), yet when some of the weird blue objects passed through me I had, again for a split second, a sensation that I could only later rationalize as reminiscent somehow of being in a sea, I guess because that's the only thing I have in my experience of going through something like that.

Practicalities
When does presence break? Visuals can be pushed quite far before they break presence. Mind you, rendering will be a huge issue there and good rendering I am sure does make a difference to remove the idea that you are immersed in something quite odd, but again it simple visuals don't break immersion. I would also have loved to see a scene with and without various rendering effects (visual hints) but alas, no such luck.
Even the low resolution and blur and ghosts are to me defects of my vision, like seeing through glasses or through a dirty motorbike helmet, not a problem of the "reality" of the scene. Impossible behaviours do. In one of the scenes for example there were some industrial machines at work behind a glass wall. Poking my head through the wall into the room breaks it. 
It's not like suddenly losing stereo, as in one of the cross-eyed stereograms where you focus on the page and lose the effect. The closest analogy I can think of is Indiana Jones' leap of faith, and you might have experienced something similar with some visual tricks in theme parks: you realize it's an illusion.

There are a myriad of ways of doing something that breaks the presence, many things that are totally acceptable on a normal display are intolerable in VR. You might know that you can't really use normal-maps or any other non-stereoscopic hints of detail for example, but you are also much more aware of errors in animation, physics, not to mention characters (which weren't demoed at all).
And it's good if the consequence of an error is only bringing back to the idea you're in a VR helmet, the bad cases are when certain hints are very strong, but certain others are completely wrong or missing, like falling without acceleration, wind and so on, as these can cause discomfort.

Conclusion
In conclusion, it was better than I expected, as I expected all the visual issues to have a bigger impact. I think it can be used to create incredible, amazing experiences, that will feel like nothing ever felt before. And it obviously has a lot of applications outside entertainment as well.
I think and hope all this research will also be useful for traditional image synthesis, as for the first time we really have to systematically study perception and how our brain works, and not just be lucky with it. Also certain technological advances, for example in low-latency rendering system, will directly apply to traditional games as well.

I also think that it will be still for a long while a very niche product, or if it will succeed it will be due to a killer app that doesn't look in any shape or form like a traditional game, as if for certain technological issues we can clearly see a roadmap (weight, tracking, resolution, lag and so on), for certain others we don't have any idea yet, mostly controls but also how to deal with all the situations where we our brain is accustomed to have more sensorial hints than just what the eyes tell.
Even tiny things, like just the fact that with position tracking we can compenetrate with everything is quite an issue to solve. Fast movement is hard as well, it exacerbates the technical issues (lag, refresh rates and so on) to a degree that even "cockpit" games are hard (not to mention the lack of acceleration), even worse if you have to move your body in any athletic way as it's easy to get the VR system out of the optimal alignment it needs for crisp vision.

I don't think games can be "ported", a FPS in VR will be much more of a gimmick than e.g. FPS with virtual joysticks on an iPhone. We will need radically new stuff, low movement (for now at least, later on maybe some cockpit games can work well enough for the masses), novel ways of interaction (gaze for example can work decently, wands do work great... kinect-like stuff is very laggy and thus limited to only gesture recognition, not direct manipulation right now), new experiences...

It will probably be for a few early adopters, but I'm quite persuaded to be among them, just to be able to create weird environments that feel real.

P.S. I saw the number "3" multiple times in Valve offices. You certainly know what that means...

Update: Sony's Morpheus prototype is worse than Oculus DK2 as far as I can tell, and Oculus DK2 is still quite a bit behind Valve's demoroom. It need much more resolution.

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