Oculus Rift First Impressions and Official Linux Support

A couple of days ago, version 0.2.3 of the official SDK (requires login) for the crowdfunded Oculus Rift was released with Linux support, and I thought now would be a good time to put together a belated unboxing/first impressions video! Watch or read on for more textual thoughts with a lot less "umm".

To the computer device itself appears as a normal display, with one half of its 1280x800 display allocated to each eye, and a raw USB HID device, making it fairly straightforward to work with (compared to devices with multiple separate screens and interfaces obscured behind drivers).

The eyepiece lenses provide a "pincushioning" effect, increasing pixel density at the FOV centre at the expense of pixel density at the periphery. This is a pretty good move - we see a lot more detail at the centre of our vision, and this approach allows for increasing detail where it matters independently of increasing resolution. Because of this approach, each eye's output needs to have compensating distortion (which is why all those screenshots look like they're fish-eye views). This distortion is well documented and exists as a GLSL fragment shader for easy implementation.

Additional eyepieces of varying height provide flexibility for people with different eyesight/glasses. The depth of the device can also be adjusted to move the eyepieces closer (watch out - you can poke yourself in the eye with the lenses if you're not careful) or farther from your face.

The Rift's FOV is impressive compared to previous head mounted displays (HMDs) I've played around with, boasting > 90 degrees horizontally and > 110 diagonally. This brings more of the image into your peripheral vision, giving you a better sense of immersion and (obviously) letting you see and respond to more visual input at the edges of your vision.

Headtracking is snappy and responsive. The Rift has a combination of 3-axis gyros, accelerometers and magnetometers, though as I understand it, the magnetometers aren't currently being utilised in the Rift SDK (and may or may not be included in the consumer version of the Rift).

The vents around the top and bottom of the Rift let a surprising amount of light in, but it's not enough to cause glare on the lenses and after an hour or two of using it, it's not noticeable.

Another stand-out feature of the Rift is its weight - or lack thereof. It weighs a little under 400 grams, which allows it to rest comfortably on the face without feeling like it's trying to drag your nose and cheeks off, and longer usage won't result in significant neck strain compared to other HMDs I've played with. Not having to fight extra mass/inertia makes rapid head movements much more comfortable.


One thing the Rift is lacking is some nice way of quickly letting you see without having to take the device off and find somewhere to put it down. Some more bulky HMDs have the screens on a flip-up shield, which makes finding a mouse, reading a chat message or acknowledging somebody who's just walked into the room a lot less disruptive. Anybody with a cluttered desk is going to find this shortcoming of the Rift pretty awkward.

The 640x800 per eye screen resolution doesn't provide a lot of clarity for small, detailed objects, with "distant" items often blurring into less distinct blobs (when testing in TF2 on a Mac, I found it difficult to make out the team colours of people on the other side of 2Fort), and whilst it's not bad enough to prevent an enjoyable or interesting experience, it does highlight that modern, consumer grade HMDs are still finding their feet and exploring some of the innate and very specific hurdles associated with putting a picture so close to a person's face (if you're interested in reading up on the sorts of problems involved, Michael Abrash' Ramblings in Valve Time blog is a great place to start).

Of course, this industry-wide state also applies on a smaller scale directly to the Rift. The Oculus Rift dev kit isn't aimed at consumers. It's for developers to evaluate and use for testing implementations in their software so that when the consumer version of the Rift does arrive, developers will have had the opportunity to provide day zero support. Its features and capabilities aren't indicative of what the first consumer ready release versions of the Rift will have under the hood. As the Oculus team has been overcoming problems and making new discoveries, the expected specs of the final device have been fluctuating, but at the moment, we should expect that it will at least sport 1920x1080, and most likely bring some enhancements to head tracking accuracy and screen response times.


So far as APIs/libs go, there are a couple around.

The official SDK comes with a configuration script which installs libudev-dev, libext-dev, mesa-common-dev, freeglut3-dev and libxinerama-dev via apt-get (I already had all of the corresponding packages installed on my Fedora box, so I was able to skip that bit), and also adds a udev rule to give 0666 (read/write for everybody) permissions to the hidraw device that the headtracking output maps as (you can also just do this manually if you're excited about that).

In addition the SDK comes with the "Tuscany" C++ demo found on other platforms, in 32/64bit bins and source. I haven't yet had a thorough delve into the LibOVR source, but I'm assuming it's more or less the same as under Windows and Mac OS.

I haven't had a chance yet to ascertain whether Unity's Linux publishing options include Rift support, but I imagine if they don't, we'll see them soon enough.

Most of the community developed Linux friendly Rift libs are direct ports of the Oculus SDK (generally adopting its licencing as well), and I suspect that these will disappear now that the official SDK supports Linux. OpenHMD, however is a F/OSS (Boost licenced) API for interacting with immersive technologies like head mounted displays and headtracking devices. It currently only supports the Rift, but I suspect that'll grow over time and I imagine it's going to become the library of choice for F/OSS projects.

OpenHMD has already found some noteworthy implementations, with Rift support to Blender's built in game engine being worked on, and Thorworks announced full Windows, Mac and Linux Rift support for MassiveEngine at the end of last month.


Before wrapping up, it's probably also worth noting that I've had a few technical issues. The power adapter the Rift shipped with popped a cap a week or two after it arrived (the Oculus support team were helpful and organised a replacement to be shipped out), and I've started to notice some faint ghosting which looks/behaves similar to "burn-in" (see here for an extreme example - thankfully mine isn't that bad). I'm not that fazed by these problems, but they do highlight again that this is pre-release hardware.

All in all, my first impressions of the Rift are positive, though its impressiveness is really in the potential it represents for the consumer version. I'm working on a few bits and pieces at the moment, hopefully I'll have some exciting native Rift experiments to share soon. I can't wait to see what people in and out of the F/OSS community manage to do with the Rift and its successors! Article taken from GamingOnLinux.com.