Re: Device Orientation: alternate representations and handling screen orientation changes

That's excellent Rich!

roBman


On 29/03/14 5:02 AM, Rich Tibbett wrote:
> I published an article a couple of days ago covering advanced
> manipulation of deviceorientation data and thought it may be of
> general interest to this group:
>
> 'Practical application and usage of the W3C Device Orientation API':
> http://dev.opera.com/articles/view/w3c-device-orientation-usage/
>
> The article above covers three main points:
>
> - Euler angles are good for _describing_ orientations in Euclidean
> space but are actually poor for practical usage since they suffer from
> gimbal lock at their poles and are hard to 'remap' as screen
> orientation changes since they don't share the same ranges.
> - Web developers can convert Tait-Bryan angles provided from
> deviceorientation events in to more practical device orientation
> representations such as Rotation Matrices and/or Quaternions and we
> describe how that can be done.
> - We need to account for screen orientation changes in any device
> orientation representation we care to use to ensure our coordinate
> frame always reflects the way a user is currently holding their
> device.
> - We can orient matrices and quaternions we've calculated herein to
> match any required 'world' coordinate frame (e.g. how to make a
> heads-up display for virtual reality and/or augmented reality use
> cases) which is difficult to do with Tait-Bryan angles (because the
> ranges don't re-wire themselves easily).
>
> A virtual reality viewer demo based on the information provided in the
> article is available @
> http://people.opera.com/richt/release/demos/orientation/virtualreality/.
>
> We are working to bring some of these concepts and examples to the W3C
> Device Orientation Events API spec by adding additional worked
> examples concerning the topics discussed in this article (and
> summarised above). That work is currently happening over on the W3C
> DeviceOrientation Github repo @
> https://github.com/w3c/deviceorientation and additional participation
> and feedback there would be welcome.
>
> In this group it would be good to discuss whether UA implementations
> could start handling screen orientation changes implicitly, how we may
> be able to do that without breaking backward compatibility and whether
> we want to consider inherently providing other alternate device
> orientation representations such as Quaternions which may be better
> suited to 3D web use cases.
>
> Looking forward to hearing how others want to see this spec and API
> evolve. We will have more spec changes to discuss soon based on work
> happening @ https://github.com/w3c/deviceorientation.
>
> - Rich
>
>

Received on Saturday, 29 March 2014 01:44:51 UTC