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Re: Media queries for stereoscopic 3D displays?

From: Douglas Crosher <dtc-style@scieneer.com>
Date: Thu, 06 Sep 2012 18:21:11 +1000
Message-ID: <50485CF7.5040501@scieneer.com>
To: David Singer <singer@apple.com>
CC: Joel Andrew Glovier <w3c@joelglovier.com>, Florian Rivoal <florian@rivoal.net>, www-style@w3.org
On 09/06/2012 09:26 AM, David Singer wrote:
> 
> On Sep 4, 2012, at 19:31 , Douglas Crosher <dtc-style@scieneer.com> wrote:
...
>> A proposal to add depth to styling would be ambitions but would seem the
>> most general solution and perhaps the best investment, and it would also
>> lead to the most consistent presentation.  Even on single view surfaces
>> the depth could be used to support automatic perspective, highlights,
>> shadows, focus, panning, and wiggle, cues.
>>
>> The question becomes how to allow the depth to be specified in CSS?
>>
>> Some options:
>> * Just the corners.
>> * Plus bump maps.
>> * Bezier or NURBS surfaces.
>> * A calculation.
>>
>> Some other issues to consider:
>> * Viewpoint
>> * Lighting
>> * Surface properties
> 
> Right.  some things need to be 'styled in depth' (notably captions and sub-titles) but this is complex and temporal.  The reason is two-fold -- you want the captions to be at the same apparent convergence as the main part of the scene, yet you don't want them 'punching holes' in things that appear to be closer.

Captions and sub-titles could be placed on a static frame outside the
image or video content and this could be done with a static depth in
webpage styling.

Placing captions within stereoscopic content does require some careful
artistic design, and this would seem to be outside the scope of page
styling and more appropriately integrated within the image or video content.

> Even if we were to style HTML in 3D, we'd need to look at this -- not only 3D transforms, but simple depth positioning, and so on.
>
> The simple way to do it is to either specify the depth and let the system work out the disparity (the left/right eye shift) or specify the disparity directly.  I suspect this will rapidly come into collision with the difficulties with physical measurements, as some of the calculations concern eye-eye distance and distance to the image plane (screen etc.), both of which are true physical questions, yet often unknown to CSS.

Specifying the depth and allowing the system to work out the disparity
would help ensure consistency of the 3D depth cues (disparity,
perspective, photometric, focus, shadow, fog, etc).  Thank you for the
feedback, this helps set a development path but there is a lot detail to
worked through.

This still leaves the issue of stereoscopic images and videos.  If media
queries are not used to select a source format that matches the target
technology then image and video elements need to be defined that can
transform the source format to a target format.  This may be outside the
scope of the www-style forum.

I'll try developing some JS using the canvas that can handle some image
format translations to explore the issues.

BTW there was a related discussion in the whatwg list, see:
http://lists.w3.org/Archives/Public/public-whatwg-archive/2010Apr/0295.html

Regards
Douglas
Received on Thursday, 6 September 2012 08:21:44 GMT

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