[filters] Shading language recommendation

The normative prose of section 38.2 'Recommended shading language' recommends 
GL SL ES [1]. Per RFC2119 this means implementers MUST support GL SL ES 
unless there exist 'valid reasons in particular circumstances' to ignore this 
recommendation. 

While Microsoft has no objection to defining how the feature works for UAs 
that choose GL SL ES as defined by Web GL 1.0, we object to its normative
recommendation. This was the reason for the note in the same section, note
which looks at best confusing if not contradictory given the normative 
recommendation that precedes it.

We would prefer to follow a pattern similar to the informative section 6.1 in 
Media Source Extension[2]: "This section defines segment formats for 
implementations that choose to support WebM". We think the ability to specify 
multiple shading languages is important, as broadly suggested by the current 
note. This allows sites to work with different user agents supporting different 
shading languages. For example, a future version of GL SL ES with fallback to 
the current version for user agents that don't yet support the new version.


[1] https://dvcs.w3.org/hg/FXTF/raw-file/tip/filters/index.html#recommendation
[2] http://dvcs.w3.org/hg/html-media/raw-file/tip/media-source/media-source.html

Received on Tuesday, 21 August 2012 16:53:35 UTC