is there a reference, tutorial or examples for using YUV** natively with openGLES,
describing what is possible, what is not....
**as output by many cameras, aka YUV420, YUV422....

Displays may rely on RGB, but 'graphics processing' itself does not,
camera encoding devices may expect YUV format, and
apparent result seems to be that it is necessary to transform data twice.

can anyone point me to a reference explaining why RGBA is the de facto standard used?

apologies for this rather open-ended query, as I have little experience as yet with openGLES 2.0