Comment 0 for bug 1420581

[enhancement] Add support for full OpenGL compositing.

libmirserver/platform presently is only compiled to use the "ES" subset of OpenGL. This works for mobile devices and many desktop use cases but not all.

There are a few pending reasons to compile for full OpenGL on desktop (and/or switch at runtime!):

1. Qt only understands full OpenGL on desktop. Presently we use a hack that makes it call ES functions pretending to be full OpenGL, but this hack will fail when we support non-Mesa desktop drivers.

2. Proprietary desktop drivers sometimes don't support ES.

3. Proprietary desktop drivers often (last I checked) perform better with full OpenGL. Not sure why, probably just driver maturity.

4. There is evidence that possibly ES doesn't work on some older chipsets and regular OpenGL is required. Although that doesn't guarantee we have full shader support (currently a requirement of both Mir and Unity8).