Going from supporting OpenGL ES to OpenGL while using EGL rather than GLX is quite easy, as shown by recent work on the open-source Doom 3 code-base.
With
Oliver McFadden's Dante project, which has
OpenGL ES 2.0 support,
EGL support,
a new GLSL back-end, and can
now run Doom 3 on Android, there is now OpenGL desktop with EGL support.
In
a recent pull there was work on "[Implementing] OpenGL over EGL api. The changes are minor and shows how clean the switch from OpenGL ES to OpenGL can be."
The
code diff shows how easy it can be switching from OpenGL ES to OpenGL while sticking with EGL windowing system API.
While it's easy on the application/game side, there's still EGL/OpenGL bugs within Mesa to be ironed out -- i.e.
this new bug for exposing OpenGL extensions rather than OpenGL ES extensions when using EGL.