Android Extension Pack Being Prepped For Mesa
Mirkin sent out a new set of patches today for completing this work, which will be of particular importance to those using Mesa on mobile devices. The work doesn't go as far as turning on GL_ANDROID_extension_pack_es31a, as first the tessellation support needs to be turned on (patches pending) and enable the relevant parts of the code.
The current Mesa patches can be found here.
The Android Extension Pack brings features to OpenGL ES 3.1 like KHR_debug, EXT_tessellation_shader, EXT_copy_image, EXT_geometry_shader, EXT_texture_buffer, and several other beneficial extensions for today's games and demanding graphical applications. These extensions have basically been already supported by Mesa since they are pretty much all based on OpenGL 4.x desktop features, it's just a matter of exposing them in the manner for OpenGL ES plumbing.
The ANDROID_extension_pack_es31a extension simply indicates all of the mandated extensions are present. Google introduced the Android Extension Pack back in 2014 as features added on top of OpenGL ES 3.1. In 2015 then The Khronos Group released OpenGL ES 3.2 that bundled in the AEP extensions and other improvements.