@SIsilicon28 I'm not looking for using MSAA, I'm looking for using FXAA. Both are different anti aliasing, and reason I'm looking for FXAA because Godot 2.1 was supported, and FXAA is the cheapest way of implementing AA in the game. Generally MSAA has better quality, but it's takes lots of performance cost.
I'm not meaning not gonna use MSAA, I just want to give the option to user can select AA option. If he has good device, he could possibly run with MSAA 8/16 samples + FXAA, otherwise turn off MSAA and FXAA or maybe turn off everything.
And yep, I already checked that link before. Unfortunately, that implemenation doesn't support GLES 3.0, that only works with GLES2.
So here's I found:
https://gist.github.com/cart/7d2da58eb28c75c0952787f29f3e562f
Above link is for GLES 3 and it worked with my project which using GLES 3.