Been researching this for many months now on and off. I finally came up with an elegant solution I think.
It will allow stand alone Unity games to launch a Facebook or Google auth popup browser window and once the login is successful the game will then receive the access token a few seconds later. It will feel identical to mobile and web authentication methods, except the process is a bit different. Will be using the OAuth 2.0.
Would anyone make use of this if I was to post it up on the asset store?
This should be useful for games on Steam, Mac App store and Google Chrome App Store. As well as just regular stand alone.
Ill post a demo when I get it fully working.
Here are the demo's:
Screen Shots of the demo process: