"It just makes so much sense for a developer who wants to supply, maybe not time-critical information, like 'that enemy is getting ready to shoot you,' but information that augments what's happening on screen," Spencer says. He used last year's Halo Waypoint Atlas app, which offered multiplayer GPS tracking, as an example of how SmartGlass features could share additional game information without hampering the moment-to-moment gameplay. "And then you're even going to see situations like with Ascend, where there's actually gameplay that happens on the phone, even when you're away from your television and that interacts back with the online game that's happening. So I think you'll see information sharing, context sharing while you're in the room, with video and with games, as well as gameplay happening in more distributed environments."
SmartGlass will be encapsulated in a single app that syncs with your Gamertag and enables features based on what you're playing or watching (provided they support SmartGlass). "You don't have to log in and out of each app – you know, 'I'm gonna start the Mass Effect app, and now I'm gonna start the Game of Thrones app.' So you have this surface, this smart surface," Spencer says, "that sits on any device that you already own that's always in sync with what's happening on the television, and it knows where to go and grab the right content to display at the right time, to make sure that if you're playing Halo, then the Halo surface is available on SmartGlass."
During its E3 2012 press conference, Microsoft showed a concept of what might become Halo 4's SmartGlass functionality. The app, as shown, allows players to track stats and send game invites via tablet or smartphone. Microsoft has said that it supports the "device you already own," but hasn't directly addressed SmartGlass variations between iOS, Android and Windows 8.