On Tuesday, the U.S. Patent and Trademark Office granted Apple's patent for a snap-on iPhone game controller that extends in-game controls onto joysticks or D-pads, saving screen space in the process.

According to Apple Insider, this is not the first handset game controller patent Apple has filed. The company's "Accessory for playing games with a portable electronic device" U.S. Patent No. 8,939,838 was filed in 2008 following the iPhone 3G announcement and describes gaming hardware designed exclusively for use with a portable media player or handset, like the iPod and iPhone. An external thumb keyboard device is also mentioned among the invention's numerous hardware variations.

It is clear by the patent document Apple recognized the iPhone's gaming potential. The patent was filed with the inception of the App Store and third-party game titles such as "FieldRunners" and "GTS World Racing." Most first- and second-generation games integrated well with the iPhone's multitouch screen, but Apple realized onscreen control methods can interfere with a player's view.

To solve the onscreen controls issue, Apple's new patent details an add-on device, or gaming pad, with joysticks, action buttons, directional pads and more. The important controls are situated around a central recess that serves as a user's iPhone dock -- it can be positioned in either portrait or landscape orientation -- which snaps or locks in place. Extras like cameras, speakers and microphones are possible as well.

The iPhone, once inserted into the gaming pad, would become part of a large portable system with multiple joysticks or D-pads, action buttons and other extras. Apple describes in the patent the controller can use either a hardwired connection or communicate with an iPhone wirelessly.

The patent also mentions wireless multiplayer gaming with additional players using the same accessory hardware. Like a typical portable gaming consoles, Apple's system would include ad-hoc connectivity by using Bluetooth or WiFi, plus gaming online.

Since Apple applied for the gaming accessory patent over six years ago, several manufacturers have created similar designs, including the $100 Moga Ace Power gaming controller.