Windows® Phone 8 Unleashed

Harnessing the XNA Game Loop Via the GameTimer Class

In XNA, responding to user input, updating your app’s state, and drawing content all happen periodically within the game loop. The game loop is the heart of every XNA game, and understanding it is fundamental to XNA development.

Unlike pure XNA games, which use the Game class for the game loop, hybrid apps rely on the Microsoft.Xna.Framework.GameTimer, which is unique to the phone.

In a pure XNA game, a Game class is used instead of an Application class. XNA games rely on overloading Game class methods that are specific to the game loop, such as Update and Draw, whereas hybrid apps (Windows Phone 7.1 apps that combine XNA and Silverlight) and apps that rely on XNA APIs, such as the sound effect ...