像所有 Microsoft XNA 项目一样，Game1 类派生自 Microsoft.Xna.Framework.Game 类，该类提供 XNA 游戏的基本图形设备初始化、游戏逻辑和呈现代码。 Game1 类相当简单，这是因为大多数工作已在 GamePiece 和 GamePieceCollection 类中完成。
该类的私有成员包括用于保存游戏块的 GamePieceCollection 对象、GraphicsDeviceManager 对象，以及用于呈现游戏块的 SpriteBatch 对象。
#region PrivateMembers
// Number of game pieces.
private const int GamePieceCount = 6;
// The collection of game pieces.
private GamePieceCollection faces;
// Graphics device manager.
private GraphicsDeviceManager graphics;
// The sprite batch used for rendering game pieces.
private SpriteBatch spriteBatch;
#endregion
在游戏初始化期间，对这些对象实例化。
#region ConstructorInitialize
public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
// This is the default but assigning here explicitly
// to show that resizing is not supported. The view port
// boundaries used to bounce a game piece would not be
// updated if the window was resized.
Window.AllowUserResizing = false;
}
/// <summary>
/// Allows the game to perform any initialization it needs to before starting to run.
/// </summary>
protected override void Initialize()
{
IsMouseVisible = true;
faces = new GamePieceCollection();
// base.Initialize calls the LoadContent method.
base.Initialize();
}
#endregion
当调用 LoadContent 方法时，会创建游戏块，并将其分配给 GamePieceCollection 对象。 有两种类型的游戏块。 游戏块的缩放比例稍微进行更改，以便有一些小游戏块和大游戏块。
#region LoadContent
/// <summary>
/// LoadContent will be called once per game. Load all content here.
/// </summary>
protected override void LoadContent()
{
spriteBatch = new SpriteBatch(GraphicsDevice);
string filename = System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName;
string path = System.IO.Path.GetDirectoryName(filename) + @"\Content";
// Scale pieces from 100% to 160%
float scale = 1.0f;
float scaleFactor = 0.60f / ((GamePieceCount/2)-1);
for (int k = 0; k < GamePieceCount / 2; k++)
{
GamePiece face1 = new GamePiece(spriteBatch, path + @"\Face1.png");
GamePiece face2 = new GamePiece(spriteBatch, path + @"\Face2.png");
face1.Scale = face2.Scale = scale;
face1.PieceColor = Color.Green;
face2.PieceColor = Color.LightSalmon;
faces.Add(face1);
faces.Add(face2);
scale += scaleFactor;
}
}
#endregion
当游戏运行时，XNA Framework 重复调用 Update 方法。 Update 方法对游戏块集合调用 ProcessInertia 和 UpdateFromMouse 方法。 创建 GamePieceCollection 类中对这些方法进行了介绍。
#region UpdateGame
/// <summary>
/// Allows the game to run logic such as updating the world,
/// checking for collisions, gathering input, and playing audio.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Update(GameTime gameTime)
{
faces.ProcessInertia();
faces.UpdateFromMouse();
base.Update(gameTime);
}
#endregion
当游戏运行时，XNA Framework 还重复调用 Draw 方法。 Draw 方法通过调用 GamePieceCollection 对象的 Draw 方法，执行游戏块的呈现。 创建 GamePieceCollection 类中对这一方法进行了说明。
#region DrawGame
/// <summary>
/// This is called when the game should draw itself.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Draw(GameTime gameTime)
{
GraphicsDevice.Clear(Color.CornflowerBlue);
spriteBatch.Begin();
faces.Draw();
spriteBatch.End();
base.Draw(gameTime);
}
#endregion