XNA游戏开发之(五)——XNA实现组件复用

    在XNA游戏开发过程中，OPP思想尤为重要，它能实现组件的复用。将特定部分从程序主体中分离出来。

    游戏开发与普通应用程序开发不同，每个游戏对象在运行过程中都会被更新Update或重绘Draw。因此分离出的对象必须要有自己的初始化方法（Initialize），LoadContent，Update，Draw，UnLoadContent方法。

在定义新类的最好方法是继承GameComponent类。这样做的目的是可将一个或多个新类的实例添加到Components集合中。每次游戏主体类如图AlexGame的Update方法被调用后，GameComponent的Update方法也会自动被调用。

如果需要绘制其他某些东西，还可以将新类继承DrawableGameComponent类。该类包含Draw方法。同样的游戏主体的Draw方法被调用后新类的Draw也被调用。



士兵类


代码

1 using System;

2  using System.Collections.Generic;

3  using System.Linq;

4  using System.Text;

5  using Microsoft.Xna.Framework;

6  using Microsoft.Xna.Framework.Audio;

7 using Microsoft.Xna.Framework.Content;

8 using Microsoft.Xna.Framework.GamerServices;

9 using Microsoft.Xna.Framework.Graphics;

10 using Microsoft.Xna.Framework.Input;

11 using Microsoft.Xna.Framework.Media;

12 using Microsoft.Xna.Framework.Net;

13 using Microsoft.Xna.Framework.Storage;

14

15 namespace Alex

16 {

17 class Soldier:GameComponent

18 {

19 public Soldier(Game game):base(game)

20 {

21

22 }

23 public override void Initialize()

24 {

25 base.Initialize();

26 }

27 public override void Update(GameTime gameTime)

28 {

29 base.Update(gameTime);

30 }

31

32 }

33 }

34

英雄类


代码

1 using System;

2 using System.Collections.Generic;

3 using System.Linq;

4 using System.Text;

5 using Microsoft.Xna.Framework;

6 using Microsoft.Xna.Framework.Audio;

7 using Microsoft.Xna.Framework.Content;

8 using Microsoft.Xna.Framework.GamerServices;

9 using Microsoft.Xna.Framework.Graphics;

10 using Microsoft.Xna.Framework.Input;

11 using Microsoft.Xna.Framework.Media;

12 using Microsoft.Xna.Framework.Net;

13 using Microsoft.Xna.Framework.Storage;

14 namespace Alex

15 {

16 class Hero:GameComponent

17 {

18 public Hero(Game game):base(game)

19 {

20 }

21 public override void Initialize()

22 {

23

24 base.Initialize();

25 }

26 public override void Update(GameTime gameTime)

27 {

28 base.Update(gameTime);

29 }

30 }

31 }

游戏主体类


代码

1 using System;

2 using System.Collections.Generic;

3 using System.Linq;

4 using Microsoft.Xna.Framework;

5 using Microsoft.Xna.Framework.Audio;

6 using Microsoft.Xna.Framework.Content;

7 using Microsoft.Xna.Framework.GamerServices;

8 using Microsoft.Xna.Framework.Graphics;

9 using Microsoft.Xna.Framework.Input;

10 using Microsoft.Xna.Framework.Media;

11 using Microsoft.Xna.Framework.Net;

12 using Microsoft.Xna.Framework.Storage;

13

14 namespace Alex

15 {

16 ///

17 /// This is the main type for your game

18 ///

19 public class AlexGame : Microsoft.Xna.Framework.Game

20 {

21 GraphicsDeviceManager graphics;

22 SpriteBatch spriteBatch;

23

24 public AlexGame()

25 {

26 graphics = new GraphicsDeviceManager(this);

27 Content.RootDirectory = "Content";

28 //游戏类初始化阶段将新类添加到组件中

29 this.Components.Add(new Hero(this));

30 this.Components.Add(new Soldier(this));

31 }

32

33 ///

34 /// Allows the game to perform any initialization it needs to before starting to run.

35 /// This is where it can query for any required services and load any non-graphic

36 /// related content. Calling base.Initialize will enumerate through any components

37 /// and initialize them as well.

38 ///

39 protected override void Initialize()

40 {

41 // TODO: Add your initialization logic here

42 this.TargetElapsedTime = TimeSpan.FromSeconds(1.0f / 1000.0f);

43 base.Initialize();

44 }

45

46 ///

47 /// LoadContent will be called once per game and is the place to load

48 /// all of your content.

49 ///

50 protected override void LoadContent()

51 {

52 // Create a new SpriteBatch, which can be used to draw textures.

53 spriteBatch = new SpriteBatch(GraphicsDevice);

54

55 // TODO: use this.Content to load your game content here

56 }

57

58 ///

59 /// UnloadContent will be called once per game and is the place to unload

60 /// all content.

61 ///

62 protected override void UnloadContent()

63 {

64 // TODO: Unload any non ContentManager content here

65 }

66

67 ///

68 /// Allows the game to run logic such as updating the world,

69 /// checking for collisions, gathering input, and playing audio.

70 ///

71 ///
Provides a snapshot of timing values.

72 protected override void Update(GameTime gameTime)

73 {

74 // Allows the game to exit

75 if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)

76 {

77 this.Exit();

78 }

79 if (Keyboard.GetState().IsKeyDown(Keys.Escape))

80 {

81 this.Exit();

82 }

83

84 // TODO: Add your update logic here

85

86 base.Update(gameTime);

87 }

88

89 ///

90 /// This is called when the game should draw itself.

91 ///

92 /// Provides a snapshot of timing values.

93
4000
protected override void Draw(GameTime gameTime)

94 {

95 GraphicsDevice.Clear(Color.CornflowerBlue);

96 // TODO: Add your drawing code here

97

98 base.Draw(gameTime);

99 }

100 }

101 }

102

103

104  

1

在士兵类和英雄类中只是继承GameComponment父类。其运行过程大家可设置相应的断点进行调试。