XNA游戏开发之(五)——XNA实现组件复用

 【原创】Alex

    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

using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
using Microsoft.Xna.Framework.Net;
using Microsoft.Xna.Framework.Storage;

namespace Alex
{
    class Soldier:GameComponent
    {
        public Soldier(Game game):base(game)
        {

        }
        public override void Initialize()
        {
            base.Initialize();
        }
        public override void Update(GameTime gameTime)
        {
            base.Update(gameTime);
        }
        
    }
}

英雄类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
using Microsoft.Xna.Framework.Net;
using Microsoft.Xna.Framework.Storage;
namespace Alex
{
    class Hero:GameComponent
    {
        public Hero(Game game):base(game)
        {
        }
        public override void Initialize()
        {
            
            base.Initialize();
        }
        public override void Update(GameTime gameTime)
        {
            base.Update(gameTime);
        }
    }
}

游戏主体类

 
using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
using Microsoft.Xna.Framework.Net;
using Microsoft.Xna.Framework.Storage;

namespace Alex
{
    /// <summary>
    /// This is the main type for your game
    /// </summary>
    public class AlexGame : Microsoft.Xna.Framework.Game
    {
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;
      
        public AlexGame()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
            //游戏类初始化阶段将新类添加到组件中
            this.Components.Add(new Hero(this));
 30             this.Components.Add(new Soldier(this));
        }

        /// <summary>
        /// Allows the game to perform any initialization it needs to before starting to run.
        /// This is where it can query for any required services and load any non-graphic
        /// related content.  Calling base.Initialize will enumerate through any components
        /// and initialize them as well.
        /// </summary>
        protected override void Initialize()
        {
            // TODO: Add your initialization logic here
            this.TargetElapsedTime = TimeSpan.FromSeconds(1.0f / 1000.0f);
             base.Initialize();
        }

        /// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
        {
            // Create a new SpriteBatch, which can be used to draw textures.
            spriteBatch = new SpriteBatch(GraphicsDevice);

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

        /// <summary>
        /// UnloadContent will be called once per game and is the place to unload
        /// all content.
        /// </summary>
        protected override void UnloadContent()
        {
            // TODO: Unload any non ContentManager content here
        }

        /// <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)
        {
            // Allows the game to exit
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
            {
                this.Exit();
            }
            if (Keyboard.GetState().IsKeyDown(Keys.Escape))
            {
                this.Exit();
            }
           
            // TODO: Add your update logic here

            base.Update(gameTime);
        }

        /// <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);
            // TODO: Add your drawing code here

            base.Draw(gameTime);
        }
    }
}

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。