XNA实践鼠标篇根据点击坐标移动图片（四）下

 /// <summary>
    /// This is the main type for your game
    /// </summary>
    public class Game1 : Microsoft.Xna.Framework.Game
    {
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;
        /// <summary>
        /// 图片的位置
        /// </summary>
        private Vector2 picPosition;
        /// <summary>
        /// 当前鼠标点击的位置
        /// </summary>
        private Vector2 CurrentPosition;

        /// <summary>
        /// 移动因子
        /// </summary>
        private Vector2 MovePix;
        /// <summary>
        /// 定义2D的纹理图片
        /// </summary>
        private Texture2D texture;
        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
            IsMouseVisible = true;//显示鼠标
            //初始化鼠标点击游戏界面的坐标
            picPosition = new Vector2();
            MovePix = new Vector2(1.0f, 1.0f);//移动一个像素
        }

        /// <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

            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);
            texture = Texture2D.FromFile(graphics.GraphicsDevice, "test.jpg");
            // 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();

            MouseState mouseState = Mouse.GetState();
            if (mouseState.LeftButton == ButtonState.Pressed)
            {
                Viewport vp = graphics.GraphicsDevice.Viewport;//获取视窗
                if (mouseState.X < vp.X || mouseState.X > vp.X + vp.Width || mouseState.Y < vp.Y || mouseState.Y > vp.Y + vp.Height)
                {
                    //点击坐标不在窗体内就不管了
                }
                else
                {
                    if (CurrentPosition.X != mouseState.X || CurrentPosition.Y != mouseState.Y)
                    {
                        CurrentPosition.X = mouseState.X;
                        CurrentPosition.Y = mouseState.Y;
                    }
                }
            }
            Mover();

            // 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
            spriteBatch.Begin();
            spriteBatch.Draw(texture, picPosition, Color.White);
            spriteBatch.End();
            base.Draw(gameTime);
        }
        /// <summary>
        /// 开始移动
        /// </summary>
        void Mover()
        {
            Vector2 v = picPosition - CurrentPosition;//向量相减
            if (v.X > 0)
                picPosition.X -= MovePix.X;//向左移动
            else if (v.X + texture.Width  < 0)
                picPosition.X += MovePix.X;//向右移动
            if (v.Y > 0)
                picPosition.Y -= MovePix.Y;//向上移动
            else if (v.Y + texture.Height < 0)
                picPosition.Y += MovePix.Y;//向一移动
        }
    }

图片还是使用上次的2维图片，现在在非图片覆盖区按住鼠标的左键并移动鼠标看看，图片是不是跟着鼠标的方向慢慢移动了，看到这里，大家会想到什么了么？

对了，就是游戏中的角色对怪的位置跟踪，但在这张图上只体现了F(G+H)，因为窗体没有任何的障碍物。