跟我一起学XNA(2)让物体动起来②(附源码)

加载一个静态图片，左右移动，真没啥意思，鼠标单击上去都没反应，这也太山寨了吧。
来点稍微给力的，\(^o^)/

新建项目，加载图片，和第一章是一样的

        Texture2D people;

        protected override void LoadContent()

        {

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

            spriteBatch = new SpriteBatch(GraphicsDevice);

            people = Content.Load<Texture2D>(@"Image/PlayerMagic");

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

        }

这里有一个地方，就是当你加载Body0这个gif的时候，最好转换成png或者jpg之类的，而且最好不要太大，因为它加载图片大会出现一个这样的异常

意思都能看懂，就是图片太大，Textrue2D容积小，当然有解决办法，我还没想到，以后知道了补上，如果是程序无法识别的图片格式，他会报格式不识别这个错误

        //这里是图片中每一帧图片的大小

        Point pictureSize = new Point(150, 150);

        Point currentFrame = new Point(0, 0);

        //这里是你的图片有几帧，10是行，1是列，因为图片只有一行，所以列没啥用，那个Body0可以用得着

        Point pictureNum = new Point(10, 1);

        public Game1()

        {

            graphics = new GraphicsDeviceManager(this);

            Content.RootDirectory = "Content";

            //因为程序1秒刷新60次，你可以自定义刷新的时间，这里是每0.12秒刷新

            TargetElapsedTime = new TimeSpan(0, 0, 0, 0, 120);

            //鼠标可见

            IsMouseVisible = true;

        }

因为是从一张图片动态取帧，所以才有Point pictureNum = new Point(10, 1);这样的变量10列1行，其实用两个变量记录也行，一个记录行，一个记录列

 protected override void Draw(GameTime gameTime)

        {

            GraphicsDevice.Clear(Color.CornflowerBlue);



            // TODO: Add your drawing code here

            spriteBatch.Begin(SpriteSortMode.FrontToBack, BlendState.AlphaBlend);

            spriteBatch.Draw(people, Vector2.Zero,

            new Rectangle(currentFrame.X * pictureSize.X,

            currentFrame.Y * pictureSize.Y,

            pictureSize.X,

            pictureSize.Y),

            Color.White, 0, Vector2.Zero,

            1, SpriteEffects.None, 0);

            spriteBatch.End();

            base.Draw(gameTime);

        }

Draw这里，要使用重载函数来动态的用new Rectangle来获取显示的位置了

        protected override void Update(GameTime gameTime)

        {

            // Allows the game to exit

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

                this.Exit();



            // TODO: Add your update logic here

            ++currentFrame.X;

            if (currentFrame.X >= pictureNum.X)

            {

                currentFrame.X = 0;

            }

            base.Update(gameTime);

        }

Update这里加入一个判断，当Rectangle超过图片大小时候，清零重来
运行，左上角会有一个gif图片，当然，还有另外一种方法

我这里面加了8张图片，可以再Draw中这么处理

        protected override void Draw(GameTime gameTime)

        {

            GraphicsDevice.Clear(Color.CornflowerBlue);



            // TODO: Add your drawing code here

            spriteBatch.Begin(SpriteSortMode.FrontToBack, BlendState.AlphaBlend);

            //spriteBatch.Draw(people, Vector2.Zero,

            //new Rectangle(currentFrame.X * pictureSize.X,

            //currentFrame.Y * pictureSize.Y,

            //pictureSize.X,

            //pictureSize.Y),

            //Color.White, 0, Vector2.Zero,

            //1, SpriteEffects.None, 0);

            spriteBatch.Draw(list[currentFrame.X], Vector2.Zero, null, Color.White);

            ++currentFrame.X;

            if (currentFrame.X >=8)

            {

                currentFrame.X = 0;

            }

            spriteBatch.End();

            base.Draw(gameTime);

        }

之前我有这样的操作，也能达到相同效果

List<Texture2D> list = new List<Texture2D>();

        protected override void LoadContent()

        {

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

            spriteBatch = new SpriteBatch(GraphicsDevice);

            people = Content.Load<Texture2D>(@"Image/PlayerMagic");

            for (int i = 0; i < 8; i++)

            {

                list.Add(Content.Load<Texture2D>(string.Format(@"Image/{0}",i)));

            }

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

        }

两个方法一样的，注意的是如果用第二种方法，你要把Update中的方法先注释掉

进入下一个问题

图片随鼠标移动

        //记录前一个鼠标的位置

        MouseState preMouseState;

        //图片的位置

        Vector2 ringsPosition = Vector2.Zero;

        //移动的速度

        const float ringsSpeed = 4;

我们新加几个变量

    protected override void Update(GameTime gameTime)

        {

            // Allows the game to exit

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

                this.Exit();



            // TODO: Add your update logic here

            ++currentFrame.X;

            if (currentFrame.X >= pictureNum.X)

            {

                currentFrame.X = 0;

            }



            MouseState mouseState = Mouse.GetState();

            if (mouseState.X != preMouseState.X ||

            mouseState.Y != preMouseState.Y)

                ringsPosition = new Vector2(mouseState.X-75, mouseState.Y-75);

            preMouseState = mouseState;

            base.Update(gameTime);

        }

Update的时候记录一下鼠标的位置，说白了就是把图片移动到当前鼠标位置呗，这里也要改一下

  protected override void Draw(GameTime gameTime)

        {

            GraphicsDevice.Clear(Color.CornflowerBlue);



            // TODO: Add your drawing code here

            spriteBatch.Begin(SpriteSortMode.FrontToBack, BlendState.AlphaBlend);

            spriteBatch.Draw(people, ringsPosition,

            new Rectangle(currentFrame.X * pictureSize.X,

            currentFrame.Y * pictureSize.Y,

            pictureSize.X,

            pictureSize.Y),

            Color.White, 0, Vector2.Zero,

            1, SpriteEffects.None, 0);

            //spriteBatch.Draw(list[currentFrame.X], ringsPosition, null, Color.White);

            //++currentFrame.X;

            //if (currentFrame.X >= 8)

            //{

            //    currentFrame.X = 0;

            //}



            spriteBatch.End();

            base.Draw(gameTime);

        }

红色也要改一下

 spriteBatch.Draw(list[currentFrame.X], Vector2.Zero, null, Color.White);

            ++currentFrame.X;

            if (currentFrame.X >=8)

            {

                currentFrame.X = 0;

            }

还有这个东西也要改一下，红色的那个，我程序已经改过了，如果注释错了可能会报错

声明一下（图片是从别的地方拿过来的，当时玩wpf的时候看过深蓝的教程，顺手把图片牵过来了）
源代码：files.cnblogs.com/fish124423/XNA.rar