如何使多个机器人跟随玩家？

Question

我正在学习C #，我正在创造一个假想的游戏让我理解语言。我想要几个机器人跟随正在移动矩形的玩家，但是我只能移动播放器，但是自动机器人不能移动。

我真的研究了我能做些什么来移动这些机器人。我得出的结论是，我必须理解线程，这只会导致程序不崩溃。

我把我正在尝试的全部代码留在这里。

public partial class Form1 : Form
{
    public enum Direction { Up, Down, Left, Right }
    private Player player;
    private List<Bot> bots;

    public Form1()
    {
        InitializeComponent();

        this.Paint += Form1_Paint;
        this.KeyPreview = true;
        this.KeyDown += Form1_KeyDown;

        this.player = new Player(new Size(8, 8));
        this.bots = new List<Bot>();

        for (int i = 0; i < 30; i++)
        {
            Bot bot = new Bot(player, new Size(8, 8));
            bot.Follow();
            this.bots.Add(bot);
        }
    }

    private void Form1_KeyDown(object sender, KeyEventArgs e)
    {
        switch (e.KeyCode)
        {
            case Keys.Up:
                player.Move(Direction.Up);
                break;
            case Keys.Down:
                player.Move(Direction.Down);
                break;
            case Keys.Left:
                player.Move(Direction.Left);
                break;
            case Keys.Right:
                player.Move(Direction.Right);
                break;
        }
        this.Invalidate();
    }

    private void Form1_Paint(object sender, PaintEventArgs e)
    {
        List<Rectangle> rs = new List<Rectangle>();
        rs = this.bots.Select(x => x.Rectangle).ToList();
        rs.Add(player.Rectangle);

        if (rs.Count > 0)
        {
            e.Graphics.FillRectangles(new SolidBrush(Color.Red), rs.ToArray());
        }
    }
}

public class Player
{
    private Rectangle rectangle;
    public Rectangle Rectangle { get => rectangle; }
    public Player(Size size)
    {
        this.rectangle = new Rectangle() { Size = size };
    }

    public void Move(Direction direction)
    {
        switch (direction)
        {
            case Direction.Up:
                this.rectangle.Y -= 3;
                break;
            case Direction.Down:
                this.rectangle.Y += 3;
                break;
            case Direction.Left:
                this.rectangle.X -= 3;
                break;
            case Direction.Right:
                this.rectangle.X += 3;
                break;
            default:
                break;
        }
    }
}

public class Bot
{
    private Rectangle rectangle;

    private Player player;
    public Rectangle Rectangle { get => rectangle; }

    public Bot(Player player, Size size)
    {
        this.player = player;
        this.rectangle = new Rectangle() { Size = size };
    }

    public void Follow()
    {
        Task.Run(() =>
        {
            while (true)
            {
                Point p = player.Rectangle.Location;
                Point bot = rectangle.Location;

                for (int i = bot.X; i < p.X; i += 2)
                {
                    Thread.Sleep(100);
                    bot.X = i;
                }

                for (int i = bot.X; i > p.X; i -= 2)
                {
                    Thread.Sleep(100);
                    bot.X = i;
                }

                for (int i = bot.Y; i < p.Y; i += 2)
                {
                    Thread.Sleep(100);
                    bot.Y = i;
                }

                for (int i = bot.Y; i > p.Y; i -= 2)
                {
                    Thread.Sleep(100);
                    bot.Y = i;
                }
            }
        });                  
    }
}

正如你所看到的，我只能移动玩家，但是机器人不能移动，我能做什么来移动机器人呢？

Answer 1

我认为计时在这里会更好地工作，并移除此时需要您完全理解线程的要求，因为它将为您处理细节。我假设您实际上希望机器人“跟随”，而不是只在Player移动时移动，如果玩家移动得很快，就会落在后面。

因此，要使用Timer，我将调整您的Bot类，如下所示，以删除线程的使用，并且只允许它朝着Follow方法中的播放器迈出一步，该方法将每100 as调用一次。注意，Rectangle是一个结构，所以它不是可变的--这就是为什么您的机器人不能移动--如果您执行以下操作：

Point bot = Rectangle.Location;
bot.X = 5;

您可能认为Rectangle.Location.X现在是5岁，但事实并非如此。所以我们用新的位置创建一个新的矩形。

public class Bot
{
    private Player player;
    public Rectangle Rectangle { get; set; }

    public Bot(Player player, Size size)
    {
        this.player = player;
        this.Rectangle = new Rectangle() { Size = size };
    }

    public void Follow()
    {
        Point p = player.Rectangle.Location;
        Point bot = Rectangle.Location;

        for (int i = bot.X + 2; i < p.X;)
        {
            bot.X = i;
            break;
        }

        for (int i = bot.X - 2; i > p.X;)
        {
            bot.X = i;
            break;
        }

        for (int i = bot.Y + 2; i < p.Y;)
        {
            bot.Y = i;
            break;
        }

        for (int i = bot.Y - 2; i > p.Y;)
        {
            bot.Y = i;
            break;
        }

        Rectangle = new Rectangle(bot, player.Rectangle.Size);
    }
}

并添加以下代码来替换现有的构造函数，并添加另一种方法来处理Timer滴答。

private Timer timer;

public Form1()
{
    InitializeComponent();

    this.Paint += Form1_Paint;
    this.KeyPreview = true;
    this.KeyDown += Form1_KeyDown;

    // setup a timer which will call Timer_Tick every 100ms
    timer = new System.Windows.Forms.Timer();
    timer.Interval = 100;
    timer.Tick += Timer_Tick;
    timer.Start();

    this.player = new Player(new Size(8, 8));
    this.bots = new List<Bot>();

    for (int i = 0; i < 30; i++)
    {
        Bot bot = new Bot(player, new Size(8, 8));
        bot.Follow();
        this.bots.Add(bot);
    }
}

private void Timer_Tick(object sender, System.EventArgs e)
{
    foreach (var bot in bots)
        bot.Follow();
    this.Invalidate();
}

Answer 2

Point是一个值类型(一个struct)。(在在.NET中，struct和class有什么区别？上阅读更多有关这方面的内容)

当你这么做的时候

Point bot = Rectangle.Location;
bot.X = i;

...you创建了一个本地点并对其进行了修改。这不会改变机器人矩形的位置。另外，矩形也是结构化的，所以您必须修改原始Bot的矩形，或者将一个新的矩形分配给Bot。

要修复，您可以替换：

bot.X = i;

...with...

this.rectangle.X = i;

并对.Y进行类似的更改(在所有for循环位置中)

把它拼出来：

        public void Follow()
        {
            Task.Run(() =>
            {
                while (true) {
                    Point p = player.Rectangle.Location;
                    Point bot = rectangle.Location;

                    for (int i = bot.X; i < p.X; i += 2) {
                        Thread.Sleep(100);
                        this.rectangle.X = i;
                    }

                    for (int i = bot.X; i > p.X; i -= 2) {
                        Thread.Sleep(100);
                        this.rectangle.X = i;
                    }

                    for (int i = bot.Y; i < p.Y; i += 2) {
                        Thread.Sleep(100);
                        this.rectangle.Y = i;
                    }

                    for (int i = bot.Y; i > p.Y; i -= 2) {
                        Thread.Sleep(100);
                        this.rectangle.Y = i;
                    }
                }
            });
        }