如何向不同方向移动球？

Question

现在当我按下空格键时它会向左或向右移动，我希望球先直线移动 time.Then 当球撞到墙、块或线之后我希望球随机移动以某种方式使用“-1”。这是我的第一个学校游戏项目，它是一个单线乒乓球游戏。

编辑：编辑我添加了 "boll_speed.X = random.Next(-1, 1);"，效果非常好！

linje = 行
liv = 生命
boll = 球
poang = 分
我现在不使用 "blockröd = blockred"

blockgrön = blockgreen

public class Game1 : Game
{
GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;
SpriteFont spritefont;
Texture2D linje_texture;
Texture2D boll_texture;
Texture2D blockröd_texture;
Texture2D blockgrön_texture;
Texture2D gameover_texture;
Rectangle linje_rect;
Rectangle boll_rect;
Rectangle blockröd_rect;
Rectangle blockgrön_rect;
Rectangle gameover_rect;

Vector2 linje_speed;
Vector2 boll_speed;

Random random;

int liv;
int poang;
int highscore;

List<Rectangle> block = new List<Rectangle>();

bool Start = false;

public Game1()
{
    graphics = new GraphicsDeviceManager(this);
    Content.RootDirectory = "Content";

    graphics.PreferredBackBufferWidth = 760; 
    graphics.PreferredBackBufferHeight = 620;
}

protected override void Initialize()
{
    linje_speed.X = 5f;
    boll_speed.X = boll_speed.X = random.Next(-1, 1);
    boll_speed.Y = 6f;
    liv = 3;
    poang = 0;

    random = new Random();

    base.Initialize();
}

protected override void LoadContent()
{
    spriteBatch = new SpriteBatch(GraphicsDevice);
    spritefont = Content.Load<SpriteFont>("Fonts/Myfont");
    linje_texture = Content.Load<Texture2D>("Pics/linje-lång");
    boll_texture = Content.Load<Texture2D>("Pics/boll");
    blockgrön_texture = Content.Load<Texture2D>("Pics/block-grön");
    blockröd_texture = Content.Load<Texture2D>("Pics/block-röd");
    gameover_texture = Content.Load<Texture2D>("Pics/GameOver");
    linje_rect = new Rectangle((Window.ClientBounds.Width - linje_texture.Width) / 2, 580, linje_texture.Width, linje_texture.Height);
    boll_rect = new Rectangle((Window.ClientBounds.Width - boll_texture.Width) / 2, 556, boll_texture.Width, boll_texture.Height);
    gameover_rect = new Rectangle((Window.ClientBounds.Width / 2) - (gameover_texture.Width / 2), (Window.ClientBounds.Height / 2) - gameover_texture.Height / 2, gameover_texture.Width, gameover_texture.Height);

    block.Add(blockgrön_rect);
    block.Add(blockröd_rect);
    for (int i = 1; i < 5; i++)
    {
        for (int g = 1; g < 13; g++)
        {
            block.Add(new Rectangle((g * 63) - 60, (i * 40), blockgrön_texture.Width, blockgrön_texture.Height));
        }
    }
}

protected override void UnloadContent()
{
    // TODO: Unload any non ContentManager content here
}

protected override void Update(GameTime gameTime)
{
    if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed || Keyboard.GetState().IsKeyDown(Keys.Escape))
        Exit();
    if (Start == true) 
    {
        boll_rect.X += (int)boll_speed.X;
        boll_rect.Y += (int)boll_speed.Y;
    }

    if(Start == false)
    {
        boll_rect.X = linje_rect.X + ((linje_texture.Width / 2) - (boll_texture.Width / 2));
    }
    if (boll_rect.X > Window.ClientBounds.Width - boll_texture.Width || boll_rect.X < 0) 
        boll_speed.X *= -1;

    if (boll_rect.Y > Window.ClientBounds.Height - boll_texture.Height || boll_rect.Y < 0) 
        boll_speed.Y *= -1;

    if (boll_rect.Y > Window.ClientBounds.Height - boll_texture.Height) 
    {
        liv -= 1;
        Start = false;
        boll_rect.X = (Window.ClientBounds.Width - boll_texture.Width) / 2; 
        boll_rect.Y = 556; 
        linje_rect.X = (Window.ClientBounds.Width - linje_texture.Width) / 2;
        linje_rect.Y = 580; 
    }

    KeyboardState ks = Keyboard.GetState();
    if (ks.IsKeyDown(Keys.Left)) 
    {
        linje_rect.X -= (int)linje_speed.X;
    }
    else if (ks.IsKeyDown(Keys.Right)) 
    {
        linje_rect.X += (int)linje_speed.X;
    }
    else if (ks.IsKeyDown(Keys.Space)) 
    {
        Start = true;
    }

    if (linje_rect.X > Window.ClientBounds.Width - linje_texture.Width) 
        linje_rect.X = (Window.ClientBounds.Width - linje_texture.Width);

    if (linje_rect.X < 0) 
        linje_rect.X = 0;

    if (linje_rect.Intersects(boll_rect)) 
    {
        boll_speed.Y *= -1;
    }

    base.Update(gameTime);
}

protected override void Draw(GameTime gameTime)
{
    GraphicsDevice.Clear(Color.Black);

    spriteBatch.Begin();
    if (liv > 0)
    {
        spriteBatch.Draw(linje_texture, linje_rect, Color.White);
        spriteBatch.Draw(boll_texture, boll_rect, Color.White);
        spriteBatch.DrawString(spritefont, "Liv kvar: " + liv, Vector2.Zero, Color.White);
        spriteBatch.DrawString(spritefont, "Points: " + poang, new Vector2(350, 0), Color.White);
        spriteBatch.DrawString(spritefont, "Highscore: " + highscore, new Vector2(660, 0), Color.White);
        foreach (Rectangle g in block) 
        {
            spriteBatch.Draw(blockgrön_texture, g, Color.White);
        }
    }
    if (liv == 0)
    {
        spriteBatch.Draw(gameover_texture, gameover_rect, Color.White);
    }
    spriteBatch.End();

    base.Draw(gameTime);
}
}

这些部分有问题：

        if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed || Keyboard.GetState().IsKeyDown(Keys.Escape))
            Exit();
        if (Start == true) 
        {
            boll_rect.X += (int)boll_speed.X;
            boll_rect.Y += (int)boll_speed.Y;
        }

        if (boll_rect.X > Window.ClientBounds.Width - boll_texture.Width || boll_rect.X < 0) 
            boll_speed.X *= -1;

        if (boll_rect.Y > Window.ClientBounds.Height - boll_texture.Height || boll_rect.Y < 0) 
            boll_speed.Y *= -1;

        else if (ks.IsKeyDown(Keys.Space)) 
        {
            Start = true;
        }

        if (linje_rect.Intersects(boll_rect)) 
        {
            boll_speed.Y *= -1;
            boll_speed.Y += random.Next(-100, 101) / 100.0f;
            boll_speed.X *= -1;
            boll_speed.X += random.Next(-100, 101) / 100.0f;
        }

Answer 1

我想你的意思是你希望球在击中 window 边界或线时随机改变方向。如果是：

您正在使用常量值来改变方向。添加一个随机化器以将您的 boll_speed 乘以。

例如，在伪代码中，执行 random(-1) 而不是 -1。

Answer 2

Random.Next(-1) 应该给你越界错误。

你可以使用类似Random.Next(-200, 0)/100.0f的东西，它会return一个介于-2和0之间的负数（包括-2，不包括0）。

但请注意，随着时间的推移，这种乘法会导致球变慢。它可能会加速到当前速度的两倍，但它可以一步减速到接近 0。所以我宁愿首先在 y 方向反转球速，如果你击中水平线，则在 x 方向保持相同，如果你击中垂直线，则在 x 方向反转并保持在 y 方向。然后随机添加一个零均值常数。

boll_speed.Y *= -1;
boll_speed.Y += random.Next(-100, 101)/100.0f; // Add random number between -1 and 1 with 0.01 precision.
// and nearly the same for X. Depending on the lines hit.

Answer 3

我给你大概的思路。请根据您的示例进行调整

假设您想移动到棋盘上的所有方向，现在将您的棋盘想象成一个二维数组（您的所有像素在该棋盘上都有一个 x,y 表示）

(0,0) 标记板的左上角，(width, height) 标记右下角。你的球位于棋盘中间的 (x, y) 位置，其中 x > 0 且 x < 宽度（棋盘的宽度）且 y > 0 且 y < 高度。

根据下图，你有8个不同的方向

现在是时候将这些说明转化为逻辑结构了。您需要为此创建一个数组，假设我们想从 NW 方向开始。我将创建一个数组，其中包含您需要添加到 (x, y) 位置的数字，以便继续朝着您选择的方向前进。如果你看到我正在创建一个双向数组

现在这是您的想法的伪代码：

    int[,] directions = new int[,]{{-1,-1,-1,0,1,1,1,0}, {-1,0,1,1,1,0,-1,-1}};

    public void Move(Game game)
    {
       Point currentPosition = GetYourCurrentPosition(); //the x, y
       int direction = GetYourRandomDirection() //this should be a random number between 0 and 7, beucase the array for directions has 8 positions. 


           int xDirection = directions[0, direction];
           int yDirection = directions[1, direction];

            //move inside the board forever
            while(true)
            {
               while(ICanMoveTo(currentPosition.X + xDirection, currentPosition.Y + yDirection)
               {
                 //keep moving on the same direction
                 currentPosition.X += xDirection;
                 currentPosition.Y += yDirection;
               } 

               //if you can't move anymore in the same direction, then change
               direction = GetYourRandomDirection();
               xDirection = directions[0, direction];
               yDirection = directions[1, direction];
             }
        }

如何向不同方向移动球？

How to move the ball in different directions?

c#

pong

monogame