如何在不同的方向移动球？

Question

现在当我点击空格键时，它会向左或向右移动，我希望球首次直线移动。然后，当球击中墙壁，阻挡线后，我希望球以“-1”不知何故。这是我的第一个学校游戏项目，这是一个单线乒乓游戏。

编辑：编辑我已经添加了“boll_speed.X = random.Next（-1，1）;”，而且完美地工作！

• linje =行
• LIV =生活
• 铃=球
• =POÄNG波昂点
• 我不使用 “blockröd= blockred” 现在

• 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); 
  } 
  } 
  

这些部件

遇到问题：我想

 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

你的意思是你想要的球改变方向随机当它碰到窗口边界或线时。如果是这样的话：

您正在使用常量值来改变方向。添加一个随机数发生器来增加你的boll_speed。

例如，在伪代码中，而不是-1，执行random（-1）。

Answer 2

Random.Next(-1)应该会给你出界的错误。

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

但请注意，这种乘法会随着时间的推移导致球的放慢。它可能会加速到当前速度的两倍，但它可以在一个步骤中减慢到接近0。所以我宁愿先在y方向上颠倒球的速度，如果你击中水平线，保持它与x相同，如果你击中垂直线，则反转x并保持y。然后做一个零均值常量的随机添加。

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

我会给你通用的想法。请把它适应您的例子

比方说，你要移动到板上各个方向，现在想象你的板作为两维数组（所有的像素有一个x，y表示对板）

（0,0）表示棋盘的左上角，您的（宽度，高度）标记为右下角。您的球位于（x，y）位置的棋盘中间，其中x> 0和x <宽度（棋盘）和y> 0和y <高度。

您有以下

上的画面8不同的方向基现在是时候那些方向翻译到的逻辑结构。你需要为此创建一个数组，可以说我们想从NW方向开始。我将创建一个包含需要添加到（x，y）位置的数字的数组，以便继续按照您选择的方向前进。如果你看到我创建一个bidimentional阵列

现在，这是为你的想法伪代码：

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]; 
      } 
     }