XNA/C＃射彈發射問題 - 需要一個射彈一次在空格鍵上發射新聞

Question

問題：在空格鍵按下時，我需要我的射彈發射並繼續其生命，無論另一次按下或放開空格鍵。

下面是代碼添加，更新和繪製射彈。我已經嘗試過許多對此代碼的修改，但是我還沒有足夠的經驗來找到合適的解決方案。下面

輸入代碼在這裏下面

private void UpdateProjectiles() 
{ 
    //update projectiles 
    for (int i = projectiles.Count - 1; i >= 0; i--) 
    { 

     if (currentKeyboardState.IsKeyDown(Keys.Space) || 
      currentGamePadState.Buttons.A == ButtonState.Pressed) 
     { 

      //adds particle to first projectile but not again until the next fire butotn press 
      //particleEngine.EmitterLocation = new Vector2(projectiles[i].Position.X, projectiles[i].Position.Y); 
      projectiles[i].Update(); 
      projectileOn = true; 


     } 
     //if projectiles not being fired remove them from the game screen 
     else 
     { 
      projectiles.RemoveAt(i); 
     } 



    } 

} 

，吸引Draw方法

//add projectile if spacebar is pressed 

private void AddProjectile(Vector2 position) 
{ 
    //i need somthing like this to make bullets autofire on phone 
    //while (TouchPanel.IsGestureAvailable) 
    //{ 
    // Projectile projectile = new Projectile(); 
    // projectile.Initialize(GraphicsDevice.Viewport, projectileTexture, position); 
    // projectiles.Add(projectile); 
    //} 

    if (currentKeyboardState.IsKeyDown(Keys.Space) || 
    currentGamePadState.Buttons.A == ButtonState.Pressed) 
    { 
     Projectile projectile = new Projectile(); 
     projectile.Initialize(GraphicsDevice.Viewport, projectileTexture, position); 
     projectiles.Add(projectile); 
    } 
} 

更新彈丸代碼

AddProjectile碼彈到屏幕

//draw the projectiles 
      //*********************************************************** 
      //using the if here allows control of projectiles to pass... 
      //...to the "currentstate of the spacebar (is pressed = fire) 
      /***/ 

      if (currentKeyboardState.IsKeyDown(Keys.Space) || 
       currentGamePadState.Buttons.A == ButtonState.Pressed) 
      { 
       for (int i = 0; i < projectiles.Count; i++) 
       { 
        projectiles[i].Draw(spriteBatch); 

       } 
      } 

      //remove projectiles and reset 
      if (currentKeyboardState.IsKeyUp(Keys.Space) || 
       currentGamePadState.Buttons.A == ButtonState.Released) 
      { 


       UpdateProjectiles(); 
      } 

所以，這是我到目前爲止所說的，並且如前所述可以使彈丸良好地工作，我不能讓他們繼續他們的生活（直到碰撞或他們到達屏幕的末端）一旦我放開鍵盤空格鍵。

Answer 1

A的我看是造成你的isses的問題簡要概述：

• 如果您添加，更新過程中按下按鍵/按鈕，並繪製方法您正在檢查。
• 如果沒有按下某個鍵，則在更新過程中刪除該項目，而在繪製過程中不繪製該項目。

要做到什麼，我認爲你要完成，我會做東西沿着這些路線（定製和清理您的需求，當然）：

private void Update(GameTime gameTime) 
{ 
    // Only add a new projectile if Space or A is pressed 
    if (currentKeyboardState.IsKeyDown(Keys.Space) || 
     currentGamePadState.Buttons.A == ButtonState.Pressed) 
    { 
     AddProjectile(); // some method that adds a new projectile to 'projectiles' 
    } 

    // Update all existing projectiles, regardless of button press. 
    // This will allow your projectiles to continue flying after they have been fired. 
    for (int i = 0; i < projectiles.Count; i++) 
    { 
     projectiles[i].Update(); 
     if (projectiles[i].Dead) // check if projectiles[i] is out of bounds or has collided with something 
     { 
     projectiles.RemoveAt(i); 
     i--; 
     } 
    } 
} 

private void Draw(GameTime gameTime) 
{ 
    // Draw all existing projectiles, regardless of button press. 
    for (int i = 0; i < projectiles.Count; i++) 
    { 
     projectiles[i].Draw(spriteBatch); 
    } 
} 

你的空格鍵或一個按鈕只用於火一個新的彈丸。你希望彈丸能夠飛行，直到它碰到屏幕的一邊或者飛到屏幕的邊上，它不應該取決於你是否按下了一個按鈕來做到這一點。也不應該畫子彈。

有意義嗎？