XNA/C#射弹发射问题-需要一次发射一枚射弹才能在空格键上发射

Question

问题：按下空格键后，我需要我的炮弹发射并继续它的生命，无论是否再次按下或松开空格键。

下面是添加、更新和绘制射弹的代码。我已经尝试过多次重新编写此代码，但遗憾的是，我的经验还不够，还没有找到合适的解决方案。

在下方添加投射代码

在此处输入代码

//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);
   }
}

更新下方的炮弹代码

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);
        }

    }
}

绘制投射物以屏蔽的绘制方法

//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，这就是我到目前为止所拥有的，正如所说的，一旦我放开键盘空格键，我就无法让他们继续他们的生活（直到碰撞或他们到达屏幕的尽头）。

Answer 1

我看到的导致isses的问题的快速概述：

• 您正在检查添加、更新和绘制方法期间是否按下了键/按钮
• 如果未按下某个键，则表示在更新过程中删除了该项目，而在绘制过程中未绘制该项目

为了实现我认为你正在努力实现的目标，我会沿着以下路线做一些事情（当然，根据你的需求进行定制和清理）：

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);
   }
}

您的空格键或A按钮仅用于发射新炮弹。你希望炮弹一直飞到击中什么东西或飞离屏幕一侧，这不应该取决于你是否按下了按钮。两人都不应该画子弹。

有道理吗？