c# - XNA - 長押しすると高くジャンプします (例を添付)

Question

私は最近質問をしましたが、まだ理解できません。つまり、答えは素晴らしかったのですが、理解できません。スペースバーを長く押し続けるほど、プレーヤーを高くジャンプさせようとしています。高さの上限も必要です。

プレーヤー クラスの例があり、これにそのような関数を追加しようとしています。誰かがこのクラスを見て、関数を追加してから、私を助けるためにいくつかのコメントを追加していただければ幸いです。- ありがとうございました。

Player.cs

namespace Jumping

{

class Player
{
    public Texture2D Texture;

    public Vector2 Velocity;
    public Vector2 Position;
    public float ground;
    private float Speed;

    private Rectangle screenBound;

    public bool isJumping; //are we jumping or not
    public bool goingUp; //if going up or not

    public float u; //initial velocity
    private float jumpU;
    private float g; //gravity
    public float t; //time

    private KeyboardState prevKB;

    public Player(Texture2D Texture, Vector2 Position, float Speed, Rectangle screenBound)
    {
        this.Texture = Texture;
        this.Position = Position;
        ground = Position.Y;
        this.Speed = Speed;
        this.screenBound = screenBound;
        Velocity = Vector2.Zero;
        isJumping = goingUp = false;
        jumpU = 2.5f;
        g = -9.8f;
        t = 0;
    }

    public void Update(GameTime gameTime)
    {

        Position.X += (Velocity.X * Speed);
        //Set the Y position to be subtracted so that the upward movement would be done by decreasing the Y value
        Position.Y -= (Velocity.Y * Speed);

        goingUp = (Velocity.Y > 0);

        // TODO: Add your update logic here
        if (isJumping == true)
        {
            //motion equation using velocity: v = u + at
            Velocity.Y = (float)(u + (g * t));
            //Increase the timer
            t += (float)gameTime.ElapsedGameTime.TotalSeconds;
        }
        if (isJumping == true && Position.Y > screenBound.Height - Texture.Height)
        {
            Position.Y = ground = screenBound.Height - Texture.Height;
            Velocity.Y = 0;
            isJumping = false;
            t = 0;
        }

        if (Position.X < 0)
        {
            //if Texture touches left side of the screen, set the position to zero and the velocity to zero.
            Position.X = 0;
            Velocity.X = 0;
        }
        else if (Position.X    + Texture.Width > screenBound.Width)
        {
            //if Texture touches left side of the screen, set the position to zero and the velocity to zero.
            Position.X = screenBound.Width - Texture.Width;
            Velocity.X = 0;
        }
        if (Position.Y < 0)
        {
            //if the Texture touches the top of the screen, reset the timer and set the initial velocity to zero.
            Position.Y = 0;
            t = 0;
            u = 0;
        }
    }

    public void Input(KeyboardState keyState)
    {
        if (keyState.IsKeyDown(Keys.Space) && (isJumping == false || Position.Y == ground))
        {
            isJumping = true;
            u = jumpU;
        }
        if (keyState.IsKeyDown(Keys.Left) && !keyState.IsKeyDown(Keys.Right))
        {
            if (keyState.IsKeyDown(Keys.A))
            {
                if (Velocity.X > -2.0f)
                Velocity.X -= (1.0f / 10);
            }
            else if (Velocity.X > -1.0f)
            {
                Velocity.X -= (1.0f / 10);
            }
            else
            {
                Velocity.X = -1.0f;
            }
        }
        else if (!keyState.IsKeyDown(Keys.Left) && keyState.IsKeyDown(Keys.Right))
        {
            if (keyState.IsKeyDown(Keys.A))
            {
                if (Velocity.X < 2.0f)
                Velocity.X += (1.0f / 10);
            }
            else if (Velocity.X < 1.0f)
            {
                Velocity.X += (1.0f / 10);
            }
            else
            {
                Velocity.X = 1.0f;
            }
        }
        else
        {
            if (Velocity.X > 0.05 || Velocity.X < -0.05)
                Velocity.X *= 0.90f;
            else
                Velocity.X = 0;
        }

        prevKB = keyState;
    }

    public void Fall()
    {
        t = 0;
        u = 0;
    }

    public void Draw(SpriteBatch spriteBatch)
    {
        spriteBatch.Draw(Texture, new Rectangle((int)Position.X, (int)Position.Y, Texture.Width, Texture.Height), Color.White);
    }
}

}