问题

我已经在这个问题上工作了一段时间，但不知道为什么它不起作用。我希望在鼠标按钮释放时，Rigidbody2D对象能够添加速度，而鼠标按下的时间决定速度的大小。

它在最开始几次按下时工作正常，但当我多次按下时，似乎它记住了之前的速度（即使我将其重置为0）。有人可以帮忙吗？以下是代码和示例：

代码：

public class PlayerControl : MonoBehaviour
{
    public UnityEngine.UI.Slider powerBar;

    private Rigidbody2D rb;
    private float holdDownStartTime;
    private float force;
    private bool moving = false;

    private Vector2 mousePosition;
    private Vector2 targetPosition;
    private Vector3 growthSize = new Vector3(0.1f, 0.1f, 0);

    private void Start()
    {
        powerBar.gameObject.SetActive(false);
        RectTransform rectTransform = powerBar.GetComponent<RectTransform>();
        rb = GetComponent<Rigidbody2D>();
    }

    void Update()
    {
        if (Input.GetMouseButtonDown(0))
        {
            //重置RigidBody
            rb.velocity = Vector3.zero;
            rb.angularVelocity = 0;
            rb.position = transform.position;
            rb.isKinematic = true;

            moving = false;
            holdDownStartTime = Time.time;
            powerBar.gameObject.SetActive(true);
        }

        if (Input.GetMouseButton(0))
        {
            if (!moving)
            {
                powerBar.value = Time.time - holdDownStartTime;
            }
        }

        if (Input.GetMouseButtonUp(0))
        {
            powerBar.gameObject.SetActive(false);
            float holdDownTime = Time.time - holdDownStartTime;
            force = CalculateHoldDownForce(holdDownTime);
            Move(force);
        }

        mousePosition = Camera.main.ScreenToWorldPoint(Input.mousePosition);
        RotateTowards(mousePosition);
    }

    private void OnTriggerEnter2D(Collider2D collision)
    {
        if (collision.tag == "Food")
        {
            Eat();
        }
    }

    private void Eat()
    {
        this.transform.localScale += growthSize;
    }

    private void Move(float force)
    {
        targetPosition = Camera.main.ScreenToWorldPoint(Input.mousePosition);
        rb.velocity = new Vector2(targetPosition.x * force / 100, targetPosition.y * force / 100);
    }

    private void RotateTowards(Vector2 target)
    {
        Vector2 direction = (target - (Vector2)transform.position).normalized;
        var angle = Mathf.Atan2(direction.y, direction.x) * Mathf.Rad2Deg;
        var offset = 90f;
        transform.rotation = Quaternion.Euler(Vector3.forward * (angle + offset));
    }

    private float CalculateHoldDownForce(float holdTime)
    {
        holdTime *= 3;
        float maxForceHoldTime = 2f;
        float holdTimeNormalized = Mathf.Clamp01(holdTime / maxForceHoldTime);
        float force = holdTimeNormalized * 100f;
        return force;
    }
}

视频示例：
https://www.loom.com/share/965cc423e13e4c19a9295f59c5fa896a?sid=8d6e30b2-7f99-4204-a3da-5a720067f292

public class PlayerControl : MonoBehaviour
{
public UnityEngine.UI.Slider powerBar;
private Rigidbody2D rb;
private float holdDownStartTime;
private float force;
private bool moving = false;
private Vector2 mousePosition;
private Vector2 targetPosition;
private Vector3 growthSize = new Vector3(0.1f,0.1f,0);
private void Start()
{
powerBar.gameObject.SetActive(false);
RectTransform rectTransform = powerBar.GetComponent<RectTransform>();
rb = GetComponent<Rigidbody2D>();
}
void Update()
{ 
if (Input.GetMouseButtonDown(0))
{
//reset RigidBody
rb.velocity = Vector3.zero;
rb.angularVelocity = 0;
rb.position = transform.position;
rb.isKinematic = true;
//rb.rotation = transform.rotation;
moving = false;
holdDownStartTime = Time.time;
powerBar.gameObject.SetActive(true);
}
if (Input.GetMouseButton(0))
{
if (!moving)
{
powerBar.value = Time.time - holdDownStartTime;
}
}
if (Input.GetMouseButtonUp(0))
{
powerBar.gameObject.SetActive(false);
float holdDownTime = Time.time - holdDownStartTime;
force = CalculateHoldDownForce(holdDownTime);
Move(force);
}
mousePosition = Camera.main.ScreenToWorldPoint(Input.mousePosition);
RotateTowards(mousePosition);
}
private void OnTriggerEnter2D(Collider2D collision)
{
if(collision.tag == "Food")
{
Eat();
}
}
private void Eat()
{
this.transform.localScale += growthSize;
}
private void Move(float force)
{ 
targetPosition = Camera.main.ScreenToWorldPoint(Input.mousePosition);
rb.velocity = new Vector2(targetPosition.x * force/100, targetPosition.y * force/100);
}
private void RotateTowards(Vector2 target)
{
Vector2 direction = (target - (Vector2)transform.position).normalized;
var angle = Mathf.Atan2(direction.y, direction.x) * Mathf.Rad2Deg;
var offset = 90f;
transform.rotation = Quaternion.Euler(Vector3.forward * (angle + offset));
}
private float CalculateHoldDownForce(float holdTime)
{
holdTime *= 3;
float maxForceHoldTime = 2f;
float holdTimeNormalized = Mathf.Clamp01(holdTime / maxForceHoldTime);
float force = holdTimeNormalized * 100f;
return force; 
}

答案1

得分: 2

问题出在Move()函数的计算上。

private void Move(float force)
{ 
    targetPosition = Camera.main.ScreenToWorldPoint(Input.mousePosition);
    rb.velocity = new Vector2(targetPosition.x * force/100, targetPosition.y * force/100);
}

在这段代码中，你将targetPosition向量作为速度输入。正如你在视频中所看到的，物体根据中心点穿过了鼠标位置。你应该像这样修改这个函数：

private void Move(float force)
{ 
    targetPosition = Camera.main.ScreenToWorldPoint(Input.mousePosition);
    var targetDirection = targetPosition - rb.transform.position;

    rb.velocity = new Vector2(targetDirection.x * force/100, targetDirection.y * force/100);
}

这样修改后，物体将根据目标方向移动，而不是直接根据鼠标位置移动。

private void Move(float force)
{ 
targetPosition = Camera.main.ScreenToWorldPoint(Input.mousePosition);
rb.velocity = new Vector2(targetPosition.x * force/100, targetPosition.y * force/100);
}

private void Move(float force)
{ 
targetPosition = Camera.main.ScreenToWorldPoint(Input.mousePosition);
var targetDirection = targetPosition - rb.transform.position;
rb.velocity = new Vector2(targetDirection.x * force/100, targetDirection.y * force/100);
}