子弹没有固定速度加力？如何在 2D 中正确地从左右两侧独立拍摄？

Question

我是编码新手，大约有一年的经验。我不明白为什么我的脚本不会为我以固定速度发射的子弹增加力量。这似乎取决于玩家移动的速度，但我对速度和移动速度使用了 2 个不同的变量，所以我不知道为什么会这样。我将如何解决这个问题？我也试图做到这一点，以便当角色面向那个方向时，我可以从左右两侧独立拍摄，但它似乎不起作用。当我尝试修复它时，它要么抛出错误，要么子弹在实例化时停留在原位，要么子弹总是向右移动。如果我做错了，正确的做法是什么？

using System.Collections.Generic;
using UnityEngine;

public class BulletScript : MonoBehaviour
{
    public GameObject Bullet;
    public float sec = 2f;

    public float speed = 80;

    public GameObject Enemy;

    public Transform spawnPoint;

    public Rigidbody2D bulletRB;

    private float timeBtwShots;
    public float startTimeBtwShots;

    public AudioSource Gunshot;

    public Animator animator;

    private float vert;
    private float horiz;

    // Start is called before the first frame update
    void Start()
    {
        if (gameObject.tag == "Bullet")

            this.gameObject.SetActive(true);

        StartCoroutine(LateCall());

        IEnumerator LateCall()
        {
            yield return new WaitForSeconds(sec);

            this.gameObject.SetActive(false);
        }
       
        
    }

    void OnCollisionEnter2D(Collision2D Other)
    {
        Destroy(this.gameObject);
    }

    void OnTriggerEnter2D(Collider2D other)
    {
        if (other.tag == "Enemy")
        {
            this.gameObject.SetActive(false);
            other.gameObject.SetActive(false);
        } 
    }

    IEnumerator ShootingAnim()
    {
       
        timeBtwShots = startTimeBtwShots;
        Gunshot.Play();
        animator.SetBool("IsShooting", true);

        yield return new WaitForSeconds(0.2f);

        animator.SetBool("IsShooting", false);


    }

    void Update()
    {
        horiz = Input.GetAxis("Horizontal");
        vert = Input.GetAxis("Vertical");

        if (Input.GetMouseButtonDown(0))
        {
            Instantiate(bulletRB, spawnPoint.position, Quaternion.identity);
        }
    }

    void FixedUpdate()
    {
        

        if (timeBtwShots <= 0)
        {

                bulletRB.AddForce(transform.TransformDirection(new Vector2(horiz, vert)).normalized * speed);

                StartCoroutine(ShootingAnim());
            }
        else
        {
            timeBtwShots -= Time.deltaTime;
        }
        if (gameObject.tag == "Bullet")
        {
            Destroy(this.gameObject, 1f);
        }
    }
}

Answer 1

不是使用输入来确定子弹的方向，而是存储玩家正在看的方向。添加一个名为“currentDirection”的新 Vector2，并将其默认为 Vector2.right 或其他名称。当你计算玩家的移动时，这样做：

if (!Mathf.Approximately(horiz, 0) || !Mathf.Approximately(vert, 0))
    currentDirection = new Vector2(horiz, vert).normalized;

您会注意到第一行检查任何一行是否不为零。我这样做是因为如果两个输入均为 0，则方向也为零。我们只想保存玩家输入的最后一个方向，而不是缺少方向。

接下来，子弹也应该有一个方向变量。生成子弹时，将子弹的方向设置为 currentDirection。您只想在生成子弹时执行此操作。如果你每帧都将子弹的方向设置为玩家当前的输入，那么它会根据玩家的输入不断改变方向。

然后让子弹朝它指定的方向移动。通常人们只会改变它的旋转以匹配方向并告诉它向前移动，但这可能取决于你希望你的艺术如何寻找子弹。

同样非常重要但无关紧要：您需要将所有刚体代码放在 FixedUpdate 中。物理只在固定更新期间发生，所以在更新之外做任何与物理相关的事情都可能导致问题。但是，当您这样做时，请在更新中保留您的输入检查。由于 FixedUpdates 不会在每一帧发生，如果将它们放在 FixedUpdate 中，输入可能会丢失。因此，添加一些输入变量并在更新中执行

jumpInput = Input.GetButtonDown("Jump");
horiz = Input.GetAxis("Horizontal");
vert = Input.GetAxis("Vertical");

然后在 FixedUpdate 中做你的物理：

if (jumpInput && Mathf.Abs(_rigidbody.velocity.y) < 0.001f)

Answer 2

终于想通了。我做了一个完整的重写，因为我使代码过于复杂。这是最终的脚本：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PlayerController : MonoBehaviour
{
    public float MovementSpeed = 1;
    public float JumpForce = 1;
    public float jumpTime = 1f;

    public Rigidbody2D _rigidbody;

    private bool facingRight;

    public float sec = 2f;

    public Vector2 bulletPos;

    public GameObject bulletToRight, bulletToLeft;

    public Transform spawnPoint;

    public Rigidbody2D bulletRB;

    public AudioSource Gunshot;

    float horizontalMove = 0f;

    public float fireRate = 0.5f;
    float nextFire = 0f;

    // public AudioSource Jump;

    public Animator animator;

    void HandleMovement(float horizontal)
    {
        transform.position += new Vector3(horizontal, 0, 0) * Time.deltaTime * MovementSpeed;
        animator.SetFloat("velX", (horizontal));
    }

    void Flip(float horizontal)
    {
        if (horizontal < 0 && !facingRight || horizontal > 0 && facingRight)
        {
            facingRight = !facingRight;

            Vector3 theScale = transform.localScale;

            theScale.x *= -1;

            transform.localScale = theScale;

            transform.position += new Vector3(horizontal, 0, 0) * Time.deltaTime * MovementSpeed;

            horizontalMove = Input.GetAxisRaw("Horizontal") * MovementSpeed;

            animator.SetFloat("velX", (horizontalMove));
        } 
    }

    IEnumerator ShootingAnim()
    {

        
        animator.SetBool("IsShooting", true);

        yield return new WaitForSeconds(0.2f);

        animator.SetBool("IsShooting", false);


    }

    void Update()
    {

        animator.SetFloat("velX", Mathf.Abs(horizontalMove));

        if (Input.GetButtonDown("Jump") && Mathf.Abs(_rigidbody.velocity.y) < 0.001f)
        {
            _rigidbody.AddForce(new Vector2(0, JumpForce), ForceMode2D.Impulse);
            animator.SetBool("IsJumping", true);
            // Jump.Play();
        }

        if (Mathf.Abs(_rigidbody.velocity.y) == 0f)
        {
            animator.SetBool("IsJumping", false);
        }

        if ((_rigidbody.velocity.x) >= 0.01f || (_rigidbody.velocity.x <= -0.01f)) 
        {
            animator.SetBool("IsRunning", true);
        }

        if (Input.GetMouseButtonDown(0) && Time.time > nextFire)
        {
            StartCoroutine(ShootingAnim());
            nextFire = Time.time + fireRate;
            Fire();

        }


        float horizontal = Input.GetAxis("Horizontal");

        HandleMovement(horizontal);

        Flip(horizontal);



    }

    void Fire()
    {
        bulletPos = spawnPoint.position;
        if (!facingRight)
        {
            bulletPos += new Vector2(+0.02f, 0f);
            Instantiate(bulletToRight, bulletPos, Quaternion.identity);
            Gunshot.Play();
        } else
        {
            bulletPos += new Vector2(-0.02f, 0f);
            Instantiate(bulletToLeft, bulletPos, Quaternion.identity);
            Gunshot.Play();
        }
        
    }
}

这是 BulletScript：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class BulletScript : MonoBehaviour
{
    public GameObject Bullet;

    public Transform spawnPoint;

    public Rigidbody2D bulletRB;

    public float velX = 5f;

    float velY = 0f;

    // Start is called before the first frame update
    void Start()
    {
        bulletRB = GetComponent<Rigidbody2D>();
    }

    void OnCollisionEnter2D(Collision2D Other)
    {
        Destroy(this.gameObject);
    }

    void OnTriggerEnter2D(Collider2D other)
    {
        if (other.tag == "Enemy")
        {
            this.gameObject.SetActive(false);
            other.gameObject.SetActive(false);
        } 
    }

    private void Update()
    {

        bulletRB.velocity = new Vector2(velX, velY);
        Destroy(gameObject, 3f);

    }
}

子弹没有固定速度加力？如何在 2D 中正确地从左右两侧独立拍摄？

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