我的角色在Unity2D中执行了意外的第三跳

Question

你好！

我目前正在Unity引擎中开发2D平台游戏，在那里我创建了可以进行双倍跳跃的角色。
在一开始的时候一切都很好，但是我现在已经意识到，存在一个打破游戏规则的错误，使他能够执行第三跳（出于某种原因）。 而且我不能为了找出问题所在。

PlayerController.cs

using UnityEngine;
using System.Collections;

public class PlayerController : MonoBehaviour {

    /*
    TODO: Find out why the character ocationally
    gets 3 jumps instead of 2.
    I think it's the "isGrounded" that returns
    a false posetive.
    */

[Header("Ground Recognition")]
public BoxCollider2D groundCollider;
public LayerMask groundAbles;

[Header("Audio")]
public GameObject jumpSound = null;

[Header("Visual")]
public GameObject jumpEffect = null;


float speed = 5f;
int maxJumps = 2;
int currentJumps = 0;

bool isGrounded = false;
float boundsLength = 0;

Vector3 movement;
// Use this for initialization
void Start () {

}

// Update is called once per frame
void Update() {
    CheckGroundCollision();
    JumpLogic();

    movement = new Vector3(Input.GetAxis("Horizontal") * speed, 0, 0);
    movement *= Time.deltaTime;
    transform.position += movement;

    CheckGroundCollision();
}

void CheckGroundCollision()
{
    isGrounded = groundCollider.IsTouchingLayers(groundAbles);
}

void JumpLogic()
{

    if (isGrounded)
        currentJumps = 0;

    if (Input.GetButtonDown("Jump") && currentJumps < maxJumps)
    {
        GameObject newJumpSound = (GameObject)GameObject.Instantiate(jumpSound, (Vector2)transform.position, transform.rotation);
        GameObject newJumpEffect = (GameObject)GameObject.Instantiate(jumpEffect, (Vector2)transform.position - new Vector2(0, 0.25f), transform.rotation);
        GameObject.Destroy(newJumpEffect, 0.2f);
        GetComponent<Rigidbody2D>().velocity = new Vector2(GetComponent<Rigidbody2D>().velocity.x, 0);
        GetComponent<Rigidbody2D>().AddForce(new Vector2(0, 10), ForceMode2D.Impulse);
        currentJumps++;
        CheckGroundCollision();
    }
}
}  

感谢所有帮助！

Answer 1

在void JumpLogic() ，您正在调用

currentJumps++;
CheckGroundCollision();

第一次按下跳转键时， currentJumps变为1（currentJumps ++），然后isGrounded再次变为true（因为在当前帧中尚未应用物理方法，并且角色仍在接触地面图层蒙版）。 因此，下次调用JumpLogic() ，由于if (isGrounded) currentJumps = 0;因此currentJumps重置为零if (isGrounded) currentJumps = 0; 在运行跳转键代码之前。

我建议删除对CheckGroundCollision();的最后一次调用CheckGroundCollision(); 在void JumpLogic()内部。 无论如何，它们都在Update()内部被调用，其顺序似乎可行。

希望对您有所帮助！

更新：我刚刚注意到您还调用CheckGroundCollision(); 第二次在Update()本身内部。 那也将重置跳转变量。

尝试对原始代码进行以下修改：

void Update() {
    CheckGroundCollision();
    JumpLogic();

    movement = new Vector3(Input.GetAxis("Horizontal") * speed, 0, 0);
    movement *= Time.deltaTime;
    transform.position += movement;

    //** NOTE- REMOVED THIS LINE
}

...

void JumpLogic()
{

    if (isGrounded)
        currentJumps = 0;

    if (Input.GetButtonDown("Jump") && currentJumps < maxJumps)
    {
        GameObject newJumpSound = (GameObject)GameObject.Instantiate(jumpSound, (Vector2)transform.position, transform.rotation);
        GameObject newJumpEffect = (GameObject)GameObject.Instantiate(jumpEffect, (Vector2)transform.position - new Vector2(0, 0.25f), transform.rotation);
        GameObject.Destroy(newJumpEffect, 0.2f);
        GetComponent<Rigidbody2D>().velocity = new Vector2(GetComponent<Rigidbody2D>().velocity.x, 0);
        GetComponent<Rigidbody2D>().AddForce(new Vector2(0, 10), ForceMode2D.Impulse);
        currentJumps++;

        //** NOTE- REMOVED THIS LINE
    }
}

希望对您有所帮助！

Answer 2

我建议让对撞机指示播放器控制器isGrounded的状态，而不要查询对撞机。 例如，继续执行andeart的建议，您的代码可能更像以下内容

void Update() {
    JumpLogic();

    movement = new Vector3(Input.GetAxis("Horizontal") * speed, 0, 0);
    movement *= Time.deltaTime;
    transform.position += movement;
}

//let the collider indicate to the player controller when
//a collision occurs, then determine if this collision is relevant
void OnCollisionEnter2D(Collision2D coll) {
    if(coll.IsTouchingLayers(groundAbles))    
      isGrounded = true;

    // or do some other check using layers or tags ....
}

void JumpLogic()
{
    if (isGrounded)
        currentJumps = 0;

    if (Input.GetButtonDown("Jump") && currentJumps < maxJumps)
    {
        GameObject newJumpSound = (GameObject)GameObject.Instantiate(jumpSound, (Vector2)transform.position, transform.rotation);
        GameObject newJumpEffect = (GameObject)GameObject.Instantiate(jumpEffect, (Vector2)transform.position - new Vector2(0, 0.25f), transform.rotation);
        GameObject.Destroy(newJumpEffect, 0.2f);
        GetComponent<Rigidbody2D>().velocity = new Vector2(GetComponent<Rigidbody2D>().velocity.x, 0);
        GetComponent<Rigidbody2D>().AddForce(new Vector2(0, 10), ForceMode2D.Impulse);
        currentJumps++;
    }
}

请参阅Collider2D.IsTouchingLayers，尤其是最下面的段落，它暗示着IsTouchingLayers方法相对于对撞机可能无法提供最准确的结果。