Unity2D中的双跳限制

Question

Looking at help forums on Unity, I figured out quickly that the syntax I was looking at was really outdated (Same thing on here: Unity Doublejump in C# ).

Here's the article I was talking about: http://answers.unity3d.com/questions/753238/restrict-number-of-double-jumps.html

For instance, in the void Awake(), in the current version of Unity I'm using, it says that rigidbody2D.fixedAngle = true; was no longer supported, and I needed to use constraints on the gameObject I was trying to program (what axis should I use... the x,y or z?). After doing some editing and after looking up the error messages, I was able to change all of the rigidbody2D.velocity into the updated syntax, which was GetComponent ().velocity .

Here's my code:

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

    public class NewBehaviourScript : MonoBehaviour {

public float speed = 6.0f;
//public float j
Transform groundCheck;
//private float overlapRadius = 0.2f;
public LayerMask whatisGround;
private bool grounded = false;
private bool jump = false;
public float jumpForce = 700f;
private bool doubleJump = false;
public int dJumpLimit = 5;

void Start()
{
    groundCheck = transform.Find ("groundcheck");
    PlayerPrefs.SetInt ("doublejumps", dJumpLimit);
}

void Update()
{
    if (Input.GetKey(KeyCode.Space)) 
    {
        jump = true;
    }
    //perhaps put A and D here?
}
void FixedUpdate()
{
    //to check if Mario is on the ground

    //overlap collider replace Overlap Circle???
    //overlap point??
    //grounded = GetComponent<Rigidbody2D> ().OverlapCollision(groundCheck.position, overlapRadius, whatisGround);

    if (grounded)
        doubleJump = false;

    if (dJumpLimit < 1)
        doubleJump = true;

    bool canJump = (grounded || !doubleJump);

    if (jump && canJump) {
        GetComponent<Rigidbody2D> ().velocity = new Vector2 (GetComponent<Rigidbody2D> ().velocity.x, 0);
        GetComponent<Rigidbody2D> ().AddForce (new Vector2 (0, jumpForce));

        if (!doubleJump && !grounded) {
            doubleJump = true;
            dJumpLimit--;

        }

    }

        jump = false;


        //code that will work with the limits?
        //GetComponent<Rigidbody2D>().velocity = new Vector2(speed,GetComponent<Rigidbody2D>().velocity.y);

        //this will make it stack?
        //GetComponent<Rigidbody2D>().velocity = new Vector2(speed,GetComponent<Rigidbody2D>().velocity.x);
        //GetComponent<Rigidbody2D>().velocity = new Vector2(speed,GetComponent<Rigidbody2D>().velocity.y);
    }

}

Good thing is that it was able to compile in the end. But I still don't know how the constraints work (they resist motion on the x,y,z axis right?). The jumps still don't have a capstone, and the variable dJumpLimit doesn't seem to stop all the jumping! I had also lot of trouble trying to decipher what the booleans were trying to accomplish, and it would help a lot if you tell me what the outdated code was trying to do, and what I failed doing so. That would help me a lot.Thanks so much for helping!!!

Answer 1

I have added the same code with some additional comments to help you.

The basic idea is to allow jumping under certain conditions, and allow double jumping under certain other conditions,

Try to think about it logically, Mario can only jump when he is on the ground, so we need to check that every frame . If he is grounded, and the player presses space, we make him jump.

Now, we want Mario to be able to double-jump but only if he is already in the air (otherwise it's just a regular jump) and only if he has not already double-jumped in this "current" jump.

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

public class NewBehaviourScript : MonoBehaviour {

    public float speed = 6.0f;
    //public float j
    Transform groundCheck;  // For checking if grounded
    //private float overlapRadius = 0.2f;  // For checking if grounded
    public LayerMask whatisGround;  // A layer mask to distinguish what is considered as ground
    private bool grounded = false;  // True when Mario is touching ground
    private bool jump = false;      // Flag to check when player intends to jump
    public float jumpForce = 700f;  // How much force we will apply to our jump
    private bool doubleJump = false;  // This becomes true once we have double-jumped
    public int dJumpLimit = 5;  // A limit to prevent too many jumps happening

    void Start()
    {
        // Find the Transform called "groundcheck"
        groundCheck = transform.Find ("groundcheck"); 
        // Set the PlayerPrefs integer called "doublejumps" to the value of dJumpLimit
        PlayerPrefs.SetInt ("doublejumps", dJumpLimit);
    }

    void Update()
    { 
        // If Space is being pressed...
        if (Input.GetKey(KeyCode.Space)) 
        {
            jump = true;  // Set jump bool to true to indicate our intention to jump
        }
    //perhaps put A and D here?
    }

    void FixedUpdate()
    {
        //to check if Mario is on the ground - this is necessary so we can't jump forever

        //overlap collider replace Overlap Circle???
        //overlap point??
        //grounded = GetComponent<Rigidbody2D> ().OverlapCollision(groundCheck.position, overlapRadius, whatisGround);

        // If Mario is touching ground...
        if (grounded)
            doubleJump = false;  // Make sure that as we are grounded we are not allowed to "jump again"

        if (dJumpLimit < 1)
            doubleJump = true;
        // Set a new bool to true if grounded is true OR doubleJump is false
        bool canJump = (grounded || !doubleJump);

        // If the player pressed space AND we are allowed to jump...
        if (jump && canJump) {
            // Apply existing x velocity to the x direction 
            GetComponent<Rigidbody2D> ().velocity = new Vector2 (GetComponent<Rigidbody2D> ().velocity.x, 0);
            // Apply our jump force to the y direction 
            GetComponent<Rigidbody2D> ().AddForce (new Vector2 (0, jumpForce));

        // If doubleJump is false AND we are not grounded...
        if (!doubleJump && !grounded) {
            doubleJump = true;  // We have double jumped so set to true
            dJumpLimit--;  // Decrement one from dJumpLimit
        }
    }

        jump = false;  // Reset the jump bool to false

        //code that will work with the limits?
        //GetComponent<Rigidbody2D>().velocity = new Vector2(speed,GetComponent<Rigidbody2D>().velocity.y);

        //this will make it stack?
        //GetComponent<Rigidbody2D>().velocity = new Vector2(speed,GetComponent<Rigidbody2D>().velocity.x);
        //GetComponent<Rigidbody2D>().velocity = new Vector2(speed,GetComponent<Rigidbody2D>().velocity.y);
    }
}