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

public class JumpBox : MonoBehaviour
{
[Range(0, 10)] public float jumpVelocity = 5f;
public LayerMask mask;
public float boxHeight;
private Vector2 playerSize;
private Vector2 boxSize;
private bool jumpRequest;
private bool grounded;
public float fallMultiplier = 2.5f;
public float LowJumpMultiplier = 2f;
private Rigidbody2D _rigidbody2D;

// Start is called before the first frame update
void Start()
{
    _rigidbody2D = GetComponent<Rigidbody2D>();
    playerSize = GetComponent<SpriteRenderer>().bounds.size;
    boxSize = new Vector2(playerSize.x * 0.8f, boxHeight);

}

// Update is called once per frame
void Update()
{
    if (Input.GetButtonDown("Jump") && grounded)
    {
        jumpRequest = true;
    }
}
private void FixedUpdate()
{
    //自然重力
    Gud();

    if (jumpRequest)
    {
        _rigidbody2D.AddForce(Vector2.up * jumpVelocity, ForceMode2D.Impulse);
        jumpRequest = false;
        grounded = false;
    }
    else
    {
        Vector2 boxCenter = (Vector2)transform.position + (Vector2.down * playerSize.y * 0.5f);
        if (Physics2D.OverlapBox(boxCenter, boxSize, 0, mask) != null)
        {
            grounded = true;
        }
        else
        {
            grounded = false;
        }
    }
}

private void Gud()
{
    if (_rigidbody2D.velocity.y < 0)
    {
        _rigidbody2D.gravityScale = fallMultiplier;
    }
    else if (_rigidbody2D.velocity.y > 0 && !Input.GetButton("Jump"))
    {
        _rigidbody2D.gravityScale = LowJumpMultiplier;
    }
    else
    {
        _rigidbody2D.gravityScale = 1f;
    }
}

private void OnDrawGizmos()
{
    if (grounded)
    {
        Gizmos.color = Color.red;
    }
    else
    {
        Gizmos.color = Color.green;
    }

    Vector2 boxCenter = (Vector2)transform.position + (Vector2.down * playerSize.y * 0.5f);
    Gizmos.DrawWireCube(boxCenter, boxSize);
}

}