为什么当玩家在空中按下空格键跳跃时，再次按下空格键会再次跳得更高？

Question

public bool useCharacterForward = false;
        public bool lockToCameraForward = false;
        public float turnSpeed = 10f;
        public KeyCode sprintJoystick = KeyCode.JoystickButton2;
        public KeyCode sprintKeyboard = KeyCode.Space;
        public bool useJump = false;
        public Vector3 jump;
        public float jumpImpulse;

        private float turnSpeedMultiplier;
        private float speed = 0f;
        private float direction = 0f;
        private bool isSprinting = false;
        private Animator anim;
        private Vector3 targetDirection;
        private Vector2 input;
        private Quaternion freeRotation;
        private Camera mainCamera;
        private float velocity;
        private bool isGrounded;
        private Rigidbody rb;

        // Use this for initialization
        void Start()
        {
            anim = GetComponent<Animator>();
            mainCamera = Camera.main;
            rb = GetComponent<Rigidbody>();
            jump = new Vector3(0.0f, 2.0f, 0.0f);
        }

        private void OnCollisionStay(Collision collision)
        {
            if (collision.gameObject.tag == "Ground")
            {
                isGrounded = true;
            }
        }

        private void Update()
        {
            if (Input.GetKeyDown(KeyCode.Space) && isGrounded && useJump)
            {
                rb.AddForce(jump * jumpImpulse, ForceMode.Impulse);
                isGrounded = false;
            }
        }

即使玩家在空中并且即使我正在检查地面标签，我仍然可以在玩家跳跃后在空中时再次按下空间，它会跳跃并移动玩家在空中更高。

但我将 isGround 设置为 false 并且玩家离地面更高，并且仍然按下空间使其在空中跳跃时已经在空中。

此屏幕截图显示了地面对象是如何在层次结构中构建的。 玩家有一个胶囊对撞机和一个刚体。

有 3 个楼层对象：

Floor example

Answer 1

物理（刚体）仅在FixedUpdate 中更新。此外，OnCollisionStay 在每个对撞机的 FixedUpdate 循环内被调用。

在您的设置中，有一点机会在您第一次按下后再次触发OnCollisionStay，并将isGrounded 再次设置为true，让您稍后再跳一次。

我认为如果您将跳转移动到FixedUpdate 甚至OnCollisonStay 本身，它已经可以防止这种情况：

private bool isJump;
private bool isGrounded;

private void OnCollisionStay(Collision collision)
{
    // In general rather use CompareTag instead of ==
    // It causes an error If the tag is non-existent or has a typo making 
    // your debugging way easier and is also slightly more efficient
    if (collision.gameObject.CompareTag("Ground"))
    {
        isGrounded = true;
    }
}

private FixedUdpate()
{
    // Should we jump?
    if(isJump && isGrounded)
    {
        rb.AddForce(jump * jumpImpulse, ForceMode.Impulse); 
        isGrounded = false;
    }

    isJump = false;
}

private void Update()
{
    // As you already did correctly get single event user input in Update
    // in order to not miss one
    // I would check the cheaper bool flag first
    if (isGrounded && useJump && Input.GetKeyDown(KeyCode.Space))
    {             
        isJump = true;
    }
}

现在应该确保只能在与地面碰撞时应用跳跃