How to check if grounded with rigidbody

Question

Does anyone have a better way to make an object with a rigidbody check for ground and then jump, right now I wrote a script where a raycast is cast downwards and it checks for distance but then I discovered that a player can still jump when close to the ground and when I decrease the distance amount on raycast then the jumping works a few times (5 or 6) and then stops working, so I had to increase the distance a bit and add a delay so the player can't jump for some time after a jump. But I think there might be a better way of doing it. So does anyone have suggestions on how can I improve my script or what other method I can use to make a character with a rigidbody to check if grounded and jump?

Answer 1

Here is a simplified example of how you could implement a check to see if your gameObject is grounded or not. It is not perfect, but should probably work for your situation:

bool Grounded;

void OnCollisionStay2D(Collision2D collider)
{
    CheckIfGrounded ();
}

void OnCollisionExit2D(Collision2D collider)
{
    Grounded = false;
}

private void CheckIfGrounded()
{
    RaycastHit2D[] hits;

    //We raycast down 1 pixel from this position to check for a collider
    Vector2 positionToCheck = transform.position;
    hits = Physics2D.RaycastAll (positionToCheck, new Vector2 (0, -1), 0.01f);

    //if a collider was hit, we are grounded
    if (hits.Length > 0) {
        Grounded = true;
    }
}

Answer 2

What worked for me is the following:

private int countColliders = 0;

private void OnCollisionEnter(Collision collision) {
    countColliders++; 
}

private void OnCollisionExit(Collision collision) {
    countColliders--; 
}

private void IsGrounded() {
    return countColliders>0;
}

(after setting the player layer to Player and the ground layer to Ground and setting the collision table so that only Player and Ground layers collide).

Answer 3

Use the following script it will work well...

Animator anim;
Rigidbody2D rigid;
bool facingRight = true;
bool canJump = true;
public Transform startpos, endpos;
public LayerMask groundLayer;

void Start()
{
    rigid = gameObject.GetComponent<Rigidbody2D>();
    anim = gameObject.GetComponent<Animator>();
}
void Update()
{
    float move = Input.GetAxisRaw("Horizontal");
    anim.SetFloat("speed", Mathf.Abs(move));
    rigid.velocity = new Vector2(move * 5f, rigid.velocity.y);


    RaycastHit2D hit = Physics2D.Linecast(startpos.position, endpos.position, groundLayer.value);

    if (hit.collider != null)
    {
        canJump = true;
        anim.SetBool("jump", false);
    }
    if (Input.GetKeyDown(KeyCode.Space) && canJump == true)
    {
        anim.SetBool("jump", true);
        rigid.velocity = Vector2.up * 10f;
        canJump = false;
    }

    if (facingRight && move < 0)
    {
        facingRight = false;
        transform.rotation = Quaternion.Euler(transform.rotation.x, 180, transform.rotation.z);
    }
    else if (!facingRight && move > 0)
    {
        facingRight = true;
        transform.rotation = Quaternion.Euler(transform.rotation.x, 0, transform.rotation.z);
    }

}

Place 'startpos' empty object on the center of the character and 'endpos' empty object on the bottom of the character.