Physics2D.OverlapBox shows inconsistent behaviour - unity3d

Question

Recently I started working with Unity, this is the first time I'm trying to build a 2d platformer.
For some reason, when I press the jump button, there is a random chance that it will actually make the player jump. Probably around 1 in 50 that it actually jumps.
I just can't figure out why its doing that. Do you know what I'm doing wrong here?
using UnityEngine;
public class Player : MonoBehaviour
{
public float movespeed = 5f;
public float jumpforce = 5f;
public Rigidbody2D player;
public LayerMask layerMaskPlatforms;
private float movementHorizontalInput;
private bool jumpInput;
private float lastTimeOnGroundInSeconds = 0f;
private float lastTimePressedJump = 0f;
void OnBecameInvisible()
{
// todo: restart game
}
void Update()
{
movementHorizontalInput = Input.GetAxisRaw("Horizontal");
jumpInput = Input.GetButtonDown("Jump");
}
void FixedUpdate()
{
if (jumpInput)
{
AttemptJump();
lastTimePressedJump = 0.2f;
}
else if (lastTimePressedJump > 0)
{
AttemptJump();
lastTimePressedJump -= Time.deltaTime;
}
if (IsOnGround())
{
lastTimeOnGroundInSeconds = 0.2f;
}
else if (lastTimeOnGroundInSeconds > 0)
{
lastTimeOnGroundInSeconds -= Time.deltaTime;
}
player.velocity = new Vector2(movementHorizontalInput * movespeed * Time.deltaTime * 50f, player.velocity.y);
}
private void AttemptJump()
{
if (lastTimeOnGroundInSeconds > 0)
{
player.AddForce(new Vector2(0, jumpforce), ForceMode2D.Impulse);
lastTimeOnGroundInSeconds = 0;
}
}
private bool IsOnGround()
{
Vector2 groundedCheckPosition = (Vector2)transform.position + new Vector2(0, -0.01f);
var overlapBox = Physics2D.OverlapBox(groundedCheckPosition, transform.localScale, 0, layerMaskPlatforms);
return overlapBox;
}
}

Answer 1

One major issue is that the jump input is being polled every frame (Update), but the jump code is done every several frames (FixedUpdate), so if you press jump, it is most likely the FixedUpdate method will never see that jump, explaining why it happens so rarely.
You'd need to save the jump state (maybe in a boolean), so by the time Fixed Update happens, it knows that that a jump occurred. Then set that jump to false, and do the jump logic.