How can I make the health points constantly go down?

Questions & Answers
1

Here is my script:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Sprites;
using UnityEngine.UI;
using UnityEngine.SceneManagement;

public class PlayerController : MonoBehaviour 
{
	public float speed;
	public float jumpSpeed;
	public Rigidbody2D rb;
	public Text coinText;
	public Text healthText;
	public int maxHealth;

	private Vector3 movement;
	private bool canJump=false;
	private int coinAmount=0;
	private int healthPoints;

	void Start ()
	{
		healthPoints = maxHealth;
		rb = GetComponent<Rigidbody2D>();
		bool canJump = true;
		coinText.text = "Coins: " + coinAmount;
		healthText.text = "Health: " + healthPoints + "/" + maxHealth;
	}

	void Update () 
	{
		transform.rotation = new Quaternion (0.0f, 0.0f, 0.0f, 0.0f);
		if (Input.GetKey (KeyCode.A)) 
		{
			transform.Translate (-Vector3.right * Time.deltaTime * speed);
		}

		if (Input.GetKey (KeyCode.D))
		{
			transform.Translate (Vector3.right * Time.deltaTime * speed);
		}

		if (Input.GetKeyDown (KeyCode.Space)&&canJump) 
		{
			rb.AddForce (transform.up * jumpSpeed);
			canJump=false;
		}
	}
	IEnumerator OnCollisionEnter2D(Collision2D col) 
	{
		if (col.gameObject.tag == "Ground") 
		{
			canJump=true;
		}

		if (col.gameObject.tag == "Enemy")
		{
			while (col.gameObject.tag == "Enemy") 
			{
				healthPoints = healthPoints - 1;
				healthText.text = "Health: " + healthPoints + "/" + maxHealth;
				if (healthPoints <= 0) 
				{
					SceneManager.LoadScene (sceneName: "Game Over");
					yield break;
				}
				yield return new WaitForSeconds (1);
				yield break;
			}
		}
	}
	void OnTriggerEnter2D(Collider2D other)
	{
		if (other.tag == "Coin") 
		{
			other.gameObject.SetActive (false);
			coinAmount = coinAmount + 1;
			coinText.text = "Health: " + coinAmount;
		}
		if (other.tag == "Void")
		{
			healthPoints = healthPoints - healthPoints;
			healthText.text = "Extra Lives: " + healthPoints + "/" + maxHealth;
			if (healthPoints <= 0) 
			{
				SceneManager.LoadScene(sceneName:"Game Over");
			}
		}
	}
}

I need to make it so that when I’m touching the enemy, my health points slowly go down, but the health points stop going down once I am no longer touching the enemy. How can I do this?

2

Use OnTriggerStay2D trigger to lower the health.

This trigger will be called when the objects are touching each other… once the player is no longer touching the enemy, this will not be called.

Do NOT do this (that you have in your script):

while (col.gameObject.tag == "Enemy")

That will create an infinite loop and eventually crash your game.

All you need to do is use OnTriggerStay2D, as I mentioned, and if the tag is your Enemy tag, then remove health. You’ll probably need some sort of timer or something to make it reduce health every so often though (or reduce a very small amount of health at a time), as otherwise it will deplete at an extremely rapid rate (once per frame).