How to Make Health Decrease Over Time

Questions & Answers
1

Hi all,

I have been trying without luck to implement other people’s code from similar questions to my own script. Basically I have a health bar that I would like to be constantly ticking down e.g. losing 1 health point/second. Here is the code, any help would be greatly appreciated. Thanks in advance.

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


public class HealthController : MonoBehaviour
{
    public UnityEngine.Events.UnityEvent OnDeath;

    [SerializeField] public float playerHealth;
    [SerializeField] public float maxHealth;
    [SerializeField] public Image healthImage;

    [SerializeField] public int damage;

    void Start()
    {

    }

    public void ButtonClick()
    {
        playerHealth -= damage;
        UpdateHealth();
        if(playerHealth < 0)
            OnDeath.Invoke();
    }



    private void UpdateHealth()
    {
        healthImage.fillAmount = playerHealth / maxHealth;
    }

   

}
2

@emersonmaxwell, you can do that in different ways, here are 3:

  1. InvokeRepeating

        void Start () 
 {
     InvokeRepeating("UpdateHealth", 1f, 1f);  //1s delay, repeat every 1s
 }

 void UpdateHealth() 
 {
 }

  2. Coroutine

        IEnumerator Start() 
 {
     while(true) 
     {
         yield return new WaitForSeconds(1f);
         UpdateHealth();
     }
 }
 void UpdateHealth() 
 {
 }

  3. Update

        float elapsed = 0f;
  
  void Update() 
  {
      elapsed += Time.deltaTime;
      if (elapsed >= 1f) 
      {
          elapsed = elapsed % 1f;
          UpdateHealth();
      }
  }
 
  void UpdateHealth() 
  { 
  }
3

Thank you very much Rodrigo this works perfectly and I really appreciate your help. I used your second method like so:

    [SerializeField] public int damagetaken;

    IEnumerator Start()
    {
        while (true)
        {
            yield return new WaitForSeconds(2f);
            playerHealth += damagetaken;
            UpdateHealth();

        }
    }

Then in the Inspector I am able to add a value to the Damage Taken thus controlling how much damage per second occurs.

Thanks again!