Trying to reduce my lives int from another script

Unity Engine
1

How could I reduce the amount of lives I have in a game based upon a collision with two different objects? I have a manager object to keep track of lives, but I want a life to be subtracted when two different objects collide. I’ll post my scripts below:

Object that I would like to subtract the life; specifically, where I placed the _gameManager.SubtractLife() method:

public class DeathBarrier : MonoBehaviour
{
    private GameManager _gameManager;

    private void Start()
    {
        GetComponent<GameManager>().SubtractLife();
    }
    private void OnCollisionEnter2D(Collision2D collision)
    {
        int NumberOfBallsLeft = FindObjectsOfType<Ball>().Length;
        if (collision.transform.CompareTag("Ball") && NumberOfBallsLeft > 1)
        {
            Destroy(collision.gameObject);
        }
        else if (collision.transform.CompareTag("Ball") && NumberOfBallsLeft <= 1)
        {
            _gameManager.SubtractLife();
            FindObjectOfType<Ball>().ResetPosition();
        }
        else if (collision.transform.CompareTag("Powerup"))
        {
            Destroy(collision.gameObject);
        }
    }
}

The game Manager itself:

namespace SampleGame
{
    public class GameManager : MonoBehaviour
    {
        #region LIVES
        // number of lives & images
        public GameObject heart1, heart2, heart3, heart4, heart5, gameover;
        public static int life;

        // are we alive?
        private bool dead;
        #endregion
        // reference to player
        private KeyboardControls _player;

        // reference to player
         private Level _level;

        private bool _isGameOver;
        public bool IsGameOver { get { return _isGameOver; } }

        private static GameManager _instance;
        public static GameManager Instance { get { return _instance; } }

       [SerializeField] private TransitionFader _endTransitionPrefab;

        // initialize references
        private void Awake()
        {
            life = 3;
            heart1.gameObject.SetActive(true);
            heart2.gameObject.SetActive(true);
            heart3.gameObject.SetActive(true);
            heart4.gameObject.SetActive(false);
            heart5.gameObject.SetActive(false);
            gameover.gameObject.SetActive(false);
            if (_instance != null)
            {
                Destroy(gameObject);
            }
            else
            {
                _instance = this;
            }

            _player = FindObjectOfType<KeyboardControls>();
            _level = FindObjectOfType<Level>();
        }

        private void OnDestroy()
        {
            if (_instance == this)
            {
                _instance = null;
            }
        }

        // end the level
       public void EndLevel()
        {
            if (_player != null)
            {
                // disable the player controls
                KeyboardControls keyboardControls =
                    _player.GetComponent<KeyboardControls>();

                if (keyboardControls != null)
                {
                    keyboardControls.enabled = false;
                }

                // remove any existing motion on the player
                Rigidbody rbody = _player.GetComponent<Rigidbody>();
                if (rbody != null)
                {
                    rbody.velocity = Vector3.zero;
                }
            }

            // check if we have set IsGameOver to true, only run this logic once
            if (!_isGameOver)
            {
                _isGameOver = true;
                StartCoroutine(WinRoutine());
            }
        }
       
        private IEnumerator WinRoutine()
        {
            TransitionFader.PlayTransition(_endTransitionPrefab);
            float fadeDelay = (_endTransitionPrefab != null) ? _endTransitionPrefab.Delay + _endTransitionPrefab.FadeOnDuration : 0f;
            yield return new WaitForSeconds(fadeDelay);
            WinScreen.Open();
        }

        // check for the end game condition on each frame
        private void Update()
        {
            {
                ParametersForDeath();
                if (dead == true)
                {
                    FindObjectOfType<SceneLoader>().LoadStartScene();
                }
            }
                if (life > 5)
            life = 5;

        switch (life)
        {

            case 5:
                heart1.gameObject.SetActive(true);
                heart2.gameObject.SetActive(true);
                heart3.gameObject.SetActive(true);
                heart4.gameObject.SetActive(true);
                heart5.gameObject.SetActive(true);
                gameover.gameObject.SetActive(false);
                break;
            case 4:
                heart1.gameObject.SetActive(true);
                heart2.gameObject.SetActive(true);
                heart3.gameObject.SetActive(true);
                heart4.gameObject.SetActive(true);
                heart5.gameObject.SetActive(false);
                gameover.gameObject.SetActive(false);
                break;
            case 3:
                heart1.gameObject.SetActive(true);
                heart2.gameObject.SetActive(true);
                heart3.gameObject.SetActive(true);
                heart4.gameObject.SetActive(false);
                heart5.gameObject.SetActive(false);
                gameover.gameObject.SetActive(false);
                break;
            case 2:
                heart1.gameObject.SetActive(true);
                heart2.gameObject.SetActive(true);
                heart3.gameObject.SetActive(false);
                heart4.gameObject.SetActive(false);
                heart5.gameObject.SetActive(false);
                gameover.gameObject.SetActive(false);
                break;
            case 1:
                heart1.gameObject.SetActive(true);
                heart2.gameObject.SetActive(false);
                heart3.gameObject.SetActive(false);
                heart4.gameObject.SetActive(false);
                heart5.gameObject.SetActive(false);
                gameover.gameObject.SetActive(false);
                break;
            case 0:
                heart1.gameObject.SetActive(false);
                heart2.gameObject.SetActive(false);
                heart3.gameObject.SetActive(false);
                heart4.gameObject.SetActive(false);
                heart5.gameObject.SetActive(false);
                gameover.gameObject.SetActive(true);
                Time.timeScale = 0;
                break;
        }
}
public void SubtractLife(){ life--; }
public void ParametersForDeath()
{
    if (life <= 0) { dead = true; }
    else { dead = false; }
}
public void AddLife()
{
    life++;
}
    }
}
2

You already appear to have a singleton setup for you GameManager, so just access it through that.

GameManager._instance.SubtractLife();

Otherwise, this code

GetComponent<GameManager>().SubtractLife();

Only works if the GameManager is on the same gameobject as the DeathBarrier script. There are ways to access it on other gameobjects, but just use the singleton instead.

1 Like
3

Ah I solved this by making my variable public and dragging the gameManager inside. So close!

4

Yep, that is another option, the downside to that is if you spawn something new in the scene, you can’t drag and drop during runtime, thus the purpose of the singleton.