Develop Reference

GameObject.FindGameObjectsWithTag("Enemy").Length off by one for some reason?

so I'm wanting to pause the game once the amount of enemies hits 0. So I'm using GameObject.FindGameObjectsWithTag("Enemy").Length to find the number of enemies. I put this in a function that's called right when the enemies are instantiated so I can see the length go to 4, as there's 4 enemies spawning. When an enemy is killed the function is called again where the length is printed to console again. For some reason, on the first enemy killed the count repeats with a 4 again despite there only being 3 enemies. Once another enemy is killed it reports 3 when there's actually 2 and so on until I get to 1 when there's 0 enemies.
Here's the first snippet of code:
public class EnemyList : MonoBehaviour
{
public List<GameObject> weakMobs = new List<GameObject>();
public List<GameObject> mediumMobs = new List<GameObject>();
public List<GameObject> bossMobs = new List<GameObject>();
public List<Transform> spawningChildren = new List<Transform>();
public static int mobCount;
void Start()
{
for (int i = 0; i < spawningChildren.Count; i++)
{
GameObject newWeakMob = Instantiate(weakMobs[0], spawningChildren[Random.Range(0, 4)]) as GameObject;
}
CheckMobCount();
}
public void CheckMobCount()
{
mobCount = GameObject.FindGameObjectsWithTag("Enemy").Length;
print(mobCount);
}
The next piece of code is where the enemy is killed and the CheckMobCount() is called again.
public void TakeDamage()
{
enemyCurrentHealth -= 25;
enemyHealthBar.SetHealth(enemyCurrentHealth);
if (enemyCurrentHealth == 0)
{
Destroy(this.gameObject);
enemyList.CheckMobCount();
//needs death animations
}
}
Here's the console messages:
Console of printed lengths
I'm self taught so I apologize if this is elementary. I've tried doing this several different ways and this is the closest I've been but I'm open to new ideas as well.
Thank you!!

As noted in this answer, the object is not actually destroyed in the current frame.
From the documentation:
The object obj is destroyed immediately after the current Update loop… Actual object destruction is always delayed until after the current Update loop, but is always done before rendering.
I also agree that using DestroyImmediate() is a bad idea.
Ultimately, your question seems to really be about pausing the game when the enemy count reaches 0, which unfortunately hasn't actually been answered yet.
In fact, you don't really need to do anything different except move the check for the enemy count to the beginning of the Update() method, and pause the game there if it's 0. Then you'll find that the component for the enemy has been destroyed at that point.
Presumably enemies are spawned before the update loop starts (i.e. before the first frame), but if not then you can use whatever logic you're already using to decide that new enemies need to be spawned, to detect the fact that you haven't spawned any yet and avoid pausing before the enemies have spawned.

Here you have attached your script to your enemy instances. And they are still alive when you are querying for the number of enemies left.
You should do the following:
public class Enemy: MonoBehaviour
{
public static int EnemyCount = 0;
private void Start()
{
EnemyCount++;
}
private void OnDestroy()
{
EnemyCount--;
}
}
And then you can query the enemy count from anywhere but just excessing the EnemyCount by Enemy.EnemyCount.
If you want to get a more difficult example then you can check out this Game Dev tutorial: https://www.youtube.com/watch?v=LPBRLg4c5F8&t=134s

Destroy is actually executed at the end of the frame. There is DestroyImmediate that is executed immidiatelly but it's not recommended to be used. What I would do is to add a field or a property to identify whether the enemy is still alive and then to check against it. Something like:
class Enemy : MonoBehaviour
{
public bool IsAlive { get; set; } = true;
}
public class EnemyList : MonoBehaviour
{
//...
public void CheckMobCount()
{
mobCount = GameObject.FindGameObjectsWithTag("Enemy").Select(x => x.GetComponent<Enemy>()).Count(x => x.IsAlive);
print(mobCount);
}
}
And then:
public void TakeDamage()
{
enemyCurrentHealth -= 25;
enemyHealthBar.SetHealth(enemyCurrentHealth);
if (enemyCurrentHealth == 0)
{
Destroy(this.gameObject);
this.GetComponent<Enemy>().IsAlive = false;
enemyList.CheckMobCount();
//needs death animations
}
}
This can be further optimized to store the Enemy somewhere and not use GetComponent every time but you get the idea.

As already mentioned by others the issue is that Destroy is executed delayed.
Actual object destruction is always delayed until after the current Update loop, but is always done before rendering.
You could simply count only the GameObjects that are still alive, those for which the bool operator is true.
Does the object exist?
It will be false for objects destroyed in that same frame.
E.g. using Linq Count
using System.Linq;
....
mobCount = GameObject.FindGameObjectsWithTag("Enemy").Count(e => e);
which basically equals doing
mobCount = 0;
foreach(e in GameObject.FindGameObjectsWithTag("Enemy"))
{
if(e) mobCount++;
}
There is no need for an additional property or Component.

I am suggesting you to use “DestroyImmediate” instead of “Destroy”，Then look at the result.
I have a better idea, why not just use static variables when spawning enemies?
void Start()
{
for (int i = 0; i < spawningChildren.Count; i++)
{
GameObject newWeakMob = Instantiate(weakMobs[0],
spawningChildren[Random.Range(0, 4)]) as GameObject;
mobCount++;
}
}

Do not use Linq
Do not use DestroyImmediate (it will freeze and bug your game, probably)
Avoid FindGameObjectsWithTag in loops, only in initialization.
Track your enemies in an array or list
When you destroy an enemy, remove it's reference from the list
Use the list count/length to get the real actual number.

Unity PlayerPrefs is not updating my 'high score'

I'm making a 2D game where you're in the middle of the screen and you move round an endless green (screen) world and white cubes spawn randomly around you, and I have finished the game mechanics and a main menu and game over screens. The one thing I'm trying to add now is a high score. I did a bit of research and found PlayerPrefs is probably the way to do it. I have a seperate scene for my main menu and my gameplay level (which includes the game over screen). I have no error messages. I have created a HSSetter (High Score Setter) script on the high score text in the main menu screen:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
public class HSSetter : MonoBehaviour
{
public Text highScoreText;
// Start is called before the first frame update
void Start()
{
highScoreText.text = "High Score: " + PlayerPrefs.GetInt("HighScore").ToString();
}
// Update is called once per frame
void Update()
{
highScoreText.text = "High Score: " + PlayerPrefs.GetInt("HighScore").ToString();
}
}
and in my score script which is in my actual game level, here's the bit where I try to create the high score:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
public class score : MonoBehaviour
{
public int scoreCount = 0;
public int highScoreIFA;
void Start()
{
highScoreIFA = PlayerPrefs.GetInt("HighScore");
}
void Update()
{
if (scoreCount >= highScoreIFA)
{
PlayerPrefs.SetInt("HighScore", scoreCount);
}
}
public void AddToScore()
{
if (isHit == true) // i know this if loop works
{
scoreCount += 1; // and this, I use it to change the score text in-game.
isHit = false;
}
}
}
In AddToScore(), I increment scoreCount.
Through some debugging, I have found that everything in the HSSetter script works - when I change the highScoreText.text, the text on screen changes, which led me to believe the issue might be with the change of scenes? Thanks!

Multiple things you should do here
The first you already updated in your question afterwards: You had the condition wrong and always updated only
if(highScoreIFA > scoreCount)
which would almost always be the case.
Now you have changed it to
if(scoreCount >= highScoreIFA)
which still is not good since if the score is equal there is no reason to update it, yet.
I would rather use
if(scoreCount > highScoreIFA)
so only really update it when needed.
Secondly in both scripts do not use Update at all! That is extremely inefficient.
I would rather use event driven approach and only change and set stuff in the one single moment it actually happens.
You should only one single class (e.g. the score) be responsible and allowed to read and write the PlayerPrefs for this. I know lot of people tent to use the PlayerPrefs for quick and dirty cross access to variables. But it is exactly this: Quick but very dirty and error prone.
If you change the keyname in the future you'll have to do it in multiple scripts.
Instead rather let only the score do it but then let other scripts reference it and retrieve the values directly from that script instead
And finally you should use
PlayerPrefs.Save();
to create checkpoints. It is automatically done in OnApplicationQuit, bit in case your app is force closed or crashes the User would lose progress ;)
Might look like
public class score : MonoBehaviour
{
public int scoreCount = 0;
// Use an event so every other script that is interested
// can just register callbacks to this
public event Action<int> onHighScoreChanged;
// Use a property that simply always invoked the event whenever
// the value of the backing field is changed
public int highScoreIFA
{
get => _highScoreIFA;
set
{
_highScoreIFA = value;
onHighScoreChanged?.Invoke(value);
}
}
// backing field for the public property
private int _highScoreIFA;
private void Start()
{
highScoreIFA = PlayerPrefs.GetInt("HighScore");
}
public void AddToScore()
{
if (isHit == true) // i know this if loop works
{
scoreCount += 1; // and this, I use it to change the score text in-game.
isHit = false;
// Only update the Highscore if it is greater
// not greater or equal
if (scoreCount > highScoreIFA)
{
PlayerPrefs.SetInt("HighScore", scoreCount);
// Save is called automatically in OnApplicationQuit
// On certain checkpoints you should call it anyway to avoid data loss
// in case the app is force closed or crashes for some reason
PlayerPrefs.Save();
}
}
}
}
Then your other script only listens to the event and updates its display accordingly. It is even questionable if both scripts should not rather simply be one ;)
public class HSSetter : MonoBehaviour
{
public Text highScoreText;
// Reference your Score script here
[SerializeField] private score _score;
private void Awake ()
{
// Find it on runtime as fallback
if(!_score) _score = FindObjectOfType<score>();
// Register a callback to be invoked everytime there is a new Highscore
// Including the loaded one from Start
_score.onHighScoreChanged += OnHighScoreChanged;
}
private void OnDestroy()
{
_score.onHighScoreChanged += OnHighScoreChanged;
}
private void OnHighScoreChanged(int newHighScore)
{
highScoreText.text = $"High Score: {newHighScore}";
}
}

How to get variables/functions from a child GameObject?

Hello! I am trying to make a room that will generate a random Layout from a list and get a variable from that layout. I have had some trouble with this since the layout is not there from the start of the game, and I have been working on this problem for a few days now. Currently, the "Room" GameObject searches it's children for the ones tagged "Layouts", then, after finding that GameObject, the code gets the "waves" variable from the Layouts component of the Layout. The code is here:
foreach (Transform child in transform)
{
if (child.tag == "Layouts")
{
layout = child.gameObject.GetComponent<Layout>();
}
}
layout.testFunction();
totalKillsNeeded = layout.waves;
When I run the code, nothing happens. No errors or anything. testFunction doesn't run, despite my Visual Studio showing the reference between the two scripts, and totalKillsNeeded returns 0 despite me checking and seeing that layout.waves equals 1 or 2. I have tried multiple methods of getting the Layout script, all of which have returned the same result. It is probably something small I havn't considered, but I still have not been able to figure it out. Thank you!

Your code should work, but in case, try this. Here's ScriptA.cs, put this on the parent
using UnityEngine;
public class ScriptA: MonoBehaviour
{
int totalKillsNeeded = 0;
ScriptB layout;
// Start is called before the first frame update
void Start()
{
foreach(Transform child in transform)
{
if(child.CompareTag("Layouts"))
{
layout = child.gameObject.GetComponent<ScriptB>();
}
}
layout.testFunction();
totalKillsNeeded = layout.waves;
Debug.Log($"Total Kills needed: {totalKillsNeeded}, layout waves {layout.waves}");
}
}
And ScriptB.cs, put this on the Child game objects, and set the wave in inspector if needed
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class ScriptB: MonoBehaviour
{
public int waves = 12;
public void testFunction()
{
Debug.Log("Test Function Called, waves: {waves}");
}
}
Console output:
The hierarchy should look something like this:
If your last child has 0 waves, your for loop will only show the last one:

Having trouble creating a duplicate of a game object with input.getkeydown(KeyCode.Space) in C# and Unity

kinda new to coding so help would be appreciated. I'm trying to duplicate this GameObject "cube" in unity and I'm having trouble with it. what im trying to do is duplicate the cube and get it to stack on top of each other over and over.
I know if i got this to work it would duplicte it in the same postion so you would only see it duplicate in the higharchy.
using System.Collections;
using UnityEngine;
public class cube : MonoBehaviour
{
public GameObject cube1;
public void update()
if(input.getKeyDown(KeyCode.Space))
{
instantiate cube1;
}
}

I assume you know the height of the cube, you are working with. In unity the default height is 1.0f(For the primitive cube).
Btw if your code is a pseudo code then its okey but if not, you need more training before writing such scripts, even tho this type of script is extremely easy to write.
(ps: i wrote this script in notepad++ hope it compiles :/)
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
// We start classes with capital letters in c# its a convention :)
public class Cube : MonoBehaviour
{
// Same applies to public class fields & Properties
// Marking a MonoBehaviour field as public will allow you to directly assign values to it
// inside the editor
public GameObject OriginalCube;
// Same can be achieved with private fields using the serializefield attribute
[SerializeField]
private float cubeHeight = 1.0f;
// In case you would like to store the duplicated cubes
public List<GameObject> Cubes = new List<GameObject>();
private void Awake()
{
// Adding the first cube to the list, i assume your cube is already in the scene
Cubes.Add(OriginalCube);
}
private void Update()
{
if(Input.GetKeyDown(KeyCode.Space))
{
// We instantiate a new cube and add it to the list
Cubes.Add(Instantiate(Cubes[Cubes.Count - 1]);
// We ask the previous cube position (the one we copied)
Vector3 previousCubePosition = Cubes[Cubes.Count - 2].transform.position;
// then we assign a new position to our cube raised by "1 unit" on the y axis which is the up axis in unity
Cubes[Cubes.Count - 1].transform.position =
new Vector3(previousCubePosition.x, previousCubePosition.y + cubeHeight, previousCubePosition.z);
}
}
}

One way you can have your goal achieved, is to add to your newly instantiated object's y position a constant amount. This constant amount will be increased each time you create a new duplicate of your object.
public GameObject cube1;
private int instantiateCounter = 0;
public float PULL_UP_AMOUNT = 30f;
public void Update()
{
if (Input.GetKeyDown(KeyCode.Space))
{
instantiateCounter++;
GameObject newCube = Instantiate(cube1);
newCube.transform.position = new Vector3(cube1.transform.position.x, cube1.transform.position.y + instantiateCounter * PULL_UP_AMOUNT, cube1.transform.position.z);
}
}
The constant amount we're talking about is PULL_UP_AMOUNT.
Keep in mind, you can access your new duplicate's properties by saving the result of Instantiate method inside a new GameObject, just like I did.

How can I get the text and save it in InputField?

I have an array InputFields, in my situation - six InputFields. How can I get the text and save it from each InputField?
Everything should work like this: I turn on the app, I change one, two or all of the input field, then turn off the application. Again, I turn on, and input fields have to be values which I wrote earlier.
I have a code that must seem to work properly, but this code works like this: it takes only the last value entered by the user and writes it to the last input field.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
public class SaveText : MonoBehaviour {
public GameObject[] InputFields;
public static string n;
public void Start ()
{
for(int i = 0; i < InputFields.Length; i++)
{
InputFields[i].GetComponent<InputField> ().text = PlayerPrefs.GetString (InputFields[i].name);
Debug.Log (PlayerPrefs.GetString (InputFields[i].name));
n = InputFields[i].name;
var input = InputFields[i].GetComponent<InputField> ();
var se = new InputField.SubmitEvent ();
se.AddListener (SubmitName);
input.onEndEdit = se;
}
}
public void SubmitName(string arg)
{
PlayerPrefs.SetString (n, arg);
}
An array of input fields I initialize dragging in Unity each input field in free cell in Script Component.

Well, you are using a single variable for all the different player prefs variables, n. So when you change a field (with SubmitName) it uses that n pref variable and changes it. This will correspond to the last value you gave to n in your loop.
An option would be to have that be an array too (private string prefValues[]) or to pass the calling input field to SubmitName (or rather it's name) and use that instead of n.
A little example (from your code you can actually change your GameObject[] to InputField[] which saves some GetComponent calls):
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
public class EventTest : MonoBehaviour
{
public InputField[] inputFields;
void Start ()
{
foreach(InputField field in inputFields)
{
var se = new InputField.SubmitEvent();
se.AddListener(delegate {
SubmitText(field.name, field.text);
});
field.onEndEdit = se;
}
}
public void SubmitText(string prefKey, string prefVal)
{
Debug.Log("Saved " + prefVal + " to " + prefKey);
}
}
Edit:
Added lines for saving/loading from prefs in the code below. For my test setup I just have two scenes. Both have two input fields and a button that calls that scene change. I can type stuff on the fields as I like, change scenes and it stays. Also upon restarting playmode in the editor.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.SceneManagement;
public class EventTest : MonoBehaviour
{
public InputField[] inputFields;
void Start ()
{
foreach(InputField field in inputFields)
{
// Get field values from player prefs if existing
// (it should only not exist the very first time or if you delete/clear the prefs)
if(PlayerPrefs.HasKey(field.name))
field.text = PlayerPrefs.GetString(field.name);
var se = new InputField.SubmitEvent();
se.AddListener(delegate {
SubmitText(field.name, field.text);
});
field.onEndEdit = se;
}
}
public void SubmitText(string prefKey, string prefValue)
{
// store the typed text of the respective input field
PlayerPrefs.SetString(prefKey, prefValue);
}
public void ChangeScene()
{
if(SceneManager.GetActiveScene().name == "Scene1")
{
SceneManager.LoadScene("Scene2");
}
else
{
SceneManager.LoadScene("Scene1");
}
}
}

If you want to save the data, after the application stopped or if it gets paused, you need to add some more functions to your MonoBehavior so that it can handle additional actions on a system end or pause.
Look at following functions in the documentation
OnApplicationQuit()
OnApplicationPause()
These functions will be called automatically. Inside these functions you need to iterate through the textfields and save them. It is one of the last functions that will be called before the program will lose it's recourses.
Regarding the Scene change, you would need the new scene to tell the old one to do any further actions. Like you can read in this post, there is only a way to know if a new scene was loaded.
Maybe you have a place where you can save the last active scene object and then call the last scenes function to do the saving process while the object is not cleared.