Develop Reference

Spawning random GameObject in map (no repetitions)

Im making a terror game, and i want to spawn little collectibles in my scene, my code works fine, but they repeat the world location in every instantiate:
using UnityEngine;
public class objectivesGeneration : MonoBehaviour
{
GameObject[] objSpawn;
GameObject objActual;
public GameObject obj;
int index;
void Start()
{
objSpawn = GameObject.FindGameObjectsWithTag("spawnObj");
}
void Update()
{
if (Input.GetKeyDown(KeyCode.I))
{
generateNewObj();
}
}
public void generateNewObj()
{
index = Random.Range(0, objSpawn.Length);
objActual = objSpawn[index];
createObj();
}
public void createObj()
{
Instantiate(obj, objActual.transform.position, objActual.transform.rotation);
}
}
Can somebody help me?

Your question can be understood in two ways. Leoverload gave the answer to the repeating position.
In case you do not want to repeat the same type of object (so all objects are unique), then do the following:
Turn objSpawn into a List<GameObject> variable and in the start() function, add all instances from the array that's returned from FindGameObjectsWithTag to it.
Turn objSpawn.Length into objSpawn.Count (which does the same but for lists)
In that same function add: objSpawn.Remove(objActual) at the end.
If those objects are destroyed at some point and you want to create new instances of destroyed objects, ensure that in their Destroy event, you Add(gameObject) to the list again.
Am giving you instructions instead of just code so you can learn to do this yourself in the future.
Also I have the feeling you need to learn how arguments\parameters work. Then you can ommit that objActual variable and instead pass the object to createObj(GameObject theObj) directly.

You are spawning the object in the same position objActual.transform.position
You should set the limits of the spawn with 2 variables, for example:
public float startx;
public float endx;
public float starty;
public float endy;
Then you can easily Instantiate randomly in this positions:
float posX = Random.Range(startx, endx);
float posy = Random.Range(starty, endy);
Instantiate(obj, new Vector3(posx, posy, transform.position.z, Quaternion.Identity);
And so you have a random spawn!

Thanks to AlexGeorg for the answer,
this was how my final code was
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.Linq;
public class objectivesGeneration : MonoBehaviour
{
public GameObject recipient;
public List<GameObject> objSpawns = new List<GameObject>();
int spawnSelected;
void Start()
{
//Set all the objs with the tag spawnLocation inside of the list
foreach (GameObject OBJ in GameObject.FindGameObjectsWithTag("spawnLocation"))
{
objSpawns.Add(OBJ);
}
}
private void Update()
{
if (Input.GetKeyDown(KeyCode.I))
{
//Check if there are more possible spawns
if (objSpawns.Count > 0)
generateNewObj(recipient);
}
}
public void generateNewObj(GameObject frasco)
{
//Get a random number of the list which contains one obj
spawnSelected = Random.Range(0, objSpawns.Count);
//Instantiate the GameObject in the location of the random selected object
Instantiate(frasco, objSpawns[spawnSelected].transform.position, objSpawns[spawnSelected].transform.rotation);
//Delete that possible location from the list
objSpawns.RemoveAt(spawnSelected);
}
}

C# spawn manager creating waves of enemies too quickly

I'm a beginner making my first game in Unity, following Unity's Create With Code course. I'm creating a shooter game that will use hand tracking. I haven't set up hand tracking yet so i created an OnTrigger input that explodes objects when I hit space. I created the spawn manager below to spawn waves of enemy attack, but they all the waves are spawning enemies too fast. It seems like they're spawning automatically instead of when the first wave has been destroyed.
Is there an easier way to spawn at a slower rate? Or spawn only when there are no more enemies alive?
EDIT: Added Attack script below
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class SpawnAttack : MonoBehaviour
{
public GameObject Trumps;
private float spawnRange = 9;
public int enemyCount;
public int waveNumber = 1;
void Start()
{
SpawnEnemyWave(waveNumber);
//InvokeRepeating("GenerateSpawnPosition", startDelay, randomInterval);
}
// Update is called once per frame
void Update()
{
enemyCount = FindObjectsOfType<Attack>().Length;
if(enemyCount == 0)
{
waveNumber++;
SpawnEnemyWave(waveNumber);
}
}
void SpawnEnemyWave(int enemiesToSpawn)
{
for (int i = 0; i < enemiesToSpawn; i++)
{
Instantiate(Trumps, GenerateSpawnPosition(), Trumps.transform.rotation);
}
}
private Vector3 GenerateSpawnPosition()
{
float spawnPosX = Random.Range(-spawnRange, spawnRange);
float spawnPosZ = Random.Range(-spawnRange, spawnRange);
Vector3 randomPos = new Vector3(spawnPosX, 0, spawnPosZ);
return randomPos;
}
}
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Attack : MonoBehaviour
{
public float speed = 0.5f;
public GameObject Player;
private Rigidbody enemyRb;
// Start is called before the first frame update
void Start()
{
enemyRb = GetComponent<Rigidbody>();
Player = GameObject.Find("Player");
this.transform.LookAt(Player.transform);
}
// Update is called once per frame
void Update()
{
Vector3 lookDirection = (Player.transform.position - transform.position).normalized;
enemyRb.AddForce(lookDirection * speed);
transform.Translate(Vector3.forward * Time.deltaTime * speed);
}
private void OnTriggerEnter(Collider other)
{
Destroy(gameObject);
Debug.Log("Game Over");
}
}

I guess that you can use the invoke method:
Invoke("NameOfTheMethod", 1f)
What this method does is that it waits a certain amount of seconds before calling a method. You have to write the name of the method in quotation marks and then select how long you want to wait before the method is called (The "1f" represents the delay in seconds.) In your case, you can make the script wait before spawning enemies.

I don't know your Attack script but I would use something like
public class Attack : MonoBehaviour
{
public static readonly HashSet<Attack> AliveAttackInstances = new HashSet<Attack>();
private void Awake()
{
AliveAttackInstances.Add(this);
}
private void OnDestroy()
{
AliveAttackInstances.Remove(this);
}
}
So you can all the time in a cheaper way check how many and which enemies are alive like
public class SpawnAttack : MonoBehaviour
{
// I would change this type here to make sure your spawned prefab actually
// HAS an Attack attached .. otherwise your enemyCount will always be 0
public Attack Trumps;
...
void Update()
{
if(Attack.AliveAttackInstances.Count == 0)
{
waveNumber++;
SpawnEnemyWave(waveNumber);
}
}
Then in order to add a certain delay before spawning the next wave you could use a simple timer like
public class SpawnAttack : MonoBehaviour
{
public Attack Trumps;
[SerializeField] private float delay = 1f;
private float timer;
...
void Update()
{
if(Attack.AliveAttackInstances.Count == 0)
{
timer -= Time.deltaTime;
if(timer <= 0)
{
timer = delay;
waveNumber++;
SpawnEnemyWave(waveNumber);
}
}
}

Try to use Coroutine.
Here's a video about Coroutines: https://www.youtube.com/watch?v=qolMYyq0nX0
My example:
public class Spawn : MonoBehaviour {
private float TimeToWait = 3f;
public int enemyCount = 0;
public int waveNumber = 0;
public GameObject enemy;
void Start()
{
StartCoroutine(SpawnEnemyWave(waveNumber));
}
void Update()
{
if (enemyCount == 0)
{
waveNumber++;
StartCoroutine(SpawnEnemyWave(waveNumber));
}
if (Input.GetMouseButtonDown(0))
{
enemyCount--;
}
}
IEnumerator SpawnEnemyWave(int enemiesToSpawn)
{
//"Things to do before the seconds."
for (int i = 0; i < enemiesToSpawn; i++)
{
enemyCount++;
}
yield return new WaitForSeconds(TimeToWait); // at this example we wait 3 seconds (float TimeToWait = 3f;)
//"Things to do after the seconds."
for (int i = 0; i < enemiesToSpawn; i++)
{
Debug.Log("New Enemy!");
Instantiate(enemy, transform.position, Quaternion.identity);
}
}
}

Unity 2D, C# - Why my OnCollisionEnter2D doesn't collide?

So, i created two scripts, one named "Stats.cs" registers the player stats and the other one named "PlayerHealth.cs" "makes" the player take damage on contact and updates the Hearts in the HUD. My problem is, whenever i collide with an object that has a tag named "Projectile" it simply doesn't work, my player doesn't take damage at all. The Stats.cs script isn't in any object, the PlayerHealth.cs is in my Player object.
Stats.cs
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
[System.Serializable]
public class Stats{
private int health;
public int maxHP = 3;
public int Health
{
get
{
//Some code
return health;
}
set
{
//Some code
health = Mathf.Clamp(value, 0, maxHP);
}
}
public void SetHealth()
{
Health = maxHP;
}
}
PlayerHealth.cs
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
public class PlayerHealth : MonoBehaviour
{
Stats playerStats = new Stats();
public int curHealth;
public int numOfHearts = 3;
public Image[] hearts;
public Sprite fullHeart;
public Sprite emptyHeart;
void OnCollisionEnter2D(Collision2D other)
{
if (other.gameObject.CompareTag("Projectile"))
{
Debug.Log("Hello");
DamagePlayer(1);
Destroy(other.gameObject);
}
}
public void DamagePlayer(int damage)
{
playerStats.Health -= damage;
}
// Start is called before the first frame update
void Start()
{
playerStats.SetHealth();
curHealth = numOfHearts;
}
// Update is called once per frame
void Update()
{
curHealth = playerStats.Health;
numOfHearts = playerStats.maxHP;
if (curHealth>numOfHearts){
curHealth = numOfHearts;
}
if(curHealth <= 0){
Die();
}
for (int i = 0; i < hearts.Length; i++)
{
if(i < curHealth){
hearts[i].sprite = fullHeart;
} else
{
hearts[i].sprite = emptyHeart;
}
if(i < numOfHearts){
hearts[i].enabled = true;
} else {
hearts[i].enabled = false;
}
}
}
void Die(){
//Restart
Application.LoadLevel(Application.loadedLevel);
}
}
curHealth is updating so it will stay as the actual Health in Stats and will change the images in HUD.
The Player has a RigidBody2D on him two colliders, one is a box for the body, and the other is a circle collider, so when the player crouches, the circle collider disables.
The Projectiles also have and RigidBody2D with 0 gravity (so it won't fall in mid air) and a BoxCollider2D.

I would check and make sure that the projectile is tagged as Projectile and that the BoxCollider doesn't have "Is Trigger" checked.
I should also say, iterating with that for loop in the Update is very bad practice performance wise. That is happening literally as fast as the machine can loop it and it is doing that every time. I would look into updating it on an event.
Hope this helps!

Next Scene Not Loading

My problem is that when all the enemies are killed the scene that should be loaded is not loading. I did add the scene to the Build setting (it has an index of 3) but it is still not loading. The script I created is attached to an empty object and not directly to the sprite (is that okay?). Can someone tell me why the scene isn't loading? Thank you.
This image is for to show you the EnemySpawner empty object inspector
EnemySpawner Script :
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
public class EnemySpawner : MonoBehaviour {
[SerializeField] GameObject EnemyPreFab;
[SerializeField] int MaxEnemies = 30;
[SerializeField] float EnemySpawnTime = 1.00001f;
[SerializeField] GameObject FirstWaypoint;
int CurrentNumOfEnemies = 0;
public LevelManager myLevelManager;
public int maximumnumberofhits = 0;
int timesEnemyHit;
IEnumerator SpawningEnemies()
{
while(CurrentNumOfEnemies <= MaxEnemies)
{
GameObject Enemy = Instantiate(EnemyPreFab, this.transform.position, Quaternion.identity);
CurrentNumOfEnemies++;
yield return new WaitForSeconds(EnemySpawnTime);
}
}
void Start()
{
StartCoroutine(SpawningEnemies());
timesEnemyHit = 0;
if (this.gameObject.tag == "EnemyHit")
{
CurrentNumOfEnemies++;
}
}
void OnCollisionEnter2D()
{
timesEnemyHit++;
if (timesEnemyHit == maximumnumberofhits)
{
CurrentNumOfEnemies--;
Destroy(this.gameObject);
}
if (CurrentNumOfEnemies == 0)
{
myLevelManager.LoadLevel("NextLevelMenu");
Debug.Log("LevelLoaded");
}
}
}
LevelManger script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;
public class LevelManager : MonoBehaviour {
public void LoadLevel(string name)
{
print("Level loading requested for" + name);
SceneManager.LoadScene(name);
}
}
EnemyShooting Script :
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class EnemyShooting : MonoBehaviour {
[SerializeField] float EnemyLaserSpeed = 10f;
[SerializeField] float EnemyLaserFireTime;
[SerializeField] GameObject LaserBulletEnemyPreFab;
[SerializeField] int MaxNumberOfHits = 1;
int CurrentNumberOfHits = 0;
Coroutine FireCoroutine;
void OnTriggerEnter2D(Collider2D collider)
{
if(collider.gameObject.tag == "PlayerLaser")
{
if(CurrentNumberOfHits < MaxNumberOfHits)
{
CurrentNumberOfHits++;
Destroy(collider.gameObject);
Score.ScoreValue += 2;//The user will be rewarded 1 point
}
}
}
void DestroyEnemy()
{
if(CurrentNumberOfHits >= MaxNumberOfHits)
{
Destroy(gameObject);
}
}
private void Fire()
{
FireCoroutine = StartCoroutine(ShootContinuously());
}
void BecomeVisible()
{
Fire();
}
IEnumerator ShootContinuously()
{
while (true)
{
GameObject LaserBulletEnemy = Instantiate(LaserBulletEnemyPreFab, this.transform.position, Quaternion.identity) as GameObject;
LaserBulletEnemy.GetComponent<Rigidbody2D>().velocity = new Vector2(0, EnemyLaserSpeed);
EnemyLaserFireTime = Random.Range(0.5f, 0.9f);
yield return new WaitForSeconds(EnemyLaserFireTime);
}
}
// Use this for initialization
void Start () {
BecomeVisible();
}
// Update is called once per frame
void Update () {
DestroyEnemy();
}
}
EnemyPathing script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class EnemyPathing : MonoBehaviour {
[SerializeField] List<Transform> WayPoints;
[SerializeField] float EnemyMovingSpeed = 5f;
int WayPointIndex = 0;
void EnemyMoving()
{
if (WayPointIndex <= WayPoints.Count - 1)
{
var TargetedPosition = WayPoints[WayPointIndex].transform.position; //The position of where the enemy needs to go
TargetedPosition.z = 0f;
var MoveThisFrame = EnemyMovingSpeed * Time.deltaTime;
transform.position = Vector2.MoveTowards(this.transform.position, TargetedPosition, MoveThisFrame);
if(transform.position == TargetedPosition)
{
WayPointIndex++;
}
}
else
{
Destroy(gameObject);
}
}
// Use this for initialization
void Start () {
transform.position = WayPoints[WayPointIndex].transform.position;
}
// Update is called once per frame
void Update () {
EnemyMoving();
}
}

Problem
You're checking for collisions on the SPAWNER; when someone hits the Spawner it counts down enemies. But the Spawner doesn't have a collision box in the screenshot so it can never be hit. The Scene changing code can never be called.
So the game, based on the code, looks like this:
Spawn X enemies,
Hit the Spawner X times,
(Removed: Destroy the Spawner,)
Change scene.
I'm guessing this is conceptually incorrect and you actually want to check collisions on the spawned enemies, which will then count up the amount of destroyed enemies, and change the scene when they are all dead.
Solution
Conceptually, what you want is:
Spawn X enemies
Count up variable for every enemy
On Enemy death, count it down
When 0, change scene
So how do we code this?
Well, every enemy needs a reference to the object that holds the count. You can do this in several ways, when I personally do it I usually have just one spawner that is responsible for everyone so I make that one a Singleton, that can be references from anywhere:
EnemySpawner
public class EnemySpawner : MonoBehaviour
{
public static Spawner Instance = null;
int CurrentNumOfEnemies = 0;
// ... etc
void Start()
{
if (Instance == null)
Instance = this;
// Spawn enemies like you do already, CurrentNumOfEnemies++ for every spawned
}
public OnEnemyDeath() {
CurrentNumOfEnemies--;
if (CurrentNumOfEnemies < 1)
{
// You killed everyone, change scene:
LevelManager.LoadLevel("Your Level");
}
}
}
Enemy script (I don't know how your current code looks, but here's a minimal solution based on how I THINK your code looks):
void OnDestroy()
{
// This will run automatically when you run Destroy() on this gameObject
EnemySpawner.Instance.OnEnemyDeath(); // Tell the EnemySpawner that someone died
}
This will only work if you have exactly only ONE spawner. If you have multiple ones you will have to send a reference to the instance of its spawner to every spawned enemy. I can show you how to do ths too, if you wish.
Bonus content
LevelManager doesn't need to be on a GameObject, it can be static instead:
Remove the LevelManager script from any GameObject
Change your LevelManager code to this:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;
public static class LevelManager
{
public static void LoadLevel(string name)
{
Debug.Log("Level loading requested for" + name);
SceneManager.LoadScene(name);
}
}
Now you can use it from ANYWHERE, without needing to initialize a reference to any script or GameObject:
LevelManager.LoadLevel("My Level");

myLevelManager.LoadLevel("NextLevelMenu"); is never executed, because you destroy the object in the if-test above.

Load the scene when all enemies die

I am creating a laser defender game in unity and I have this problem where when I shoot the first enemy it takes me directly to the NextLevelMenu scene but I want it to load when all the enemies are killed(on this level I have 5 enemies to kill). I have been told that I need to send a reference to the instance of its spawner to every spawned enemy but I did not quite understand. Can someone help, please?
EnemySpawner Script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
public class EnemySpawner : MonoBehaviour {
[SerializeField] GameObject EnemyPreFab;
[SerializeField] int MaxEnemies = 30;
[SerializeField] float EnemySpawnTime = 1.00001f;
[SerializeField] GameObject FirstWaypoint;
int CurrentNumOfEnemies = 0;
public LevelManager myLevelManager;
public int maximumnumberofhits = 0;
public static EnemySpawner Instance = null;
int timesEnemyHit;
IEnumerator SpawningEnemies()
{
while(CurrentNumOfEnemies <= MaxEnemies)
{
GameObject Enemy = Instantiate(EnemyPreFab, this.transform.position, Quaternion.identity);
CurrentNumOfEnemies++;
yield return new WaitForSeconds(EnemySpawnTime);
}
}
void Start()
{
if (Instance == null)
Instance = this;
StartCoroutine(SpawningEnemies());
timesEnemyHit = 0;
if (this.gameObject.tag == "EnemyHit")
{
CurrentNumOfEnemies++;
}
}
public void OnEnemyDeath()
{
CurrentNumOfEnemies--;
if (CurrentNumOfEnemies < 1)
{
// You killed everyone, change scene:
LaserLevelManager.LoadLevel("NextLevelMenu");
}
}
}
EnemyShooting script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class EnemyShooting : MonoBehaviour {
[SerializeField] float EnemyLaserSpeed = 10f;
[SerializeField] float EnemyLaserFireTime;
[SerializeField] GameObject LaserBulletEnemyPreFab;
[SerializeField] int MaxNumberOfHits = 1;
int CurrentNumberOfHits = 0;
Coroutine FireCoroutine;
void OnTriggerEnter2D(Collider2D collider)
{
if(collider.gameObject.tag == "PlayerLaser")
{
if(CurrentNumberOfHits < MaxNumberOfHits)
{
CurrentNumberOfHits++;
Destroy(collider.gameObject);
Score.ScoreValue += 2;//The user will be rewarded 1 point
}
}
}
void DestroyEnemy()
{
if(CurrentNumberOfHits >= MaxNumberOfHits)
{
Destroy(gameObject);
EnemySpawner.Instance.OnEnemyDeath(); // Tell the EnemySpawner that someone died
}
}
private void Fire()
{
FireCoroutine = StartCoroutine(ShootContinuously());
}
void BecomeVisible()
{
Fire();
}
IEnumerator ShootContinuously()
{
while (true)
{
GameObject LaserBulletEnemy = Instantiate(LaserBulletEnemyPreFab, this.transform.position, Quaternion.identity) as GameObject;
LaserBulletEnemy.GetComponent<Rigidbody2D>().velocity = new Vector2(0, EnemyLaserSpeed);
EnemyLaserFireTime = Random.Range(0.5f, 0.9f);
yield return new WaitForSeconds(EnemyLaserFireTime);
}
}
// Use this for initialization
void Start () {
BecomeVisible();
}
// Update is called once per frame
void Update () {
DestroyEnemy();
}
}

I would add a two fields to the spawner script. EnemiesToNextLevel and KilledEnemies. Then in the OnEnemyDeath() of your spawner, you may increase KilledEnemies everytime it is called, and then ask if KilledEnemies >= EnemiesToNextLevel, before changing the scene.
Sure there are a lot of other ways to do it, but for me thats the easiest.