Hey guys I want to make a sword attack. But I get the error of:
NullReferenceException: Object reference not set to an instance of an
object
These are my codes:
My weaponattack script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Weaponattack : MonoBehaviour
{
Enemy Enemy;
public float power;
// Use this for initialization
void Start () {
}
// Update is called once per frame
void Update () {
}
public void OnTriggerEnter(Collider col)
{
if(col.tag == "Enemy")
{
var kılıc = GetComponent<Enemy>();
Enemy.currentHealt -= 10;
Enemy.TakeDamage();
Debug.Log("Düşman Vuruldu");
}
}
}
This is my Enemy Health scrpt:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Enemy : MonoBehaviour {
public float currentHealt;
public float maxHealth;
// Use this for initialization
void Start () {
currentHealt = maxHealth;
}
// Update is called once per frame
void Update () {
}
public void TakeDamage()
{
currentHealt -= 10;
if(currentHealt < 0)
{
die();
}
}
void die()
{
Destroy(gameObject);
}
}
Can you helo em I couldnt understan why these codes are not working why am I getting that error.
I think your problem is in this line here GetComponent<Enemy>(); This needs a game object to get the component of
Enemy = col.GetComponent<Enemy>();
Should be what you're doing
You also may have issue calling your variable Enemy exactly the same as your class Enemy, I would change this to Enemy enemy; and
enemy = col.GetComponent<Enemy>();
respectivley
It seems pretty straightforward. You don't assign an Enemy to Weaponattack and so it's barfing when you first reference Enemy (Enemy.currentHealt). Either make Enemy public or a SerializedField so you can assign it in the Inspector, or however else you want to get an Enemy into Weaponattack.
Also don't name your property the same name as your script (Enemy Enemy). Surprised you didn't get a compile error.
EDIT Based on comments:
Enemy enemy;
public void OnTriggerEnter(Collider col)
{
if(col.tag == "Enemy")
{
var kılıc = GetComponent<Enemy>();
kilic.currentHealt -= 10;
kilic.TakeDamage();
Debug.Log("Düşman Vuruldu");
}
}
This also assumes you have an Enemy attached to your Weaponattack (GetComponent)
Related
I am creating this flappy bird style game in unity with C#.
I have a scored function in the Game Controller script. Here it is...
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;
using UnityEngine.UI;
public class GameController : MonoBehaviour
{
private int score = 0;
public float starScrollSpeed;
public float groundScrollSpeed;
public float skyScrollSpeed;
public GameObject gameOverText;
public GameObject playAgain;
public bool gameOver = false;
public static GameController instance;
public Text scoreText;
// Start is called before the first frame update
void Awake()
{
if(instance == null)
{
instance = this;
}
else if(instance != this)
{
Destroy(gameObject);
}
}
// Update is called once per frame
void Start()
{
}
void Update()
{
}
public void BirdScored()
{
if (gameOver)
{
return;
}
score++;
scoreText.text = "SCORE " + score.ToString();
}
public void PlaneDestroyed()
{
gameOverText.SetActive(true);
playAgain.SetActive(true);
gameOver = true;
}
}
Actually Bird and Plane is the same thing.
What I want to do is to make the bird score/run the BirdScored() function when the Plane overlaps with a star. The Plane has a Rigidbody2D and a collider and stars have a Rigidbody2D but no collider because In the bird script if the plane collide, it destroys.
Here is the Bird Script
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Bird : MonoBehaviour
{
private bool isDead = false;
private Rigidbody2D rb2d;
public float upforce = 200f;
private Animator anim;
// Start is called before the first frame update
void Start()
{
rb2d = GetComponent<Rigidbody2D>();
anim = GetComponent<Animator>();
}
// Update is called once per frame
void Update()
{
if (isDead == false)
{
if (Input.GetMouseButtonDown(0))
{
rb2d.velocity = Vector2.zero;
rb2d.AddForce(new Vector2(0, upforce));
}
}
anim.SetTrigger("Flap");
}
void OnCollisionEnter2D()
{
isDead = true;
anim.SetTrigger("Die");
GameController.instance.PlaneDestroyed();
}
}
And here is the star script...
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Stars : MonoBehaviour
{
// Start is called before the first frame update
void Start()
{
}
// Update is called once per frame
void Update()
{
}
public void OnTriggerEnter2D(Collider2D other)
{
if (other.gameObject.name == "Plane")
{
GameController.instance.BirdScored();
}
}
}
What is wrong and what should I do?
Put a Colider2D on the star, and check the Is Trigger option in the inspector.
The Is Trigger is disable the collision with any other collider2d so your plane wont be destroyed by the OnCollisionEnter2D, but the OnTriggerEnter2D will trigger properly.
I can see in your screenshot that the collider isn't set to "is trigger", which makes it unable to register trigger collisions.
I have a script that makes the camera do a shake by putting a button because
It is a public access function, if I do it that way when placing a button it works well but what I cannot achieve is to call the function so that every time my player collides with an enemy he makes the shake. I hope you can help me.
The shake code in camera is:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class ScreenShaker : MonoBehaviour {
private float shakeAmount = 0.5f;
private float shakeTime = 0.0f;
private Vector3 initialPosition;
private bool isScreenShaking = false;
void Update () {
if(shakeTime > 0)
{
this.transform.position = Random.insideUnitSphere * shakeAmount + initialPosition;
shakeTime -= Time.deltaTime;
}
else if(isScreenShaking)
{
isScreenShaking = false;
shakeTime = 0.0f;
this.transform.position = initialPosition;
}
}
public void ScreenShakeForTime(float time)
{
initialPosition = this.transform.position;
shakeTime = time;
isScreenShaking = true;
}
}
The enemy code is:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class ControladorEnemigoCirculoMediano : MonoBehaviour
{
void OnTriggerEnter2D(Collider2D other)
{
if (other.tag == "Player")
{
Here I don't know what to call the public void function ScreenShakeForTime (float time);
I already tried many things online but when my character comes into contact with the character, I don't do the shake in the camera.
}
}
}
You can create Unity-singleton in your ScreenShaker class like:
class ScreenShaker
{
public static ScreenShaker Instance {private set; get;};
void Awake() {
Instance = this;
}
}
And than from any place to call like:
ScreenShaker.Instance.ScreenShakeForTime(2f);
This is the easiest way, but maybe it's better to create standard singeleton(it's up to you).
And also don;t forget to destroy it on OnDestroy()
can you tell me in enemy game object collider isTrigger is enable or not
if it is not enable then use OnColliderEnter2D(Collision2D other){} for collision detection
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.
[enter image description here][1]Originally, this was a null reference exception, which is a problem that occur when a variable is used/referenced but hasn't been initialized. I used an if statement that checks if an instance is NOT null it would instantiate. The Null reference exception problem is gone but it still wouldn't instantiate.
ScraptScript.cs
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class ScrapScript : MonoBehaviour
{
public GameObject[] ScrapSprite;
EnemyScript Es;
void Start ()
{
Es = GameObject.FindObjectOfType<EnemyScript> ();
foreach(GameObject SSprite in ScrapSprite)
{
print (SSprite);
}
}
void Update ()
{
}
public void SpawnScraps()
{
if(Es != null )
{
Instantiate (ScrapSprite[0], Es.transform.position, Es.transform.rotation);
}
}
}
EnemyDestroyed.cs
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class EnemyDestroyed : MonoBehaviour {
BulletScript.BulletType theBulletType = 0;
ScrapScript SS;
void Start ()
{
SS = GameObject.FindObjectOfType<ScrapScript> ();
}
void Update ()
{
}
void OnTriggerEnter(Collider collider)
{
if(collider.tag == "PlayerBullet" && theBulletType == BulletScript.BulletType.PlayerBullet)
{
print ("ship destroyed");
Destroy(collider.gameObject);
Destroy(gameObject);
SS.SpawnScraps ();
}
if(collider.tag == "L.Collider Det")
{
Destroy(gameObject);
}
}
}
EnemyScript.cs
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class EnemyScript : MonoBehaviour {
public int enemyHP;
public float enemySpeed;
public GameObject enemyBullet;
internal int enemyBulletCount = 0;
public int maxAllowableBulletCount;
public Transform enemyBulletSpawn;
public EnemyType ET;
public enum EnemyType
{
Grunt,
Boss,
}
void Awake()
{
StartCoroutine (MyShootCoroutine ());
}
void Start ()
{
}
void Update ()
{
if (ET == EnemyType.Grunt)
{
transform.Translate (-enemySpeed * Time.deltaTime, 0f, 0f);
}
}
IEnumerator MyShootCoroutine()
{
for(enemyBulletCount = 0; enemyBulletCount <= maxAllowableBulletCount; enemyBulletCount++)
{
yield return new WaitForSeconds (1.5f);
Instantiate (enemyBullet, enemyBulletSpawn.position, enemyBulletSpawn.rotation);
}
}
}
Expectation: What I expected of my code is to spawn a pickup currency called "Scraps" that the player will get upon contact when the enemy is destroyed. It spawns exactly where the enemy is destroyed through the player's bullets.
Screenshot link
[enter image description here][1][1]: https://i.stack.imgur.com/6iq11.png
Given that you had a null reference exception in SpawnScraps method on the Es object the only issue is that when your method is called the Es object has been destroyed.
Given that you kill your ennemy instance before trying to call a method on him, you get a null reference exception :
Destroy(collider.gameObject);
Destroy(gameObject);
SS.SpawnScraps ();
Just make call the SpawnScraps method before destroying the ennemy GameObject :
SS.SpawnScraps ();
Destroy(collider.gameObject);
Destroy(gameObject);
Within your scrap script, your Es is likely still null. This may because your script only finds the Enemyscript during Start().
You can remove this check and simplify things by passing the transform of the enemy into your SpawnScraps function.
within Enemydestroyed change your line to:
SS.SpawnScraps (transform);
within Scraptscript change existing function to:
public void SpawnScraps(Transform enemy)
{
Instantiate (ScrapSprite[0], enemy.position, enemy.rotation);
}
im having a problem from my enemyDamage script in unity5 when i play it and stick to the enemy i died instantly even the enemy damage is 10 and my health was 100
well this is my first time to make this things on unity hope you helps me :(
heres my code
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class enemydmg : MonoBehaviour {
public float damage;
public float damagerate;
public float pushbackforce;
float nextdamage;
bool playerInRange = false;
GameObject theplayer;
playerHealth theplayerhealth;
// Use this for initialization
void Start () {
nextdamage = Time.time;
theplayer = GameObject.FindGameObjectWithTag ("Player");
theplayerhealth = theplayer.GetComponent<playerHealth> ();
}
// Update is called once per frame
void Update () {
if (playerInRange)
Attack ();
}
void OnTriggerEnter (Collider other)
{
if (other.tag == "Player")
{
playerInRange = true;
}
}
void OnTriggerExit (Collider other)
{
if (other.tag == "Player")
{
playerInRange = false;
}
}
void Attack()
{
if (nextdamage <= Time.time)
{
theplayerhealth.addDamage(damage);
nextdamage = Time.time + damagerate;
pushback (theplayer.transform);
}
}
void pushback(Transform pushObject)
{
Vector3 pushDirection = new Vector3 (0, (pushObject.position.y - transform.position.y), 0).normalized;
pushDirection *= pushbackforce;
Rigidbody pushedRB = pushObject.GetComponent<Rigidbody> ();
pushedRB.velocity = Vector3.zero;
pushedRB.AddForce (pushDirection, ForceMode.Impulse);
}
}
and this was my playerhealth
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class playerHealth : MonoBehaviour {
public float fullhealth;
float currentHealth;
// Use this for initialization
void Start () {
currentHealth = fullhealth;
}
// Update is called once per frame
void Update () {
}
public void addDamage(float damage)
{
currentHealth -= damage;
if (currentHealth <= 0) {
makeDead ();
}
}
public void makeDead()
{
Destroy (gameObject);
}
}
theplayerhealth = theplayer.GetComponent<playerHealth> ();
I think this line of code fails you because the player is a GameObject. theplayerhealth is or should already be initialized in your other script. I think you could approach polymorphism in a better way.
public class enemydmg : playerHealth{
}
This will allow you to directly inherit everything you need from the playerHealth script without having to grab extra components. You can also use this technique for may other scripts in the future.
Another approach that you could use is calling your class directly:
playerHealth.addDamage(damage);
From now on when you name your scripts use capitalization. PlayerHealth, EnemyDamage, etc... That's just a pro-tip to make your code look a bit cleaner when you're doing things like this. (Optional)