Develop Reference

Why doesn't "OnTriggerEnter2D()" work when two specific objects collide?

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.

Unity Sword Collision Attack

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)

Unity problem activating a function with parameters in camera from another script in GameObject Enemy

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

Stone not spawning at correct place after player respawns

When the player reSpawns I want the stones(which can be moved by the player), to go to their original spot. This is not working for me. Instead, the stone spawn on other nearby locations and sometimes off the map. All stones are tagged stone.
I have tried reversing the Vectors and reversing the signs on the subtraction and such.
This is the player script.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerControll : MonoBehaviour
{
public bool isTouchingGround = false;
public GameObject locater1;
public GameObject locater2;
public GameObject currentCheckPoint;
public GameObject playerPrefab;
public Rigidbody2D myRigidBody;
public GameObject GameMaster;
// Start is called before the first frame update
void Start()
{
isTouchingGround = false;
GameObject MyGameMaster= Instantiate(GameMaster, new Vector3(0, 0, 0), Quaternion.identity);
GameMaster = MyGameMaster;
}
// Update is called once per frame
void Update()
{
if (Input.GetKey("a"))
{
transform.Translate(-0.1f, 0, 0);
}
if (Input.GetKey("d"))
{
transform.Translate(0.1f, 0, 0);
}
if ((Input.GetKey("w") || Input.GetKey("space")) && isTouchingGround == true)
{
myRigidBody.AddForce(new Vector2(0f, 130f));
}
if (locater1.transform.position.y <= locater2.transform.position.y)
{
ReSpawn();
}
}
private void OnCollisionEnter2D(Collision2D collision)
{
if (collision.gameObject.tag == "Platform" || collision.gameObject.tag == "Stone")
{
isTouchingGround = true;
}
}
private void OnCollisionExit2D(Collision2D collision)
{
if ((collision.gameObject.tag == "Platform" || collision.gameObject.tag == "Stone") && locater2.transform.position.y > collision.transform.position.y)
{
isTouchingGround = false;
}
}
private void OnTriggerEnter2D(Collider2D collision)
{
if (collision.gameObject.tag == "CheckPoint")
{
currentCheckPoint = collision.gameObject;
}
if (collision.gameObject.tag == "Radiation")
{
ReSpawn();
}
}
public void ReSpawn()
{
GameMaster.gameObject.GetComponent<ReverToOriginalPositions>().RevertToOrignalPosition();
GameObject currentPlayer=Instantiate(playerPrefab, currentCheckPoint.transform.position, currentCheckPoint.transform.rotation);
currentPlayer.GetComponent<PlayerControll>().isTouchingGround = false;
Destroy(this.gameObject);
}
}
This is the RememberPositions script. This belongs to every stone to remember the position is has during the start.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class RememberPositions : MonoBehaviour
{
public float StartXPosition;
public float StartYPosition;
float StartRotation;
// Start is called before the first frame update
void Start()
{
StartXPosition = transform.position.x;
StartYPosition = transform.position.y;
StartRotation = transform.rotation.z;
}
// Update is called once per frame
void Update()
{
}
}
this is the RevertToOriginalPosition Script. This reverts the stones to their original positions. This is in the GameMaster/MasterControll.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class ReverToOriginalPositions : MonoBehaviour
{
public GameObject[] allStones;
// Start is called before the first frame update
void Start()
{
allStones = GameObject.FindGameObjectsWithTag("Stone");
}
// Update is called once per frame
void Update()
{
}
public void RevertToOrignalPosition()
{
for (int i = 0; i < allStones.Length; i++)
{
allStones[i].gameObject.transform.Translate((new Vector3((allStones[i].gameObject.GetComponent<Transform>().position.x- allStones[i].gameObject.GetComponent<RememberPositions>().StartXPosition) , (allStones[i].gameObject.GetComponent<Transform>().position.y- allStones[i].gameObject.GetComponent<RememberPositions>().StartYPosition), 0)));
allStones[i].gameObject.transform.Rotate(0, 0, -allStones[i].gameObject.transform.rotation.z);
}
}
}
This is the Store reciever Script. This is for another game mechanic called an Activator. This is not that important but I am including it anyway.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class StoreReciever : MonoBehaviour
{
public GameObject reciever;
// Start is called before the first frame update
void Start()
{
}
// Update is called once per frame
void Update()
{
}
void OnTriggerEnter2D(Collider2D collision)
{
reciever.gameObject.GetComponent<PolygonCollider2D>().enabled = true;
}
void OnTriggerExit2D(Collider2D collision)
{
reciever.gameObject.GetComponent<PolygonCollider2D>().enabled = false;
}
}
No error messages at all. Just Stones reSpawning in locations they are not supposed to. Thank You for helping.

Just make some fields/properties they dont even have to be private static readonly
public static readonly Vector3 StartPos = new Vector3(1.0f, 2.0f, 3.0f);
public static readonly Vector3 StartRot_In_EulerAngles = new Vector3(1.0f, 2.0f, 3.0f);
Then you can do something like this in a method:
public static void ResetMyStones()
{
var allStones = GameObject.FindGameObjectsWithTag("Stone");
foreach(var stone in allStones)
{
stone.transform.position = StartPos;
stone.transform.eulerAngles = StartRot_In_EulerAngles;
}
}
About Euler Angle:
Why Euler Angle? - because for rotations Unity uses so called Quaternions, so Gimbal lock will not happen, but the bad thing about this is that you cannot really set x y z component individually without deep understanding of Quaternions, however if you just wanna set and get a current rotation Euler Angle is perfect, because you can use the traditional x,y,z components for setting the value.
Additional Notes:
Your code is kinda long and not well structured, like ReverToOriginalPositions should be a method and not a component, also not evrything has to be a derived from monobehaviour.
Also remove the unused Update methods, they have a small overhead if its in a script but not used(Usually its immeasurable but in bigger project it can effect performance :)), and maybe if your game is structured that way you could store all your current stones in a GameManager class list so you dont need to call GameObject.FindGameObjectsWithTag("Stone");

Bullet not going towards target

Not sure why, I've done this sort of this a bunch of times, but this is giving me some issues. Making a project for Game AI, I have a whole bunch of stuff already done, now just making some turrets that if the player is in a certain range it will fire, which I have already. The turret fires the bullet and then for some reason they just start destroying themselves and they don't go towards my player. Wondering if anyone on here can help, thanks in advance!
Some details you may need to know:
I have a Base, a Gun nose and a Gun for my turret. My Gun has a GunLook.cs script that makes it look at the player (so when they shoot it should go towards them), I'm not sure if that has anything to do with why I'm having these issues, but I'll post that code as well just incase
How my Hierchy for my turret is
Turret_AI (Base)
Gun (child of Turret_AI)
bulletSpawn (child of Gun)
Gun_Nose (child of turret_AI)
bulletSpawn is an empty GameObject I created in hopes to solve my problem. I set it just off the Gun so that it wouldn't just collide with gun and destroy itself (what I thought it might be doing, but not correct).
That should be all the info needed, if anyone needs more I will be checking this every 2 seconds so let me know and I will get back to you with quick response.
TurretScript.cs
(I did set the GameObject to Player in Unity, before anyone asks)
using UnityEngine;
using System.Collections;
public class TurretScript : MonoBehaviour {
[SerializeField]
public GameObject Bullet;
public float distance = 3.0f;
public float secondsBetweenShots = 0.75f;
public GameObject followThis;
private Transform target;
private float timeStamp = 0.0f;
void Start () {
target = followThis.transform;
}
void Fire() {
Instantiate(Bullet, transform.position , transform.rotation);
Debug.Log ("FIRE");
}
void Update () {
if (Time.time >= timeStamp && (target.position - target.position).magnitude < distance) {
Fire();
timeStamp = Time.time + secondsBetweenShots;
}
}
}
GunLook.cs
// C#
using System;
using UnityEngine;
public class GunLook : MonoBehaviour
{
public Transform target;
void Update()
{
if(target != null)
{
transform.LookAt(target);
}
}
}
BulletBehavior.cs
using UnityEngine;
using System.Collections;
public class BulletBehavior : MonoBehaviour {
// Use this for initialization
void Start () {
}
// Update is called once per frame
void Update () {
if (rigidbody.velocity.magnitude <= 0.5)
Destroy (gameObject);
}
void OnCollisionEnter(Collision collision)
{
if (collision.collider)
{
if(collision.gameObject.tag == "Enemy" || collision.gameObject.tag == "EnemyProjectile")
{
Physics.IgnoreCollision(rigidbody.collider,collision.collider);
//Debug.Log ("Enemy");
}
if(collision.gameObject.tag == "SolidObject")
{
Destroy(gameObject);
}
if(collision.gameObject.tag == "Player")
{
Destroy(gameObject);
}
}
}
}

You're never moving your bullet.
public class BulletBehavior : MonoBehaviour
{
private const float DefaultSpeed = 1.0f;
private float startTime;
public Vector3 destination;
public Vector3 origin;
public float? speed;
public void Start()
{
speed = speed ?? DefaultSpeed;
startTime = Time.time;
}
public void Update()
{
float fracJourney = (Time.time - startTime) * speed.GetValueOrDefault();
this.transform.position = Vector3.Lerp (origin, destination, fracJourney);
}
}
Then call it like so:
void Fire()
{
GameObject bullet = (GameObject)Instantiate(Bullet, transform.position , transform.rotation);
BulletBehavior behavior = bullet.GetComponent<BulletBehavior>();
behavior.origin = this.transform.position;
behavior.destination = target.transform.position;
Debug.Log ("FIRE");
}
Note: If you're trying to mix this approach with trying to use physics to move the bullet you may end up with strange results.