OnCollisionEnter does not work upon initial collision - Unity 3D - c#

I am a beginner in Unity and I am currently making a simple game. I have a problem where upon initial collision, the event that I wanted to happen does not trigger or in other words the OnCollisionEnter is not working upon initial collision.
The process of my script is when colliding which is the OnCollisionEnter the button will appear or it will be set active to true. But in the first collision it does not trigger or it is not working, I need to walk away a bit and go back in that way it only works. Sometimes I need to do it 2 or more times for the collider to trigger. I don't know if the script has problem or the collider itself but I made sure it is colliding properly when I look at the editor.
I set the object to static so it will not be pushed when walking and colliding towards it. I wonder if that has to do with this problem because even disabled it is the same. But can anyone give suggestions on how not to make the objects move or be pushed away upon collision?
Here is the script for my collision:
using UnityEngine;
using UnityEngine.UI;
public class InteractNPC : MonoBehaviour
{
//public Button UI;
[SerializeField] GameObject uiUse, nameBtn;
private Transform head;
private Vector3 offset = new Vector3(0, 1.0f, 0);
// Start is called before the first frame update
void Start()
{
//uiUse = Instantiate(UI, FindObjectOfType<Canvas>().transform).GetComponent<Button>();
uiUse.gameObject.SetActive(true);
head = transform.GetChild(0);
uiUse.transform.position = Camera.main.WorldToScreenPoint(head.position + offset);
}
// Update is called once per frame
void Update()
{
uiUse.transform.position = Camera.main.WorldToScreenPoint(head.position + offset);
nameBtn.transform.position = Camera.main.WorldToScreenPoint(head.position + offset);
}
private void OnCollisionEnter(Collision collisionInfo)
{
//Debug.Log("wews2");
if(collisionInfo.collider.name == "Player")
{
nameBtn.gameObject.SetActive(true);
}
}
private void OnCollisionExit(Collision collisionInfo)
{
if(collisionInfo.collider.name == "Player")
{
nameBtn.gameObject.SetActive(false);
}
}
}
Here is another script with collision and has the same problem:
using UnityEngine;
using UnityEngine.UI;
public class InteractButtonPosition : MonoBehaviour
{
//public Button UI;
[SerializeField] GameObject uiUse;
private Vector3 offset = new Vector3(0, 0.5f, 0);
// Start is called before the first frame update
void Start()
{
//uiUse = Instantiate(UI, FindObjectOfType<Canvas>().transform).GetComponent<Button>();
//uiUse = GameObject.FindGameObjectWithTag("ViewButton");
}
// Update is called once per frame
void Update()
{
uiUse.transform.position = Camera.main.WorldToScreenPoint(this.transform.position + offset);
}
private void OnCollisionEnter(Collision collisionInfo)
{
if(collisionInfo.collider.name == "Player")
{
Debug.Log("wews");
uiUse.gameObject.SetActive(true);
}
}
private void OnCollisionExit(Collision collisionInfo)
{
if(collisionInfo.collider.name == "Player")
{
//Destroy(uiUse.gameObject);
uiUse.gameObject.SetActive(false);
}
}
}

Try changing Colision detection from Descrete to Continuous
collission detection

I solved this issue by using OntriggerEnter instead of OnCollisionEnter. In the editor, for the NPC I put a Collider on each part of the body and check the IsTrigger in the parent Object so it will still collide with my character even if the IsTrigger is enabled that will make the character go through the object. I just enlarged the scale of the collider with IsTrigger enabled so the collision will be detected immediately.

Related

OnCollisionEnter is not called

I need some help with Unity.
I try to make an object to detect a collision, but for some reason, the OnColissionEnter function is not called.
Both my objects have rigidBody and Box Collider attached, isTrigger is unenabled as well.
I supposed it's because I have AddForce in my code, but I am not sure. Have anybody a clue what is going wrong there?
Here is the code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Cuplat2 : MonoBehaviour
{
public Vector3 Target = new Vector3();
private Rigidbody rb;
public float thrust;
private void Start()
{
rb = GetComponent<Rigidbody>();
}
void FixedUpdate()
{
Vector3 NewPosition = transform.position + Target;
Vector3 Position = transform.position;
if (transform.position.x < Target.x)
{
rb.AddForce(transform.position * thrust);
}
else
{
//rb.isKinematic = true;
}
}
public void OnCollisionEnter(Collision collision)
{
Debug.Log("stop");
if (collision.gameObject.name == "Cupla T2")
{
Debug.Log("stop");
}
}
}
One of your rigidbodies has to have isKinematic = false;
If it's not possible in your case I see they have workaround for that:
https://forum.unity.com/threads/collision-detection-for-kinematic-rigidbodies.885778/
Other option would be that the collision is disabled in collision layer mask, but that would cause objects to pass trough each other (I believe that's not the case)
Third option: your rigidbody does not have collider (maybe collider is on parent, has enabled = false, or inactive game object?)
Fourth option: If your object moves very fast you should change Collision Detection Mode to Continous Dynamic
How about the collision layer matrix? Go into Edit > Project Settings, then select the Physics. Check if the layers set to the GameObjects are actually having any collision between them. Collision Layer matrix

Sprites wont detect collision

Sorry for the bad formatting I don't know how to do this. I'm using 2020.3.21f1 and following a tutorial and when the enemy circle hits the player he doesn't take damage. when they collide they don't overlap at all, but the Debug.log isn't registering either so I think that the circle collider 2D is the problem. the enemy sprite still moves towards the player when it is in range. another problem (that will turn into a feature if I cant figure out how to change it) is that when the enemy collides with the player and the player pushes it goes the direction it was pushed until it runs into something Here's the tutorial I'm following
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Enemy: MonoBehaviour
{
public float speed = 3f;
private Transform target;
[SerializeField] private float attackDamage = -10f;
private void Update(){
if (target != null){
float step = speed*Time.deltaTime;
transform.position = Vector2.MoveTowards(transform.position, target.position, step);
}
}
private void OnCollision(Collision2D other){
if (other.gameObject.tag == "player"){
Debug.Log("hit");
other.gameObject.GetComponent<PlayerHealth>().UpdateHealth(attackDamage);
}
}
private void OnTriggerEnter2D(Collider2D other) {
if(other.gameObject.tag == "Player"){
target = other.transform;
Debug.Log(target);
}
}
private void OnTriggerExit2D(Collider2D other) {
if(other.gameObject.tag == "Player"){
target = null;
Debug.Log(target);
}
}
}
The sprite by itself wont detect collision, you need to add a box collider for that. If you add that component to the player then modify your code to include those collision detections then it should function ad intended.:)
-TheHackintoshProgrammer;

OnCollisionStay not working in 2D movement script

So, I'm still not the best at this but I'm trying to use this script for 2D movement but the jumping isn't working for some reason. It keeps saying that the OnCollisionEnter function "is declared but never used". Can someone tell me what im doing wrong? Thanks
If I remove the (Collision col) part it says that "void cannot be used in this context".
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class RonyWalking : MonoBehaviour
{
Rigidbody2D rigid;
SpriteRenderer sprite;
public bool isJumping;
public float spd = 2.0f;
// Start is called before the first frame update
void Start()
{
rigid = GetComponent<Rigidbody2D>();
sprite = GetComponent<SpriteRenderer>();
}
// Update is called once per frame
void Update()
{
if(Input.GetKey("d")){rigid.velocity = new Vector2(spd, 0);}
else if(Input.GetKey("a")){rigid.velocity = new Vector2(-spd, 0);}
if(Input.GetKeyDown("w") && isJumping == false)
{
rigid.velocity = new Vector2(0, 5);
isJumping = true;
}
void OnCollisionStay(Collision col)
{
isJumping = false;
}
}
}
When using 2D physics, you need to use the 2D lifecycle methods;
void OnCollisionStay2D(Collision2D col)
{
isJumping = false;
}
And you shouldn't put this method inside your Update method... It should be on class level:
public class RonyWalking
{
void Update()
{
// ...
}
void OnCollisionStay2D(Collision2D col)
{
// ...
}
}
Don't worry about "Is declared but never used", this may be because you don't have specific code referencing the method, but Unity will raise events that calls it, "automagically"
Another thing that I can see while reading your code, that may be unintentional behaviour for you, is that when clicking left/right, you set velocity UP to 0, and when clicking up you set LEFT/RIGHT velocity to 0; this will result in freezing the movement mid-air if you jump, then move while in air:
Click D; velocity = 2, 0
Click W; velocity = 0, 5
Character will now move upwards until another input is given
Click D; velocity = 2, 0 and the character will continue moving while in air because when moving sideways the up/down velocity is set to 0
To solve this, either set the other to existing velocity or make the inputs manipulate a Vector that you then apply at the end of the movement code:
Vector2 existingMovement = rigid.velocity;
if (Input.GetKey(KeyCode.D))
existningMovement.x = spd;
else if (Input.GetKey(KeyCode.A))
existningMovement.x = -spd;
if (Input.GeyKeyDown(KeyCode.W) && !isJumping)
{
existningMovement.y = 5f;
isJumping = true;
}
Furthermore, I think you may have some unexpected behaviour with OnCollisionStay; it will fire every frame that you're colliding with the ground, I assume. But I think it may also fire a frame or two AFTER you've jumped since the physics of your character will not INSTANTLY leave the collision, so isJumping will be set to false even after your jump, letting you jump while in the air one more time.
I would recommend that you use OnCollisionExit2D(Collision2D col) to set isJumping = true instead, or OnCollisionEnter2D(Collision2D col) and set it to isJumping = false, depending on the functionality you desire (if you want the ability to jump after walking out of a cliff)

Snap object to place when hit by collider

How do I snap an object with a rigidbody when it gets hit by a box collider?
The object needs to be snapped to a position when it enters a collider.
I have tried to make it happen but as soon as the box enters the collider, the object gets thrown away.
Thanks, I did it using Box Collider itself. here is the working code, it works now:
public class SnapModelToPosition : MonoBehaviour {
public Rigidbody rb;
Vector3 newPos = new Vector3(0.1192573f, -0.630803f, 0.02599394f);
// Use this for initialization
void Start () {
rb.GetComponent<Rigidbody>();
}
void OnCollisionEnter(Collision col)
{
if(col.gameObject.name == "SnapToPosition")
{
Destroy(rb);
this.transform.localPosition = newPos;
this.transform.localEulerAngles = new Vector3(0, -90.00001f, 0);
}
}
}

Despite Force Applied, No Movement

This code is for an elevator-type platform, where once the player stands on it, it 'takes' the player up by adding force onto it.
The thing is, while the force is created, the rigidbody (the player) does not move when the elevator moves. The code was written in C#, using Unity 5. In the code, the player is assigned the public 'rb', and contains a rigidbody.
The animation is a simple animation clip that moves the elevator up. Any ideas? Thank you for your time and answers in advance.
The elevator is Kinematic, the Player is not.
using UnityEngine;
using System.Collections;
/*This script activates when the player steps on the elevator, as it takes them up a floor.*/
public class ElevatorMovementScript : MonoBehaviour
{
private bool elevatorUp = false;
public Animation anim;
public int elevatorDelay = 5;
public int force = 800;
public Rigidbody rb;
// Use this for initialization
void Start ()
{
anim = GetComponent<Animation>();
}
// Update is called once per frame
void Update ()
{
}
/*Checks if the player has stepped onto the elevator. If the player has, it waits five seconds, and then pushes the player up.*/
void OnTriggerStay(Collider other)
{
if (other.gameObject.tag == "Player" && !elevatorUp)
{
Invoke("AnimationPlay",elevatorDelay);
elevatorUp = true;
}
}
/*Plays the animation of the player going up. Used for the 'Invoke' method.*/
void AnimationPlay()
{
rb.AddForce(transform.up * force);
Debug.Log (transform.up * force);
anim.Play ("Up");
}
}
It looks like this script is on your elevator's game object, in which case this line:
rb.AddForce(transform.up * force);
Will try to apply a force to the elevator, not the player. You've got to keep track of the player's rigidbody or somehow get it on demand in AnimationPlay.
You said that
the player is assigned the public 'rb'
But rb = GetComponent<Rigidbody>(); will ignore this and use the rigidbody attached to the gameobject that ElevatorMovementScript is attached to.

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