Develop Reference

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

Moving Game Object with UI Buttons

I am trying to set up control of Player game object by UI buttons.
2d top down view scene.
I want to transfer Player object smoothly on fixed distance (0.8 for Axix X for left-right direction and 2.4 for up-down)when I release left/right/up/down ui buttons.
Here i found code for smooth movement but there Player is moving all the time while ui button is pressed.
Can you help me to make it move on mouse up (pointer up) and to move for public x= 0.8f for left/right, and public y = 2.4f for up/down
And at the same time i want to use different speed (peblic) for moves on x and y Axis
Its ok if it should be totally other script using smth like transform.translate
Kindly guide to for any possible solution for this. Thanks
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityStandardAssets.CrossPlatformInput;
public class PlayerControl : MonoBehaviour
{
float movX;
float movY;
Rigidbody2D rb;
void Start()
{
rb = GetComponent<Rigidbody2D>();
}
void Update()
{
movX = CrossPlatformInputManager.GetAxisRaw("Horizontal");
movY = CrossPlatformInputManager.GetAxisRaw("Vertical");
rb.velocity = new Vector2(movX * 1, movY * 1);
}
}

This script can be moved by the WASD keys.
This should move your gameObject by the requested amount over x amount of time(speed).
Currently it can be only moved when it'S reached its destionation but you can easily modify this :), by stopping the coroutine
using System.Collections;
using UnityEngine;
public class PlayerControl : MonoBehaviour
{
// We gonna move by WASD keys
[Header("Speed & Movement settings")]
[SerializeField]
float Speed = 2.0f;
[SerializeField]
float movSpeedX = 0.8f;
[SerializeField]
float movSpeedY = 2.4f;
bool ReachedTarget = true;
void Update()
{
if (ReachedTarget)
{
Vector2 dest = Vector2.zero;
Vector2 currentPos = transform.position;
if (Input.GetKeyUp(KeyCode.W))
{
dest = currentPos + (Vector2.up * movSpeedY);
StartCoroutine(moveTo(dest, Speed));
}
else if (Input.GetKeyUp(KeyCode.S))
{
dest = currentPos + (Vector2.down * movSpeedY);
StartCoroutine(moveTo(dest, Speed));
}
else if (Input.GetKeyUp(KeyCode.D))
{
dest = currentPos + (Vector2.right * movSpeedX);
StartCoroutine(moveTo(dest, Speed));
}
else if (Input.GetKeyUp(KeyCode.A))
{
dest = currentPos + (Vector2.left * movSpeedX);
StartCoroutine(moveTo(dest, Speed));
}
}
}
// Time to take is in seconds
IEnumerator moveTo(Vector2 TargetPosition, float TimetoTake)
{
Vector2 originalPosition = transform.position;
float Time_taken = 0f;
ReachedTarget = false;
while (Time_taken < 1)
{
Time_taken += Time.deltaTime / TimetoTake;
// Interpolating between the original and target position this basically provides your "speed"
transform.position = Vector2.Lerp(originalPosition, TargetPosition, Time_taken);
yield return null;
}
Time_taken = 0;
transform.position = TargetPosition;
ReachedTarget = true;
}
}

I can't find any documentation of CrossPlatformInputManager, and I know nothing about it. But if you need to get the event of "release a key" instead of "press the key", try this: Input.GetKeyUp.
Description
Returns true during the frame the user releases the key identified by
name.
You need to call this function from the Update function, since the
state gets reset each frame. It will not return true until the user
has pressed the key and released it again.
For the list of key identifiers see Conventional Game Input. When
dealing with input it is recommended to use Input.GetAxis and
Input.GetButton instead since it allows end-users to configure the
keys.
using UnityEngine;
using System.Collections;
public class ExampleClass : MonoBehaviour
{
void Update()
{
if (Input.GetKeyUp("space"))
{
print("Space key was released");
}
}
}
If you want to stop the rigid body, you need to reset its velocity to
zero. Or you can use
Rigidbody2D.MovePosition
to move it a certain distance.
Parameters
position The new position for the Rigidbody object.
Description
Moves the rigidbody to position.
Moves the rigidbody to the specified position by calculating the
appropriate linear velocity required to move the rigidbody to that
position during the next physics update. During the move, neither
gravity or linear drag will affect the body. This causes the object to
rapidly move from the existing position, through the world, to the
specified position.
Because this feature allows a rigidbody to be moved rapidly to the
specified position through the world, any colliders attached to the
rigidbody will react as expected i.e. they will produce collisions
and/or triggers. This also means that if the colliders produce a
collision then it will affect the rigidbody movement and potentially
stop it from reaching the specified position during the next physics
update. If the rigidbody is kinematic then any collisions won't affect
the rigidbody itself and will only affect any other dynamic colliders.
2D rigidbodies have a fixed limit on how fast they can move therefore
attempting to move large distances over short time-scales can result
in the rigidbody not reaching the specified position during the next
physics update. It is recommended that you use this for relatively
small distance movements only.
It is important to understand that the actual position change will
only occur during the next physics update therefore calling this
method repeatedly without waiting for the next physics update will
result in the last call being used. For this reason, it is recommended
that it is called during the FixedUpdate callback.
Note: MovePosition is intended for use with kinematic rigidbodies.
// Move sprite bottom left to upper right. It does not stop moving.
// The Rigidbody2D gives the position for the cube.
using UnityEngine;
using System.Collections;
public class Example : MonoBehaviour
{
public Texture2D tex;
private Vector2 velocity;
private Rigidbody2D rb2D;
private Sprite mySprite;
private SpriteRenderer sr;
void Awake()
{
sr = gameObject.AddComponent<SpriteRenderer>();
rb2D = gameObject.AddComponent<Rigidbody2D>();
}
void Start()
{
mySprite = Sprite.Create(tex, new Rect(0.0f, 0.0f, tex.width, tex.height), new Vector2(0.5f, 0.5f), 100.0f);
velocity = new Vector2(1.75f, 1.1f);
sr.color = new Color(0.9f, 0.9f, 0.0f, 1.0f);
transform.position = new Vector3(-2.0f, -2.0f, 0.0f);
sr.sprite = mySprite;
}
void FixedUpdate()
{
rb2D.MovePosition(rb2D.position + velocity * Time.fixedDeltaTime);
}
}
Both documents have an example.
Or you don't want to user keyboard but UI buttons, try this: IPointerDownHandler and IPointerUpHandler
Description
Interface to implement if you wish to receive OnPointerDown callbacks.
Detects ongoing mouse clicks until release of the mouse button. Use
IPointerUpHandler to handle the release of the mouse button.
//Attach this script to the GameObject you would like to have mouse clicks detected on
//This script outputs a message to the Console when a click is currently detected or when it is released on the GameObject with this script attached
using UnityEngine;
using UnityEngine.EventSystems;
public class Example : MonoBehaviour, IPointerDownHandler, IPointerUpHandler
{
//Detect current clicks on the GameObject (the one with the script attached)
public void OnPointerDown(PointerEventData pointerEventData)
{
//Output the name of the GameObject that is being clicked
Debug.Log(name + "Game Object Click in Progress");
}
//Detect if clicks are no longer registering
public void OnPointerUp(PointerEventData pointerEventData)
{
Debug.Log(name + "No longer being clicked");
}
}

My 2D Character is not jumping at all

I am having an issue with my character which is not jumping at all. I am new to Unity, but I made sure to apply the script to the player and adjust the speed, I did not touch the Rigidbody 2D. If any one can help me figure our the issue, it will be much appreciated.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerController : MonoBehaviour {
public float moveSpeed;
public float jumpSpeed;
public bool grounded = false;
private Rigidbody2D rb;
void Start() {
rb = GetComponent<Rigidbody2D>();
}
void Update () {
transform.Translate (Input.GetAxisRaw ("Horizontal") * moveSpeed * Time.deltaTime, 0, 0);
if (grounded)
{
if (Input.GetButtonDown ("Jump"))
{
rb.AddForce (Vector2.up * jumpSpeed);
grounded = false;
}
}
}
void OnCollisionEnter2D (Collision2D coll){
if (coll.transform.tag == "Ground")
{
grounded = true;
}
}
}
Inspector window of the Player GameObject
Inspector window of the Ground GameObject

Your problem is you haven't tag the Ground GameObject as so. So in the OnCollisionEnter2D the character detects the collision, but the if (coll.transform.tag == "Ground") will never be true. So it means the character can't be grounded
Since to be grounded is the first condition to check if the player pressed the Jump key. It is impossible it will ever jump
if (grounded)
{
if (Input.GetButtonDown ("Jump"))
{
rb.AddForce (Vector2.up * jumpSpeed);
grounded = false;
}
}
To solve this issue: You need to tag the Ground GameObject as so. In case you are not sure how to do that, on the Tag menu, create (if it doesnt exist already) a new tag called Ground. Then assign in that same menu the Ground Tag to the Ground GameObject. Here you can learn how in case you need a visual reference:
https://docs.unity3d.com/Manual/Tags.html
Edit: You can try this script if everything fails. It should work. I used my self some time ago, I cleaned the code so to leave only what you need to move the character in the x and y axis. Hope to have included everything you need:
public class CharacterController2D : MonoBehaviour {
// LayerMask to determine what is considered ground for the player
public LayerMask whatIsGround;
// Transform just below feet for checking if player is grounded
public Transform groundCheck;
// store references to components on the gameObject
Transform transform;
Rigidbody2D rigidbody;
bool isGrounded = false;
float vy;
float vx;
public float jumpForce = 600f;
void Awake () {
transform = GetComponent<Transform> ();
rigidbody = GetComponent<Rigidbody2D> ();
}
void Update()
{
// determine horizontal velocity change based on the horizontal input
vx = Input.GetAxisRaw ("Horizontal");
vy = rigidbody.velocity.y;
// Check to see if character is grounded by raycasting from the middle of the player
// down to the groundCheck position and see if collected with gameobjects on the
// whatIsGround layer
isGrounded = Physics2D.Linecast(transform.position, groundCheck.position, whatIsGround);
if(isGrounded && Input.GetButtonDown("Jump")) // If grounded AND jump button pressed, then allow the player to jump
{
DoJump();
}
// Change the actual velocity on the rigidbody
rigidbody.velocity = new Vector2(_vx * MoveSpeed, _vy);
}
//Make the player jump
void DoJump()
{
// reset current vertical motion to 0 prior to jump
vy = 0f;
// add a force in the up direction
rigidbody.AddForce (new Vector2 (0, jumpForce));
}
}
So things to take into account:
Instead of tag the ground, you create a layer with everything you
consider ground. That will include possible platforms the character
may jump over. Pass as a parameter this layer to the script in the
inspector
You need to place an empty GameObject in the feet of the character.
You will drag and drop that GameObject in the editor onto the
groundCheck public variable.
Instead of OnTriggerEnter, you will use Physics2D.Linecast which
will trave a line from the position of the character to under its
feet (where you should have place the Transform mentioned in the
previous step) and if in the middle there is an element of the
groundLayer, it means the character will be grounded.
Let me know if anything is not clear or if you find some bug.

As mentioned your problem is deffinetly that your missing to tag your ground object :)
A tip: What i like to do when i have problems like this is to use the unitys Debug.Log() to locate where the problem is it. It will let you know easily in the console what code is run and which is not. Try do the following:
void Update () {
transform.Translate (Input.GetAxisRaw ("Horizontal") * moveSpeed * Time.deltaTime, 0, 0);
if (grounded)
{
Debug.Log("Is grounded");
if (Input.GetButtonDown ("Jump"))
{
Debug.Log("Jump clicked");
rb.AddForce (Vector2.up * jumpSpeed);
grounded = false;
}
}
}

How do I make my player with a Rigidbody move with isKinematic checked?

My game is a topdown zombie shooter and whenever the zombies get to the player they bunch up underneath them, to the point where the player can just walk over the zombies. I noticed that when I check isKinematic on the Rigidbody the zombies cant push the player up to go underneath him, so they just run into him(which is what I want). Despite this I am then unable to move. How can i fix this?
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerMoving1 : MonoBehaviour {
public float moveSpeed;
private Rigidbody myRigidbody;
private Vector3 moveInput;
private Vector3 moveVelocity;
private Camera mainCamera;
public GunController theGun;
void Start () {
myRigidbody = GetComponent <Rigidbody>();
mainCamera = FindObjectOfType<Camera>();
}
// Update is called once per frame
void Update () {
moveInput = new Vector3(Input.GetAxisRaw("Horizontal"), 0f, Input.GetAxisRaw("Vertical"));
moveVelocity = moveInput * moveSpeed;
Ray cameraRay = mainCamera.ScreenPointToRay(Input.mousePosition);
Plane groundPlane = new Plane(Vector3.up, Vector3.zero);
float rayLength;
if(groundPlane.Raycast(cameraRay,out rayLength))
{
Vector3 pointToLook = cameraRay.GetPoint(rayLength);
transform.LookAt(new Vector3(pointToLook.x,transform.position.y,pointToLook.z));
}
if (Input.GetMouseButtonDown(0))
theGun.isFiring = true;
if (Input.GetMouseButtonUp(0))
theGun.isFiring = false;
}
void FixedUpdate(){
myRigidbody.velocity = moveVelocity;
}
}

With isKinematic == true You can't change object position through rigidbody, You can only change transform.position.
I think it could be better, if You set isKinematic to false and add stopping distance to enemies, so they can't get too close to player.

Being that your player can no longer be effected by the physics engine, you'd have to manipulate the object's transform manually. Your script isn't ideally setup for it currently, but if I was to hack it into it and try to make it work it would look something like this:
(you can change it from fixedUpdate to update if you're no longer utilizing the physics engine)
void update(){
float x = Input.GetAxisRaw("Horizontal")* Time.Deltatime;
float z = Input.GetAxisRaw("Vertical") * Time.Deltatime;
transform.position = new Vector3(transform.position.x+x,0,transform.position.z+z);

Another way of doing this is to lock the position of Y for the player (assuming Y is the positive "up" direction). isKinimatic is best when you want to move the player or objects around yourself.
I would say upping the mass is better in this case, and you can keep isKinematic unchecked in this case then too. Also apply the lock for Y movement (again if it is the "up" direction from the plane)
Let me know what your solution is regardless, I've had some issues in the past as well with these types of events happening

Use AddForce to knock back Player after contact with Enemy

I'm working on my very first Unity game. It's still in prototype and will be very simple anyways, consisting of a cube as the player and spheres as enemies.
I'm trying to write a code with AddForce to knock the player a pretty good distance in an arc in the direction opposite of the enemy when they come in contact, but I still have a primitive understanding of how to use AddForce and can't seem to get force applied in any direction at all. The player just moves through the enemy.
Here's the only thing I could manage to scrap together and it is obviously insufficient:
if (other.gameObject.tag == "Enemy")
{
playerDead = true;
Rigidbody rigidbody = other.GetComponent<Rigidbody> ();
rigidbody.AddForce (transform.forward * 100);
}
I can post a screenshot if it helps.

Instead of transform.forward, use a more tailored direction depending on the position of both units
public float speed = 100;
if (other.gameObject.tag == "Enemy")
{
playerDead = true;
Vector3 direction = (transform.position - other.transform.position).normalized;
other.GetComponent<Rigidbody>().AddForce (direction * speed);
}
Edit: You must make sure that the rigidbody is on the game object calling the OnCollisionEnter function, it cant just be on any of the objects involved in the collision.

I cannot comment so I must make an answer.
You have an isTrigger set up apparenty. Be sure to turn isTrigger OFF or your player will walk through the enemy collider.
[SerializeField]
private float speed = 100;
private bool playerDead;
OnCollisionEnter(Collision collision)
{
if(collision.gameObject.tag == "Enemy")
{
playerDead = true;
Vector3 direction = (transform.position - collision.transform.position).normalized;
collision.GetComponent<Rigidbody>().AddForce (direction * speed,0,0);
//AddForce is a vector3 apparently and requires (x,y,z)
// Also note that I'm getting errors with the "collision.GetComponent<>"
// You're going to want to remove "collision"
// I think the smarter approach maybe to declare a public Rigidbody variable ( Up Top )
[SerializeField]
private Rigidbody playerRidg;
playerRidg = GetComponent<Rigidbody>().AddForce(direction * speed,0,0);
}
}

My solution using coroutine which toggles a bool "spikes":
Player collision:
private void OnTriggerEnter2D(Collider2D collision){
if (collision.gameObject.tag == "Spike" )
{
StartCoroutine(Knockback());
}
}
Coroutine:
IEnumerator Knockback()
{
spikes = true;
yield return new WaitForSecondsRealtime(0.3f);
spikes = false;
}
Whenever the spikes bool is true player will be moved
void FixedUpdate()
{
if (spikes ==true)
{
Vector2 NewPosition = new Vector2(10.0f, 10.0f);
moveCharacter(NewPosition);
}
}