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Move Object to the last position or position just outside the collision area

I am using a Player rigid body object and there are walls around the Player. These walls are restricting the Player to go through. The Player gets collided with these walls and then falls. The Player uses teleport function to jump from one area to next. Is there a way to make the Player jump to a position just outside the collision area after the Player is collided with these walls?
That is, Player A gets collided with the wall and does not jump to last position, but the position before the collision happened?
public GameObject Player;
public Vector3 PlayerPos;
public bool RecordPos = true;
// Start is called before the first frame update
void Start()
{
}
// Update is called once per frame
void Update()
{
if(RecordPos == true)
{
PlayerPos = Player.transform.position;
}
}
public void OnTriggerEnter(Collider col)
{
if(col.gameObject.name == "Cube(3)" )
{
RecordPos = false;
Player.transform.position = PlayerPos;
}
}
In this script, the Player moves to last position it teleported from.

The "last" position before colliding is 1 frame before the collision. If you capture this position, the character will probably just fall on the obstacle again. Imagine you have a platform ___...___ and an obstacle. The easiest solution is to have 1 trigger at the left side of the obstacles and 1 trigger at the right side. If the player hasn't overcome the obstacle yet, he will be teleported to a chosen destination by you (before the obstacle) and if he's already overcome the obstacle, he will be teleported at the right side. __S_..._S__ (S stands for save/checkpoint trigger)
You need the following script on the gameobject with the Trigger collider. You also need to create a child object to the gameobject with the trigger:
private void OnTriggerEnter2D(Collider2D collision)
{
SaveManager.Instance.LastCheckpointOnHit = transform.GetChild(0).position;
}
And I suppose you have some sort of a singleton for data persistance. Now you can move the child gameobject whereever you want to teleport the player. And BTW I named the property LastCheckpointOnHit, because I was thinking of Holow Knight where if you get hit by spikes it instantly teleports you.
Then you just move the player: Player.transform.position = SaveManager.Instance.LastCheckpointOnHit;

In general when dealing with Rigidbody you shouldn't apply positions through the Transform component but rather through the Rigidbody.
I could imagine something like if you collide with a wall you get pushed away from the wall a bit in the direction where you came from like e.g.
[SerializeField] private float someDistanceThreshold = 0.01f;
[SerializeField] private Rigidbody _rigidbody;
private void Start()
{
if(!_rigidbody) _rigidbody = Player.GetComponent<Rigidbody>();
}
private void FixedUpdate()
{
PlayerPos = _rigidbody.position;
}
public void OnTriggerEnter(Collider col)
{
// instead of the name I would rather use a tag later to cover all obstacles
if(col.gameObject.name == "Cube(3)")
{
_rigidbody.position -= (_rigidbody.position - PlayerPos).normalized * someDistanceThreshold;
// For stopping the player here
_rigidbody.velocity = Vector3.zero;
}
}

How to stop trigger animation when player colliding the ground?

I'm a new unity's user, and I'm trying to make a little 2D plateformer.
I can controle my player but I have a little problem with my jump.
I made it with a trigger in animator, it works, but I want to stop the animation when player touching the ground.
The best will be to keep the last jump's frame prep until the player touch the ground, and after stop it.
I have a collider2D on a gameObjet who's attached to the player with this code:
void Start()
{
Audio = GetComponent<AudioSource>();
Anim = transform.parent.GetComponent<Animator>();
}
void OnTriggerEnter2D (Collider2D col)
{
if (col.gameObject.tag == "Sol" || col.gameObject.tag == "Plateforme")
{
Anim.SetTrigger("stopJump");
transform.parent.GetComponent<playerController>().isGrounded = true;
Audio.pitch = 0.7f;
Audio.volume = 0.7f;
Audio.PlayOneShot(soundGround);
}
}
My animator have a transition 'stopJump' between 'jump' 'idle' and run. Is it the right thing to do?
see my animator here
The animation Jump doesn't want to stop before the ending frame. If i disable 'has exit time', the jump stop too early...
The trigger 'stopJump' does not have priority...
Thanks!

In your state machine of the animator,
just add an idle state and a trigger which will transfer from JUMP state to that IDLE(which will loop when the player is standing on the ground and do nothing) state, then from the OnTriggerEnter2D you could use Animator.setTrigger("triggerName") to transfer the state to idle.
As in our project player should become idle in lots of condition, so we just made an AnyStat transfer to the idle state by trigging backIdel here is the example:

Check if object is not colliding with anything

Is there a way to detect if the collider on the player (with a rigidbody) object is not colliding with any other collider in a 2D environment?

Not per se, but there are two ways you can get the information. It's easiest to keep an int counter, and increment it in OnCollisionEnter and decrement in OnCollisionExit. When the counter is 0, there are no collisions.
Another way, which will tell you which colliders are overlapping but not necessarily if they are touching, is to use a physics function. Note which type of collider you have--sphere, capsule, box. Knowing the size/shape/position of the collider, you can call Physics.OverlapBox, Physics.OverlapCapsule, or Physics.OverlapSphere. Give the function the same shape as your collider, and it will return the colliders that overlap that space. (For 2D colliders, you can use the Physics2D.Overlap* functions.)

/edit - actually piojo's idea with counters is better, just use int instead of bool.
One way would be to add an int to your script called collisions and set it to 0. Then if at any point the collider fires OnCollisionEnter just increment it, and in OnCollisionExit decrement it.
Something like this should work for 3D:
public int collisions = 0;
void OnCollisionEnter(Collision collision)
{
collisions++;
}
void OnCollisionExit(Collision collision)
{
collisions--;
}
https://docs.unity3d.com/ScriptReference/Collider.OnCollisionEnter.html
https://docs.unity3d.com/ScriptReference/Collider.OnCollisionExit.html

I don't understand what's with all the number keeping. I just did this for when my character jumps or falls off the edge and it works great.
Both my player and terrain have colliders. I tagged my terrain with a "Ground" tag.
Then check if I am currently in contact with the collider with OnCollisionStay()
void OnCollisionStay(Collision collision)
{
if (collision.collider.tag == "Ground")
{
if(animator.GetBool("falling") == true)
{
//If I am colliding with the Ground, and if falling is set to true
//set falling to false.
//In my Animator, I have a transition back to walking when falling = false.
animator.SetBool("falling", false);
falling = false;
}
}
}
void OnCollisionExit(Collision collision)
{
if (collision.collider.tag == "Ground")
{
//If I exit the Ground Collider, set falling to True.
//In my animator, I have a transition that changes the animation
//to Falling if falling is true.
animator.SetBool("falling", true);
falling = true;
}
}
void OnCollisionEnter(Collision collision)
{
if (collision.collider.tag == "Obstacle")
{
//If I collide with a wall, I want to fall backwards.
//In my animator controller, if ranIntoWall = true it plays a fall-
//backwards animation and has an exit time.
animator.SetBool("ranIntoWall", true);
falling = true;
//All player movement is inside of an if(!falling){} block
}
}

How do I detect if a sprite is touching another sprite

How do I determine if a sprite (Sprite1) if on top of (Sprite2)
I need this to switch levels when you touch another sprite with your sprite.
I tried:
void OnCollisionEnter2D(Collision2D other)
{
//code to run
}
But this made it so that everything it touched ran the code. :(

You should attach the script that contains oncollisioneneter to your sprite1 game object for example and in your sprite 2 game object add a tag like sp2 or whatever you want , then in your script when collision happens you check if the object that sprite one collided with is sprite 2 you check it with tag property of sprite 2 like this
void OnCollisionEnter2D(Collision2D other)
{
if(other.gameObject.tag == "sp2")
{
//put your change levelcode here
}
}

Your halfway there. Right now you are running the code whenever the sprite collides with another 2D collider. What you then need to do is determine if that collider is the one attached to the particular sprite we want to trigger the code.
Tag the object containing your level exit, and check for the tag when you get a hit.
void OnCollisionEnter2D(Collision2D other)
{
if(other.gameObject.tag == "levelExit")
{
Debug.Log("next level");
}
}

Identify a selected enemy prefab to play death particle system

I am trying to play a particle effect when an enemy is killed but it seems to play on a randomly selected one rather than the one that was hit. However the enemy that was hit still disappears and still add points to the score.
At the moment I have three scripts to carry this out (All have been shortened so I'm only showing the relevant code):
One which is attached to boxes that are thrown at enemies that detects if they have collided with an enemy prefab.
void OnCollisionEnter (Collision theCollision) {
if (canProjectileKill == true) {
// If the projectile hits any game object with the tag "Enemy" or "EnemyContainer".
if (theCollision.gameObject.tag == "Enemy") {
GameObject.Find("EnemyExplosion").GetComponent<enemyDeath>().ProjectileHasHitEnemy();
// Destroy the projectile itself.
Destroy (gameObject);
// Destroy the game object that the projectile has collided with (E.g. the enemy).
Destroy (theCollision.gameObject);
GameObject.Find("Manager").GetComponent<projectileSpawner>().deleteProjectile();
}
}
}
Another that is attached to the enemy prefabs which detects if they have been hit by a box.
void OnCollisionEnter (Collision theCollision) {
if(theCollision.gameObject.tag == "Projectile") {
GameObject.Find("EnemyExplosion").GetComponent<enemyDeath>().EnemyHasBeenHit();
}
}
I then run an if statement asking if both the box has hit the enemy prefab AND if the enemy prefab has been hit by the box in an attempt to identify a single prefab rather than all of them. However this still doesn't work.
public bool HasProjectileHitEnemy;
public bool HasEnemyBeenHitByProjectile;
void Start () {
gameObject.particleSystem.Stop();
HasProjectileHitEnemy = false;
HasEnemyBeenHitByProjectile = false;
}
public void ProjectileHasHitEnemy () {
// From projectile.
HasProjectileHitEnemy = true;
}
public void EnemyHasBeenHit () {
// From enemy.
HasEnemyBeenHitByProjectile = true;
PlayParticleSystem();
}
public void PlayParticleSystem () {
if (HasEnemyBeenHitByProjectile == true && HasProjectileHitEnemy == true) {
gameObject.particleSystem.Play();
HasProjectileHitEnemy = false;
HasEnemyBeenHitByProjectile = false;
}
}
}
I am aware this is a long question but I have been stuck on this for over a week, so any help would be much appreciated. Thank you :)

I'm not sure what kind of object EnemyExplosion is, but your problem seems to be the search for this object. During OnCollisionEnter you know exactly between which objects the collision occurred. But now you're starting a search for any object that is called EnemyExplosion. That's the reason your particles appear random.
Update:
Ok, with your structure something like that
EnemyContainer
- EnemyExplosion
- Particle System
- EnemyModel
- Collider
If EnemyModel contains the collider, you can get to EnemyExplosion and finally enemyDeath the following way.
var explosion = theCollision.transform.parent.gameObject.GetComponent<EnemyExplosion>();
explosion.GetComponent<enemyDeath>().ProjectileHasHitEnemy();
Now that you're accessing the correct object, you can remove some of your double checks and rely on one collider event.

I seem to have found a way around this. Instead I've just set it to instantiate the particle system whenever an enemy detects that it has collided with a projectile. I then use a Coroutine to delete the particle system 2 seconds after.