Unity collision not being detected - unity3d

I am learning to create a simple fps game in unity the problem is that the collision does not update itself for example initially when my player is on the ground console prints "floor" by "Debug.log(collision.gameObject)" but when it intersects other objects such as a cube console will print out "cube" but when I walk away from it , console does not change back to "floor" Why????
I am using transform.translate to move and jump and using method OnCollisionEnter for collision detection

OnCollisionEnter is triggered only when object enters the collider.
A) Make a list of all encountered objects by adding them when OnCollisionEnter happens and removing when OnCollisionExit happens. Then whenever you need to make sure you are on "floor" check it in the list.
B) Use OnCollisionStay and every frame you will be notified if you are touching the "floor".

Remember one thing, the other object you want to collide with need to have a collider component asigned, make sure of it. Join this with the previous answer.

I recommend to verify collision.
Here on simple example:
void OnCollisionEnter (Collision col){
if (col.gameObject){
Debug.Log("Object name : "+ col.gameObject.name);
}
}

Related

Unity collison not detected 2d

I am building a 2d game and I run this code with a collider on both the other objects (on trigger: on to the other object) but nothing works)The other object is name Coin and also it has the tag Coin.
I added kinematic rigid body to the coin and still no work :( (If I deleted it still the same). Also, my player has to colliders and the collision detected on both coin and player are discrete. Also, they are prefabs both
void OnTriggerEnter2d(Collider2D other) {
Debug.Log("detected");
if (other.gameObject.CompareTag("Coin")) {
other.gameObject.SetActive(false);
}
}
Typo mistake: instead OnTriggerEnter2d try OnTriggerEnter2D. with a capital D. ;)
In order to get a OnTrigger collision triggered, you must have the following requirements:
1-The 2 objects need to have a collider attached it.
2-Only one of the objects needs to be a trigger
3-One of the 2 objects must have a rigidbody attached to it.
Did you fulfill the requirement n°3 ?
Typo mistake: instead OnTriggerEnter2d try OnTriggerEnter2D. with a capital D. ;)

unity2D: Make enemies ignore OnTriggerEnter2D when they are traveling down

I have two scripts, one attached to a gameobject and the other attached to an enemy prefab that is instantiated over time. The script attached to the gameobject uses OnTriggerEnter2D to detect when the enemy has entered, then the health bar for the object goes down by one. Iit works, the only problem is now is that because of the fact that the enemy comes up then walks back down, the enemy is colliding with the objects more than once which is not what I want.
I have tried things like using booleans to stop it colliding more than once but other prefabs enemies isn't able to collide with the gameobject because of the boolean is being set to true and not being set back to false. I don't want to use yield wait for seconds because enemies do spawn often and so it won't really look normal; I also tried onTriggerExit2D but you get the idea if I try that method. Is there any other way of detecting if an enemy has entered the objects collider damaging the object once but then when the enemy comes back down he ignores the collision (without turning off the enemies or the gameobject's collider) aka all instantiated enemies is able to collide with the gameobject when they are going up but not when they are coming back down.
Your best bet is to simply do a bool check on the monsters if they're going north or not. There are several ways to go about this. If you know where they are going you can simply compare where they are going to where they are and compare the y vector values. so something like this:
public bool monsterNorthChecker(){
if(monsterDestination.y > currentLocation.y){
return true;
}
else{
return false;
}
}
Then you can simply call that function OnTriggerEnter and verify if the monster is going north or not, if he is, take away his health. If you don't know his destination, you'll probably have to resort to more tedious means of determining destination direction. Something like comparing the y values of last frame's vector2 to this one and see which way he's moved.

Two collider in one game object how to distinguish between them when colliding with another?

I'm making a 2D game, there is one player with two collider : a box collider 2D on top and a small circle collider 2D bottom. When the player jump on the box he will be ok, but when he collide with the box with his face(box collider 2D) he will die ? How can I do that? I tried the following code , but it not work. Please help me.Thanks!
if (GetComponent<Collider2D>().GetType() == typeof(BoxCollider2D))
{
//do something
}
if (GetComponent<Collider2D>().GetType() == typeof(CircleCollider2D))
{
//do something
}
If you want to get a certain BoxCollider, you can use GetComponent<BoxCollider2D>() and GetComponent<CircleCollider2D>()
However, I am not sure how to take this information and check which one fired the the OnCollisionEnter, unless you set one collider to a trigger, and use OnTriggerEnter for one, and OnCollisionEnter for the other.
What I would recommend is having two child game objects on the player and put both colliders on each game object, and handle each event in their own OnCollisonEnter

How to detect two object collide or not?

I am making one unity game in which two objects having collider in which I have select isTriger and does not have rigid body, if I put the rigid body then they are kinematic object, So that gravity did not effect on that object, Even also i don't want any physic operation on this object also. but I want to detect whether this two object collide which each other or not.
How can I do this ?
When 2 colliders make contact with each other,
OnCollisionEnter2D
OnCollisionExit2D
OnCollisionStay2D
are called for 2D games, likewise for 3D(remove 2D in names) also.
Check out this link: http://docs.unity3d.com/ScriptReference/MonoBehaviour.OnCollisionEnter2D.html
Sorry man, but unity use the phsysics engine to detect collision so you have to add the rigidbody to the item you want to to plug the script.
PS:remeber if you want to detect collisions with Trigger collider, you need to use
void OnTriggerEnter(){
//your code
}
void OnTriggerStay(){
//your code
}
void OnTriggerLeave(){
//your code
}

Getting collisions for multiple object without the collision callbacks

I'm making a platformer (sidescroller), and right now I'm making a grenade-launcher for the player.
It spawns grenades which is a prefab, this prefab has a Circle Collider 2D which is the blast radius for the explosion.
When a grenade is spawned I run this (amongst other things);
// Add the initial force
rBody.AddForce(new Vector2(forceX, forceY) *300f);
Invoke("Explode", 2.5f);
I'm having trouble figuring out how I should handle the Explode function.
I would like to find all the GameObjects that are colliding with the Circle Collider 2D at that point, but I can't find a way to do it.
I would like to be able to do something like this (not real code but you understand what I'm trying to do)
void Explode () {
collidingObjects = circleCollider.getCollisions();
foreach(collidingObject as entity) {
if(entity = 'player')
player.pushLeftOrRight()
elseif(entity = 'enemy')
grenade.dealDamage(grenade.damage)
}
Debug.Log("Explode");
Destroy(gameObject);
}
I'm guessing that it wouldn't work so can anyone point me in the right direction?
In your grenade's script, use OnTriggerEnter or OnCollisionEnter to log collisions; basically just have a HashSet for each grenade that is updated and keeps track of what it is colliding with. Then Explode just has to iterate through this set when you call it.