We Keep Coding

OnTriggerEnter not firing when character enters

I am new to unity. I am trying to make a character walk into a spinning gold coin and collect it.
I have a character downloaded from mixamo named 'brute'. in CoinScript.cs:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class CoinScript : MonoBehaviour {
// Use this for initialization
void Start(){
}
// update is called once per frame
void Update(){
transform.Rotate(0, 0, 90 * Time.deltaTime);
}
private void OnTriggerEnter(Collider other){
GUI.Label (new Rect (10, 10, 100, 20), "name: " + other.name);
if (other.name == "brute") {
other.GetComponent<PlayerScript> ().points++;
// Add 1 to points
Destroy (gameObject); // this destroy things
}
}
}
PlayerScript.cs
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerScript : MonoBehaviour {
public int points = 0;
// Use this for initialization
void Start () {
}
// Update is called once per frame
void Update () {
}
private void onGUI(){
GUI.Label (new Rect (10, 10, 100, 20), "Score: " + points);
}
}
I added CoinScript to Coin which is a cylinder object. coin:
Transform
Clinder
Mesh Renderer
Box Collider
CoinScript
(I tried to add and remove RigidBody but, OnTriggerEnter did not fire)
and for brute
Transform
Animator
RigidBody
Character Controller
Box Collider
Capsule Collider
Player Script
Move Script
I want OnTriggerEnter to be triggered when brute walk into the coin. thanks for your help.

Here are the basic conditions for OnTriggerEnter to work correctly:
Both objects much have a collider, and one of them should have a rigid body and a collider. the other one may just be a collider.
One of colliders should have IsTrigger = true (set from the inspector). if both of them has IsTrigger = true it will not work.
If you dont want physics, you may use isKinematic = true on the Rigidbody.
In your case, you also happen to have Multiple colliders on the player's body. make sure they all/ the colliders of interest have isTrigger set to true. The coin, on the other hand can have a collider and a RigidBody with isKinematic = true, and the trigger events should work correctly.

One of the object must have the "Is trigger"-property checked. If one of your objects (e.g. the coin) is a trigger you can use the OnCollisionEnter function.
Read it: https://docs.unity3d.com/ScriptReference/Collider.OnCollisionEnter.html

I want my object to fall when the player is near it

I want my objects to fall when the player got to that scene . My game have a long map and I want them not to fall when I start the game .There is any code for player detection in the view? for the objects to fall?
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class FallDown : MonoBehaviour
{
public float fallSpeed = 8.0f;
//Variables for starting position and length until reset
private Vector3 _startingPos;
public float FallDistance = 5f;
void Start()
{
transform.Translate(Vector3.down * fallSpeed * Time.deltaTime, Space.World);
// Save starting position
_startingPos = transform.position;
}
void Update()
{
transform.Translate(Vector3.down * fallSpeed * Time.deltaTime, Space.World);
// If the object has fallen longer than
// Starting height + FallDistance from its start position
if (transform.position.y > _startingPos.y + FallDistance)
{
transform.position = _startingPos;
}
}
}

While the answer above is correct, Colliders might not be what you want to implement in this case. Colliders are used to, well, detect collisions, while you want the objects to fall when the player is at a specific distance from them. For this, I'd suggest adding a reference to the player GameObject first:
private GameObject playerRef;
And in the Start function find the player:
playerRef = GameObject.Find("yourPlayerGameObjectNameHere");
Get the GameObjects that you want to fall either by finding them, like above, or by passing a public reference to them through the inspector. Afterwards, you can use Vector3.distance between each GameObject and the player, like so:
if( Vector3.Distance(player.transform.position, fallingObject.transform.position) < yourDistanceHere ){
// Make the object fall
}

Have you tried implementing this behavior using Colliders?
To do it so, all you've got to do is add both a Collider Component and a RigidBody to your player and to the falling objects.
Once you've added them and configured their parameters, you can check the collision by using the method OnColissionEnter. This method will be triggered every time that a collision is detected by the GameObject that is holding the script. In your case, the falling objects should hold it.
private void OnCollisionEnter(Collision other)
{
//MAKE THE OBJECTS FALL
}

What code do I need for my Unity character to shoot the bullet correctly?

I am not new to programming, but I am new to C#. I am experienced in Python, Java, and HTML. My game is 2D I have a game where my character currently has to touch the enemy to kill it. Now I added code for shooting a bullet to kill the enemy. I also want the bullet to be shot if the spacebar is pressed. The character is supposed to a shoot bullet in either direction. I have taken my code from an example my professor gave me which was originally Javascript and I converted it to C#. Unity no longer supports Javascript. The example code he gave me was basically a rocket shooting as many bullets as I clicked (clicking the mouse shoots bullets) to eliminate an enemy, however the rocket in that example does not move. In my game, the character moves, so the bullet has to get the position of the character. What is the correct code for getting the character position and shooting a bullet correctly?
I tested my game with my current code. The bullet is being spit out of nowhere (from the bottom of my background wallpaper [smack in the middle of the bottom] to a little below the wallpaper). Not even from the character...
Also, I added the Hit class script to my Bullet category in Unity.
Complete Camera Controller (no issues here at all)
using UnityEngine;
using System.Collections;
public class CompleteCameraController : MonoBehaviour {
public GameObject player; //Public variable to store a reference to the player game object
private Vector3 offset; //Private variable to store the offset distance between the player and camera
// Use this for initialization
void Start ()
{
//Calculate and store the offset value by getting the distance between the player's position and camera's position.
offset = transform.position - player.transform.position;
}
// LateUpdate is called after Update each frame
void LateUpdate ()
{
// Set the position of the camera's transform to be the same as the player's, but offset by the calculated offset distance.
transform.position = player.transform.position + offset;
}
}
Complete Player Control Class (If you read the comments in the code that say the "BULLET CODE", that's new code I have placed in the game for the bullets.
using UnityEngine;
using System.Collections;
//Adding this allows us to access members of the UI namespace including Text.
using UnityEngine.UI;
public class CompletePlayerController : MonoBehaviour
{
public float speed; //Floating point variable to store the player's movement speed.
public Text countText; //Store a reference to the UI Text component which will display the number of pickups collected.
public Text winText; //Store a reference to the UI Text component which will display the 'You win' message.
private Rigidbody2D rb2d; //Store a reference to the Rigidbody2D component required to use 2D Physics.
private int count; //Integer to store the number of pickups collected so far.
Rigidbody2D bullet;
float speed2 = 30f; //BULLET CODE
// Use this for initialization
void Start()
{
//Get and store a reference to the Rigidbody2D component so that we can access it.
rb2d = GetComponent<Rigidbody2D> ();
//Initialize count to zero.
count = 0;
//Initialze winText to a blank string since we haven't won yet at beginning.
winText.text = "";
//Call our SetCountText function which will update the text with the current value for count.
SetCountText ();
}
//FixedUpdate is called at a fixed interval and is independent of frame rate. Put physics code here.
void FixedUpdate()
{
//Store the current horizontal input in the float moveHorizontal.
float moveHorizontal = Input.GetAxis ("Horizontal");
//Store the current vertical input in the float moveVertical.
float moveVertical = Input.GetAxis ("Vertical");
Rigidbody2D bulletInstance; //BULLET CODE
//Use the two store floats to create a new Vector2 variable movement.
Vector2 movement = new Vector2 (moveHorizontal, moveVertical);
//Call the AddForce function of our Rigidbody2D rb2d supplying movement multiplied by speed to move our player.
rb2d.AddForce (movement * speed);
if(Input.GetKeyDown(KeyCode.Space)&& Hit.hit == false) //BULLET CODE IN HERE
{
// ... instantiate the bullet facing right and set it's velocity to the right.
bulletInstance = Instantiate(bullet, transform.position, Quaternion.Euler(new Vector3(0,0,0)));
bulletInstance.velocity = new Vector2(speed2, 0);
bulletInstance.name = "Bullet";
}
}
//OnTriggerEnter2D is called whenever this object overlaps with a trigger collider.
void OnTriggerEnter2D(Collider2D other)
{
//Check the provided Collider2D parameter other to see if it is tagged "PickUp", if it is...
if (other.gameObject.CompareTag ("PickUp"))
{
//... then set the other object we just collided with to inactive.
other.gameObject.SetActive(false);
transform.localScale += new Vector3(0.1f, 0.1f, 0);
//Add one to the current value of our count variable.
count = count + 1;
//Update the currently displayed count by calling the SetCountText function.
SetCountText ();
}
}
//This function updates the text displaying the number of objects we've collected and displays our victory message if we've collected all of them.
void SetCountText()
{
//Set the text property of our our countText object to "Count: " followed by the number stored in our count variable.
countText.text = "Count: " + count.ToString ();
//Check if we've collected all 12 pickups. If we have...
if (count >= 12)
//... then set the text property of our winText object to "You win!"
winText.text = "You win!";
}
}
Hit code. All code in this class is made for the bullet.
using UnityEngine;
using System.Collections;
public class Hit : MonoBehaviour
{
GameObject[] gameObjects;
public static bool hit = false;
void Removal ()
{
gameObjects = GameObject.FindGameObjectsWithTag("Bullet");
for(var i= 0 ; i < gameObjects.Length ; i ++)
Destroy(gameObjects[i]);
}
void OnCollisionEnter2D ( Collision2D other )
{
if(other.gameObject.name=="Bullet")
{
Removal();
Destroy(gameObject);
hit = true;
}
}
}

I see several issues with the code you wrote. as #Kyle Delaney suggested, I'd also highly recommend you check out the Unity Learn website, and go through several tutorials before moving through. I've highlighted a few issues below that may help solve your problem, but you could really benefit from changing your approach in the first place to avoid many of these issues. See below.
In your camera controller class, why not make the offset public so you can set it yourself in the inspector>
In Player controller class:
changed:
if (Input.GetKeyDown(KeyCode.Space)) //Shoot bullet
{
// ... instantiate the bullet facing right and set it's velocity to the right.
Rigidbody2D bulletRB = Instantiate(bullet, transform.position, transform.rotation);
bulletRB.AddForce(new Vector2(speed2,0), ForceMode2D.Impulse);
}
On a click, this instantiates the bullet prefab and sets its transform to copy the position and rotation of the player. It then adds a force to it to the right. You should avoid setting the velocity manually with rigidbodies, this can cause unwanted behaviour. Use the Addforce/addTorque methods instead. The ForceMode says to ignore its mass and set its velocity.
Then delete your Hit class, and replace with this Bullet class, which you drag onto the bullet prefab. Your player shouldn't be in charge of checking for bullet hits. that's the bullet's job. The player just launches the bullets and then the bullets do what bullets do. this just checks to see if the bullet hit anything, if so it destroys it. You can make this more complicated if you want. I would recommend using layers to determine which layers the bullet checks collisions with. You probably don't want bullets destroying your terrain. and you definitely don't want bullets destroying the player itself!
public class Bullet : MonoBehaviour
{
private void OnCollisionEnter2D(Collision2D collision)
{
Destroy(collision.gameObject);
Destroy(this.gameObject);
}
}
Also you shouldn't need to set the name of the bullet, since your prefab bullet should already be named "bullet".
I hope this gets you started in the right direction. But based on your code, I HIGHLY recommend you work through the tutorials before continuing with any projects. The unity staff that make them are super helpful and the tutorials start off really simple but get really complicated fast, so you actually come away learning a ton!

Perhaps the problem has to do with the player's parent transform. You could try something like this to make sure the bullet has the right parent:
bulletInstance = Instantiate(bullet);
bulletInstance.transform.parent = transform.parent;
bulletInstance.transform.position = transform.position;
bulletInstance.velocity = new Vector2(speed2, 0);
bulletInstance.name = "Bullet";
If that doesn't work it may be worthwhile to check the player's Rect Transform to see where the anchors and pivot are. Perhaps the player's actual "position" coordinates aren't where you think they are.
Have you done the Space Shooter tutorial? It has a segment about shooting bullets.

Building a rotatable lift in Unity

I got a "cube" in Unity. This cube has a Trigger, when moving into it, the object gets grabbed into the air. This is working as a lift, you can see an example what I mean here. It is a small scene taken from Spyro 2.
https://youtu.be/f8wWMa4N5mE?t=643
The code I use is really small for now
private float liftSpeed = 10; // the speed, the object is flying up
private void OnTriggerStay(Collider col)
{
Rigidbody objectRigid = col.gameObject.GetComponent<Rigidbody>(); // get the rigidbody from the object in the trigger
if (objectRigid != null) // does it have a rigidbody?
objectRigid.velocity = new Vector3(objectRigid.velocity.x, liftSpeed, objectRigid.velocity.z); // make it fly in the air
}
So I have a lift, that totally works fine. But I when I rotate my lift I want it to work aswell.
Some examples (my gamne is 3D)
So how can I make my lift work for all "rotations"?

You can use transform.up to get the up direction of your lift, and then multiply by the lift speed.
objectRigid.velocity = transform.up * liftSpeed;
transform.up changes depending on how the object is rotated, so if your lift is rotated to the left, then the lift will carry objects to the left.

You can use the transforms RotateAround Method for a rotation like in the video clip.
Transform t = col.gameObject.GetComponent<Transform>();
transform.RotateAround(Vector3.zero, Vector3.up, 20 * Time.deltaTime);
The given snipet lets the object rotate around it's axis, which is pointing up.

Make the player child of the lift OnTriggerEnter.
Move the lift as you do
You can rotate the lift using RotateAround function. The player should also rotate along with the lift, as it's a child of the lift now.
make player's parent to null when it's out of lift trigger using OnTriggerExit

This is my solution to the problem.
The lift and the EndPoint will be Empty GameObjects. If you want the lift has a platform or a base you can add a GameObject as child of the lift with the shape you prefer.
You need to attach a Collider to the lift and set it as trigger.
Then you add the following script to the lift Empty GameObject
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class MoveLift : MonoBehaviour {
public Transform end;
float speed = 4f;
bool liftActivated = false;
// Use this for initialization
void Start () {
}
// Update is called once per frame
void Update () {
if(liftActivated)
{
float step = speed * Time.deltaTime;
//To move up the lift
transform.position = Vector3.MoveTowards(transform.position, end.position, step);
//To spin the lift
transform.RotateAround(Vector3.up, 2 * Time.deltaTime);
//To stop spining the lift when it reaches the end of the path
if(transform.position.Equals(end.position))
liftActivated = false;
}
}
void OnTriggerEnter(Collider other){
liftActivated = true;
other.gameObject.transform.parent = this.transform;
other.gameObject.GetComponent<Rigidbody>().isKinematic=true;
}
}
Then you should decide if once the lift reaches its destination it is the player who has to move out of the platform, or if you unparent it and let it fall down as the end of the trip

2D Collision & Stop in Unity 3D

I have a simple scene in 2D. The right yellow box is the "Player", while the green & brown thing is the "Obstacle".
Player has a BoxCollider2D, RigidBody2D and a C# script named Hero.cs attached to it. BoxCollider2D enabled Is Trigger; RigidBody2D enabled Is Kinematics; other settings are left in default values.
Obstacle has only a BoxCollider2D with Is Trigger enabled.
and here is the Hero.cs:
using UnityEngine;
using System.Collections;
public class Hero : MonoBehaviour {
public float moveSpeed = 0.1f;
private Vector3 moveDirection;
// Use this for initialization
void Start () {
}
// Update is called once per frame
void Update () {
Vector3 currentPos = transform.position;
if(Input.GetKey("left")) {
transform.Translate(new Vector3(-1, 0, 0));
} else if(Input.GetKey("right")) {
transform.Translate(new Vector3(1, 0, 0));
}
}
void OnCollisionEnter2D(Collision2D collision) {
Debug.Log("Colliding");
}
void OnTriggerEnter2D(Collider2D other) {
Debug.Log("Triggering");
}
}
Only "Triggering" appears in Console Log.
My question is: What should I add to make the "Player" inaccessible to the "Obstacle" (no need to bounce away)?
Note: Using Unity 4.5
Update: After I set Gravity Scale to 0, collision detection works, but in a strange way. The "Player" go sideway during collision. Watch this YouTube video for action.
I expect the Player only go along X or Y axis. What did I miss ?

IsTrigger
Triggers let other colliders pass through without any collision happening. They are only triggering an event, hence the name.
If you disable IsTrigger for both objects, you will get collisions and the corresponding events are fired.
More infos here: http://docs.unity3d.com/Manual/CollidersOverview.html
IsKinematic
Kinematic rigidbody colliders will only collide with other non-kinematic rigidbody colliders.
Have a look at this matrix http://docs.unity3d.com/Manual/CollisionsOverview.html
Disable IsKinematic and move the player with MovePosition if you don't want to use force values to move the player.