So I have the following script which applies force when a player gets hit. I like the speed that the knockback is currently set to, but I would like for the player to move back more smoothly (as in you can see the object slide back) instead of him instantly moving back. Here is the script:
public class meleeAttack : MonoBehaviour
{
int speed = 1000;
void Start()
{
}
void Update()
{
}
void OnTriggerStay(Collider other)
{
if (other.gameObject.tag == "Player" && Input.GetKeyUp(KeyCode.F))
{
other.GetComponent<Rigidbody>().AddForce(transform.forward * speed);
}
}
}
What would be the best approach to achieving this?
Related
So I'm developing my first game in Unity currently (following a series by Mister Taft on YouTube called "Make a game like Zelda using Unity and C#" and just finished the 19th video).
I've currently got a "Log" enemy and am working on a knockback feature. I've followed the way that it is approached in the series is by creating a state machine that changes the Log's state to "stagger" for a couple of seconds, then return it to "idle" so it can change itself to "walk."
Whenever I hit the Log, however, it gets stuck in the stagger state and drifts without stopping until it hits a collider (note it doesn't change back to idle/walk even when it does hit the collider). If I can hit the Log correctly, sometimes, the player will actually also drift in the opposite direction.
Relevant code:
public class Log : Enemy {
private Rigidbody2D myRigidBody;
public Transform target;
public float chaseRadius;
public float attackRadius;
public Transform homePosition;
public Animator anim;
// Use this for initialization
void Start () {
currentState = EnemyState.idle;
myRigidBody = GetComponent<Rigidbody2D> ();
anim = GetComponent<Animator> ();
target = GameObject.FindWithTag ("Player").transform;
}
// FixedUpdate is called by physics.
void FixedUpdate () {
CheckDistance ();
}
//Log finds and walks towards Player.
void CheckDistance(){
if (Vector3.Distance (target.position, transform.position) <= chaseRadius && Vector3.Distance (target.position, transform.position) > attackRadius
&& currentState != EnemyState.stagger)
{
Vector3 temp = Vector3.MoveTowards (transform.position, target.position, moveSpeed * Time.deltaTime);
myRigidBody.MovePosition (temp);
ChangeState (EnemyState.walk);
}
}
private void ChangeState(EnemyState newState){
if (currentState != newState)
{
currentState = newState;
}
}
}
public class Knockback : MonoBehaviour {
public float thrust;
public float knockTime;
private void OnTriggerEnter2D(Collider2D other){
if (other.gameObject.CompareTag ("breakable"))
{
other.GetComponent<Pot>().Smash();
}
if(other.gameObject.CompareTag("enemy"))
{
Rigidbody2D enemy = other.GetComponent<Rigidbody2D>();
if (enemy != null)
{
enemy.GetComponent<Enemy> ().currentState = EnemyState.stagger;
Vector2 difference = enemy.transform.position - transform.position;
difference = difference.normalized * thrust;
enemy.AddForce (difference, ForceMode2D.Impulse);
StartCoroutine (KnockCo (enemy));
}
}
}
private IEnumerator KnockCo(Rigidbody2D enemy){
if (enemy != null)
{
yield return new WaitForSeconds (knockTime);
enemy.velocity = Vector2.zero;
enemy.GetComponent<Enemy>().currentState = EnemyState.idle;
}
}
}
public enum EnemyState{
idle,
walk,
attack,
stagger
}
public class Enemy : MonoBehaviour {
public EnemyState currentState;
public int enemyHealth;
public string enemyName;
public int baseAttack;
public float moveSpeed;
}
I've tried to add an else statement after the void CheckDistance in Log.cs, but that resulted in the Log having jittery movement and jumping back along its path. I'm at a loss. Any help would be greatly appreciated!
This question already has answers here:
What is a NullReferenceException, and how do I fix it?
(27 answers)
Closed 1 year ago.
For some reason when I'm in the normal view in-game I am able to link the scripts that I need to call in order to make an animation like so
however, whenever I start the game it automatically removes them from the slots, and it doesn't work
I am completely clueless as to why this may be happening and unity keep giving me errors that say that I'm not setting an instance to my script I really have no clue why this may be happening.
I have 3 scripts that I'm working with that is giving me the problem
one is the main script for the enemy vision (I am referencing the other scripts in this one)
the second is the enemy animation script which makes him go from idle to attack and the third is an animation for the gun model since I had to make it follow the hands of the enemy
scripts attached bellow
1st script(enemyAI):
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class EnemyAi : MonoBehaviour
{
public bool detected;
GameObject target;
public Transform enemy;
public GameObject Bullet;
public Transform shootPoint;
public float shootSpeed = 10f;
public float timeToShoot = 1f;
public EnemyAni Animation;
public GunAni GunAnimation;
void Start()
{
Animation = GetComponent<EnemyAni>();
GunAnimation = GetComponent<GunAni>();
}
public void Update()
{
//makes the enemy rotate on one axis
Vector3 lookDir = target.transform.position - transform.position;
lookDir.y = 0f;
//makes enemy look at the players position
if (detected)
{
enemy.LookAt(target.transform.position, Vector3.up);
enemy.rotation = Quaternion.LookRotation(lookDir, Vector3.up);
}
if (detected == true)
{
Animation.LookPlayer = true;
GunAnimation.ShootPlayer = true;
}
if (detected == false)
{
Animation.LookPlayer = false;
GunAnimation.ShootPlayer = false;
}
}
//detects the player
void OnTriggerEnter(Collider other)
{
if (other.tag == "Player")
{
detected = true;
target = other.gameObject;
}
}
void OnTriggerExit(Collider other)
{
if (other.tag == "Player")
{
detected = false;
}
}
}
2nd Script (EnemyAnimation):
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class EnemyAni : MonoBehaviour
{
public Animator animator;
public bool LookPlayer;
public void Start()
{
animator = GetComponent<Animator>();
}
public void Update()
{
if (LookPlayer == true)
{
animator.SetBool("IsShootingStill", true);
}
else
{
animator.SetBool("IsShootingStill", false);
}
}
}
3rd script (GunAnimation):
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class GunAni : MonoBehaviour
{
public Animator animator;
public bool ShootPlayer;
public void Start()
{
animator = GetComponent<Animator>();
}
public void Update()
{
if (ShootPlayer == true)
{
animator.SetBool("IsShooting", true);
}
else
{
animator.SetBool("IsShooting", false);
}
}
}
Your code:
void Start()
{
Animation = GetComponent<EnemyAni>();
GunAnimation = GetComponent<GunAni>();
}
Searches the GameObject that holds the EnemyAI script for EnemyAni and GunAni. If the GameObject doesn't have those it will return null.
Sounds like you want to remove that code.
Note that if the scripts exist on a child of that GameObject you will need to use GetComponentInChildren
There are some things to review, good practices:
GameObject target is private for C#, but it is better to put private before.
variable names like Bullet Animation GunAnimation should always begin with lowercase, because they might be confused with a Class Name (search in internet for CamelCase and PascalCase).
Name should be clear. EnemyAni Animation is not clear enough, because Animation maybe any animation (player, enemy, cube, car, etc.).
It is better enemyAnimation to be clear, as you did with GunAnimation (only just with lower case at beginning)
As slaw said, the Animation must be in the GO attached.
about last item
Let's say you have an empty GO (GameObject) called GameObject1 and you attach EnemyAi script to it.
In Runtime (when game mode begins), it will try to find Animation = GetComponent<EnemyAni>();, but it won't find it
Why?
Because GetComponent<> searches for the Component(Class) that is in the <> (in this case EnemyAni) in its GO (in this case, GameObject1), but the unique script attached to GameObject1 is EnemyAI.
So, you have 3 options:
Attach EnemyAni to GameObject1
Create another GO (for example, GameObjectEnemyAni), attach the script EnemyAni and drag and drop GameObjectEnemyAni to GameObject1 and delete Animation = GetComponent<EnemyAni>(); in Start
Keep in mind: if you leave that line of code, instead of getting the script EnemyAni from GameObjectEnemyAni, it will run the code Animation = GetComponent<EnemyAni>(); in Start, and obviously, it won't find it
Create events. It's a really good practice for avoiding code tight coupling, but that is more advanced stuff.
In my project I have a Ground Plane Stage with an child object. Now I want to rotate this object with a UI Button. If i hold the button down it should rotate and if I release the button the rotation should stop. Unfortunately I´m not able to do this.
This is my script:
public class RotateObject : MonoBehaviour
{
public float rotationSpeed = 45f;
public bool isPressed = false;
public void TogglePressed(bool value)
{
isPressed = !isPressed;
} //edit added missing Brace
void Update()
{
if (isPressed)
{
transform.Rotate(Vector3.up * rotationSpeed * Time.deltaTime);
}
}
}
I added Event Trigger with Pointer Down and Pointer Up to the button.
The script is attached to my gameObject and the TogglePressedfunction is linked to Pointer Down with the checkbox checked and to Pointer Up, here checkbox is not checked.
If I test it in Unity and click the button, the inspector shows that it works, but if I upload it to my phone, there is no rotation of the object.
EDIT:
Input.GetMouseButtonDown()
void Update()
{
if (isPressed && Input.GetMouseButtonDown(0))
{
// Same Code
}
}
Input.GetButtonDown()
void Update()
{
if(isPressed && Input.GetButtonDown("Fire1"))
{
//Same Code
}
}
EDIT2:
This is my script i use now:
public class RoatateObject : MonoBehaviour
{
public float rotationSpeed = 45f;
void Update()
{
if(Input.GetMouseButtonDown(0))
{
transform.Rotate(Vector3.up * rotationSpeed * Time.deltaTime);
}
}
}
i dont know exactly if pointerdown is recognized on phones, do you have tried Input.GetMouseButtonDown() (also trigger on phones)?
maybe to speed up your testing try unity remote to test local instead of uploading to your phone
I have 2 script, playerMachanics and enemyBehavior. My enemyBehavior has a boolean that when the boolean is true it moves away from the player. Instead i'm getting the error: "object reference not set to an instance of an object".
I'm sure it means the script can't find the component but i can't quite figure out what's wrong.
public class enemyBehavior : MonoBehaviour
{
public bool evade = false;
public GameObject Player;
public float movementSpeed = 4;
// Start is called before the first frame update
void Start()
{
Player = GameObject.FindGameObjectWithTag("Player");
}
// Update is called once per frame
void Update()
{
transform.LookAt(Player.transform);
transform.position += transform.forward * movementSpeed * Time.deltaTime;
if (evade == true)
{
movementSpeed = -4;
}
}
}
public class playerMechanics : MonoBehaviour
{
// Start is called before the first frame update
void Start()
{
}
// Update is called once per frame
void Update()
{
}
void OnCollisionEnter(Collision collision)
{
enemyBehavior evade = gameObject.GetComponent<enemyBehavior>();
if (collision.gameObject.name == "coin")
{
Destroy(collision.gameObject);
enemyBehavior script = GetComponent<enemyBehavior>();
script.evade = script.evade == true;
}
}
}
I expected that the movementSpeed would go to -4 but now i'm just getting an error.
Calling getComponent by itself will look for the component attached to the parent object of the script, which is the player in this case I think. So it will always return null.
Add
Public GameObject enemy;
to the playerMechanics class and then go into the designer and drag the game object that has the enemyBehavior script attached into it. There are several problems with the onCollisionEnter method. Something like this
void OnCollisionEnter(Collision collision)
{
if (collision.gameObject.name == "coin")
{
Destroy(collision.gameObject);
enemyBehavior script = enemy.GetComponent<enemyBehavior>();
script.evade = false;
}
}
should get you going in the right direction.
Is the enemy behavior on the player object? See here
enemyBehavior evade = gameObject.GetComponent<enemyBehavior>();
and here
enemyBehavior script = GetComponent<enemyBehavior>();
You need to implement a way to track which enemy instance you are grabbing. Do this by making a variable to hold the enemy script, or by using a singleton on the enemy script (if there is one enemy).
Variable:
public enemyBehaviour enemy;
Singleton:
(enemyBehaviour)
public static enemyBehaviour instance = null;
private static readonly object padLock = new object();
void Awake(){
lock(padLock){
if(instance == null)
instance = this;
}
}
(player)
enemyBehaviour.instance.evade = false;
Look up singletons if you want to learn more.
If I'm right, I think your game mechanics works like this: The player's objective is to collect coins. When they collect one, the enemy near it will come and evade the player.
If that's the case, you should use this:
public class enemyBehavior : MonoBehaviour
{
public bool evade = false;
public GameObject Player;
public float movementSpeed = 4;
void Start()
{
Player = GameObject.FindGameObjectWithTag("Player");
}
void Update()
{
transform.LookAt(Player.transform);
transform.position += transform.forward * movementSpeed * Time.deltaTime;
if (evade)
{
movementSpeed = -4;
}
}
}
public class playerMechanics : MonoBehaviour
{
[SerializeField] enemyBehvaior enemy;
void OnCollisionEnter(Collision collision)
{
if (collision.collider.name == "coin")
{
Destroy(collision.collider.gameObject);
enemy.evade = true;
}
}
}
In your code, you wrote 'collision.gameObject.' This refers to the object the script is attached to. If you want to reference to the object that we hit, use 'collision.collider'.
'[SerializeField]' is a unity attribute, which is used to make a field show up in the inspector without making it public.
Just a heads up, if you're using 2D, make sure the method is signatured 'OnCollisionEnter2D(Collision2D collision)'.
I hope I answered your question. :)
Not sure why, I've done this sort of this a bunch of times, but this is giving me some issues. Making a project for Game AI, I have a whole bunch of stuff already done, now just making some turrets that if the player is in a certain range it will fire, which I have already. The turret fires the bullet and then for some reason they just start destroying themselves and they don't go towards my player. Wondering if anyone on here can help, thanks in advance!
Some details you may need to know:
I have a Base, a Gun nose and a Gun for my turret. My Gun has a GunLook.cs script that makes it look at the player (so when they shoot it should go towards them), I'm not sure if that has anything to do with why I'm having these issues, but I'll post that code as well just incase
How my Hierchy for my turret is
Turret_AI (Base)
Gun (child of Turret_AI)
bulletSpawn (child of Gun)
Gun_Nose (child of turret_AI)
bulletSpawn is an empty GameObject I created in hopes to solve my problem. I set it just off the Gun so that it wouldn't just collide with gun and destroy itself (what I thought it might be doing, but not correct).
That should be all the info needed, if anyone needs more I will be checking this every 2 seconds so let me know and I will get back to you with quick response.
TurretScript.cs
(I did set the GameObject to Player in Unity, before anyone asks)
using UnityEngine;
using System.Collections;
public class TurretScript : MonoBehaviour {
[SerializeField]
public GameObject Bullet;
public float distance = 3.0f;
public float secondsBetweenShots = 0.75f;
public GameObject followThis;
private Transform target;
private float timeStamp = 0.0f;
void Start () {
target = followThis.transform;
}
void Fire() {
Instantiate(Bullet, transform.position , transform.rotation);
Debug.Log ("FIRE");
}
void Update () {
if (Time.time >= timeStamp && (target.position - target.position).magnitude < distance) {
Fire();
timeStamp = Time.time + secondsBetweenShots;
}
}
}
GunLook.cs
// C#
using System;
using UnityEngine;
public class GunLook : MonoBehaviour
{
public Transform target;
void Update()
{
if(target != null)
{
transform.LookAt(target);
}
}
}
BulletBehavior.cs
using UnityEngine;
using System.Collections;
public class BulletBehavior : MonoBehaviour {
// Use this for initialization
void Start () {
}
// Update is called once per frame
void Update () {
if (rigidbody.velocity.magnitude <= 0.5)
Destroy (gameObject);
}
void OnCollisionEnter(Collision collision)
{
if (collision.collider)
{
if(collision.gameObject.tag == "Enemy" || collision.gameObject.tag == "EnemyProjectile")
{
Physics.IgnoreCollision(rigidbody.collider,collision.collider);
//Debug.Log ("Enemy");
}
if(collision.gameObject.tag == "SolidObject")
{
Destroy(gameObject);
}
if(collision.gameObject.tag == "Player")
{
Destroy(gameObject);
}
}
}
}
You're never moving your bullet.
public class BulletBehavior : MonoBehaviour
{
private const float DefaultSpeed = 1.0f;
private float startTime;
public Vector3 destination;
public Vector3 origin;
public float? speed;
public void Start()
{
speed = speed ?? DefaultSpeed;
startTime = Time.time;
}
public void Update()
{
float fracJourney = (Time.time - startTime) * speed.GetValueOrDefault();
this.transform.position = Vector3.Lerp (origin, destination, fracJourney);
}
}
Then call it like so:
void Fire()
{
GameObject bullet = (GameObject)Instantiate(Bullet, transform.position , transform.rotation);
BulletBehavior behavior = bullet.GetComponent<BulletBehavior>();
behavior.origin = this.transform.position;
behavior.destination = target.transform.position;
Debug.Log ("FIRE");
}
Note: If you're trying to mix this approach with trying to use physics to move the bullet you may end up with strange results.