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Feedback Attempting to make an enemy move towards the player using move towards...

Discussion in 'Scripting' started by Tsupek23, Jul 23, 2023.

  1. Tsupek23

    Tsupek23

    Joined:
    Dec 12, 2022
    Posts:
    2
    I'm a little new to Unity, and I'm trying to make an enemy move towards the player, but all it does is move to the center of the area it's in and stops. I've followed a tutorial and thought I did it correctly, but it doesn't do what happened in the tutorial. The Code is below.


    Code (CSharp):
    1.  
    2. using System.Collections;
    3. using System.Collections.Generic;
    4. using UnityEngine;
    5. using static PlayerUI;
    6.  
    7. public class BasicSlimeEnemy : MonoBehaviour
    8. {
    9.     private PlayerUI playerUI;
    10.     [SerializeField] private GameObject player;
    11.  
    12.     [SerializeField] private float speed = 15.0f;
    13.  
    14.     public void Update()
    15.     {
    16.         SlimeMovement();
    17.     }
    18.     public void SlimeMovement()
    19.     {
    20.        
    21.         transform.position = Vector3.MoveTowards(transform.position, player.transform.position, speed * Time.deltaTime);
    22.         Debug.Log("Targeting Player");
    23.     }
    24.  
    25.     public void OnCollisionEnter(Collision other)
    26.     {
    27.         if (other.gameObject.CompareTag("Player"))
    28.         {
    29.  
    30.             playerUI.DamagePlayer(4);
    31.  
    32.             Debug.Log("You have been attacked!!");
    33.         }
    34.     }
    35. }
    36.  
     
  2. ijmmai

    ijmmai

    Joined:
    Jun 9, 2023
    Posts:
    188
    It is a longshot but did you drop the player object in that SerializeField slot, or something else by mistake?
     
  3. Kurt-Dekker

    Kurt-Dekker

    Joined:
    Mar 16, 2013
    Posts:
    36,563
    That means it is ...

    ... time to start debugging! Here is how you can begin your exciting new debugging adventures:

    You must find a way to get the information you need in order to reason about what the problem is.

    Once you understand what the problem is, you may begin to reason about a solution to the problem.

    What is often happening in these cases is one of the following:

    - the code you think is executing is not actually executing at all
    - the code is executing far EARLIER or LATER than you think
    - the code is executing far LESS OFTEN than you think
    - the code is executing far MORE OFTEN than you think
    - the code is executing on another GameObject than you think it is
    - you're getting an error or warning and you haven't noticed it in the console window

    To help gain more insight into your problem, I recommend liberally sprinkling
    Debug.Log()
    statements through your code to display information in realtime.

    Doing this should help you answer these types of questions:

    - is this code even running? which parts are running? how often does it run? what order does it run in?
    - what are the names of the GameObjects or Components involved?
    - what are the values of the variables involved? Are they initialized? Are the values reasonable?
    - are you meeting ALL the requirements to receive callbacks such as triggers / colliders (review the documentation)

    Knowing this information will help you reason about the behavior you are seeing.

    You can also supply a second argument to Debug.Log() and when you click the message, it will highlight the object in scene, such as
    Debug.Log("Problem!",this);


    If your problem would benefit from in-scene or in-game visualization, Debug.DrawRay() or Debug.DrawLine() can help you visualize things like rays (used in raycasting) or distances.

    You can also call Debug.Break() to pause the Editor when certain interesting pieces of code run, and then study the scene manually, looking for all the parts, where they are, what scripts are on them, etc.

    You can also call GameObject.CreatePrimitive() to emplace debug-marker-ish objects in the scene at runtime.

    You could also just display various important quantities in UI Text elements to watch them change as you play the game.

    Visit Google for how to see console output from builds. If you are running a mobile device you can also view the console output. Google for how on your particular mobile target, such as this answer for iOS: https://forum.unity.com/threads/how-to-capturing-device-logs-on-ios.529920/ or this answer for Android: https://forum.unity.com/threads/how-to-capturing-device-logs-on-android.528680/

    If you are working in VR, it might be useful to make your on onscreen log output, or integrate one from the asset store, so you can see what is happening as you operate your software.

    Another useful approach is to temporarily strip out everything besides what is necessary to prove your issue. This can simplify and isolate compounding effects of other items in your scene or prefab.

    If your problem is with OnCollision-type functions, print the name of what is passed in!

    Here's an example of putting in a laser-focused Debug.Log() and how that can save you a TON of time wallowing around speculating what might be going wrong:

    https://forum.unity.com/threads/coroutine-missing-hint-and-error.1103197/#post-7100494

    "When in doubt, print it out!(tm)" - Kurt Dekker (and many others)

    Note: the
    print()
    function is an alias for Debug.Log() provided by the MonoBehaviour class.
     
  4. Tsupek23

    Tsupek23

    Joined:
    Dec 12, 2022
    Posts:
    2
    I re-edited the script to remove the Serilized field for the player. and then placed my player prefab into the inspector. but its still not working. I';ve added another debug log before the transform. so i know it's working. but it's not working like in the tutorial

    for refereance: Tutorials used

     
  5. ijmmai

    ijmmai

    Joined:
    Jun 9, 2023
    Posts:
    188
    The whole "Follow that cab" principle only takes one line of code. There is nothing wrong with the line of code in your code you shared. The error is somewhere else, in a part you haven't shared. Something in your Scene setup for example.
     
    Kurt-Dekker likes this.
  6. Kurt-Dekker

    Kurt-Dekker

    Joined:
    Mar 16, 2013
    Posts:
    36,563
    Again, that just means you haven't finished debugging it.

    The answer will come through you carefully inspecting (via Debug.Log()) both the contents of various variables and properties (yours and those from Unity you are using, such as tags) as well as decisions leading to your code running or not.