Question Enemy doesn't move. How can I solve it?

Hi! I'm a newbie trying to make a platformer but I ran into a problem which I can't seem to solve by myself.

I have my enemy prefab, which contains scripts for a State machine. One of those States is Patrol and while it gets to that State, rigidbody.velocity doesn't really do anything.

Moving animation plays and all, and with console logs I can see it gets to where rigidbody.velocity is.

It used to work right before I deleted the test terrain and added the tilemap with the respective collider. (or at least as far as my memory can go, I may have changed something).

This is how it looks like:

and these are the scripts for the states:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class EnemyStateManager : MonoBehaviour
6. {
7.     public Animator anim;
8.     public EnemyBaseState currentState;
9.     public EnemyAttack attackState = new EnemyAttack();
10.     public EnemyPatrol patrol = new EnemyPatrol();
11.     public EnemyStill stayStill = new EnemyStill();
12.     public GameObject player;
13.     public Rigidbody2D rb;
14.     public float currentDistance;
15.     public CapsuleCollider2D capcoll;
16.     public float speed;
17.     public float attackRange;
18.     public float attackCooldown;
19.  
20.     // Start is called before the first frame update
21.     void Start()
22.     {
23.         capcoll = GetComponent<CapsuleCollider2D>();
24.         rb = GetComponent<Rigidbody2D>();
25.         player = GameObject.FindGameObjectWithTag("Player");
26.         anim = GetComponent<Animator>();
27.         currentState = patrol;
28.         currentState.EnterState(this);
29.     }
30.  
31.     // Update is called once per frame
32.     void Update()
33.     {
34.         currentState.UpdateState(this);
35.         currentDistance = Vector2.Distance(player.transform.position, transform.position);
36.        
37.     }
38.  
39.     public void SwitchState(EnemyBaseState enemy)
40.     {
41.         currentState = enemy;
42.         enemy.EnterState(this);
43.     }
44.  
45.     private void OnTriggerExit2D(Collider2D collision)
46.     {
47.         if (collision.gameObject.tag.Equals("Ground"))
48.         {
49.             gameObject.transform.localScale = new Vector2(-(Mathf.Sign(rb.velocity.x)), transform.localScale.y);
50.         }
51.     }
52.  
53.    
54. }

for the EnemyPatrol state:

Code (CSharp):

1.  
2. using UnityEngine;
3.  
4. public class EnemyPatrol : EnemyBaseState
5. {
6.     public float idleCounter;  
7.    
8.     public override void EnterState(EnemyStateManager enemy)
9.     {
10.         idleCounter = Random.Range(4f, 10f);
11.         enemy.anim.SetBool("Idle", false);
12.         enemy.anim.SetBool("Moving", true);
13.     }
14.  
15.     public override void OnTriggerEnter2D(EnemyStateManager enemy)
16.     {
17.  
18.     }
19.  
20.     public override void UpdateState(EnemyStateManager enemy)
21.     {
22.  
23.         if (enemy.currentDistance <= enemy.attackRange)
24.         {
25.             enemy.SwitchState(enemy.attackState);
26.         }
27.         if (idleCounter <= 0)
28.         {
29.             enemy.SwitchState(enemy.stayStill);
30.         }
31.         else
32.         {
33.             idleCounter -= Time.deltaTime;
34.         }
35.         if (isFacingRight(enemy))
36.         {
37.            
38.             enemy.rb.velocity = new Vector2(enemy.speed, 0f);
39.         }
40.         else
41.         {
42.            
43.             enemy.rb.velocity = new Vector2(-enemy.speed, 0f);
44.         }
45.     }
46.  
47.     public bool isFacingRight(EnemyStateManager enemy)
48.     {
49.         return enemy.transform.localScale.x > Mathf.Epsilon;
50.     }
51. }
52.  

Respective collider and rigidbody:



Ground stuff:


I hope I made everything clear, thanks in advance!

 

If you're already using Debug.Log() to output stuff, that is AWESOME because that is what I would tell you to do.

In this case, I will just tell you to print out the actual values that are being stuffed into the rigidbody.velocity.

Are they what you expect?

Here's my standard blurb:

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.

This is why we use source control to control our projects.

PROPERLY CONFIGURING AND USING ENTERPRISE SOURCE CONTROL

I'm sorry you've had this issue. Please consider using proper industrial-grade enterprise-qualified source control in order to guard and protect your hard-earned work.

Personally I use git (completely outside of Unity) because it is free and there are tons of tutorials out there to help you set it up as well as free places to host your repo (BitBucket, Github, Gitlab, etc.).

You can also push git repositories to other drives: thumb drives, USB drives, network drives, etc., effectively putting a complete copy of the repository there.

As far as configuring Unity to play nice with git, keep this in mind:

https://forum.unity.com/threads/prefab-links-keep-getting-dumped-on-git-pull.646600/#post-7142306

I usually make a separate repository for each game, but I have some repositories with a bunch of smaller test games.

Here is how I use git in one of my games, Jetpack Kurt:

https://forum.unity.com/threads/2-steps-backwards.965048/#post-6282497

Using fine-grained source control as you work to refine your engineering:

https://forum.unity.com/threads/whe...grammer-example-in-text.1048739/#post-6783740

Share/Sharing source code between projects:

https://forum.unity.com/threads/your-techniques-to-share-code-between-projects.575959/#post-3835837

Setting up an appropriate .gitignore file for Unity3D:

https://forum.unity.com/threads/removing-il2cpp_cache-from-project.1084607/#post-6997067

Generally the ONLY folders you should ever source control are:

Assets/
ProjectSettings/
Packages/

NEVER source control Library/ or Temp/ or Logs/
NEVER source control anything from Visual Studio (.vs, .csproj, none of that noise)

Setting git up with Unity (includes above .gitignore concepts):

https://thoughtbot.com/blog/how-to-git-with-unity

It is only simple economics that you must expend as much effort into backing it up as you feel the work is worth in the first place. Digital storage is so unbelievably cheap today that you can buy gigabytes of flash drive storage for about the price of a cup of coffee. It's simply ridiculous not to back up.

If you plan on joining the software industry, you will be required and expected to know how to use source control.

"Use source control or you will be really sad sooner or later." - StarManta on the Unity3D forum boards

 

My guess is at the bottom... I don't quite understand the details but let me suggest a few things. Too much code makes it harder to track the logic (at least that's what I've found). It distorts what the goal is in each step.

Code (CSharp):

1. if (isFacingRight(enemy))
2. {
3.  
4.     enemy.rb.velocity = new Vector2(enemy.speed, 0f);
5. }
6. else
7. {
8.  
9.     enemy.rb.velocity = new Vector2(-enemy.speed, 0f);
10. }
11.  

Those lines can be expressed as follows:

Code (CSharp):

1. enemy.rb.velocity = new Vector2(isFacingRight(enemy) ? enemy.speed : -enemy.speed, 0f);
2.  

Perhaps you can have the EnterState method return the state it entered. Notice that you set the state on the manager before you actually enter the state.

Code (CSharp):

1. public override EnemyStateManager EnterState(EnemyStateManager enemy)
2. {
3.     idleCounter = Random.Range(4f, 10f);
4.     enemy.anim.SetBool("Idle", false);
5.     enemy.anim.SetBool("Moving", true);
6.    
7.     return enemy;
8. }
9.  

And so my guess is that EnemyStateManager Updates are occurring while the state reference has changed but EnterState may not have completed.

<"pure speculation" indicator here>

 

Thanks a ton for this useful info! Will surely be really helpful in the future.

As for my problem, everything seems to be working fine (as for all the logs i've tried.), even the rigidbody velocity values are correct, its just the object doesn't move at all. It has gravity though, but weirdly enough, it falls very slow when "Patrolling".

In the update call, I have set the debug.log to show me the enemy.rigidbody.velocity.x value.



This was working right before I created the tilemap with its respective colliders (As far as I remember, that's all I changed right before it started failing.)

It was working like this: