Character won't stop rotating!

Hello everyone!

I have currently created player movement where you will rotate towards the direction you are moving relative to the current camera (think resident evil). One of the issues I’ve been having is that the character will not stop rotating even when I am not inputing any controls! Here is my code and set-up:

using System.Collections;
using System.Collections.Generic;
using Cinemachine;
using UnityEngine;
using UnityEngine.InputSystem;

public class PlayerMovement : MonoBehaviour
{
    private Rigidbody _rb;
    private Vector3 moveDirection;
    [SerializeField] public CinemachineVirtualCamera currentCamera;
    [SerializeField] private float _movementSpeed;
    [SerializeField] private float _turnSpeed;
   
    // Start is called before the first frame update
    void Start()
    {
        _rb = GetComponent<Rigidbody>();
    }

    // Update is called once per frame
    void Update()
    {
        _rb.velocity = _movementSpeed * Time.deltaTime * moveDirection;
        if (moveDirection != Vector3.zero)
        {
            Quaternion toRotation = Quaternion.LookRotation(moveDirection, Vector3.up);
            _rb.rotation = Quaternion.RotateTowards(transform.rotation, toRotation, _turnSpeed * Time.deltaTime);
        }
    }

    void OnMove(InputValue inputValue)
    {
        moveDirection = inputValue.Get<Vector2>();
        moveDirection = new Vector3(moveDirection.x, 0 ,moveDirection.y);
        moveDirection = ChangeMoveDirectionRelativeToCamera();
        //transform.Translate(moveDirection * _movementSpeed * Time.deltaTime );
    }

    Vector3 ChangeMoveDirectionRelativeToCamera()
    {
        var camForward = currentCamera.transform.forward;
        var camRight = currentCamera.transform.right;
        camForward.y = 0;
        camRight.y = 0;
        camForward.Normalize();
        camRight.Normalize();
        var desiredMoveDirection = camForward * moveDirection.z + camRight * moveDirection.x ;
        return desiredMoveDirection;
    }

}

And here are my input actions and RigidBody settings:

I would make line 25 test if the magnitude of the movement is ABOVE a certain amount rather than just nonzero, perhaps something like:

// replace line 25 above
if (moveDirection.magnitude >= 0.1f)

The thinking behind this suggestion is that as the two axes approach zero, one may reach zero before the other, giving you highly erroneous directional results as you near Vector.zero

If that’s not it, here’s how to get to debugging:

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 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.

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 or iOS: How To - Capturing Device Logs on iOS or this answer for Android: How To - Capturing Device Logs on Android

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.

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:

When in doubt, print it out!™

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