how to make player run-speed independent of computer?

Questions & Answers
1

Hi everyone, I’m new to unity and I’ve written a script for my player run. Although I used Time.deltaTime but yet the run speed is changing in different computers. Could you please check my code and tell me where I’m doing wrong?

Thanks in advance

using UnityEngine;

// attach the script to the player
public class PlayerMovement : MonoBehaviour
{
    public float runSpeed = 140f;
    public float jumpSpeed = 9f;
    public float gravity = 9.81f;
    public float laneWidth = 2.5f;
    public float smooth;

    public float minRunSpeed = 130f;
    public float maxRunSpeed = 250f;
    public float accelerationTime = 60;
    private float time;

    CharacterController controller;
    Vector3 direction;
    float directionY;
    bool isMoveStarted = false;
    int lane = 1;  // 0:left 1:middle 2:righ;


    void Start()
    {
        controller = GetComponent<CharacterController>();
        direction = new Vector3(0, 0, 0);
        time = 0;
    }


    void Update()
    {

        if (isMoveStarted)
        {

            runSpeed = Mathf.SmoothStep(minRunSpeed, maxRunSpeed, time / accelerationTime);

            time += Time.deltaTime;

            ProcessUserInput();
            direction.z = runSpeed * Time.deltaTime;
            HandleSliding();
            Run();

        }

    }


    void LateUpdate()
    {
        UpdateXPosition();
    }

    void Jump()
    {
        directionY = jumpSpeed;
    }

    void Run()
    {

        directionY -= gravity * Time.deltaTime;
        direction.y = directionY;
        controller.Move(direction * Time.deltaTime);
    }

    void StartMoving()
    {
        isMoveStarted = true;
        GameObject.Find("TileManager").SendMessage("PlayEnvironmentSound");
    }


    void ProcessUserInput()
    {
        if ((Input.GetKeyDown(KeyCode.LeftArrow) || Input.GetKeyDown(KeyCode.A)) && lane > 0)
        {
            lane--;
        }

        if ((Input.GetKeyDown(KeyCode.RightArrow) || Input.GetKeyDown(KeyCode.D)) && lane < 2)
        {
            lane++;
        }

    }

    void UpdateXPosition()
    {

        if (!controller.isGrounded)
        {
            return;
        }
        Vector3 newPosition = transform.localPosition.z * transform.forward + transform.localPosition.y * transform.up;
        if (lane == 0)
        {
            newPosition += Vector3.left * laneWidth;
        }
        else if (lane == 2)
        {
            newPosition += Vector3.right * laneWidth;
        }

        transform.localPosition = Vector3.Lerp(transform.localPosition, newPosition, smooth);

    }

    void HandleSliding()
    {
        if (Input.GetKeyDown(KeyCode.S) || Input.GetKeyDown(KeyCode.DownArrow))
        {
            controller.height = 1.5f;
            Vector3 tempCenter = controller.center;
            tempCenter.y = controller.height / 2;
            controller.center = tempCenter;
            Invoke("SetCenter", 2f);

        }

    }


    void SetCenter()
    {
        controller.height = 3.64f;
        Vector3 tempCenter = controller.center;
        tempCenter.y = 1.91f;
        controller.center = tempCenter;
    }

    void UpdateRunSpeed()
    {
        runSpeed = runSpeed + 1;
    }

}
2

Step 1:

Fix whatever this is:

    transform.localPosition = Vector3.Lerp( transform.localPosition , newPosition , smooth );

because smooth is at fault here and should be understood as some kind of local_move_speed implemented as local_move_speed * Time.deltaTime here. Otherwise Lerp alone makes this frame-dependent.

Step 2:

Simplify your code

PlayerMovement.cs

public class PlayerMovement : MonoBehaviour
{
	[SerializeField] float
		runSpeed = 140f ,
		jumpSpeed = 9f ,
		gravity = 9.81f,
		laneWidth = 2.5f,
		localMoveSpeed = 1f,
		minRunSpeed = 130f,
		maxRunSpeed = 250f,
		accelerationTime = 60f;
  
	CharacterController _controller = null;
	TileManager _tileManager = null;
	Vector3 _velocity = Vector3.zero;
	bool _isMoveStarted = false;
	float _moveStartedTime = 0f;
	Lane _lane = Lane.Middle;
  
	void Awake ()
	{
		_controller = GetComponent<CharacterController>();
		_tileManager = FindObjectOfType<TileManager>();
	}
	void Update ()
	{
		if( _isMoveStarted )
		{
			float timeSinceMoveStart = Time.time - _moveStartedTime;
			runSpeed = Mathf.SmoothStep( minRunSpeed , maxRunSpeed , timeSinceMoveStart / accelerationTime );
			
			// lane change:
			if( (Input.GetKeyDown(KeyCode.LeftArrow) || Input.GetKeyDown(KeyCode.A)) && (int)_lane > (int)Lane.Left )
				_lane--;
			if( (Input.GetKeyDown(KeyCode.RightArrow) || Input.GetKeyDown(KeyCode.D)) && (int)_lane < (int)Lane.Right )
				_lane++;
  
			_velocity.z = runSpeed;
			
			// sliding:
			if( Input.GetKeyDown(KeyCode.S) || Input.GetKeyDown(KeyCode.DownArrow) )
			{
				_controller.height = 1.5f;
				Vector3 tempCenter = _controller.center;
				tempCenter.y = _controller.height / 2;
				_controller.center = tempCenter;
				Invoke( nameof(SetCenter) , 2f );
			}
  
			// jumping and falling:
			if( Input.GetKeyDown(KeyCode.Space) && _controller.isGrounded )
				_velocity.y = jumpSpeed;
			else
				_velocity.y = -gravity;
  
			// run:
			_controller.Move( _velocity * Time.deltaTime );
		}
  
		// ( im not sure what this is )
		if( _controller.isGrounded )
		{
			// update x position:
			Vector3 src = transform.localPosition;
			Vector3 dst = transform.localPosition.z * transform.forward + transform.localPosition.y * transform.up;
			if( _lane==Lane.Left ) dst += Vector3.left * laneWidth;
			else if( _lane==Lane.Right ) dst += Vector3.right * laneWidth;
			transform.localPosition = Vector3.Lerp( src , dst , localMoveSpeed * Time.deltaTime );
		}
	}
	void StartMoving ()
	{
		_isMoveStarted = true;
		_moveStartedTime = Time.time;
		_tileManager.PlayEnvironmentSound();
	}
	void SetCenter ()
	{
		_controller.height = 3.64f;
		Vector3 oldCenter = _controller.center;
		_controller.center = new Vector3( oldCenter.x , 1.91f , oldCenter.z );
	}
	void UpdateRunSpeed ()
	{
		runSpeed += 1;
	}
  
	public enum Lane
	{
		Left = 0 ,
		Middle = 1 ,
		Right = 2
	}
  
}

TileManager.cs

public class TileManager : MonoBehaviour
{
	public void PlayEnvironmentSound ()
	{
		Debug.Log("(play a sound here)");
	}
}