Beginner - need help with SmoothDamp

Unity Engine
1

Hello. I’m a very fresh newbie with Unity and i’m trying to do simple stuff : I have a cube (figuring a car), that is set on a ground with 5 rows. I want that when I press “Q”, it moves to the row to its left, and I want it not to be instantaneous but smooth. Si I’m trying out to use Smoothdamp but when I hit Q, the command makes it jump instead of moving on to the X axis. Here is the code. Can you guys tell me what I am missing ? :slight_smile: Thanks a lot !

using UnityEngine;

public class RowPlayerMovement : MonoBehaviour {

    public Rigidbody rb;
    private bool left = false;
    public float smoothTime = 0.3f;
    public Vector3 velocity;
   

    void Start() {
        velocity = Vector3.zero;
    }
    void Update() {
         if (Input.GetKeyDown(KeyCode.Q)) {
            left = true;
         }
     }

    void FixedUpdate() {
        if (left == true) {
            MovePlayerLeft();
        }
    }
    void MovePlayerLeft() {
        rb.MovePosition(transform.position + Vector3.SmoothDamp(transform.position, Vector3.left, ref velocity, 0.3f));
        // OR
        // transform.Translate(Vector3.SmoothDamp(transform.position, Vector3.left, ref velocity, smoothTime));
        Debug.Log("going left");
        left = false;
    }
}
//

6422394–717840–RowPlayerMovement.cs (848 Bytes)

2

You want two variables:

  • currentLane
  • desiredLane

When you process user input, you set desiredLane to what it should be.

Every Update() you use Mathf.MoveTowards() (or Vector.MoveTowards() ) to move currentLane gradually to desiredLane.

3

Thanks for the answer. However as I said, I am very newbie, and I tried to play with these functions with no result. My cube doesn’t even move. Could be a more explicit please ? It’s not easy getting started :stuck_out_tongue:

4

Up. I’m really stuck with this one. Tried a new thing, works fines when I have only 3 lanes, can’t manage to make it work properly with 5. I’m probably missing something very very simple here… here is the new code.

using UnityEngine;

public class LaneMovement : MonoBehaviour {
    private int desiredLane = 2;
    private int currentLane = 2;
    public Rigidbody rb;
    public float speed = 5f;
    private float laneDistance = 2f;

    private void Update() {
        //gathering inputs
        if (Input.GetKeyDown(KeyCode.Q)) {
            MoveLane(false);
        }
        if (Input.GetKeyDown(KeyCode.D)) {
            MoveLane(true);
        }
        //calculate where we should be in the future
        Vector3 targetPosition = transform.position.z * Vector3.forward;
        if (desiredLane < currentLane) {
            targetPosition += Vector3.left * laneDistance;
        }
        else if (desiredLane > currentLane) {
            targetPosition += Vector3.right * laneDistance;
        }
        // calculate move delta
        Vector3 moveVector = Vector3.zero;
        moveVector.x = (targetPosition - transform.position).normalized.x * speed;
        moveVector.y = 0f;
        moveVector.z = speed;

        //move the Cube
        rb.MovePosition(transform.position + moveVector * Time.deltaTime);
    }

    private void MoveLane(bool goingRight) {

        desiredLane += goingRight ? 1 : -1;
        desiredLane = Mathf.Clamp(desiredLane, 0, 4);
    }
}

Problem is that it won’t move to the 0 and 4th lane. I’m guessing it is because I have the change the currentLane value somehow, but I don’t know where and how to do it. If I add “currentLane–;”’ at lane 23 it doesn’t move at all. I don’t really get it…

5

The problem is the choice of integer values for lanes. They can only either be lane 0, 1 or 2. They can’t be in between round numbers. It needs to be a floating point value so that it can be between lanes.

This type of question comes up so universally I have finally just made a sample package to demonstrate the basic concept. Read my first post above and see if you can correlate each part of the code to the steps indicated.

Code located here: SmoothMovement.cs · GitHub

6430100–719246–SmoothMovement.unitypackage (4.39 KB)

2 Likes
6

As a solution I’ve used this one

    void MovementProcess()
    {
        if (rotatingOn)
        {
            var step = rotateSpeed * Time.deltaTime;
            transform.rotation = Quaternion.RotateTowards(transform.rotation, target.rotation, step);
        }
    }