Move Player relative to Camera

Unity Engine
1

I’ve been trying to figure this out for a while but I can’t seem to get my player to move relative to the camera. When I press W and S I move up and down in world space and left and right in world space when I press A and D. How can I make it so that W moves me forward in the direction the camera is looking, A and D left and right of where the camera is looking and S moving towards the camera.

Here’s the player movement script:

using UnityEngine;
using System.Collections;

public class Player : MonoBehaviour
{
    public float moveSpeed;
    public float rotationSpeed;
    Vector3 previousLocation;
    Vector3 moveDirection;

    void Update ()
    {
        moveDirection = Vector3.zero;
        previousLocation = transform.position;
        if (Input.GetKey (KeyCode.W)) moveDirection.z = 1;
        if (Input.GetKey (KeyCode.S)) moveDirection.z = -1;
        if (Input.GetKey (KeyCode.A)) moveDirection.x = -1;
        if (Input.GetKey (KeyCode.D)) moveDirection.x = 1;

        transform.position = Vector3.Lerp(transform.position, transform.position +
        moveDirection.normalized, Time.fixedDeltaTime * moveSpeed);

        if (moveDirection != Vector3.zero)
        transform.rotation = Quaternion.Lerp(
        transform.rotation, Quaternion.LookRotation(transform.position - previousLocation),
        Time.fixedDeltaTime * rotationSpeed);
     }
}
1 Like
2

So if you want to move relative to the direction of the camera (or any object), then we first need to know the rotation of that object. So let’s add a reference in your script:

public Transform relativeTransform;

Next, instead of using absolute values, when setting your move direction, let’s use the direction the camera is facing:

        if(Input.GetKey(KeyCode.W)) moveDirection += relativeTransform.forward;
        if(Input.GetKey(KeyCode.S)) moveDirection += -relativeTransform.forward;
        if(Input.GetKey(KeyCode.A)) moveDirection += -relativeTransform.right;
        if(Input.GetKey(KeyCode.D)) moveDirection += relativeTransform.right;

Now, based off your code so far, it seems that you only want the player to move on a plane (only x and z directions), so we will want to remove any y movement that the camera’s rotation may have included.

        moveDirection.y = 0f;

Here is the entire script, modified with a few extra changes. Basically, I just cleaned up and simplified the code so that the speed values aren’t arbitrary. Now moveSpeed is in units/second, and rotationSpeed is in degrees/second.

using UnityEngine;
using System.Collections;

public class TempPlayer : MonoBehaviour
{
    public float moveSpeed;
    public float rotationSpeed;

    public Transform relativeTransform;

    void Update()
    {
        Vector3 moveDirection = Vector3.zero;
        if(Input.GetKey(KeyCode.W)) moveDirection += relativeTransform.forward;
        if(Input.GetKey(KeyCode.S)) moveDirection += -relativeTransform.forward;
        if(Input.GetKey(KeyCode.A)) moveDirection += -relativeTransform.right;
        if(Input.GetKey(KeyCode.D)) moveDirection += relativeTransform.right;

        moveDirection.y = 0f;

        transform.position += moveDirection.normalized * moveSpeed * Time.deltaTime;

        if(moveDirection != Vector3.zero)
            transform.rotation = Quaternion.RotateTowards(transform.rotation, Quaternion.LookRotation(moveDirection), rotationSpeed * Time.deltaTime);
    }
}

Just make sure to assign your camera to relativeTransform in the inspector. Hope this helps!

5 Likes
3

Thank you! I really appreciate you going through it step by step, it really becomes clear that way. Also, thank you for cleaning up the code too.

4

I signed up just to thank you my friend. You are awesome!

5

5 years later, this script and fix have helped me so much. Thank you!!!

1 Like