I followed a tutorial about an enemy detecting your player when you are near their radius. It worked, but I wanted my enemy to move only horizontal and vertical. What should I put or change on my code?

using System.Collections.Generic;
using UnityEngine;

public class Enemy : MonoBehaviour
{
    public float speed = 3f;
    private Transform target;

    private void Update()
    {

        if(target != null)
        {

            float step = speed * Time.deltaTime;
            transform.position = Vector2.MoveTowards(transform.position, target.position, step);
        }


    }

    private void OnTriggerEnter2D(Collider2D other)
    {
        if(other.gameObject.tag == "Player")
        {
            target = other.transform;
        }
    }

    private void OnTriggerExit2D(Collider2D other)
    {
        if (other.gameObject.tag == "Player")
        {
            target = null;
        }
    }
}
`

CodePudding user response：

We need to calculate new Vector based on the direction of our target and modify that vector to not move diognally, something like following would work

private Vector2 newPosition;

private void Awake() {
    newPosition = transform.position;
}

private void Update() {
    if (target != null) {
        float step = speed * Time.deltaTime;
        float threshold = .1f;

        // Only calculate new position if we are under the "threshold"
        if (Vector2.Distance(transform.position, newPosition) < threshold) {
            newPosition = target.position - transform.position;

            if (Mathf.Abs(newPosition.x) > Mathf.Abs(newPosition.y)) {
                newPosition.x = target.position.x;
                newPosition.y = transform.position.y;
            }
            else {
                newPosition.x = transform.position.x;
                newPosition.y = target.position.y;
            }
        }

        transform.position = Vector2.MoveTowards(transform.position, newPosition, step);
    }
}

In here I am only calculating newPosition if the distance between current position and newPosition is less then some threshold, after that I am getting new direction vector which points toward our target, and then modifying that vector based on the biggest component of that vector.

CodePudding user response：

You could simply check which axis has the smaller delta and move in this axis first, then do the other one

private void Update()
{
    if(target == null) return;
    
    Vector2 endPosition = target.position;
    Vector2 delta = target.position - transform.position;

    if(Mathf.Abs(delta.x) > Mathf.Abs(delta.y))
    {
        // Y is the smaller delta => move only in Y
        // => keep your current X
        endPosition.x = transform.position.x;
    }
    else
    {
        // X is the smaller delta => move only in X
        // => keep your current Y
        endPosition.y = transform.position.y;
    }

    transform.position = Vector2.MoveTowards(transform.position, target.position, speed * Time.deltaTime);
    
}