Using Unity: Scripting Enemy AI - Follow Player

Question

I am trying to have my enemy Follow my player when in range, otherwise the enemy is Wandering. I'm quite new to C-Sharp so have been piecing bits of other tutorials code together.

Currently the enemy Wanders back and forth between the trigger box collider I have set. The enemy switches state to Follow when the player is within range, however the enemy will only move towards the player if the player is on the left hand side of the enemy, if I am on the right side of the enemy it is stuck until I am out of range, then it resumes Wandering. Also the enemy does not flip to face the enemy when Following.

Any help would be appreciated.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public enum EnemyState
   {
      Wander,   
      Follow,
      Die,
   };


public class EnemyController : MonoBehaviour
   {
     GameObject player;    
     public EnemyState currState = EnemyState.Wander; 
     public Transform target;
     Rigidbody2D myRigidbody;

     public float range = 2f;    
     public float moveSpeed = 2f;



void Start()
{
    player = GameObject.FindGameObjectWithTag("Player");
    myRigidbody = GetComponent<Rigidbody2D>();
    target = GameObject.FindGameObjectWithTag("Player").GetComponent<Transform>();
}

void Update()
{

    switch (currState)
    {
        case (EnemyState.Wander):
            Wander();
            break;
        case (EnemyState.Follow):
            Follow();
            break;
        case (EnemyState.Die):
           // Die();
            break;
    }    

    if(IsPlayerInRange(range) && currState != EnemyState.Die)
    {
        currState = EnemyState.Follow;
    }
    else if(!IsPlayerInRange(range)&& currState != EnemyState.Die)
    {
        currState = EnemyState.Wander;
    }
}

private bool IsPlayerInRange(float range)
{
    return Vector3.Distance(transform.position, player.transform.position) <= range;
}

bool isFacingRight()
{
    return transform.localScale.x > 0;
}

void Wander()
{
    {
        if (isFacingRight())
        {
            myRigidbody.velocity = new Vector2(moveSpeed, 0f);
        }
        else
        {
            myRigidbody.velocity = new Vector2(-moveSpeed, 0f);
        }
    }

}

void OnTriggerExit2D(Collider2D collision) //this is to flip the sprite when it reaches the end of its path - a box 2d collider trigger
{
    transform.localScale = new Vector2(-(Mathf.Sign(myRigidbody.velocity.x)), 1f);

}

void Follow()
{
    if (isFacingRight())
    {
        myRigidbody.velocity = new Vector2(-moveSpeed, 0f);
        transform.position = Vector2.MoveTowards(transform.position, new Vector2(target.position.x, transform.position.y), moveSpeed * Time.deltaTime);

    }
   /* else //this seems to have no effect on the code
    {
        myRigidbody.velocity = new Vector2(moveSpeed, 0f);
        transform.position = Vector2.MoveTowards(transform.position, new Vector2(target.position.x, transform.position.y), -moveSpeed * Time.deltaTime);
    }*/

}

}

Answer 1

ok I figured out my own issues, here is the working script:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public enum EnemyState
{
  Wander,
  Follow,
  Die,
};

public class EnemyController : MonoBehaviour
{
  GameObject player;
  public EnemyState currState = EnemyState.Wander;

  public Transform target;

  Rigidbody2D myRigidbody;

  public float range = 2f;
  public float moveSpeed = 2f;






// Start is called before the first frame update
void Start()
{
    player = GameObject.FindGameObjectWithTag("Player");
    myRigidbody = GetComponent<Rigidbody2D>();
    target = GameObject.FindGameObjectWithTag("Player").GetComponent<Transform>();



}

// Update is called once per frame
void Update()
{

    switch (currState)
    {
        case (EnemyState.Wander):
            Wander();
            break;
        case (EnemyState.Follow):
            Follow();
            break;
        case (EnemyState.Die):
           // Die();
            break;
    }    

    if(IsPlayerInRange(range) && currState != EnemyState.Die)
    {
        currState = EnemyState.Follow;
    }
    else if(!IsPlayerInRange(range)&& currState != EnemyState.Die)
    {
        currState = EnemyState.Wander;
    }
}

private bool IsPlayerInRange(float range)
{
    return Vector3.Distance(transform.position, player.transform.position) <= range;
}

bool isFacingRight()
{
    return transform.localScale.x > 0;
}

void Wander()
{
    {
        if (isFacingRight())
        {
            myRigidbody.velocity = new Vector2(moveSpeed, 0f);
        }
        else
        {
            myRigidbody.velocity = new Vector2(-moveSpeed, 0f);
        }
    }


}

void OnTriggerExit2D(Collider2D collision)
{
    transform.localScale = new Vector2(-(Mathf.Sign(myRigidbody.velocity.x)), 1f);

}


void Follow()
{

    if (transform.position.x > target.position.x)
    {
        //target is left
        transform.localScale = new Vector2(-1, 1);
        myRigidbody.velocity = new Vector2(-moveSpeed, 0f);
        transform.position = Vector2.MoveTowards(transform.position, new Vector2(target.position.x, transform.position.y), moveSpeed * Time.deltaTime);
    }
    else if (transform.position.x < target.position.x)
    {
        //target is right
        transform.localScale = new Vector2(1, 1);
        myRigidbody.velocity = new Vector2(moveSpeed, 0f);
        transform.position = Vector2.MoveTowards(transform.position, new Vector2(target.position.x, transform.position.y), moveSpeed * Time.deltaTime);
    }

}

}