Is there a way to optimize this else ifs tree? If there is, what would be the best?

Questions & Answers
1

Hello, I’m new to Unity and C# and currently making a stealth sim.

This is a part of a script that makes it’s sprite match it’s npc’s walk direction. It is being called in Update() and what it does it taking npc’s position a frame before and at the moment and compares them, deciding which coordinate has changed more and how.
I can’t seem to figure out how to make this another way, if you know how to, please, help me.
Thanks in advance!

`

    void SpriteUpdate()
{
	nowPos = transform.position;
	/* Code below is made in case
	if coordinates are negative, since
	otherwise it would return reversed
				direction
	*/
	if(prevPos.x <= 0)
	{
		xDiff = Mathf.Abs(prevPos.x) - Mathf.Abs(nowPos.x);
	}
	else
	{
		xDiff = Mathf.Abs(nowPos.x) - Mathf.Abs(prevPos.x);
	}
	if(prevPos.y <= 0)
	{
		yDiff = Mathf.Abs(prevPos.y) - Mathf.Abs(nowPos.y);
	}
	else
	{
		yDiff = Mathf.Abs(nowPos.y) - Mathf.Abs(prevPos.y);
	}
	// Sprite changing part
	if(Mathf.Abs(xDiff) > Mathf.Abs(yDiff))
	{
		if(xDiff > 0)
		{
			GetComponent<SpriteRenderer>().sprite = sprites[0]; //Right look sprite
			VisionField.transform.localPosition = new Vector2(3, 0);
		}
		else if(xDiff < 0)
		{
			GetComponent<SpriteRenderer>().sprite = sprites[1]; //Left look sprite
			VisionField.transform.localPosition = new Vector2(-3, 0);
		}
	}
	else if(Mathf.Abs(yDiff) > Mathf.Abs(xDiff))
	{
		if(yDiff > 0)
		{
			GetComponent<SpriteRenderer>().sprite = sprites[2]; //Up look sprite
			VisionField.transform.localPosition = new Vector2(0, 3);
		}
		else if(yDiff < 0)
		{
			GetComponent<SpriteRenderer>().sprite = sprites[3]; //Down look sprite
			VisionField.transform.localPosition = new Vector2(0, -3);
		}
	}
	else
	{
		GetComponent<SpriteRenderer>().sprite = sprites[4]; // Idle sprite
		VisionField.transform.localPosition = new Vector2(0, 0);
	}
}

`

2

Hi,
I’m not sure why your sprite is not just a child object of your NPC?
Just drag and drop it the sprite on the NPC in the project window.
Remove this script and see if that works.

3

I have tried to reuse your code so its easier for you to understand, but it is untested could have someerrors

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

public class EnemyPatrolingScript : MonoBehaviour
{
    public bool shouldMove = false;
    public float speed;
    public float waitTime;
    private float waitingTime;
    public GameObject VisionField;
    [HideInInspector]
    public bool isAlive = true;

    public Transform[] points;
    public bool reverseOnLoop;
    [SerializeField]
    private int currentPoint;

    public Sprite[] sprites;

    private Vector2 prevPos;
    private Vector2 nowPos;
    private float xDiff;
    private float yDiff;

    private SpriteRenderer renderer;

    void Start()
    {
        waitingTime = waitTime;
        renderer = GetComponent<SpriteRenderer>();
    }

    void Update()
    {
        if (isAlive && shouldMove)
        {
            prevPos = transform.position;
            transform.position = Vector2.MoveTowards(transform.position, points[currentPoint].position,
                                                     speed * Time.deltaTime);
            GetNextPoint();
        }
        if (!isAlive)
        {
            Death();
        }
    }

    void Death()
    {
        Destroy(VisionField.gameObject);
        //TODO: add animator controller
    }

    void GetNextPoint()
    {
        if (Vector2.Distance(transform.position, points[currentPoint].position) < 0.2f) //if close to point
        {                                                                              // get next point
            if (waitingTime <= 0)
            {
                waitingTime = waitTime;
                Vector3 prevPoint = points[currentPoint].position;

                if (currentPoint < points.Length - 1)
                {
                    currentPoint += 1;
                }
                else
                {
                    if (reverseOnLoop)
                    {
                        System.Array.Reverse(points); //reversing to go all the way back
                        currentPoint = 0;
                    }
                    else
                    {
                        currentPoint = 0;
                    }
                }

                Vector3 point = points[currentPoint].position;

                if (prevPoint.x <= 0)
                {
                    xDiff = Mathf.Abs(prevPoint.x) - Mathf.Abs(point.x);
                }
                else
                {
                    xDiff = Mathf.Abs(point.x) - Mathf.Abs(prevPoint.x);
                }
                if (prevPos.y <= 0)
                {
                    yDiff = Mathf.Abs(prevPoint.y) - Mathf.Abs(point.y);
                }
                else
                {
                    yDiff = Mathf.Abs(point.y) - Mathf.Abs(prevPoint.y);
                }
                if (Mathf.Abs(xDiff) > Mathf.Abs(yDiff))
                {
                    if (xDiff > 0)
                    {
                        //To be replaced with animation
                        renderer.sprite = sprites[0]; //Right look sprite
                        VisionField.transform.rotation = Quaternion.Euler(new Vector3(0f, 0f, 180f));
                        //rotation field of view
                    }
                    else if (xDiff < 0)
                    {
                        renderer.sprite = sprites[1]; //Left look sprite
                        VisionField.transform.rotation = Quaternion.Euler(new Vector3(0f, 0f, 0f));
                    }
                }
                else if (Mathf.Abs(yDiff) > Mathf.Abs(xDiff))
                {
                    if (yDiff > 0)
                    {
                        renderer.sprite = sprites[2]; //Up look sprite
                        VisionField.transform.rotation = Quaternion.Euler(new Vector3(0f, 0f, -90f));
                    }
                    else if (yDiff < 0)
                    {
                        renderer.sprite = sprites[3]; //Down look sprite
                        VisionField.transform.rotation = Quaternion.Euler(new Vector3(0f, 0f, 90f));
                    }
                }

            }
            else
            {
                renderer.sprite = sprites[4];
                waitingTime -= Time.deltaTime; //idling after reaching the point
            }
        }
    }
}