C# Array problems

Question

I create an array of GameObjects called WayPoints and then find the closest one, but then I can't seem to understand how to delete the waypoint from the Array once my cube reaches it?

HELP! :/

public GameObject[] WayPoints;

 GameObject FindWaypoint()
     {
         WayPoints = GameObject.FindGameObjectsWithTag("Waypoint");
         GameObject closest = null;
         float distance = Mathf.Infinity;
         Vector3 position = transform.position;
         
         foreach (GameObject item in WayPoints) 
         {
             Vector3 diff = item.transform.position - position;
             float curDistance = diff.sqrMagnitude;
             
             if (curDistance < distance) 
             {
                 closest = item;
                 distance = curDistance;
             }
         }
         return closest;
     }
 
 void Awake () 
 {
 WayPoints = GameObject.FindGameObjectsWithTag("Waypoint");
 }
 
 void Update()
 {
 if(Vector3.Distance(gameObject.transform.position,TargetTile.transform.position) > 0.1)
         {
             transform.position = Vector3.Lerp(transform.position, TargetTile.transform.position, (Time.time - startTime) / duration);
         }
         else {
             TargetTile = FindWaypoint();
         }
 }

Answer 1

Answer by Robinmtb · Jan 15, 2012 at 12:35 AM

Hi!

This should do the trick :)

 int WaypointIndex = Array.IndexOf(Waypoints, TargetTile); //Find index of reached waypoint
 List<GameObject> temp = new List<GameObject>(Waypoints); //Duplicate old Array into a List
 temp.RemoveAt(WaypointIndex); //Remove reached waypoint from templist
 Waypoints = temp.ToArray(); //Update array

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Wikened · Jan 15, 2012 at 12:52 AM 0

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Where do I place everything? I keep getting errors:

"CS0246: The type or namespace name List1' could not be found. Are you missing a using directive or an assembly reference?"

Bunny83 · Jan 15, 2012 at 02:48 AM 0

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You need the System.Collections.Generic namespace where the generic List<> is defined in by adding

 using System.Collections.Generic;

at the top of your script.

Alternatively you can use the full classname:

 System.Collections.Generic.List<GameObject> temp = new System.Collections.Generic.List<GameObject>(Waypoints);

which is not really a good thing ;)

Answer 2

WayPoints is a builtin array, and you can't remove elements from it easily - you must create a temp array with one less element, copy to it all waypoints but the one you want to delete and assign the temp array to WayPoints.
I made a few changes in your script to include this delete function, and reload the waypoints when needed. I also changed Lerp to MoveTowards and defined a speed variable instead of duration: this is a better alternative when you want to move at constant speed.

public float duration = 10; public float speed = 2.5f; public GameObject[] WayPoints; private GameObject TargetTile;

void DeleteWaypoint(GameObject waypoint) { GameObject[] temp = new GameObject[WayPoints.Length-1]; int i = 0; foreach (GameObject elem in WayPoints){ if (elem != waypoint) temp[i++] = elem; } WayPoints = temp; }

GameObject FindWaypoint() { if (WayPoints.Length == 0){ // if no waypoints, find them WayPoints = GameObject.FindGameObjectsWithTag("Waypoint"); } GameObject closest = null; float distance = Mathf.Infinity; Vector3 position = transform.position; foreach (GameObject item in WayPoints) { Vector3 diff = item.transform.position - position; float curDistance = diff.sqrMagnitude; if (curDistance < distance) { closest = item; distance = curDistance; } } DeleteWaypoint(closest); // delete this waypoint from the list return closest; }

void Update() { if (TargetTile && Vector3.Distance(transform.position, TargetTile.transform.position) > 0.1) { transform.position = Vector3.MoveTowards(transform.position, TargetTile.transform.position, Time.deltaTime * speed); } else { TargetTile = FindWaypoint(); // get next waypoint; } }

C# Array problems

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