Finding multiple gameobjects with tag error

Question

Ok i have multiple enemies and multiple players in my scene. My problem was that when i an enemy killed a player they would stop searching for players tagged "playerguy". So i tried changing GameObject.FindWithTag("PlayerGuy").Transform to GameObject.FindGameObjectsWithTag("PlayerGuy").Transform. Problem is i get this error

`Assets/TankMan/TankManScripts/EnemyScripts/Lvl1TerroristAI.js(29,74): BCE0019: 'transform' is not a member of 'UnityEngine.GameObject[]'.

I understand why im getting this error, I just dont know how to fix it. If anyone can point me in the direction of fixing the problem that would be great.

     static var target1 : Transform;
     var moveSpeed : int = 6;  // chase speed
     var rotationSpeed : int = 1;  // speed to turn to the player
     var maxDistance : int = 10;  // attack distance
     var minDistance : int = 15;  // detection distance
     
     private var myTransform : Transform;
     
     function Awake() {
         myTransform = transform;
     }
     
     // Cache the controller 
     private var characterController : CharacterController; 
     characterController = GetComponent(CharacterController);
     
     function Start () { 
         target1 = GameObject.FindWithTag ("PlayerGuy").transform; 
         maxDistance = 2;
        
     }
     
     //------------------------------------------------------------------ 
 
     function Update(){
     if (target1 == null){
         target1 = GameObject.FindGameObjectsWithTag("PlayerGuy").transform;
         if (target1) {
         var dist = Vector3.Distance(target1.position, transform.position);
         if (dist > minDistance){  // if dist > minDistance: enters idle mode
             Idle(); 
         }
         else
         if (dist <= maxDistance) {  // if dist <= maxDistance: stop and attack        
             print ("Attack!");
 
         } 
         else {  // if maxDistance < dist < minDistance: chase the player
           //  print ("I found you "+ dist);
             myTransform.rotation = Quaternion.Slerp(myTransform.rotation,
             Quaternion.LookRotation(target1.position -                                         myTransform.position) , rotationSpeed * Time.deltaTime);
             
             // Move towards target
             characterController.Move(myTransform.forward * moveSpeed * Time.deltaTime);
             //
             //
         }
          if (dist <= maxDistance){
              myTransform.rotation = Quaternion.Slerp(myTransform.rotation,
             Quaternion.LookRotation(target1.position -                                         myTransform.position) , rotationSpeed * Time.deltaTime);
             }
         }
     }
     }
 
 //------------------------------------------------------------------
 
     var walkSpeed = 3.0; 
     var directionTraveltime = 2.0;
     var idleTime = 1.5; 
     var rndAngle = 45; 
     // enemy will turn +/- rndAngle
     
     private var timeToNewDirection = 0.0; 
     private var turningTime = 0.0; 
     private var turn: float;
     
     function Idle () { 
         // Walk around and pause in random directions unless the player is within range 
         if (Time.time > timeToNewDirection) { 
           // time to change direction? 
           if(Random.value > 0.5) // choose new direction 
               turn = rndAngle; 
          else { turn = -rndAngle; }
          turningTime = Time.time + idleTime; 
          // will stop and turn during idleTime... 
          timeToNewDirection = turningTime + directionTraveltime; 
          // and travel during directionTraveltime
        } 
        if (Time.time < turningTime) { 
            // rotate during idleTime... 
           transform.Rotate(0, turn*Time.deltaTime/idleTime, 0); 
        } else { 
           // and travel until timeToNewDirection 
           characterController.SimpleMove(transform.forward * walkSpeed); 
        }
     }
 
     function OnCollisionEnter(collision : Collision) { 
         transform.Rotate(0, turn*Time.deltaTime/idleTime, 0); 
     }

Answer 1

Best Answer

Answer by Airmand · Jul 31, 2011 at 02:33 AM

Got help from someone on the scripting forums and figured it out

 function Update () {
 
 var target1 : Transform;
 var gOs = GameObject.FindGameObjectsWithTag("PlayerGuy");
 
 if (gOs.Length > 0) {
     var closestDistance : float=Mathf.Infinity;
    for(var g : GameObject in gOs) {
         var distance : float = Vector3.Distance (transform.position, g.transform.position);
 
         if (distance < closestDistance) {
             target1 = g.transform;
             closestDistance = distance;
             }
         }
     }

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Answer 2

Answer by Peter G · Jul 29, 2011 at 04:44 PM

The problem is that you can't access the Transform of a collection of GameObjects like that. You have an array of GameObjects that you found with FindGameObjectsWithTag(). To access a specific one, you need a specific GameObject, now there are a number of ways to do this.

  //The easiest
  var gOs = GameObject.FindGameObjectsWithTag("PlayerGuy");
  target1 = gOs[0].transform;
  //Get the first element in the array.

or convert the entire array. If you only need one element, this might be a waste of memory.

  //C#.
  var gOs = GameObject.FindGameObjectsWithTag("");
  var targets = Array.ConvertAll<GameObject , Transform>( gOs ,  x => x.transform );

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Airmand · Jul 29, 2011 at 05:00 PM 0

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ok with this updated script i get this error and now my enemies wont move at all.

UnityException: You are not allowed to call this function when declaring a variable. $$anonymous$$ove it to the line after without a variable declaration. If you are using C# don't use this function in the constructor or field initializers, Ins$$anonymous$$d move initialization to the Awake or Start function. Lvl1TerroristAI..ctor () (at Assets/Tank$$anonymous$$an/Tank$$anonymous$$anScripts/EnemyScripts/Lvl1TerroristAI.js:3)

  var gOs = GameObject.FindGameObjectsWithTag("PlayerGuy");
  var target1 = gOs[3].transform;
 var moveSpeed : int = 6;  // chase speed
 var rotationSpeed : int = 1;  // speed to turn to the player
 var maxDistance : int = 10;  // attack distance
 var $$anonymous$$Distance : int = 1000;  // detection distance
 
 private var myTransform : Transform;
 
 function Awake() {
     myTransform = transform;
 }
 
 // Cache the controller 
 private var characterController : CharacterController; 
 characterController = GetComponent(CharacterController);
 
 function Start () { 
    target1 = gOs[3].transform; 
    maxDistance = 2;
    
 }

Peter G · Jul 29, 2011 at 06:20 PM 0

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There not moving because you have an error and the script won't compile properly. $$anonymous$$ove the "var gOs = ..." into the first line of the Start() function

Airmand · Jul 29, 2011 at 06:27 PM 0

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when i move that into start() i get a whole new slew of errors. so i moved var target 1 in the start as well and then that gave me about 10 more errors as well

Peter G · Jul 29, 2011 at 06:32 PM 0

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Alright, move gOs into the start function, and delete the assignment to target1 in the field initializer. Change this:

 var target1 = gOs[3].transform;

into:

 var target1;

Does gOs appear anywhere else in your code? If it does then you will need to make a few more $$anonymous$$or adjustments.

Airmand · Jul 29, 2011 at 06:41 PM 0

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alright i dont get any more errors but my enemies still arent moving...

var target1; var moveSpeed : int = 6; // chase speed var rotationSpeed : int = 1; // speed to turn to the player var maxDistance : int = 10; // attack distance var $$anonymous$$Distance : int = 1000; // detection distance

 private var myTransform : Transform;
 
 function Awake() {
     myTransform = transform;
 }
 
 // Cache the controller 
 private var characterController : CharacterController; 
 characterController = GetComponent(CharacterController);
 
 function Start () { 
  
  var gOs = GameObject.FindGameObjectsWithTag("PlayerGuy");
    maxDistance = 2;

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Answer 3

Answer by Airmand · Jul 30, 2011 at 05:03 AM

hmm in runtime i get a null reference exception object reference not set to an instance of an object. and nothing shows up in the inspector to set...

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Peter G · Jul 30, 2011 at 04:45 PM 0

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well that's the problem, check if the NRE is because the gOs is null or if its because the target1 is null.

Finding multiple gameobjects with tag error

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