Parenting problem

Question

Hi guys I'm trying to instantiate an object with a parent to a point of view but i get null reference. Here is the code:

 var showMessage : boolean;
 var someMessage : String;
 var prefab : Transform;
 var pov : GameObject;
 
 private var video : GameObject;
 
 function OnGUI(){
     if(showMessage){
         GUI.Box(Rect(Screen.width/2,Screen.height/2, 100, 25),someMessage);
     }
 }
 
 function OnTriggerEnter(){
     showMessage = true;
     videostart();
 }
 
 function OnTriggerExit(){
     showMessage = false;
 }
 
 function videostart() {
     video = Instantiate(prefab, pov.position, pov.rotation) as GameObject;
     video.transform.parent = pov.transform;
 }

Answer 1

Answer by kolban · May 20, 2012 at 03:10 PM

When you get a null reference error, the error will be said to have happened at a particular source line. When posting these questions, always identify which source line in the script code Unity has detected the error upon. Also, have a practice with "code" formatting in the posts.

Assuming that the error occurs at the Instantiate line then either:

prefab is null
pov is null

Check, check and double check that these publicly exported variables have values.

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Bunny83 · May 20, 2012 at 03:20 PM 1

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I would say this is a valid answer ;) converted!

Bunny83 · May 20, 2012 at 03:24 PM 0

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BTW: just realised that "pov" is a GameObject. A GameObject doesn't have a position or rotation property, only the Transform component. The best thing is to change the type of the pov variable to Transform and reassign the object to the variable.

Berenger · May 20, 2012 at 03:25 PM 0

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Furthermore, please do not write parts of your code that are obviously not relevant. OnTriggerExit and the GUI, for instance.

Bunny83 · May 20, 2012 at 03:27 PM 0

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Argh :D another thing:

prefab is of type Transform and you try to as-cast it to GameObject. This will always fail since a GameObject and a Transform are two totally different things. The as-cast in it's nature will return null when the cast fails, so your "video" variable will always be null. Get your types right. You might want to use pragma strict to avoid such mistakes in the future.

Parenting problem

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