NullReferenceException

Hello

I have 1 GameObject : player with 2 components attached : UpdatePlayer and GetTarget

In GetTarget I calculate the angle (ang) between player and enemy
Using a cross product I see if the enemy is on the right or on the left side(dir[1])

In UpdatePlayer I call ang and dir[1] but I get the error msg :

NullReferenceException: Object reference not set to an istance of an object

However everything is working fine

I quote only up to the line which generates the error msg

function Update () {

var Target = GetComponent(GetTarget);

// ruota player
var angle = Target.ang;
var k = Target.dir[1];

var rot = k*angle ; // here I get the error msg


................

}

What am I doing wrong ?

Thanks in advance

 

That's hard to say. On one hand you claim everything is working ok (what makes you say that?) and on the other you cite an error (NullReferenceException), which is it? Have you done anything to verify that Target is a valid reference to your GetTarget component?

 

Thanks

I want to make an RPG movement

My player must rotate and translate , following the mouse pointer regardless of the camera position and orientation

Well, it works

I can drag my character around on the terrain

If I print(Target.ang) I get the right angle
If I print(Target) I get GetTarget
If I dont print anything I get that bloody msg

P.S.

To make it simple I said the angle between the player and the enemy but I meant the mouse pointer

 

If it's not too lengthy can you post your full script? If the reference being shown is valid and "working" then it's not the source of the error. The fact that the line number being referred to seems "off" I'm suspecting something else in your code is causing these issues.

 

No problem, it is quite simple
I am making some test , I purchased Unity just a couple of weeks ago

The componets attached ro the player are :

GetTarget

var targetDir : Vector3;
var hit : RaycastHit ;

var ang;
var dir : Vector3;
var dist;

function Update () {

var ray = Camera.main.ScreenPointToRay (Input.mousePosition);
Physics.Raycast (Camera.main.transform.position,ray.direction,hit,1000);

targetDir.x = hit.point.x - transform.position.x;
targetDir.y = 0;
targetDir.z = hit.point.z - transform.position.z;

ang = Vector3.Angle(targetDir, transform.forward);
dir = Vector3.Cross(targetDir, transform.forward);
dir.Normalize();

}

and UpdatePlayer

function Update () {

var Target = GetComponent(GetTarget);

// ruota player
var angle = Target.ang;
var k = Target.dir[1];

var rot = -100*k*angle / 180;
transform.Rotate(Vector3.up *rot*Time.deltaTime);

transform.Translate(0,0, 10*Time.deltaTime);

}

Then I have an UpdateCamera attached to the camera

 

Don't you usually have to put scriptname types in quotes?

 

No, that slows things down. It's faster to specify the type directly instead of parsing strings. The only time you'd want to use strings is if you're doing something like trying to access a C# script from Javascript and because of script compilation order issues, you can't directly specify the type.

--Eric

 

GetComponent takes a string or a type.
http://unity3d.com/support/documentation/ScriptReference/Component.GetComponent.html

The other GetComponent methods take just a type. A minor inconsistency.

Code (csharp):

1. var Target = GetComponent(GetTarget);
2.  
3. if (null != Target)
4. {
5.  
6. // ruota player
7. var angle = Target.ang;
8. var k = Target.dir[1];
9.  
10. var rot = -100*k*angle / 180;
11. transform.Rotate(Vector3.up *rot*Time.deltaTime);
12.  
13. transform.Translate(0,0, 10*Time.deltaTime);
14. }

Don't call GetComponent in every update frame.