Preventing use class variables

Hello.

I'm completely new to Unity and thus need some help because I have a problem I cannot solve the way I'd usually do.

Before I start working on the project I have in mind, I need to get some experience with Unity so I do smaller stuff (at the moment I do pong) to get used with Unity. So far I have to say that Unity has a unique, very comfortable workflow, but there's one thing I cannot do the way I wanted to.

The problem I have is that I need to manipulate/access properties of different GameObjects.
Usually I would write a game or a logic-Object, create a new instance and call some sort of start()-Method from withing the main-Method. This logic-method would then manage everything (or most of the stuff) and if I needed to access a variable from another part of the script, I could just use base.getBLAH().
The problem is that in Unity, when you attach a script to a GameObject, it's isolated since there is no main-Method.

I worked around the problem by turning the variables I need into public class variables. While this is the most convenient and performance-efficient way, it also has a major drawback. The variable shared across all instances and thus totally useless when I create anything more complex than pong.

So far I've read about SendMessage() and GetComponent(), but I don't quite understand how to use them yet. I would appreciate it if someone would help me at one part of my code.

Here's my specific problem:
I'm writing pong and have a "Ball" component. I need to access the position of the Ball from within the "Player" GameObject (and other places too, but this one should do for me to understand).

Ball.cs:

Code (csharp):

1. public class Ball : MonoBehaviour {
2.    
3.     [...]
4.     public static Vector3 pos;
5.     [...]
6.    
7.     // Update is called once per frame
8.     void Update () {
9.         [...]
10.         pos = mytransform.position;
11.     }

Player.cs

Code (csharp):

1. public class Player : MonoBehaviour {
2.  
3.     [...]
4.  
5.     void OnCollisionEnter(Collision collision)
6.     {
7.         if(mytransform.position.z > Ball.pos.z) {
8.             [...]
9.         }
10.  
11.         [...]
12.  
13.     }
14. }

You should get the idea.
I also need to access other stuff from within different classes, but I think that if someone shows/explains me how to solve this problem here, I'll be able to do the rest.

Thanks in advance.

 

http://docs.unity3d.com/Documentation/ScriptReference/index.Accessing_Other_Game_Objects.html

http://answers.unity3d.com/questions/50466/get-variables-from-other-scripts.html

 

*facepalm*

I already saw that page and tried to apply it but failed.
Turned out I confused GameObject.Find() with GetComponent(). I used the latter where I should have used the former and always got a Null-Pointer exception (or the Unity equivalent).

Player.cs

Code (csharp):

1. public class Player : MonoBehaviour {
2.    
3.     private Transform mytransform;
4.     private Transform balltransform;
5.     [...]
6.    
7.     void Awake () {
8.         mytransform = transform;
9.         balltransform = GameObject.Find("Ball").transform;
10.         [...]
11.     }
12.  
13.     [...]

Works perfectly fine.

Thanks anyway!

 

Move the Find call to Start to ensure that Ball is properly initialized before you find it.

 

Thanks for the hint.

So if I understand it correctly Awake() is executed before Start() and thus I can use them like this:

Awake: Do stuff with this Object.
Start: Do stuff with other Objects (Initialization for example).

Is this correct?

 

Exactly correct. Anything called in Start can be called with the confidence that the scene is fully initialized.