Reading variables on another GameObject

Pretty straightforward (or at least it should be) but I've been wrestling with it for quite some time.

GameObject A (named "Galactic Map") has the following:

Code (csharp):

1.  
2. var fundsCounter : int;
3.  
4. function Funding () {
5.     fundsCounter = Random.Range (1000, 10000);
6. }
7.  

Game Object B ("Planet") needs to be able to read the value of that variable "fundsCounter". GetComponent doesn't work for this (apparently) and Messages can't include variables.

Any ideas?

 

GetComponent works fine, and is what you'd use. http://docs.unity3d.com/412/Documentation/ScriptReference/index.Accessing_Other_Game_Objects.html

--Eric

 

I've tried GetComponent (and read that page and everything else I can find) a hundred ways to Sunday. It seems to only work for altering that variable, not simply reading it. The idea is to set that variable (fundsCounter) as the upper spending limit when building units/structures/etc, so I don't need to actually change it.

 

There is no issue reading it...if you can alter it then logically you must be able to read it. print (someObject.GetComponent(Foo).someVar);. Simple as that.

--Eric

 

So theoretically.....

Having this in the "MainScreen" script on one GameObject

Code (csharp):

1.  
2. var fundsCounter : int;
3.  
4. function Funding () {
5.     fundsCounter = Random.Range (1000, 10000);
6. }
7.  

and this on the other

Code (csharp):

1.  
2.  
3. var mainScript : GameObject;
4.  
5. function Start () {
6. print (mainScript.GetComponent(MainScreen).Funding);
7. }
8.  
9.  

should work..... but.....doesn't.

 

Because Funding is a method that assigns fundsCounter. It doesn't return a value and you're not calling it like a method to begin with.

So no - theoretically that shouldn't work

 

No, that shouldn't work. Your Funding function doesn't return anything, so you can't use it with print. Also, you have to call functions like this: Funding(). You can either use print(GetComponent(MainScreen).fundsCounter) after calling the Funding function, or you can make the Funding function return fundsCounter.

--Eric

 

I get that. Using the name of the variable (fundsCounter) also doesn't work. So..... if it's not the variable, or the method, what's left?

 

Because fundsCounter is private. Or GetComponent is returning a Component and you have to cast it to the correct type. I'm not sure because I don't use UnityScript. Depends on the error message you're getting.

The easiest thing to do would be to change mainScript to a MainScreen instead of a GameObject and skip the GetComponent call completely.

 

"fundsCounter is not a member of MainScreen"

That would be easier if I knew what that meant.


EDIT: fundsCounter is a public variable.

 

Has anyone ever gotten GetComponent working for them in MonoScript? Based on what I'm seeing around here (my ?'s and others) there's a ton of questions and no real answers.

 

in script A attached to a GameObject:

Code (csharp):

1. var icecream : int = 5;
2.  
3. function GetIcecream()
4. {
5.      return icecream;
6. }

in script B where the GameObject is referenced to in the inspector

Code (csharp):

1.  
2. var fridge : GameObject;
3.  
4. function DoSomething()
5. {
6.      var how_many = fridge.GetComponent(A).GetIcecream();
7.      Debug.Log("I have " + how_many + "icecreams!" );
8. }

 

Please post the latest version of your scripts.

 

Script A (named FundingGenerator) :

Code (csharp):

1.  
2. #pragma strict
3.  
4. var funds : int;
5.  
6. function Start () {
7.     Invoke ("Funding", 0);
8. }
9.  
10. function Funding () {
11.     funds = Random.Range (0, 10);
12. }
13.  
14. function OnGUI () {
15.     GUI.Label (Rect (100, 100, 100, 20), funds.ToString ());
16. }
17.  

Script B (named "FundingReader"):

Code (csharp):

1.  
2. #pragma strict
3.  
4. var mainObject : GameObject;
5. var availableFunds : int;
6.  
7. function Start () {
8.     var availableFunds = mainObject.GetComponent(FundingGenerator).Funding();
9. }
10.  
11. function OnGUI () {
12.     GUI.Label (Rect (100, 100, 100, 20), availableFunds.ToString ());
13. }
14.  

Script B shows compiler error:

(6,13) : Invalid declaration type "void"


I assume something needs to be inside the parentheses here - .Funding(); - but I have no idea what

 

The reason you have that error is because Funding doesn't return anything, but you're trying to get an int out of it.

You have two solutions you can do.

One, you can access funds directly.

Code (csharp):

1.  
2. #pragma strict
3.  
4. var mainObject : GameObject;
5. var availableFunds : int;
6.  
7. function Start () {
8.     var availableFunds = mainObject.GetComponent(FundingGenerator).funds;
9. }
10.  
11. function OnGUI () {
12.     GUI.Label (Rect (100, 100, 100, 20), availableFunds.ToString ());
13. }
14.  

Or, you can have Funding return a value

Code (csharp):

1.  
2. #pragma strict
3.  
4. var funds : int;
5.  
6. function Funding () {
7.     funds = Random.Range (0, 10);
8.     return funds;
9. }
10.  
11. function OnGUI () {
12.     GUI.Label (Rect (100, 100, 100, 20), funds.ToString ());
13. }
14.  

 

Hmmmm both of those return "null reference exception"...... I dragged the proper GameObject into the inspector slot though. Always one little problem :/

 

Post the full error.

 

Nevermind I got that fixed. However..... the two GUI labels are showing different values (using both methods you showed above, the label on script B always shows 0, regardless of what int the other shows.)

 

Using the second solution it should work. Using the first solution, there's no guarantee which Start method will be called first. You'd need to call Funding in FundingGenerator from the Awake function.

 

Well dang. The second solution returns two different int's with no logical reason, and the second I'm sure how to accomplish. Much appreciated though, you're the only one who got me past error messages.

 

You did take out this portion of the code correct?

Code (csharp):

1.  
2. function Start () {
3.     Invoke ("Funding", 0);
4. }
5.  

 

Nope. I assume that's an important oversight on my part.

Should I do so regardless of which solution I use?

 

For the first solution it would be changed to:

Code (csharp):

1.  
2. function Awake () {
3.     Funding ();
4. }
5.  

For the second solution it would be removed.

 

Ok I think I see what you're saying. Running the two scripts like this:

A -

Code (csharp):

1.  
2. #pragma strict
3.  
4. var funds : int;
5.  
6. function Awake () {
7.     Funding();
8. }
9.  
10. function Funding () {
11.     funds = Random.Range (0, 10);
12. }
13.  
14. function OnGUI () {
15.     GUI.Label (Rect (100, 100, 100, 20), funds.ToString ());
16. }
17.  

B -

Code (csharp):

1.  
2. #pragma strict
3.  
4. var mainObject : GameObject;
5. var availableFunds : int;
6.  
7. function Start () {
8.     var availableFunds = mainObject.GetComponent(FundingGenerator).funds;
9. }
10.  
11. function OnGUI () {
12.     GUI.Label (Rect (100, 120, 100, 20), availableFunds.ToString ());
13. }
14.  

still results in two different int's showing up.

 

Oops, a little oversight.

You're creating a new variable in your Start function in the second script.

Remove 'var' from line 7 and it will work.

 

Thank you, sir, I am indeed much in your debt. It works to perfection.