Methods in my IComponentData struct

Hello, I'm having trouble trying to get something to work, probably something I don't know about C# so it would be nice to learn from this.

I have a method in my IComponentData struct, which turns a bool1 to true.

Example:

Code (CSharp):

1.  
2. public struct Test: IComponentData
3. {
4.     public bool1 testBool;
5.  
6.     public void MakeTrue()
7.     {
8.         testBool = true;
9.     }
10. }
11.  

So in my system, I have it calling:

Code (CSharp):

1.     protected override void OnUpdate()
2.     {
3.         for (var i = 0; i < data.Length; i++)
4.         {
5.             data.Test[i].MakeTrue();
6.             Debug.Log(data.Test[i].testBool);
7.         }
8.     }

but it doesn't seem to work, still returns false. If anyone can lecture me on why this doesn't work, it would be awesome

 

It's late, I'm tired and lying in bed but I think the problem is you're misunderstanding how structs work.

Structs are copied so if you break it up this is what you're code is doing is

Code (CSharp):

1.             var test = data.Test[i];
2.             test.MakeTrue();
3.             Debug.Log(data.Test[i].testBool); // false
4.             Debug.Log(test.testBool); // true

To get the behaviour you want you have to apply it back.

Code (CSharp):

1.             var test = data.Test[i];
2.             test.MakeTrue();
3.             data.Test[i]  = test;
4.             Debug.Log(data.Test[i].testBool); // true

This is why mutable structs are considered evil and something you should avoid in general

 

Thank you! Yeah, it was just my misunderstanding on how structs work. If mutable structs should be avoided, as an alternative solution, if I want my values to be changed through a method, should I use a monobehaviour instead?

 

You shouldn't have any methods in your components. Use systems only

 

So instead of having a method in my struct, for example, changing 3 booleans to true, I would have the method in my system change the variables instead.

Like this?

Code (CSharp):

1.     void Test(int index)
2.     {
3.         Test t = data.Test[index];
4.         t.testBool1 = true;
5.         t.testBool2 = true;
6.         t.testBool3 = true;
7.         data.Test[index] = t;
8.     }

 

Yep. Or you may even not use a separate method - simply embed this code in your struct's loop