Alternative to getComponent?

Questions & Answers
1

Ive been reading around, and it sounds like getComponent() is fairly slow. In my game (which I would like to port to mobile in the future) I use it fairly often just to check/change a single variable in a script attached to an object. Is there a more efficient way of accomplishing this to increase performance or is this the only option?

Thanks, Any ideas are appreciated.

2

Lookup “unity getComponent cache.”

Whenever you compute something you’re going to use a few times, you can save it in a variable. Nothing fancy at all. Instead of if(A.magnitude<10 && A.magnitude>3 ... you write float Amag=A.magnitude; if(aMag<10 && Amag>3). If you have to think harder about how and where to save it, the fancy term is “cache-ing” it, like canned goods in a safehouse.

The trick with getCompnenent is, you can declare variables of type Rigidbody, or script names, Renderer… . Then you have a place to save a GetComponent.

But, if you only use it once a every few seconds, maybe not worth the effort and harder to read code.

3

There’s a few options.

  1. As @hamster said, it’s typically not a terrible thing to do a GetComponent on Start and save it to a variable. Usually performance hits at startup are okay because people expect that games have to load:

     private SomeScript foo;

 void Start()
 {
      foo = GetComponent<SomeScript>();
 }

  2. If you make a public variable you can drag the gameobject with that component to it in the editor:

     public SomeScript foo;

 void Start()
 {
     if(!foo)
         Debug.LogError("No SomeScript component");
 }

And then you can drag a gameobject with a SomeScript component on it to the foo slot in the editor

4

GetComponent is really not particularly slow. You should profile/benchmark first to be sure it’s actually a problem rather than relying on misinformation.