GameObserver Input.touches GC Alloc

We are currently in the process of optimizing the iOS version of our game. Our game involves dragging objects around the screen and we noticed in the profiler that whenever a finger is touching the screen GameObserver.Update() is allocating 56B of garbage per frame. Digging around I discovered that GameObserver is part of Unity Analytics, and checking out GameObserver.Update() in MonoDevelop's Assembly Browser this is what's going on:

Code (CSharp):

1. if (Input.touchCount > 0 && Input.touches [0].phase == TouchPhase.Began)
2. {
3.     this.OnClick ();
4. }

This is something we also saw in our own code recently, and is noted in the documentation, Input.touches allocates but using Input.GetTouch instead does not. It would be great if GameObserver could use Input.GetTouch(0) and not allocate every frame a finger is touching the screen. Also, I'm curious why Unity Analytics is listening for all clicks?

 

@mbirk Thanks for the quick reply. Other than this one issue I'm really enjoying Unity Analytics so far, it has the easiest and smoothest onboarding I've seen in an analytics package. Keep up the good work!

 

This issue still persists in the latest patch version. We're not even using analytics, but we rely on the new IAP functionality that forces analytics on, so now the code snippet above is generating garbage on every frame.

If you want to check the state of touch input, you should really use Input.GetTouch(0), which won't cause any allocation. Honestly, the Input.touches API should be removed altogether, because it's just begging to be misused...

 

@mbirk @JoshPeterson @Mantas Puida Hi guys! There is one thing I don't understand, and I wonder if any of you guys would be kind enough to explain it to me.

1. There are cool PC and console games made with Unity, but I believe most of your customer base is developing for iOS and Android.
2. Pauses caused by garbage collection are one of the most common reasons for frame drops in mobile games made with Unity, and you have been doing big changes to improve the situation.
3. This issue causes 100 bytes of garbage on every frame. It's not much, but it does add up.
4. Fixing this issue requires one minor, safe change on one line in the Unity code base.

Am I misunderstanding something? If all of the statements above are true, how is it possible that the issue has not been resolved in one year? What am I missing?

 

@erika_d A big thank you for taking care of the issue!

 

february 2021, unity 2019.4.13f1,
Input.touches still produces 100bytes of garbage.

plse fix.

 

Ah sorry, my fault. Used the wrong interface.
for all others coming here: the solution is to use Input.GetTouch(index) instead of Input.touches.