Controller Inputs Changing Unexpectedly First Time Run

Hey there,

Think I've got a bug here. Anybody else seen this?

For reference, I am using:
1: An Xbox Elite Series Two Controller.
2. Unity 2021.3.0f1

I've broken it down to a simple script to isolate behavior.

Problem Description:

When I leave the Unity Editor for another window (e.g., Visual Studio Code) and then return, the first time I press the play button and enter into the game world (either maximized / focused or unfocused and clicking in), my inputs joystick axis inputs change unexpectedly.

Code (CSharp):

1. using UnityEngine;
2.  
3. public class InputTest : MonoBehaviour
4. {
5.     void Update()
6.     {
7.         PanCamera();
8.     }
9.  
10.     private void PanCamera()
11.     {
12.         {
13.             float horizontalInput = Input.GetAxis("Horizontal");
14.             float verticalInput = Input.GetAxis("Vertical");
15.             print("Horz" + horizontalInput);
16.             print("Vert" + verticalInput);
17.         }
18.     }
19. }

Script is on an empty, I am using unfocused to debug, and I never touch the controller during this process.

Repro steps:
1. I press play and the scripts yields 0 for horizontal and 0 for vertical as expected.



2. I left mouse-click into the window and the script yields -1 for horizontal and 1 for vertical unexpectedly.



3. I click play to stop.
4. I click play to start.
5. I left mouse-click into the window and the script yields 0 for horizontal and 0 for vertical as expected and performs normally throughout play.

 

Desktop on Win11.

Just for reference, I have another older project running on 2019.4.37f1 and it doesn't see this behavior.

I updated to latest 2021.3.1f1 and it still exists.

For clarification on behavior, it sets those values and holds them; they don't revert at any point. So, essentially, I end up with a camera that pans in 2d flying off northwest / top left.

 

I went ahead and did some further testing on this.

• The controller is an unrelated component.
• I first saw the behavior in 2021.3.1f1 and then also checked for and found it in 2020.3.33f1.
• Retested with current LTS versions and the issue still appears in 2021.3.2.f1 and 2020.3.34f1.
• It does not appear on 2019.4.38f1.
• I have not checked any other versions.
• I am playing in Unfocused Play mode.
• I am using default Axes without any modification.

Reproduction steps are the same. I tested with a simple script attached to the default camera of brand new URP pipeline projects:

Code (CSharp):

1. using UnityEngine;
2.  
3. public class GetInputAndPrint : MonoBehaviour
4. {
5.     float x;
6.     float y;
7.  
8.     void Start()
9.     {
10.         x = Input.GetAxis("Horizontal");
11.         y = Input.GetAxis("Vertical");
12.         print("initial x " + x);//comment
13.         print("initial y " + y);
14.     }
15.  
16.     void Update()
17.     {
18.         if (Input.GetAxis("Horizontal") != x) {
19.             x = Input.GetAxis("Horizontal");
20.             print("updated x " + x);
21.         }
22.                 if (Input.GetAxis("Vertical") != y) {
23.             y = Input.GetAxis("Vertical");
24.             print("updated y " + y);
25.         }
26.     }
27. }
28.  

It essentially just prints the initial state as well as any updates to the axis.

Here are some behavioral observations:
When I edit and save a script and click back into the editor while the Game view is the active tab, it incorrectly initializes the inputs to x=-1, y=1 the first time I enter the game view.

If my first click into the Unity editor is a left mouse-click in a tab other than the game tab while playing unfocused (e.g., the console), it then correctly updates to x=0,y=0. My first click into the Game view sets it to x=-1, y=1.

It does the same when I just click directly into the game tab; x=-1, y=1.

If I connect a controller while in this state, I am only ever to get update to change y to -1 by pressing down. It then returns to 1 upon release. X never changes regardless of where I tilt the stick.

When I hit play again to stop the game, update returns x=0, y=0 correctly before stopping. Then, when I play again, it correctly starts at x=0, y=0 and proceeds to behave normally until I update scripts again.

I can also correctly reset the inputs by clicking into another tab (e.g., console) and then back into the game tab again. This is my current workaround since I don't have to play and stop repetitively.