New Input System returns zero Touch position on first call

Question

Hello. This is slice of my code:

 using UnityEngine;
 
 public class Swipe : MonoBehaviour
 {
     InputMaster input;
 
     Vector2 startPos;
 
     void Awake()
     {
         input = new InputMaster();
         input.Enable();
     }
 
     void Start()
     {
         input.Touch.Tap.performed += ctx => CachePosition();
     }
 
     void CachePosition()
     {
         startPos = input.Touch.Position.ReadValue<Vector2>();
         print(startPos)  // !prints  "(0,0)" on first call and then prints appropriate values.
     }
 }

What I'm trying to accomplish here is to cache screen position of tap on tap (event). And it works fine from the second call onwards. But on the first call it returns Vector.zero (0,0). I don't get what the problem might be caused by, I'll try to leave any releavant information here. These 2 input actions has no interactions or processors. "Tap" action is button bind to "Primary Touch/Tap [Touchscreen]". "Position" action is of type "value" - "Vector2" and pretty self explainatory bind to "Position [Touchscreen]".

Maybe my input settings are wrong.

Answer 1

Answer by YienHoe · Nov 02, 2021 at 09:18 AM

@yanerobot My solution for this is to make the programme wait until the end of the first frame before calling the function again. Link to the code answer below:

https://stackoverflow.com/a/69807869/15167614

Hope this helps

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Answer 2

Answer by msanatan · Aug 19, 2021 at 01:32 AM

I'm having the same problems... no solution as yet. I'm using v2020.3.10f1 LTS, hoping that an upgrade to 2021 would stop this issue

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msanatan · Aug 19, 2021 at 02:09 AM 0

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@yanerobot don't upgrade to 2021, all the screen coordinates are now (Infinity, Infinity). I can't believe it got worse lol

Answer 3

Answer by Ercova · Aug 19, 2021 at 07:04 AM

Ok, Let me tell the possibilies then. First => make sure your Tap action is Button and interactions is selected press and release. and for Bindings for Tap action will be PrimaryTouch/TouchContact? and Left Mouse Button.

Second make sure your Position action is Pass through and Type is Vector2. and For bindings will be again Primary Touch/Position and Mouse Position.

 input.Touch.Tap.canceled+= _ => CachePosition();

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msanatan · Aug 19, 2021 at 10:39 AM 0

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I did your set up, with the exception of mouse pointers:

Here's the input action for pressing: https://ibb.co/98fr3qn

And the input action for position: https://ibb.co/bLL8vTg

And these are my logs of screen and world coordinates: https://ibb.co/JxKnWYR

When I read the value, I always get (0, 0), like the OP.

msanatan msanatan · Aug 19, 2021 at 01:32 PM 1

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I realized the bug happens when the binding is Primary Touch/Touch Contact. It picks up the right position when I set it to Touch 0/Touch Contact, or event Primary Touch/Tap. It's just Primary Touch/Touch Contact that's not working. Give it a try @yanerobot

joext msanatan · Mar 30 at 09:28 AM 0

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@msanatan you are right! Thanks.

Answer 4

I think this should help you:

Pressing and position actions

Subscribing to events Note: Subscribing to the "PrimaryTouch.started" event is done after "PrimaryTouchPosition.started" event is called once.

 m_InputControllers.Touch.PrimaryTouchPosition.started += (context) => {
       StartPrimaryTouch(context);
       m_InputControllers.Touch.PrimaryTouch.started += context => StartPrimaryTouch(context);
 };
 m_InputControllers.Touch.PrimaryTouch.canceled += context => EndPrimaryTouch(context);

read positions

 private void EndPrimaryTouch(InputAction.CallbackContext context) => Debug.Log(m_InputControllers.Touch.PrimaryTouchPosition.ReadValue<Vector2>());
 
 private void StartPrimaryTouch(InputAction.CallbackContext context) => Debug.Log(m_InputControllers.Touch.PrimaryTouchPosition.ReadValue<Vector2>());

UPD: I forked their repo on github (v 1.1.0), made some fixes and improvements. So now this seems to be fixed, at least for me. Check this out at: GitHub

now it works right (without subscription inside the "PrimaryTouchPosition.started" event)

 private void Start()
 {
     m_InputControllers.Touch.PrimaryTouch.started += context => StartPrimaryTouch(context);
     m_InputControllers.Touch.PrimaryTouch.canceled += context => EndPrimaryTouch(context);
 }
 
 
 private void EndPrimaryTouch(InputAction.CallbackContext context) => Debug.Log(m_InputControllers.Touch.PrimaryTouchPosition.ReadValue<Vector2>());
     
 private void StartPrimaryTouch(InputAction.CallbackContext context) => Debug.Log(m_InputControllers.Touch.PrimaryTouchPosition.ReadValue<Vector2>());

Note: There are no changes in the Input Actions (looks the same as on the screenshot above), but you should add a new component.

Answer 5

Answer by davidhernandez · Mar 04 at 05:23 AM

Still an issue on 2020.3.23 with Input System 1.3.0

It also happens when I disable the Touch input, the first touch event will return a vector2 with zero values

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New Input System returns zero Touch position on first call

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