Fix for ScrollRect multi-touch?

Please note: There is an open bounty for this question on StackOverflow: https://stackoverflow.com/questions/56221113/fix-for-scrollrect-multi-touch-in-unity

Currently, ScrollRect is extremely buggy when it comes to multi-touch on mobile devices.

If you try it out yourself, you will see that whenever you place two fingers on the screen, the content will jump around, and produce some unexpected behaviour.

Are there any solutions to this? Currently, this only solution I have found, but it is still buggy in some cases, and most importantly, does not determine the average input position for all your fingers on the screen.

Here is my modified version of the MultiTouchScrollRect.cs script from the UnityUIExtensions bitbucket, but it jumps every-time I place my next finger on the screen:

Code (CSharp):

1. using UnityEngine;
2. using UnityEngine.EventSystems;
3. using UnityEngine.UI;
4.  
5. public class MultiTouchScrollRect : ScrollRect
6. {
7.     private int minimumTouchCount = 1, maximumTouchCount = 2, pointerId = -100;
8.  
9.     public Vector2 MultiTouchPosition
10.     {
11.         get
12.         {
13.             Vector2 position = Vector2.zero;
14.             for (int i = 0; i < Input.touchCount && i < maximumTouchCount; i++)
15.             {
16.                 position += Input.touches[i].position;
17.             }
18.             position /= ((Input.touchCount <= maximumTouchCount) ? Input.touchCount : maximumTouchCount);
19.             return position;
20.         }
21.     }
22.  
23.     public override void OnBeginDrag(PointerEventData eventData)
24.     {
25.         if (Input.touchCount >= minimumTouchCount)
26.         {
27.             pointerId = eventData.pointerId;
28.             eventData.position = MultiTouchPosition;
29.             base.OnBeginDrag(eventData);
30.         }
31.     }
32.     public override void OnDrag(PointerEventData eventData)
33.     {
34.         if (Input.touchCount >= minimumTouchCount)
35.         {
36.             eventData.position = MultiTouchPosition;
37.             if (pointerId == eventData.pointerId)
38.             {
39.                 base.OnDrag(eventData);
40.             }
41.         }
42.     }
43.     public override void OnEndDrag(PointerEventData eventData)
44.     {
45.         if (Input.touchCount >= minimumTouchCount)
46.         {
47.             pointerId = -100;
48.             eventData.position = MultiTouchPosition;
49.             base.OnEndDrag(eventData);
50.         }
51.     }
52. }

Thanks for your time!

 

Supporting this post. Also have this issue and looking for solution

 

bump

 

Hi Daniel, do you know if any quality solution has been found for this?

 

Hi, I answered my question here: https://stackoverflow.com/questions/56221113/fix-for-scrollrect-multi-touch-in-unity

 

This man deserves a medal for this I swear, not sure why Unity scrollfields don't have this fix integrated as it was simple to replicate on mobile