From 90a87e6e4d8ed8da51752fffcab8960c729378eb Mon Sep 17 00:00:00 2001
From: PixelEnvision <erdenerg@gmail.com>
Date: Thu, 30 Mar 2017 20:42:37 +0000
Subject: [PATCH] I've found out today that Unity's ScrollRect is behaving
 erratic when more than one touch is used for drag. I think that's a bug with
 UI. It jumps between fingers (to moving one), this script fixes it by
 blocking event data based on touch id.

---
 Scripts/Utilities/ScrollRectMultiTouchFix.cs | 45 ++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 Scripts/Utilities/ScrollRectMultiTouchFix.cs

diff --git a/Scripts/Utilities/ScrollRectMultiTouchFix.cs b/Scripts/Utilities/ScrollRectMultiTouchFix.cs
new file mode 100644
index 0000000..2ee875a
--- /dev/null
+++ b/Scripts/Utilities/ScrollRectMultiTouchFix.cs
@@ -0,0 +1,45 @@
+/// Credit Erdener Gonenc - @PixelEnvision
+/*USAGE: Simply use that instead of the regular ScrollRect */
+
+using System;
+using UnityEngine.EventSystems;
+
+namespace UnityEngine.UI.Extensions
+{
+	[AddComponentMenu ("UI/Extensions/ScrollRectMultiTouchFix")]
+	public class ScrollRectMultiTouchFix : ScrollRect
+	{
+
+		private int pid = -100;
+
+		/// <summary>
+		/// Begin drag event
+		/// </summary>
+		public override void OnBeginDrag (UnityEngine.EventSystems.PointerEventData eventData)
+		{
+			pid = eventData.pointerId;
+			base.OnBeginDrag (eventData);
+		}
+
+		/// <summary>
+		/// Drag event
+		/// </summary>
+		public override void OnDrag (UnityEngine.EventSystems.PointerEventData eventData)
+		{
+			if (pid == eventData.pointerId)
+				base.OnDrag (eventData);
+		}
+
+		/// <summary>
+		/// End drag event
+		/// </summary>
+		public override void OnEndDrag (UnityEngine.EventSystems.PointerEventData eventData)
+		{
+			if (pid == eventData.pointerId) {
+				pid = -100;
+				base.OnEndDrag (eventData);
+			}
+		}
+
+	}
+}
\ No newline at end of file