The Touch Manager, Input Manager and Pointer classes all now handle the touchcancel event, such as triggered on iOS when activating an out of browser UI gesture, or in Facebook Instant Games when displaying an overlay ad. This should prevent issues with touch input becoming locked on iOS specifically. Fix phaserjs#3756

Author: photonstorm

src/input/InputManager.js

@@ -493,6 +493,10 @@ var InputManager = new Class({
                     this.stopPointer(event, time);
                     break;
 
+                case CONST.TOUCH_CANCEL:
+                    this.cancelPointer(event, time);
+                    break;
+
                 case CONST.POINTER_LOCK_CHANGE:
                     this.events.emit('pointerlockchange', event, this.mouse.locked);
                     break;
@@ -698,6 +702,37 @@ var InputManager = new Class({
         }
     },
 
+    /**
+     * Called by the main update loop when a Touch Cancel Event is received.
+     *
+     * @method Phaser.Input.InputManager#cancelPointer
+     * @private
+     * @since 3.15.0
+     *
+     * @param {TouchEvent} event - The native DOM event to be processed.
+     * @param {number} time - The time stamp value of this game step.
+     */
+    cancelPointer: function (event, time)
+    {
+        var pointers = this.pointers;
+
+        for (var c = 0; c < event.changedTouches.length; c++)
+        {
+            var changedTouch = event.changedTouches[c];
+
+            for (var i = 1; i < this.pointersTotal; i++)
+            {
+                var pointer = pointers[i];
+
+                if (pointer.active && pointer.identifier === changedTouch.identifier)
+                {
+                    pointer.touchend(changedTouch, time);
+                    break;
+                }
+            }
+        }
+    },
+
     /**
      * Adds new Pointer objects to the Input Manager.
      *
@@ -841,6 +876,21 @@ var InputManager = new Class({
         }
     },
 
+    /**
+     * Queues a touch cancel event, as passed in by the TouchManager.
+     * Also dispatches any DOM callbacks for this event.
+     *
+     * @method Phaser.Input.InputManager#queueTouchCancel
+     * @private
+     * @since 3.15.0
+     *
+     * @param {TouchEvent} event - The native DOM Touch event.
+     */
+    queueTouchCancel: function (event)
+    {
+        this.queue.push(CONST.TOUCH_CANCEL, event);
+    },
+
     /**
      * Queues a mouse down event, as passed in by the MouseManager.
      * Also dispatches any DOM callbacks for this event.