From 17b6f9f7a3912c40bee5bc3a3585b1969ac7fcb4 Mon Sep 17 00:00:00 2001
From: Xiong Shimin <xiongshimin1997@126.com>
Date: Mon, 1 May 2017 17:58:35 +0800
Subject: [PATCH] Fix: in some extreme case on-screen touch controls get stuck
 on iOS

---
 ios/ViewController.mm | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/ios/ViewController.mm b/ios/ViewController.mm
index b1bb24a6a9..0be72eecb7 100644
--- a/ios/ViewController.mm
+++ b/ios/ViewController.mm
@@ -344,6 +344,17 @@ static GraphicsContext *graphicsContext;
 	}
 }
 
+- (void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
+{
+    for(UITouch* touch in touches)
+    {
+        CGPoint point = [touch locationInView:self.view];
+        NSDictionary* dict = [self touchDictBy:touch];
+        [self touchX:point.x y:point.y code:2 pointerId:[[dict objectForKey:@"index"] intValue]];
+        [self.touches removeObject:dict];
+    }
+}
+
 - (void)bindDefaultFBO
 {
 	[(GLKView*)self.view bindDrawable];