From 9d18b269292e31525760dc879fa0fa3fe102c86a Mon Sep 17 00:00:00 2001
From: Light Ning <lightning1141@gmail.com>
Date: Mon, 10 Oct 2022 17:43:10 +0000
Subject: [PATCH] bevy_input: Fix process touch event (#4352)

# Objective

- `process_touch_event` in `bevy_input` don't update position info. `TouchPhase::Ended` and `TouchPhase::Cancelled` should use the position info from `pressed`. Otherwise, it'll not update. The position info is updated from `TouchPhase::Moved`.

## Solution

- Use updated touch info.

---

## Changelog

> This section is optional. If this was a trivial fix, or has no externally-visible impact, feel free to skip this section.

- Fixed: bevy_input, fix process touch event, update touch info
---
 crates/bevy_input/src/touch.rs | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/crates/bevy_input/src/touch.rs b/crates/bevy_input/src/touch.rs
index e7565b594adb5b..3b43a7c7e377ca 100644
--- a/crates/bevy_input/src/touch.rs
+++ b/crates/bevy_input/src/touch.rs
@@ -297,12 +297,22 @@ impl Touches {
                 }
             }
             TouchPhase::Ended => {
-                self.just_released.insert(event.id, event.into());
-                self.pressed.remove_entry(&event.id);
+                // if touch `just_released`, add related event to it
+                // the event position info is inside `pressed`, so use it unless not found
+                if let Some((_, v)) = self.pressed.remove_entry(&event.id) {
+                    self.just_released.insert(event.id, v);
+                } else {
+                    self.just_released.insert(event.id, event.into());
+                }
             }
             TouchPhase::Cancelled => {
-                self.just_cancelled.insert(event.id, event.into());
-                self.pressed.remove_entry(&event.id);
+                // if touch `just_cancelled`, add related event to it
+                // the event position info is inside `pressed`, so use it unless not found
+                if let Some((_, v)) = self.pressed.remove_entry(&event.id) {
+                    self.just_cancelled.insert(event.id, v);
+                } else {
+                    self.just_cancelled.insert(event.id, event.into());
+                }
             }
         };
     }
@@ -427,8 +437,8 @@ mod test {
         touches.update();
         touches.process_touch_event(&cancel_touch_event);
 
-        assert!(touches.just_cancelled.get(&cancel_touch_event.id).is_some());
-        assert!(touches.pressed.get(&cancel_touch_event.id).is_none());
+        assert!(touches.just_cancelled.get(&touch_event.id).is_some());
+        assert!(touches.pressed.get(&touch_event.id).is_none());
 
         // Test ending an event
 
@@ -436,15 +446,19 @@ mod test {
             phase: TouchPhase::Ended,
             position: Vec2::splat(4.0),
             force: None,
-            id: 4,
+            id: touch_event.id,
         };
 
         touches.update();
         touches.process_touch_event(&touch_event);
+        touches.process_touch_event(&moved_touch_event);
         touches.process_touch_event(&end_touch_event);
 
         assert!(touches.just_released.get(&touch_event.id).is_some());
         assert!(touches.pressed.get(&touch_event.id).is_none());
+        let touch = touches.just_released.get(&touch_event.id).unwrap();
+        // Make sure the position is updated from TouchPhase::Moved and TouchPhase::Ended
+        assert!(touch.previous_position != touch.position);
     }
 
     #[test]