From 09c15ea890c3d2d13e6238ec4fa45ea58901a450 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fran=C3=A7ois?= <mockersf@gmail.com>
Date: Wed, 23 Dec 2020 23:10:39 +0100
Subject: [PATCH] do not check for focus until cursor position has been set
 (#1070)

do not check for focus until cursor position has been set
---
 crates/bevy_ui/src/focus.rs | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/crates/bevy_ui/src/focus.rs b/crates/bevy_ui/src/focus.rs
index 663b27b4c63db..814bed2baab2d 100644
--- a/crates/bevy_ui/src/focus.rs
+++ b/crates/bevy_ui/src/focus.rs
@@ -1,11 +1,9 @@
 use crate::Node;
-use bevy_app::{EventReader, Events};
 use bevy_core::FloatOrd;
 use bevy_ecs::prelude::*;
 use bevy_input::{mouse::MouseButton, touch::Touches, Input};
-use bevy_math::Vec2;
 use bevy_transform::components::GlobalTransform;
-use bevy_window::CursorMoved;
+use bevy_window::Windows;
 
 #[derive(Copy, Clone, Eq, PartialEq, Debug)]
 pub enum Interaction {
@@ -34,15 +32,13 @@ impl Default for FocusPolicy {
 
 #[derive(Default)]
 pub struct State {
-    cursor_moved_event_reader: EventReader<CursorMoved>,
-    cursor_position: Vec2,
     hovered_entity: Option<Entity>,
 }
 
 pub fn ui_focus_system(
     mut state: Local<State>,
+    windows: Res<Windows>,
     mouse_button_input: Res<Input<MouseButton>>,
-    cursor_moved_events: Res<Events<CursorMoved>>,
     touches_input: Res<Touches>,
     mut node_query: Query<(
         Entity,
@@ -52,12 +48,14 @@ pub fn ui_focus_system(
         Option<&FocusPolicy>,
     )>,
 ) {
-    if let Some(cursor_moved) = state.cursor_moved_event_reader.latest(&cursor_moved_events) {
-        state.cursor_position = cursor_moved.position;
-    }
-    if let Some(touch) = touches_input.get_pressed(0) {
-        state.cursor_position = touch.position();
-    }
+    let cursor_position = if let Some(cursor_position) = windows
+        .get_primary()
+        .and_then(|window| window.cursor_position())
+    {
+        cursor_position
+    } else {
+        return;
+    };
 
     if mouse_button_input.just_released(MouseButton::Left) || touches_input.just_released(0) {
         for (_entity, _node, _global_transform, interaction, _focus_policy) in node_query.iter_mut()
@@ -85,8 +83,8 @@ pub fn ui_focus_system(
                     let min = ui_position - extents;
                     let max = ui_position + extents;
                     // if the current cursor position is within the bounds of the node, consider it for clicking
-                    if (min.x..max.x).contains(&state.cursor_position.x)
-                        && (min.y..max.y).contains(&state.cursor_position.y)
+                    if (min.x..max.x).contains(&cursor_position.x)
+                        && (min.y..max.y).contains(&cursor_position.y)
                     {
                         Some((entity, focus_policy, interaction, FloatOrd(position.z)))
                     } else {