From 359e4ae5f7e096f9b9dd2c532a285b2f48dd4dfd Mon Sep 17 00:00:00 2001
From: Rich Churcher <rich.churcher@gmail.com>
Date: Sat, 21 Dec 2024 13:00:41 +1300
Subject: [PATCH] ui_root

---
 src/lib.rs             |  1 +
 src/screens/loading.rs | 15 ++++++++++++++-
 src/ui.rs              | 23 +++++++++++++++++++++++
 3 files changed, 38 insertions(+), 1 deletion(-)
 create mode 100644 src/ui.rs

diff --git a/src/lib.rs b/src/lib.rs
index 991bc9a..ee7e696 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,6 +2,7 @@ mod assets;
 #[cfg(feature = "dev")]
 mod dev_tools;
 mod screens;
+mod ui;
 
 use bevy::{
     asset::AssetMetaCheck,
diff --git a/src/screens/loading.rs b/src/screens/loading.rs
index 3b544a8..45edda0 100644
--- a/src/screens/loading.rs
+++ b/src/screens/loading.rs
@@ -1,3 +1,16 @@
 use bevy::prelude::*;
 
-pub fn plugin(app: &mut App) {}
+use crate::{screens::Screen, ui::Containers};
+
+pub(super) fn plugin(app: &mut App) {
+    app.add_systems(OnEnter(Screen::Loading), spawn_loading_screen);
+}
+
+fn spawn_loading_screen(mut commands: Commands) {
+    commands
+        .ui_root()
+        .insert(StateScoped(Screen::Loading))
+        .with_children(|p| {
+            p.spawn(Text::new("Loading..."));
+        });
+}
diff --git a/src/ui.rs b/src/ui.rs
new file mode 100644
index 0000000..aae16ab
--- /dev/null
+++ b/src/ui.rs
@@ -0,0 +1,23 @@
+use bevy::{ecs::system::EntityCommands, prelude::*, ui::Val::*};
+
+/// An extension trait for spawning UI containers.
+pub trait Containers {
+    /// Spawns a root node that covers the full screen
+    /// and centers its content horizontally and vertically.
+    fn ui_root(&mut self) -> EntityCommands;
+}
+
+impl Containers for Commands<'_, '_> {
+    fn ui_root(&mut self) -> EntityCommands {
+        self.spawn((Name::new("UI Root"), Node {
+            align_items: AlignItems::Center,
+            flex_direction: FlexDirection::Column,
+            height: Percent(100.0),
+            justify_content: JustifyContent::Center,
+            position_type: PositionType::Absolute,
+            row_gap: Px(10.0),
+            width: Percent(100.0),
+            ..default()
+        }))
+    }
+}