add HUD with FPS display

src/hud.rs

@@ -0,0 +1,68 @@
+use bevy::prelude::*;
+use bevy::diagnostic::{DiagnosticsStore, FrameTimeDiagnosticsPlugin};
+
+pub struct OutFlyHudPlugin;
+impl Plugin for OutFlyHudPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_systems(Startup, setup);
+        app.add_systems(Update, update);
+        app.insert_resource(FPSUpdateTimer(Timer::from_seconds(0.25, TimerMode::Repeating)));
+    }
+}
+
+#[derive(Component)]
+struct FpsText;
+
+#[derive(Resource)]
+struct FPSUpdateTimer(Timer);
+
+fn setup(
+    mut commands: Commands,
+) {
+    commands.spawn((
+        TextBundle::from_sections([
+            TextSection::new(
+                "FPS: ",
+                TextStyle {
+                    //font: asset_server.load("fonts/FiraSans-Bold.ttf"),
+                    font_size: 60.0,
+                    ..default()
+                },
+            ),
+            TextSection::from_style(if cfg!(feature = "default_font") {
+                TextStyle {
+                    font_size: 60.0,
+                    color: Color::GOLD,
+                    ..default()
+                }
+            } else {
+                // "default_font" feature is unavailable, load a font to use instead.
+                TextStyle {
+                    //font: asset_server.load("fonts/FiraMono-Medium.ttf"),
+                    font_size: 60.0,
+                    color: Color::GOLD,
+                    ..default()
+                }
+            }),
+        ]),
+        FpsText,
+    ));
+}
+
+fn update(
+    diagnostics: Res<DiagnosticsStore>,
+    time:Res<Time>,
+    mut timer: ResMut<FPSUpdateTimer>,
+    mut query: Query<&mut Text, With<FpsText>>,
+) {
+    if timer.0.tick(time.delta()).just_finished() {
+        for mut text in &mut query {
+            if let Some(fps) = diagnostics.get(&FrameTimeDiagnosticsPlugin::FPS) {
+                if let Some(value) = fps.smoothed() {
+                    // Update the value of the second section
+                    text.sections[1].value = format!("{value:.0}");
+                }
+            }
+        }
+    }
+}

src/main.rs

@@ -3,6 +3,7 @@ mod player;
 mod camera;
 mod world;
 mod settings;
+mod hud;
 
 use bevy::window::{Window, WindowMode, PrimaryWindow, CursorGrabMode };
 use bevy::diagnostic::{FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin};
@@ -24,7 +25,10 @@ fn main() {
                 world::asset_loaded.after(world::load_cubemap_asset),
         ))
         .add_plugins(DefaultPlugins.set(ImagePlugin::default_nearest()))
-        .add_plugins(camera::CameraControllerPlugin)
+        .add_plugins((
+            camera::CameraControllerPlugin,
+            hud::OutFlyHudPlugin,
+        ))
         .add_plugins((
             FrameTimeDiagnosticsPlugin,
             LogDiagnosticsPlugin::default(),