outfly/src/hud.rs

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: 30.0,
                    ..default()
                },
            ),
            TextSection::from_style(if cfg!(feature = "default_font") {
                TextStyle {
                    font_size: 30.0,
                    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: 30.0,
                    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}");
                }
            }
        }
    }
}