logs.rs:
use bevy::log::once;
use bevy::prelude::*;
fn main() {
App::new()
.add_plugins(DefaultPlugins.set(bevy::log::LogPlugin {
..default()
}))
.add_systems(Startup, setup)
.add_systems(Update, log_system)
.add_systems(Update, log_once_system)
.add_systems(Update, panic_on_p)
.run();
}
fn setup(mut commands: Commands) {
commands.spawn(Camera2dBundle::default());
commands.spawn(TextBundle {
text: Text::from_section("Press P to panic", TextStyle::default()),
style: Style {
position_type: PositionType::Absolute,
top: Val::Px(12.0),
left: Val::Px(12.0),
..default()
},
..default()
});
}
fn panic_on_p(keys: Res<ButtonInput<KeyCode>>) {
if keys.just_pressed(KeyCode::KeyP) {
panic!("P pressed, panicking");
}
}
fn log_system() {
trace!("very noisy");
debug!("helpful for debugging");
info!("helpful information that is worth printing by default");
warn!("something bad happened that isn't a failure, but thats worth calling out");
error!("something failed");
}
fn log_once_system() {
trace_once!("one time noisy message");
debug_once!("one time debug message");
info_once!("some info which is printed only once");
warn_once!("some warning we wish to call out only once");
error_once!("some error we wish to report only once");
for i in 0..10 {
info_once!("logs once per call site, so this works just fine: {}", i);
}
once!({
info!("doing expensive things");
let mut a: u64 = 0;
for i in 0..100000000 {
a += i;
}
info!("result of some expensive one time calculation: {}", a);
});
}