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95//! This example demonstrates how to hot patch systems.
//!
//! It needs to be run with the dioxus CLI:
//! ```sh
//! dx serve --hot-patch --example hotpatching_systems --features hotpatching
//! ```
//!
//! All systems are automatically hot patchable.
//!
//! You can change the text in the `update_text` system, or the color in the
//! `on_click` system, and those changes will be hotpatched into the running
//! application.
//!
//! It's also possible to make any function hot patchable by wrapping it with
//! `bevy::dev_tools::hotpatch::call`.
use std::time::Duration;
use bevy::{color::palettes, prelude::*};
fn main() {
let (sender, receiver) = crossbeam_channel::unbounded::<()>();
// This function is here to demonstrate how to make something hot patchable outside of a system
// It uses a thread for simplicity but could be an async task, an asset loader, ...
start_thread(receiver);
App::new()
.add_plugins(DefaultPlugins)
.insert_resource(TaskSender(sender))
.add_systems(Startup, setup)
.add_systems(Update, update_text)
.run();
}
fn update_text(mut text: Single<&mut Text>) {
// Anything in the body of a system can be changed.
// Changes to this string should be immediately visible in the example.
text.0 = "before".to_string();
}
fn on_click(
_click: On<Pointer<Click>>,
mut color: Single<&mut TextColor>,
task_sender: Res<TaskSender>,
) {
// Observers are also hot patchable.
// If you change this color and click on the text in the example, it will have the new color.
color.0 = palettes::tailwind::RED_600.into();
let _ = task_sender.0.send(());
}
#[derive(Resource)]
struct TaskSender(crossbeam_channel::Sender<()>);
fn setup(mut commands: Commands) {
commands.spawn(Camera2d);
commands
.spawn((
Node {
width: percent(100),
height: percent(100),
align_items: AlignItems::Center,
justify_content: JustifyContent::Center,
flex_direction: FlexDirection::Column,
..default()
},
children![(
Text::default(),
TextFont {
font_size: 100.0,
..default()
},
)],
))
.observe(on_click);
}
fn start_thread(receiver: crossbeam_channel::Receiver<()>) {
std::thread::spawn(move || {
while receiver.recv().is_ok() {
let start = bevy::platform::time::Instant::now();
// You can also make any part outside of a system hot patchable by wrapping it
// In this part, only the duration is hot patchable:
let duration = bevy::app::hotpatch::call(|| Duration::from_secs(2));
std::thread::sleep(duration);
info!("done after {:?}", start.elapsed());
}
});
}