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https://github.com/bevyengine/bevy
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015f2c69ca
# Objective Continue improving the user experience of our UI Node API in the direction specified by [Bevy's Next Generation Scene / UI System](https://github.com/bevyengine/bevy/discussions/14437) ## Solution As specified in the document above, merge `Style` fields into `Node`, and move "computed Node fields" into `ComputedNode` (I chose this name over something like `ComputedNodeLayout` because it currently contains more than just layout info. If we want to break this up / rename these concepts, lets do that in a separate PR). `Style` has been removed. This accomplishes a number of goals: ## Ergonomics wins Specifying both `Node` and `Style` is now no longer required for non-default styles Before: ```rust commands.spawn(( Node::default(), Style { width: Val::Px(100.), ..default() }, )); ``` After: ```rust commands.spawn(Node { width: Val::Px(100.), ..default() }); ``` ## Conceptual clarity `Style` was never a comprehensive "style sheet". It only defined "core" style properties that all `Nodes` shared. Any "styled property" that couldn't fit that mold had to be in a separate component. A "real" style system would style properties _across_ components (`Node`, `Button`, etc). We have plans to build a true style system (see the doc linked above). By moving the `Style` fields to `Node`, we fully embrace `Node` as the driving concept and remove the "style system" confusion. ## Next Steps * Consider identifying and splitting out "style properties that aren't core to Node". This should not happen for Bevy 0.15. --- ## Migration Guide Move any fields set on `Style` into `Node` and replace all `Style` component usage with `Node`. Before: ```rust commands.spawn(( Node::default(), Style { width: Val::Px(100.), ..default() }, )); ``` After: ```rust commands.spawn(Node { width: Val::Px(100.), ..default() }); ``` For any usage of the "computed node properties" that used to live on `Node`, use `ComputedNode` instead: Before: ```rust fn system(nodes: Query<&Node>) { for node in &nodes { let computed_size = node.size(); } } ``` After: ```rust fn system(computed_nodes: Query<&ComputedNode>) { for computed_node in &computed_nodes { let computed_size = computed_node.size(); } } ```
81 lines
2.8 KiB
Rust
81 lines
2.8 KiB
Rust
//! This example illustrates how to use logs in bevy.
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use bevy::{log::once, prelude::*};
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fn main() {
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App::new()
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.add_plugins(DefaultPlugins.set(bevy::log::LogPlugin {
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// Uncomment this to override the default log settings:
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// level: bevy::log::Level::TRACE,
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// filter: "wgpu=warn,bevy_ecs=info".to_string(),
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..default()
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}))
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.add_systems(Startup, setup)
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.add_systems(Update, log_system)
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.add_systems(Update, log_once_system)
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.add_systems(Update, panic_on_p)
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.run();
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}
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fn setup(mut commands: Commands) {
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commands.spawn(Camera2d);
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commands.spawn((
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Text::new("Press P to panic"),
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Node {
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position_type: PositionType::Absolute,
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top: Val::Px(12.0),
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left: Val::Px(12.0),
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..default()
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},
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));
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}
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fn panic_on_p(keys: Res<ButtonInput<KeyCode>>) {
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if keys.just_pressed(KeyCode::KeyP) {
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panic!("P pressed, panicking");
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}
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}
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fn log_system() {
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// here is how you write new logs at each "log level" (in "least important" to "most important"
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// order)
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trace!("very noisy");
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debug!("helpful for debugging");
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info!("helpful information that is worth printing by default");
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warn!("something bad happened that isn't a failure, but thats worth calling out");
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error!("something failed");
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// by default, trace and debug logs are ignored because they are "noisy"
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// you can control what level is logged by setting up the LogPlugin
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// alternatively you can set the log level via the RUST_LOG=LEVEL environment variable
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// ex: RUST_LOG=trace, RUST_LOG=info,bevy_ecs=warn
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// the format used here is super flexible. check out this documentation for more info:
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// https://docs.rs/tracing-subscriber/*/tracing_subscriber/filter/struct.EnvFilter.html
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}
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fn log_once_system() {
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// The 'once' variants of each log level are useful when a system is called every frame,
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// but we still wish to inform the user only once. In other words, use these to prevent spam :)
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trace_once!("one time noisy message");
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debug_once!("one time debug message");
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info_once!("some info which is printed only once");
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warn_once!("some warning we wish to call out only once");
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error_once!("some error we wish to report only once");
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for i in 0..10 {
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info_once!("logs once per call site, so this works just fine: {}", i);
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}
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// you can also use the `once!` macro directly,
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// in situations where you want to do something expensive only once
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// within the context of a continuous system.
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once!({
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info!("doing expensive things");
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let mut a: u64 = 0;
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for i in 0..100000000 {
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a += i;
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}
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info!("result of some expensive one time calculation: {}", a);
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});
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}
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