1ba7429371
# Objective Provide a starting point for #3951, or a partial solution. Providing a few comment blocks to discuss, and hopefully find better one in the process. ## Solution Since I am pretty new to pretty much anything in this context, I figured I'd just start with a draft for some file level doc blocks. For some of them I found more relevant details (or at least things I considered interessting), for some others there is less. ## Changelog - Moved some existing comments from main() functions in the 2d examples to the file header level - Wrote some more comment blocks for most other 2d examples TODO: - [x] 2d/sprite_sheet, wasnt able to come up with something good yet - [x] all other example groups... Also: Please let me know if the commit style is okay, or to verbose. I could certainly squash these things, or add more details if needed. I also hope its okay to raise this PR this early, with just a few files changed. Took me long enough and I dont wanted to let it go to waste because I lost motivation to do the whole thing. Additionally I am somewhat uncertain over the style and contents of the commets. So let me know what you thing please.
53 lines
1.5 KiB
Rust
53 lines
1.5 KiB
Rust
//! This example illustrates how to react to component change.
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use bevy::prelude::*;
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use rand::Rng;
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fn main() {
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App::new()
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.add_plugins(DefaultPlugins)
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.add_startup_system(setup)
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.add_system(change_component)
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.add_system(change_detection)
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.add_system(tracker_monitoring)
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.run();
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}
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#[derive(Component, Debug)]
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struct MyComponent(f64);
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fn setup(mut commands: Commands) {
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commands.spawn().insert(MyComponent(0.));
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commands.spawn().insert(Transform::identity());
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}
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fn change_component(time: Res<Time>, mut query: Query<(Entity, &mut MyComponent)>) {
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for (entity, mut component) in query.iter_mut() {
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if rand::thread_rng().gen_bool(0.1) {
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info!("changing component {:?}", entity);
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component.0 = time.seconds_since_startup();
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}
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}
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}
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// There are query filters for `Changed<T>` and `Added<T>`
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// Only entities matching the filters will be in the query
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fn change_detection(query: Query<(Entity, &MyComponent), Changed<MyComponent>>) {
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for (entity, component) in query.iter() {
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info!("{:?} changed: {:?}", entity, component,);
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}
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}
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// By looking at trackers, the query is not filtered but the information is available
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fn tracker_monitoring(
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query: Query<(
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Entity,
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Option<&MyComponent>,
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Option<ChangeTrackers<MyComponent>>,
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)>,
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) {
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for (entity, component, trackers) in query.iter() {
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info!("{:?}: {:?} -> {:?}", entity, component, trackers);
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}
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}
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