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Cleaned up example by organizing code into modules
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@alice-i-cecile
alice-i-cecile committed May 8, 2021
1 parent 88052f3 commit feb3d37
Showing 1 changed file with 137 additions and 121 deletions.
258 changes: 137 additions & 121 deletions examples/ecs/per_entity_events.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,6 @@ use bevy::{
///
/// This specific example shows a simple input -> action dispatch use case,
/// where this pattern helps to avoid messy rechecking and allows simple merging of multiple event input streams.
///
fn main() {
App::build()
.add_plugins(DefaultPlugins)
Expand All @@ -45,110 +44,78 @@ fn main() {
.add_system(
move_text
.system()
.label("action_handling")
.with_run_criteria(FixedTimestep::step(TIME_STEP)),
)
.run()
}

// Tracks which entity is selected
struct Selected {
entity: Entity,
}
// Marks entities as selectable
struct Selectable;
#[derive(Bundle)]
struct InteractableBundle {
#[bundle]
text_bundle: TextBundle,
selectable: Selectable,
rainbow: ColorChoices,
cycle_color_events: Events<CycleColorAction>,
move_events: Events<MoveAction>,
add_number_events: Events<AddNumberAction>,
}

impl InteractableBundle {
// FIXME: fix position
fn new(x: f32, y: f32, font_handle: &Handle<Font>) -> Self {
InteractableBundle {
text_bundle: TextBundle {
text: Text::with_section(
"0",
TextStyle {
font: font_handle.clone(),
font_size: 60.0,
color: Color::WHITE,
},
TextAlignment {
vertical: VerticalAlign::Center,
horizontal: HorizontalAlign::Center,
},
),
transform: Transform::from_xyz(x, y, 0.0),
..Default::default()
},
selectable: Selectable,
rainbow: ColorChoices::Red,
cycle_color_events: Events::<CycleColorAction>::default(),
move_events: Events<MoveAction>::default(),
add_number_events: Events::<AddNumberAction>::default(),
}
pub mod setup {
#[derive(Bundle)]
struct InteractableBundle {
#[bundle]
text_bundle: TextBundle,
selectable: Selectable,
rainbow: ColorChoices,
cycle_color_events: Events<CycleColorAction>,
move_events: Events<MoveAction>,
add_number_events: Events<AddNumberAction>,
}
}

enum ColorChoices {
Red,
Blue,
Violet,
}

impl Iterator for ColorChoices {
type Item = Self;

fn next(&mut self) -> Option<ColorChoices> {
use ColorChoices::*;
Some(match *self {
Red => Blue,
Blue => Violet,
Violet => Red,
})
}
}

impl From<&ColorChoices> for Color {
fn from(rainbow: &ColorChoices) -> Color {
use ColorChoices::*;
match rainbow {
Red => Color::RED,
Blue => Color::BLUE,
Violet => Color::VIOLET,

impl InteractableBundle {
// FIXME: fix position
fn new(x: f32, y: f32, font_handle: &Handle<Font>) -> Self {
InteractableBundle {
text_bundle: TextBundle {
text: Text::with_section(
"0",
TextStyle {
font: font_handle.clone(),
font_size: 60.0,
color: Color::WHITE,
},
TextAlignment {
vertical: VerticalAlign::Center,
horizontal: HorizontalAlign::Center,
},
),
transform: Transform::from_xyz(x, y, 0.0),
..Default::default()
},
selectable: Selectable,
rainbow: ColorChoices::Red,
cycle_color_events: Events::<CycleColorAction>::default(),
move_events: Events<MoveAction>::default(),
add_number_events: Events::<AddNumberAction>::default(),
}
}
}

fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
commands.spawn_bundle(OrthographicCameraBundle::new_2d());

let font_handle = asset_server.load("fonts/FiraSans-Bold.ttf");
// Spawns the first entity, and grabs the Entity id that is being allocated
let first_entity = commands
.spawn_bundle(InteractableBundle::new(-200.0, 0.0, &font_handle))
.id();
commands.insert_resource(Selected {
entity: first_entity,
});

commands.spawn_bundle(InteractableBundle::new(0.0, 0.0, &font_handle));
commands.spawn_bundle(InteractableBundle::new(200.0, 0.0, &font_handle));
}

}

// Events can be simple unit structs
struct CycleColorAction;
// Or store data to be responded to
struct AddNumberAction {
number: u8,
}

fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
// Don't forget to include a camera!
commands.spawn_bundle(UiCameraBundle::default());

let font_handle = asset_server.load("fonts/FiraSans-Bold.ttf");
// Spawns the first entity, and grabs the Entity id that is being allocated
let first_entity = commands
.spawn_bundle(InteractableBundle::new(-200.0, 400.0, &font_handle))
.id();
commands.insert_resource(Selected {
entity: first_entity,
});

commands.spawn_bundle(InteractableBundle::new(0.0, 400.0, &font_handle));
commands.spawn_bundle(InteractableBundle::new(200.0, 400.0, &font_handle));
pub mod selection {
// Tracks which entity is selected
struct Selected {
entity: Entity,
}
// Marks entities as selectable
struct Selectable;

enum CycleBehavior {
Forward,
Expand Down Expand Up @@ -204,6 +171,9 @@ fn scale_selected(
}
}

}

pub mod input {
/// Dispatches actions to entities based on the input
/// Note that we can store several events at once!
/// Try pressing both "1" and "3" to add 4 to the selected display
Expand Down Expand Up @@ -255,20 +225,85 @@ fn input_dispatch(
}
}

fn cycle_color(mut query: Query<(&mut ColorChoices, EventReader<CycleColorAction>)>) {
for (mut color, action_queue) in query.iter_mut() {
for _ in action_queue.iter() {
*color = color.next().unwrap();
}

pub mod colors {
struct CycleColorAction;
enum ColorChoices {
Red,
Blue,
Violet,
}

impl Iterator for ColorChoices {
type Item = Self;

fn next(&mut self) -> Option<ColorChoices> {
use ColorChoices::*;
Some(match *self {
Red => Blue,
Blue => Violet,
Violet => Red,
})
}
}

impl From<&ColorChoices> for Color {
fn from(rainbow: &ColorChoices) -> Color {
use ColorChoices::*;
match rainbow {
Red => Color::RED,
Blue => Color::BLUE,
Violet => Color::VIOLET,
}
}
}

fn cycle_color(mut query: Query<(&mut ColorChoices, EventReader<CycleColorAction>)>) {
for (mut color, action_queue) in query.iter_mut() {
for _ in action_queue.iter() {
*color = color.next().unwrap();
}
}
}

fn update_text_color(mut query: Query<(&mut Text, &ColorChoices), Changed<ColorChoices>>) {
for (mut text, rainbow) in query.iter_mut() {
text.sections[0].style.color = rainbow.into();
}
}

}

fn update_text_color(mut query: Query<(&mut Text, &ColorChoices), Changed<ColorChoices>>) {
for (mut text, rainbow) in query.iter_mut() {
text.sections[0].style.color = rainbow.into();
pub mod movement {
struct MoveAction {
transform: Transform,
}

const MOVE_DISTANCE: f32 = 100.0;
const TIME_STEP: f32 = 2;

// When events are registered in the AppBuilder using .add_event(),
// a system will automatically be created to clean them up after two frames.
// This can be problematic if your event-consuming systems ever skip frames (such as due to a fixed timestep run criteria).
// We can get around this by not registering them, and instead handling clean-up by consuming them when read.
// Be careful though: once consumed, other systems will not be able to read them!
fn move_text(query: Query<(&mut Transform, EventConsumer<MoveAction>)>) {
for (mut transform, events) in query.iter() {
// Unlike EventReaders which simply iterate, EventConsumers drain the events they read
for move_action in events.drain() {
*transform += move_action.transform * TIME_STEP;
}
}
}

}

pub mod addition {
// Or store data to be responded to
struct AddNumberAction {
number: u8,
}
// Just as when using Events as a resource, you can work with `Events<T>` directly instead
// EventReader and EventWriter are just convenient wrappers that better communicate intent
// And store state automatically for you
Expand All @@ -294,23 +329,4 @@ fn add_number(
}
}

const MOVE_DISTANCE: f32 = 100.0;
const TIME_STEP: f32 = 2;
#[derive(Default)]
struct MoveAction {
transform: Transform,
}

// When events are registered in the AppBuilder using .add_event(),
// a system will automatically be created to clean them up after two frames.
// This can be problematic if your event-consuming systems ever skip frames (such as due to a fixed timestep run criteria).
// We can get around this by not registering them, and instead handling clean-up by consuming them when read.
// Be careful though: once consumed, other systems will not be able to read them!
fn move_text(query: Query<(&mut Transform, EventConsumer<MoveAction>)>) {
for (mut transform, events) in query.iter() {
// Unlike EventReaders which simply iterate, EventConsumers drain the events they read
for move_action in events.drain() {
*transform += move_action.transform * TIME_STEP;
}
}
}
}

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