bevy/examples/games/game_menu.rs
ira 9f906fdc8b Improve ergonomics and reduce boilerplate around creating text elements. (#5343)
# Objective

Creating UI elements is very boilerplate-y with lots of indentation.
This PR aims to reduce boilerplate around creating text elements.

## Changelog

* Renamed `Text::with_section` to `from_section`.
  It no longer takes a `TextAlignment` as argument, as the vast majority of cases left it `Default::default()`.
* Added `Text::from_sections` which creates a `Text` from a list of `TextSections`.
  Reduces line-count and reduces indentation by one level.
* Added `Text::with_alignment`.
  A builder style method for setting the `TextAlignment` of a `Text`.
* Added `TextSection::new`.
  Does not reduce line count, but reduces character count and made it easier to read. No more `.to_string()` calls!
* Added `TextSection::from_style` which creates an empty `TextSection` with a style.
  No more empty strings! Reduces indentation.
* Added `TextAlignment::CENTER` and friends.
* Added methods to `TextBundle`. `from_section`, `from_sections`, `with_text_alignment` and `with_style`.

## Note for reviewers.
Because of the nature of these changes I recommend setting diff view to 'split'.
~~Look for the book icon~~ cog in the top-left of the Files changed tab.

Have fun reviewing ❤️
<sup> >:D </sup>

## Migration Guide

`Text::with_section` was renamed to `from_section` and no longer takes a `TextAlignment` as argument.
Use `with_alignment` to set the alignment instead.

Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-07-20 14:14:29 +00:00

754 lines
30 KiB
Rust

//! This example will display a simple menu using Bevy UI where you can start a new game,
//! change some settings or quit. There is no actual game, it will just display the current
//! settings for 5 seconds before going back to the menu.
use bevy::prelude::*;
const TEXT_COLOR: Color = Color::rgb(0.9, 0.9, 0.9);
// Enum that will be used as a global state for the game
#[derive(Clone, Eq, PartialEq, Debug, Hash)]
enum GameState {
Splash,
Menu,
Game,
}
// One of the two settings that can be set through the menu. It will be a resource in the app
#[derive(Debug, Component, PartialEq, Eq, Clone, Copy)]
enum DisplayQuality {
Low,
Medium,
High,
}
// One of the two settings that can be set through the menu. It will be a resource in the app
#[derive(Debug, Component, PartialEq, Eq, Clone, Copy)]
struct Volume(u32);
fn main() {
App::new()
.add_plugins(DefaultPlugins)
// Insert as resource the initial value for the settings resources
.insert_resource(DisplayQuality::Medium)
.insert_resource(Volume(7))
.add_startup_system(setup)
// Declare the game state, and set its startup value
.add_state(GameState::Splash)
// Adds the plugins for each state
.add_plugin(splash::SplashPlugin)
.add_plugin(menu::MenuPlugin)
.add_plugin(game::GamePlugin)
.run();
}
fn setup(mut commands: Commands) {
commands.spawn_bundle(Camera2dBundle::default());
}
mod splash {
use bevy::prelude::*;
use super::{despawn_screen, GameState};
// This plugin will display a splash screen with Bevy logo for 1 second before switching to the menu
pub struct SplashPlugin;
impl Plugin for SplashPlugin {
fn build(&self, app: &mut App) {
// As this plugin is managing the splash screen, it will focus on the state `GameState::Splash`
app
// When entering the state, spawn everything needed for this screen
.add_system_set(SystemSet::on_enter(GameState::Splash).with_system(splash_setup))
// While in this state, run the `countdown` system
.add_system_set(SystemSet::on_update(GameState::Splash).with_system(countdown))
// When exiting the state, despawn everything that was spawned for this screen
.add_system_set(
SystemSet::on_exit(GameState::Splash)
.with_system(despawn_screen::<OnSplashScreen>),
);
}
}
// Tag component used to tag entities added on the splash screen
#[derive(Component)]
struct OnSplashScreen;
// Newtype to use a `Timer` for this screen as a resource
#[derive(Deref, DerefMut)]
struct SplashTimer(Timer);
fn splash_setup(mut commands: Commands, asset_server: Res<AssetServer>) {
let icon = asset_server.load("branding/icon.png");
// Display the logo
commands
.spawn_bundle(ImageBundle {
style: Style {
// This will center the logo
margin: UiRect::all(Val::Auto),
// This will set the logo to be 200px wide, and auto adjust its height
size: Size::new(Val::Px(200.0), Val::Auto),
..default()
},
image: UiImage(icon),
..default()
})
.insert(OnSplashScreen);
// Insert the timer as a resource
commands.insert_resource(SplashTimer(Timer::from_seconds(1.0, false)));
}
// Tick the timer, and change state when finished
fn countdown(
mut game_state: ResMut<State<GameState>>,
time: Res<Time>,
mut timer: ResMut<SplashTimer>,
) {
if timer.tick(time.delta()).finished() {
game_state.set(GameState::Menu).unwrap();
}
}
}
mod game {
use bevy::prelude::*;
use super::{despawn_screen, DisplayQuality, GameState, Volume, TEXT_COLOR};
// This plugin will contain the game. In this case, it's just be a screen that will
// display the current settings for 5 seconds before returning to the menu
pub struct GamePlugin;
impl Plugin for GamePlugin {
fn build(&self, app: &mut App) {
app.add_system_set(SystemSet::on_enter(GameState::Game).with_system(game_setup))
.add_system_set(SystemSet::on_update(GameState::Game).with_system(game))
.add_system_set(
SystemSet::on_exit(GameState::Game).with_system(despawn_screen::<OnGameScreen>),
);
}
}
// Tag component used to tag entities added on the game screen
#[derive(Component)]
struct OnGameScreen;
#[derive(Deref, DerefMut)]
struct GameTimer(Timer);
fn game_setup(
mut commands: Commands,
asset_server: Res<AssetServer>,
display_quality: Res<DisplayQuality>,
volume: Res<Volume>,
) {
let font = asset_server.load("fonts/FiraSans-Bold.ttf");
commands
// First create a `NodeBundle` for centering what we want to display
.spawn_bundle(NodeBundle {
style: Style {
// This will center the current node
margin: UiRect::all(Val::Auto),
// This will display its children in a column, from top to bottom. Unlike
// in Flexbox, Bevy origin is on bottom left, so the vertical axis is reversed
flex_direction: FlexDirection::ColumnReverse,
// `align_items` will align children on the cross axis. Here the main axis is
// vertical (column), so the cross axis is horizontal. This will center the
// children
align_items: AlignItems::Center,
..default()
},
color: Color::BLACK.into(),
..default()
})
.insert(OnGameScreen)
.with_children(|parent| {
// Display two lines of text, the second one with the current settings
parent.spawn_bundle(
TextBundle::from_section(
"Will be back to the menu shortly...",
TextStyle {
font: font.clone(),
font_size: 80.0,
color: TEXT_COLOR,
},
)
.with_style(Style {
margin: UiRect::all(Val::Px(50.0)),
..default()
}),
);
parent.spawn_bundle(
TextBundle::from_sections([
TextSection::new(
format!("quality: {:?}", *display_quality),
TextStyle {
font: font.clone(),
font_size: 60.0,
color: Color::BLUE,
},
),
TextSection::new(
" - ",
TextStyle {
font: font.clone(),
font_size: 60.0,
color: TEXT_COLOR,
},
),
TextSection::new(
format!("volume: {:?}", *volume),
TextStyle {
font: font.clone(),
font_size: 60.0,
color: Color::GREEN,
},
),
])
.with_style(Style {
margin: UiRect::all(Val::Px(50.0)),
..default()
}),
);
});
// Spawn a 5 seconds timer to trigger going back to the menu
commands.insert_resource(GameTimer(Timer::from_seconds(5.0, false)));
}
// Tick the timer, and change state when finished
fn game(
time: Res<Time>,
mut game_state: ResMut<State<GameState>>,
mut timer: ResMut<GameTimer>,
) {
if timer.tick(time.delta()).finished() {
game_state.set(GameState::Menu).unwrap();
}
}
}
mod menu {
use bevy::{app::AppExit, prelude::*};
use super::{despawn_screen, DisplayQuality, GameState, Volume, TEXT_COLOR};
// This plugin manages the menu, with 5 different screens:
// - a main menu with "New Game", "Settings", "Quit"
// - a settings menu with two submenus and a back button
// - two settings screen with a setting that can be set and a back button
pub struct MenuPlugin;
impl Plugin for MenuPlugin {
fn build(&self, app: &mut App) {
app
// At start, the menu is not enabled. This will be changed in `menu_setup` when
// entering the `GameState::Menu` state.
// Current screen in the menu is handled by an independent state from `GameState`
.add_state(MenuState::Disabled)
.add_system_set(SystemSet::on_enter(GameState::Menu).with_system(menu_setup))
// Systems to handle the main menu screen
.add_system_set(SystemSet::on_enter(MenuState::Main).with_system(main_menu_setup))
.add_system_set(
SystemSet::on_exit(MenuState::Main)
.with_system(despawn_screen::<OnMainMenuScreen>),
)
// Systems to handle the settings menu screen
.add_system_set(
SystemSet::on_enter(MenuState::Settings).with_system(settings_menu_setup),
)
.add_system_set(
SystemSet::on_exit(MenuState::Settings)
.with_system(despawn_screen::<OnSettingsMenuScreen>),
)
// Systems to handle the display settings screen
.add_system_set(
SystemSet::on_enter(MenuState::SettingsDisplay)
.with_system(display_settings_menu_setup),
)
.add_system_set(
SystemSet::on_update(MenuState::SettingsDisplay)
.with_system(setting_button::<DisplayQuality>),
)
.add_system_set(
SystemSet::on_exit(MenuState::SettingsDisplay)
.with_system(despawn_screen::<OnDisplaySettingsMenuScreen>),
)
// Systems to handle the sound settings screen
.add_system_set(
SystemSet::on_enter(MenuState::SettingsSound)
.with_system(sound_settings_menu_setup),
)
.add_system_set(
SystemSet::on_update(MenuState::SettingsSound)
.with_system(setting_button::<Volume>),
)
.add_system_set(
SystemSet::on_exit(MenuState::SettingsSound)
.with_system(despawn_screen::<OnSoundSettingsMenuScreen>),
)
// Common systems to all screens that handles buttons behaviour
.add_system_set(
SystemSet::on_update(GameState::Menu)
.with_system(menu_action)
.with_system(button_system),
);
}
}
// State used for the current menu screen
#[derive(Clone, Eq, PartialEq, Debug, Hash)]
enum MenuState {
Main,
Settings,
SettingsDisplay,
SettingsSound,
Disabled,
}
// Tag component used to tag entities added on the main menu screen
#[derive(Component)]
struct OnMainMenuScreen;
// Tag component used to tag entities added on the settings menu screen
#[derive(Component)]
struct OnSettingsMenuScreen;
// Tag component used to tag entities added on the display settings menu screen
#[derive(Component)]
struct OnDisplaySettingsMenuScreen;
// Tag component used to tag entities added on the sound settings menu screen
#[derive(Component)]
struct OnSoundSettingsMenuScreen;
const NORMAL_BUTTON: Color = Color::rgb(0.15, 0.15, 0.15);
const HOVERED_BUTTON: Color = Color::rgb(0.25, 0.25, 0.25);
const HOVERED_PRESSED_BUTTON: Color = Color::rgb(0.25, 0.65, 0.25);
const PRESSED_BUTTON: Color = Color::rgb(0.35, 0.75, 0.35);
// Tag component used to mark wich setting is currently selected
#[derive(Component)]
struct SelectedOption;
// All actions that can be triggered from a button click
#[derive(Component)]
enum MenuButtonAction {
Play,
Settings,
SettingsDisplay,
SettingsSound,
BackToMainMenu,
BackToSettings,
Quit,
}
// This system handles changing all buttons color based on mouse interaction
fn button_system(
mut interaction_query: Query<
(&Interaction, &mut UiColor, Option<&SelectedOption>),
(Changed<Interaction>, With<Button>),
>,
) {
for (interaction, mut color, selected) in &mut interaction_query {
*color = match (*interaction, selected) {
(Interaction::Clicked, _) | (Interaction::None, Some(_)) => PRESSED_BUTTON.into(),
(Interaction::Hovered, Some(_)) => HOVERED_PRESSED_BUTTON.into(),
(Interaction::Hovered, None) => HOVERED_BUTTON.into(),
(Interaction::None, None) => NORMAL_BUTTON.into(),
}
}
}
// This system updates the settings when a new value for a setting is selected, and marks
// the button as the one currently selected
fn setting_button<T: Component + PartialEq + Copy>(
interaction_query: Query<(&Interaction, &T, Entity), (Changed<Interaction>, With<Button>)>,
mut selected_query: Query<(Entity, &mut UiColor), With<SelectedOption>>,
mut commands: Commands,
mut setting: ResMut<T>,
) {
for (interaction, button_setting, entity) in &interaction_query {
if *interaction == Interaction::Clicked && *setting != *button_setting {
let (previous_button, mut previous_color) = selected_query.single_mut();
*previous_color = NORMAL_BUTTON.into();
commands.entity(previous_button).remove::<SelectedOption>();
commands.entity(entity).insert(SelectedOption);
*setting = *button_setting;
}
}
}
fn menu_setup(mut menu_state: ResMut<State<MenuState>>) {
let _ = menu_state.set(MenuState::Main);
}
fn main_menu_setup(mut commands: Commands, asset_server: Res<AssetServer>) {
let font = asset_server.load("fonts/FiraSans-Bold.ttf");
// Common style for all buttons on the screen
let button_style = Style {
size: Size::new(Val::Px(250.0), Val::Px(65.0)),
margin: UiRect::all(Val::Px(20.0)),
justify_content: JustifyContent::Center,
align_items: AlignItems::Center,
..default()
};
let button_icon_style = Style {
size: Size::new(Val::Px(30.0), Val::Auto),
// This takes the icons out of the flexbox flow, to be positioned exactly
position_type: PositionType::Absolute,
// The icon will be close to the left border of the button
position: UiRect {
left: Val::Px(10.0),
right: Val::Auto,
top: Val::Auto,
bottom: Val::Auto,
},
..default()
};
let button_text_style = TextStyle {
font: font.clone(),
font_size: 40.0,
color: TEXT_COLOR,
};
commands
.spawn_bundle(NodeBundle {
style: Style {
margin: UiRect::all(Val::Auto),
flex_direction: FlexDirection::ColumnReverse,
align_items: AlignItems::Center,
..default()
},
color: Color::CRIMSON.into(),
..default()
})
.insert(OnMainMenuScreen)
.with_children(|parent| {
// Display the game name
parent.spawn_bundle(
TextBundle::from_section(
"Bevy Game Menu UI",
TextStyle {
font: font.clone(),
font_size: 80.0,
color: TEXT_COLOR,
},
)
.with_style(Style {
margin: UiRect::all(Val::Px(50.0)),
..default()
}),
);
// Display three buttons for each action available from the main menu:
// - new game
// - settings
// - quit
parent
.spawn_bundle(ButtonBundle {
style: button_style.clone(),
color: NORMAL_BUTTON.into(),
..default()
})
.insert(MenuButtonAction::Play)
.with_children(|parent| {
let icon = asset_server.load("textures/Game Icons/right.png");
parent.spawn_bundle(ImageBundle {
style: button_icon_style.clone(),
image: UiImage(icon),
..default()
});
parent.spawn_bundle(TextBundle::from_section(
"New Game",
button_text_style.clone(),
));
});
parent
.spawn_bundle(ButtonBundle {
style: button_style.clone(),
color: NORMAL_BUTTON.into(),
..default()
})
.insert(MenuButtonAction::Settings)
.with_children(|parent| {
let icon = asset_server.load("textures/Game Icons/wrench.png");
parent.spawn_bundle(ImageBundle {
style: button_icon_style.clone(),
image: UiImage(icon),
..default()
});
parent.spawn_bundle(TextBundle::from_section(
"Settings",
button_text_style.clone(),
));
});
parent
.spawn_bundle(ButtonBundle {
style: button_style,
color: NORMAL_BUTTON.into(),
..default()
})
.insert(MenuButtonAction::Quit)
.with_children(|parent| {
let icon = asset_server.load("textures/Game Icons/exitRight.png");
parent.spawn_bundle(ImageBundle {
style: button_icon_style,
image: UiImage(icon),
..default()
});
parent.spawn_bundle(TextBundle::from_section("Quit", button_text_style));
});
});
}
fn settings_menu_setup(mut commands: Commands, asset_server: Res<AssetServer>) {
let button_style = Style {
size: Size::new(Val::Px(200.0), Val::Px(65.0)),
margin: UiRect::all(Val::Px(20.0)),
justify_content: JustifyContent::Center,
align_items: AlignItems::Center,
..default()
};
let button_text_style = TextStyle {
font: asset_server.load("fonts/FiraSans-Bold.ttf"),
font_size: 40.0,
color: TEXT_COLOR,
};
commands
.spawn_bundle(NodeBundle {
style: Style {
margin: UiRect::all(Val::Auto),
flex_direction: FlexDirection::ColumnReverse,
align_items: AlignItems::Center,
..default()
},
color: Color::CRIMSON.into(),
..default()
})
.insert(OnSettingsMenuScreen)
.with_children(|parent| {
for (action, text) in [
(MenuButtonAction::SettingsDisplay, "Display"),
(MenuButtonAction::SettingsSound, "Sound"),
(MenuButtonAction::BackToMainMenu, "Back"),
] {
parent
.spawn_bundle(ButtonBundle {
style: button_style.clone(),
color: NORMAL_BUTTON.into(),
..default()
})
.insert(action)
.with_children(|parent| {
parent.spawn_bundle(TextBundle::from_section(
text,
button_text_style.clone(),
));
});
}
});
}
fn display_settings_menu_setup(
mut commands: Commands,
asset_server: Res<AssetServer>,
display_quality: Res<DisplayQuality>,
) {
let button_style = Style {
size: Size::new(Val::Px(200.0), Val::Px(65.0)),
margin: UiRect::all(Val::Px(20.0)),
justify_content: JustifyContent::Center,
align_items: AlignItems::Center,
..default()
};
let button_text_style = TextStyle {
font: asset_server.load("fonts/FiraSans-Bold.ttf"),
font_size: 40.0,
color: TEXT_COLOR,
};
commands
.spawn_bundle(NodeBundle {
style: Style {
margin: UiRect::all(Val::Auto),
flex_direction: FlexDirection::ColumnReverse,
align_items: AlignItems::Center,
..default()
},
color: Color::CRIMSON.into(),
..default()
})
.insert(OnDisplaySettingsMenuScreen)
.with_children(|parent| {
// Create a new `NodeBundle`, this time not setting its `flex_direction`. It will
// use the default value, `FlexDirection::Row`, from left to right.
parent
.spawn_bundle(NodeBundle {
style: Style {
align_items: AlignItems::Center,
..default()
},
color: Color::CRIMSON.into(),
..default()
})
.with_children(|parent| {
// Display a label for the current setting
parent.spawn_bundle(TextBundle::from_section(
"Display Quality",
button_text_style.clone(),
));
// Display a button for each possible value
for quality_setting in [
DisplayQuality::Low,
DisplayQuality::Medium,
DisplayQuality::High,
] {
let mut entity = parent.spawn_bundle(ButtonBundle {
style: Style {
size: Size::new(Val::Px(150.0), Val::Px(65.0)),
..button_style.clone()
},
color: NORMAL_BUTTON.into(),
..default()
});
entity.insert(quality_setting).with_children(|parent| {
parent.spawn_bundle(TextBundle::from_section(
format!("{quality_setting:?}"),
button_text_style.clone(),
));
});
if *display_quality == quality_setting {
entity.insert(SelectedOption);
}
}
});
// Display the back button to return to the settings screen
parent
.spawn_bundle(ButtonBundle {
style: button_style,
color: NORMAL_BUTTON.into(),
..default()
})
.insert(MenuButtonAction::BackToSettings)
.with_children(|parent| {
parent.spawn_bundle(TextBundle::from_section("Back", button_text_style));
});
});
}
fn sound_settings_menu_setup(
mut commands: Commands,
asset_server: Res<AssetServer>,
volume: Res<Volume>,
) {
let button_style = Style {
size: Size::new(Val::Px(200.0), Val::Px(65.0)),
margin: UiRect::all(Val::Px(20.0)),
justify_content: JustifyContent::Center,
align_items: AlignItems::Center,
..default()
};
let button_text_style = TextStyle {
font: asset_server.load("fonts/FiraSans-Bold.ttf"),
font_size: 40.0,
color: TEXT_COLOR,
};
commands
.spawn_bundle(NodeBundle {
style: Style {
margin: UiRect::all(Val::Auto),
flex_direction: FlexDirection::ColumnReverse,
align_items: AlignItems::Center,
..default()
},
color: Color::CRIMSON.into(),
..default()
})
.insert(OnSoundSettingsMenuScreen)
.with_children(|parent| {
parent
.spawn_bundle(NodeBundle {
style: Style {
align_items: AlignItems::Center,
..default()
},
color: Color::CRIMSON.into(),
..default()
})
.with_children(|parent| {
parent.spawn_bundle(TextBundle::from_section(
"Volume",
button_text_style.clone(),
));
for volume_setting in [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] {
let mut entity = parent.spawn_bundle(ButtonBundle {
style: Style {
size: Size::new(Val::Px(30.0), Val::Px(65.0)),
..button_style.clone()
},
color: NORMAL_BUTTON.into(),
..default()
});
entity.insert(Volume(volume_setting));
if *volume == Volume(volume_setting) {
entity.insert(SelectedOption);
}
}
});
parent
.spawn_bundle(ButtonBundle {
style: button_style,
color: NORMAL_BUTTON.into(),
..default()
})
.insert(MenuButtonAction::BackToSettings)
.with_children(|parent| {
parent.spawn_bundle(TextBundle::from_section("Back", button_text_style));
});
});
}
fn menu_action(
interaction_query: Query<
(&Interaction, &MenuButtonAction),
(Changed<Interaction>, With<Button>),
>,
mut app_exit_events: EventWriter<AppExit>,
mut menu_state: ResMut<State<MenuState>>,
mut game_state: ResMut<State<GameState>>,
) {
for (interaction, menu_button_action) in &interaction_query {
if *interaction == Interaction::Clicked {
match menu_button_action {
MenuButtonAction::Quit => app_exit_events.send(AppExit),
MenuButtonAction::Play => {
game_state.set(GameState::Game).unwrap();
menu_state.set(MenuState::Disabled).unwrap();
}
MenuButtonAction::Settings => menu_state.set(MenuState::Settings).unwrap(),
MenuButtonAction::SettingsDisplay => {
menu_state.set(MenuState::SettingsDisplay).unwrap();
}
MenuButtonAction::SettingsSound => {
menu_state.set(MenuState::SettingsSound).unwrap();
}
MenuButtonAction::BackToMainMenu => menu_state.set(MenuState::Main).unwrap(),
MenuButtonAction::BackToSettings => {
menu_state.set(MenuState::Settings).unwrap();
}
}
}
}
}
}
// Generic system that takes a component as a parameter, and will despawn all entities with that component
fn despawn_screen<T: Component>(to_despawn: Query<Entity, With<T>>, mut commands: Commands) {
for entity in &to_despawn {
commands.entity(entity).despawn_recursive();
}
}