use std::{collections::VecDeque, time::Duration};
use bevy::{
color::palettes::css::*,
diagnostic::{DiagnosticsStore, FrameTimeDiagnosticsPlugin},
prelude::*,
ui::widget::TextUiWriter,
window::PresentMode,
};
fn main() {
App::new()
.add_plugins((
DefaultPlugins.set(WindowPlugin {
primary_window: Some(Window {
present_mode: PresentMode::AutoNoVsync,
..default()
}),
..default()
}),
FrameTimeDiagnosticsPlugin,
))
.add_systems(Startup, infotext_system)
.add_systems(Update, change_text_system)
.run();
}
#[derive(Component)]
struct TextChanges;
fn infotext_system(mut commands: Commands, asset_server: Res<AssetServer>) {
let font = asset_server.load("fonts/FiraSans-Bold.ttf");
let background_color = MAROON.into();
commands.spawn(Camera2d);
let root_uinode = commands
.spawn(Node {
width: Val::Percent(100.),
height: Val::Percent(100.),
justify_content: JustifyContent::SpaceBetween,
..default()
})
.id();
let left_column = commands
.spawn(Node {
flex_direction: FlexDirection::Column,
justify_content: JustifyContent::SpaceBetween,
align_items: AlignItems::Start,
flex_grow: 1.,
margin: UiRect::axes(Val::Px(15.), Val::Px(5.)),
..default()
}).with_children(|builder| {
builder.spawn((
Text::new("This is\ntext with\nline breaks\nin the top left."),
TextFont {
font: font.clone(),
font_size: 25.0,
..default()
},
BackgroundColor(background_color)
));
builder.spawn((
Text::new(
"This text is right-justified. The `JustifyText` component controls the horizontal alignment of the lines of multi-line text relative to each other, and does not affect the text node's position in the UI layout.",
),
TextFont {
font: font.clone(),
font_size: 25.0,
..default()
},
TextColor(YELLOW.into()),
TextLayout::new_with_justify(JustifyText::Right),
Node {
max_width: Val::Px(300.),
..default()
},
BackgroundColor(background_color)
));
builder.spawn((
Text::new(
"This\ntext has\nline breaks and also a set width in the bottom left."),
TextFont {
font: font.clone(),
font_size: 25.0,
..default()
},
Node {
max_width: Val::Px(300.),
..default()
},
BackgroundColor(background_color)
)
);
}).id();
let right_column = commands
.spawn(Node {
flex_direction: FlexDirection::Column,
justify_content: JustifyContent::SpaceBetween,
align_items: AlignItems::End,
flex_grow: 1.,
margin: UiRect::axes(Val::Px(15.), Val::Px(5.)),
..default()
})
.with_children(|builder| {
builder.spawn((
Text::new("This text is very long, has a limited width, is center-justified, is positioned in the top right and is also colored pink."),
TextFont {
font: font.clone(),
font_size: 33.0,
..default()
},
TextColor(Color::srgb(0.8, 0.2, 0.7)),
TextLayout::new_with_justify(JustifyText::Center),
Node {
max_width: Val::Px(400.),
..default()
},
BackgroundColor(background_color),
));
builder.spawn((
Text::new("This text is left-justified and is vertically positioned to distribute the empty space equally above and below it."),
TextFont {
font: font.clone(),
font_size: 29.0,
..default()
},
TextColor(YELLOW.into()),
TextLayout::new_with_justify(JustifyText::Left),
Node {
max_width: Val::Px(300.),
..default()
},
BackgroundColor(background_color),
));
builder.spawn((
Text::new("This text is fully justified and is positioned in the same way."),
TextFont {
font: font.clone(),
font_size: 29.0,
..default()
},
TextLayout::new_with_justify(JustifyText::Justified),
TextColor(GREEN_YELLOW.into()),
Node {
max_width: Val::Px(300.),
..default()
},
BackgroundColor(background_color),
));
builder
.spawn((
Text::default(),
TextFont {
font: font.clone(),
font_size: 21.0,
..default()
},
TextChanges,
BackgroundColor(background_color),
))
.with_children(|p| {
p.spawn((
TextSpan::new("\nThis text changes in the bottom right"),
TextFont {
font: font.clone(),
font_size: 21.0,
..default()
},
));
p.spawn((
TextSpan::new(" this text has zero fontsize"),
TextFont {
font: font.clone(),
font_size: 0.0,
..default()
},
TextColor(BLUE.into()),
));
p.spawn((
TextSpan::new("\nThis text changes in the bottom right - "),
TextFont {
font: font.clone(),
font_size: 21.0,
..default()
},
TextColor(RED.into()),
));
p.spawn((
TextSpan::default(),
TextFont {
font: font.clone(),
font_size: 21.0,
..default()
},
TextColor(ORANGE_RED.into()),
));
p.spawn((
TextSpan::new(" fps, "),
TextFont {
font: font.clone(),
font_size: 10.0,
..default()
},
TextColor(YELLOW.into()),
));
p.spawn((
TextSpan::default(),
TextFont {
font: font.clone(),
font_size: 21.0,
..default()
},
TextColor(LIME.into()),
));
p.spawn((
TextSpan::new(" ms/frame"),
TextFont {
font: font.clone(),
font_size: 42.0,
..default()
},
TextColor(BLUE.into()),
));
p.spawn((
TextSpan::new(" this text has negative fontsize"),
TextFont {
font: font.clone(),
font_size: -42.0,
..default()
},
TextColor(BLUE.into()),
));
});
})
.id();
commands
.entity(root_uinode)
.add_children(&[left_column, right_column]);
}
fn change_text_system(
mut fps_history: Local<VecDeque<f64>>,
mut time_history: Local<VecDeque<Duration>>,
time: Res<Time>,
diagnostics: Res<DiagnosticsStore>,
query: Query<Entity, With<TextChanges>>,
mut writer: TextUiWriter,
) {
time_history.push_front(time.elapsed());
time_history.truncate(120);
let avg_fps = (time_history.len() as f64)
/ (time_history.front().copied().unwrap_or_default()
- time_history.back().copied().unwrap_or_default())
.as_secs_f64()
.max(0.0001);
fps_history.push_front(avg_fps);
fps_history.truncate(120);
let fps_variance = std_deviation(fps_history.make_contiguous()).unwrap_or_default();
for entity in &query {
let mut fps = 0.0;
if let Some(fps_diagnostic) = diagnostics.get(&FrameTimeDiagnosticsPlugin::FPS) {
if let Some(fps_smoothed) = fps_diagnostic.smoothed() {
fps = fps_smoothed;
}
}
let mut frame_time = time.delta_secs_f64();
if let Some(frame_time_diagnostic) =
diagnostics.get(&FrameTimeDiagnosticsPlugin::FRAME_TIME)
{
if let Some(frame_time_smoothed) = frame_time_diagnostic.smoothed() {
frame_time = frame_time_smoothed;
}
}
*writer.text(entity, 0) =
format!("{avg_fps:.1} avg fps, {fps_variance:.1} frametime variance",);
*writer.text(entity, 1) = format!(
"\nThis text changes in the bottom right - {fps:.1} fps, {frame_time:.3} ms/frame",
);
*writer.text(entity, 4) = format!("{fps:.1}");
*writer.text(entity, 6) = format!("{frame_time:.3}");
}
}
fn mean(data: &[f64]) -> Option<f64> {
let sum = data.iter().sum::<f64>();
let count = data.len();
match count {
positive if positive > 0 => Some(sum / count as f64),
_ => None,
}
}
fn std_deviation(data: &[f64]) -> Option<f64> {
match (mean(data), data.len()) {
(Some(data_mean), count) if count > 0 => {
let variance = data
.iter()
.map(|value| {
let diff = data_mean - *value;
diff * diff
})
.sum::<f64>()
/ count as f64;
Some(variance.sqrt())
}
_ => None,
}
}
