f0047899d7
# Objective I have an application where I'd like to measure average frame rate over the entire life of the application, and it would be handy if I could just configure this on the existing `FrameTimeDiagnosticsPlugin`. Probably fixes #10948? ## Solution Add `max_history_length` to `FrameTimeDiagnosticsPlugin`, and because `smoothing_factor` seems to be based on history length, add that too. ## Discussion I'm not totally sure that `DEFAULT_MAX_HISTORY_LENGTH` is a great default for `FrameTimeDiagnosticsPlugin` (or any diagnostic?). That's 1/3 of a second at typical game frame rates. Moreover, the default print interval for `LogDiagnosticsPlugin` is 1 second. So when the two are combined, you are printing the average over the last third of the duration between now and the previous print, which seems a bit wonky. (related: #11429) I'm pretty sure this default value discussed and the current value wasn't totally arbitrary though. Maybe it would be nice for `Diagnostic` to have a `with_max_history_length_and_also_calculate_a_good_default_smoothing_factor` method? And then make an explicit smoothing factor in `FrameTimeDiagnosticsPlugin` optional? Or add a `new(max_history_length: usize)` method to `FrameTimeDiagnosticsPlugin` that sets a reasonable default `smoothing_factor`? edit: This one seems like a no-brainer, doing it. ## Alternatives It's really easy to roll your own `FrameTimeDiagnosticsPlugin`, but that might not be super interoperable with, for example, third party FPS overlays. Still, might be the right call. ## Testing `cargo run --example many_sprites` (modified to use a custom `max_history_length`) ## Migration Guide `FrameTimeDiagnosticsPlugin` now contains two fields. Use `FrameTimeDiagnosticsPlugin::default()` to match Bevy's previous behavior or, for example, `FrameTimeDiagnosticsPlugin::new(60)` to configure it.
325 lines
11 KiB
Rust
325 lines
11 KiB
Rust
//! Shows various text layout options.
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use std::{collections::VecDeque, time::Duration};
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use bevy::{
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color::palettes::css::*,
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diagnostic::{DiagnosticsStore, FrameTimeDiagnosticsPlugin},
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prelude::*,
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ui::widget::TextUiWriter,
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window::PresentMode,
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};
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fn main() {
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App::new()
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.add_plugins((
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DefaultPlugins.set(WindowPlugin {
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primary_window: Some(Window {
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present_mode: PresentMode::AutoNoVsync,
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..default()
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}),
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..default()
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}),
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FrameTimeDiagnosticsPlugin::default(),
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))
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.add_systems(Startup, infotext_system)
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.add_systems(Update, change_text_system)
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.run();
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}
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#[derive(Component)]
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struct TextChanges;
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fn infotext_system(mut commands: Commands, asset_server: Res<AssetServer>) {
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let font = asset_server.load("fonts/FiraSans-Bold.ttf");
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let background_color = MAROON.into();
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commands.spawn(Camera2d);
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let root_uinode = commands
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.spawn(Node {
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width: Val::Percent(100.),
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height: Val::Percent(100.),
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justify_content: JustifyContent::SpaceBetween,
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..default()
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})
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.id();
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let left_column = commands
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.spawn(Node {
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flex_direction: FlexDirection::Column,
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justify_content: JustifyContent::SpaceBetween,
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align_items: AlignItems::Start,
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flex_grow: 1.,
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margin: UiRect::axes(Val::Px(15.), Val::Px(5.)),
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..default()
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}).with_children(|builder| {
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builder.spawn((
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Text::new("This is\ntext with\nline breaks\nin the top left."),
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TextFont {
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font: font.clone(),
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font_size: 25.0,
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..default()
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},
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BackgroundColor(background_color)
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));
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builder.spawn((
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Text::new(
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"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.",
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),
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TextFont {
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font: font.clone(),
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font_size: 25.0,
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..default()
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},
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TextColor(YELLOW.into()),
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TextLayout::new_with_justify(JustifyText::Right),
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Node {
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max_width: Val::Px(300.),
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..default()
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},
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BackgroundColor(background_color)
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));
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builder.spawn((
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Text::new(
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"This\ntext has\nline breaks and also a set width in the bottom left."),
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TextFont {
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font: font.clone(),
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font_size: 25.0,
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..default()
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},
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Node {
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max_width: Val::Px(300.),
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..default()
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},
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BackgroundColor(background_color)
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)
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);
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}).id();
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let right_column = commands
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.spawn(Node {
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flex_direction: FlexDirection::Column,
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justify_content: JustifyContent::SpaceBetween,
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align_items: AlignItems::End,
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flex_grow: 1.,
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margin: UiRect::axes(Val::Px(15.), Val::Px(5.)),
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..default()
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})
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.with_children(|builder| {
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builder.spawn((
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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."),
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TextFont {
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font: font.clone(),
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font_size: 33.0,
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..default()
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},
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TextColor(Color::srgb(0.8, 0.2, 0.7)),
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TextLayout::new_with_justify(JustifyText::Center),
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Node {
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max_width: Val::Px(400.),
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..default()
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},
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BackgroundColor(background_color),
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));
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builder.spawn((
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Text::new("This text is left-justified and is vertically positioned to distribute the empty space equally above and below it."),
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TextFont {
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font: font.clone(),
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font_size: 29.0,
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..default()
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},
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TextColor(YELLOW.into()),
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TextLayout::new_with_justify(JustifyText::Left),
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Node {
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max_width: Val::Px(300.),
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..default()
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},
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BackgroundColor(background_color),
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));
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builder.spawn((
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Text::new("This text is fully justified and is positioned in the same way."),
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TextFont {
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font: font.clone(),
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font_size: 29.0,
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..default()
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},
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TextLayout::new_with_justify(JustifyText::Justified),
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TextColor(GREEN_YELLOW.into()),
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Node {
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max_width: Val::Px(300.),
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..default()
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},
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BackgroundColor(background_color),
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));
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builder
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.spawn((
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Text::default(),
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TextFont {
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font: font.clone(),
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font_size: 21.0,
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..default()
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},
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TextChanges,
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BackgroundColor(background_color),
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))
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.with_children(|p| {
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p.spawn((
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TextSpan::new("\nThis text changes in the bottom right"),
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TextFont {
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font: font.clone(),
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font_size: 21.0,
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..default()
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},
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));
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p.spawn((
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TextSpan::new(" this text has zero fontsize"),
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TextFont {
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font: font.clone(),
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font_size: 0.0,
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..default()
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},
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TextColor(BLUE.into()),
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));
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p.spawn((
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TextSpan::new("\nThis text changes in the bottom right - "),
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TextFont {
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font: font.clone(),
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font_size: 21.0,
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..default()
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},
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TextColor(RED.into()),
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));
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p.spawn((
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TextSpan::default(),
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TextFont {
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font: font.clone(),
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font_size: 21.0,
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..default()
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},
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TextColor(ORANGE_RED.into()),
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));
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p.spawn((
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TextSpan::new(" fps, "),
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TextFont {
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font: font.clone(),
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font_size: 10.0,
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..default()
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},
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TextColor(YELLOW.into()),
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));
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p.spawn((
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TextSpan::default(),
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TextFont {
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font: font.clone(),
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font_size: 21.0,
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..default()
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},
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TextColor(LIME.into()),
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));
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p.spawn((
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TextSpan::new(" ms/frame"),
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TextFont {
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font: font.clone(),
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font_size: 42.0,
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..default()
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},
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TextColor(BLUE.into()),
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));
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p.spawn((
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TextSpan::new(" this text has negative fontsize"),
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TextFont {
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font: font.clone(),
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font_size: -42.0,
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..default()
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},
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TextColor(BLUE.into()),
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));
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});
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})
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.id();
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commands
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.entity(root_uinode)
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.add_children(&[left_column, right_column]);
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}
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fn change_text_system(
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mut fps_history: Local<VecDeque<f64>>,
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mut time_history: Local<VecDeque<Duration>>,
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time: Res<Time>,
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diagnostics: Res<DiagnosticsStore>,
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query: Query<Entity, With<TextChanges>>,
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mut writer: TextUiWriter,
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) {
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time_history.push_front(time.elapsed());
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time_history.truncate(120);
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let avg_fps = (time_history.len() as f64)
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/ (time_history.front().copied().unwrap_or_default()
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- time_history.back().copied().unwrap_or_default())
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.as_secs_f64()
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.max(0.0001);
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fps_history.push_front(avg_fps);
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fps_history.truncate(120);
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let fps_variance = std_deviation(fps_history.make_contiguous()).unwrap_or_default();
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for entity in &query {
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let mut fps = 0.0;
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if let Some(fps_diagnostic) = diagnostics.get(&FrameTimeDiagnosticsPlugin::FPS) {
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if let Some(fps_smoothed) = fps_diagnostic.smoothed() {
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fps = fps_smoothed;
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}
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}
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let mut frame_time = time.delta_secs_f64();
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if let Some(frame_time_diagnostic) =
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diagnostics.get(&FrameTimeDiagnosticsPlugin::FRAME_TIME)
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{
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if let Some(frame_time_smoothed) = frame_time_diagnostic.smoothed() {
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frame_time = frame_time_smoothed;
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}
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}
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*writer.text(entity, 0) =
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format!("{avg_fps:.1} avg fps, {fps_variance:.1} frametime variance",);
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*writer.text(entity, 1) = format!(
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"\nThis text changes in the bottom right - {fps:.1} fps, {frame_time:.3} ms/frame",
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);
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*writer.text(entity, 4) = format!("{fps:.1}");
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*writer.text(entity, 6) = format!("{frame_time:.3}");
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}
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}
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fn mean(data: &[f64]) -> Option<f64> {
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let sum = data.iter().sum::<f64>();
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let count = data.len();
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match count {
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positive if positive > 0 => Some(sum / count as f64),
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_ => None,
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}
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}
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fn std_deviation(data: &[f64]) -> Option<f64> {
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match (mean(data), data.len()) {
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(Some(data_mean), count) if count > 0 => {
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let variance = data
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.iter()
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.map(|value| {
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let diff = data_mean - *value;
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diff * diff
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})
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.sum::<f64>()
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/ count as f64;
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Some(variance.sqrt())
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}
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_ => None,
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}
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}
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