# 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.
		
			
				
	
	
		
			91 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			91 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! Text pipeline benchmark.
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//!
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//! Continuously recomputes a large block of text with 100 text spans.
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use bevy::{
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    color::palettes::basic::{BLUE, YELLOW},
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    diagnostic::{FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
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    prelude::*,
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    text::{LineBreak, TextBounds},
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    window::{PresentMode, WindowResolution},
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    winit::{UpdateMode, WinitSettings},
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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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                    resolution: WindowResolution::new(1920.0, 1080.0)
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                        .with_scale_factor_override(1.0),
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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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            LogDiagnosticsPlugin::default(),
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        ))
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        .insert_resource(WinitSettings {
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            focused_mode: UpdateMode::Continuous,
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            unfocused_mode: UpdateMode::Continuous,
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        })
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        .add_systems(Startup, spawn)
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        .add_systems(Update, update_text_bounds)
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        .run();
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}
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fn spawn(mut commands: Commands, asset_server: Res<AssetServer>) {
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    warn!(include_str!("warning_string.txt"));
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    commands.spawn(Camera2d);
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    let make_spans = |i| {
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        [
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            (
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                TextSpan("text".repeat(i)),
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                TextFont {
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                    font: asset_server.load("fonts/FiraMono-Medium.ttf"),
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                    font_size: (4 + i % 10) as f32,
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                    ..Default::default()
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                },
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                TextColor(BLUE.into()),
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            ),
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            (
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                TextSpan("pipeline".repeat(i)),
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                TextFont {
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                    font: asset_server.load("fonts/FiraSans-Bold.ttf"),
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                    font_size: (4 + i % 11) as f32,
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                    ..default()
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                },
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                TextColor(YELLOW.into()),
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            ),
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        ]
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    };
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    let spans = (1..50).flat_map(|i| make_spans(i).into_iter());
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    commands
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        .spawn((
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            Text2d::default(),
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            TextLayout {
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                justify: JustifyText::Center,
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                linebreak: LineBreak::AnyCharacter,
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            },
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            TextBounds::default(),
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        ))
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        .with_children(|p| {
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            for span in spans {
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                p.spawn(span);
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            }
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        });
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}
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// changing the bounds of the text will cause a recomputation
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fn update_text_bounds(time: Res<Time>, mut text_bounds_query: Query<&mut TextBounds>) {
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    let width = (1. + ops::sin(time.elapsed_secs())) * 600.0;
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    for mut text_bounds in text_bounds_query.iter_mut() {
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        text_bounds.width = Some(width);
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    }
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}
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