# 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.
		
			
				
	
	
		
			31 lines
		
	
	
		
			761 B
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			31 lines
		
	
	
		
			761 B
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! Shows how to disable/re-enable a Diagnostic during runtime
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use std::time::Duration;
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use bevy::{
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    diagnostic::{DiagnosticsStore, FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
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    prelude::*,
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    time::common_conditions::on_timer,
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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,
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            FrameTimeDiagnosticsPlugin::default(),
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            LogDiagnosticsPlugin::default(),
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        ))
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        .add_systems(
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            Update,
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            toggle.run_if(on_timer(Duration::from_secs_f32(10.0))),
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        )
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        .run();
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}
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fn toggle(mut store: ResMut<DiagnosticsStore>) {
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    for diag in store.iter_mut() {
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        info!("toggling diagnostic {}", diag.path());
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        diag.is_enabled = !diag.is_enabled;
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    }
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}
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