bevy/examples/stress_tests/text_pipeline.rs
Rob Parrett f0047899d7
Allow users to customize history length in FrameTimeDiagnosticsPlugin (#17259)
# 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.
2025-01-12 18:18:14 +00:00

91 lines
2.7 KiB
Rust

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