Stress Tests / Many Glyphs

Back to examples View in GitHub

Support Warning

WebGPU is currently only supported on Chrome starting with version 113, and only on desktop. If they don't work on your configuration, you can check the WebGL2 examples here.

//! Simple text rendering benchmark.
//!
//! Creates a text block with a single span containing `100_000` glyphs,
//! and renders it with the UI in a white color and with Text2d in a red color.
//!
//! To recompute all text each frame run
//! `cargo run --example many_glyphs --release recompute-text`
use bevy::{
    color::palettes::basic::RED,
    diagnostic::{FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
    prelude::*,
    text::{LineBreak, TextBounds},
    window::{PresentMode, WindowResolution},
    winit::{UpdateMode, WinitSettings},
};

fn main() {
    let mut app = App::new();
    app.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,
        LogDiagnosticsPlugin::default(),
    ))
    .insert_resource(WinitSettings {
        focused_mode: UpdateMode::Continuous,
        unfocused_mode: UpdateMode::Continuous,
    })
    .add_systems(Startup, setup);

    if std::env::args().any(|arg| arg == "recompute-text") {
        app.add_systems(Update, force_text_recomputation);
    }

    app.run();
}

fn setup(mut commands: Commands) {
    warn!(include_str!("warning_string.txt"));

    commands.spawn(Camera2d);
    let text_string = "0123456789".repeat(10_000);
    let text_font = TextFont {
        font_size: 4.,
        ..Default::default()
    };
    let text_block = TextLayout {
        justify: JustifyText::Left,
        linebreak: LineBreak::AnyCharacter,
    };

    commands
        .spawn(Node {
            width: Val::Percent(100.),
            align_items: AlignItems::Center,
            justify_content: JustifyContent::Center,
            ..default()
        })
        .with_children(|commands| {
            commands
                .spawn(Node {
                    width: Val::Px(1000.),
                    ..Default::default()
                })
                .with_child((Text(text_string.clone()), text_font.clone(), text_block));
        });

    commands.spawn((
        Text2d::new(text_string),
        TextColor(RED.into()),
        bevy::sprite::Anchor::Center,
        TextBounds::new_horizontal(1000.),
        text_block,
    ));
}

fn force_text_recomputation(mut text_query: Query<&mut TextLayout>) {
    for mut block in &mut text_query {
        block.set_changed();
    }
}