Stress Tests / Many Glyphs

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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.
Support for WebGPU in Bevy hasn't been released yet, this example has been compiled using the main branch.

//! Simple text rendering benchmark.
//!
//! Creates a `Text` with a single `TextSection` 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::{
    diagnostic::{FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
    prelude::*,
    text::{BreakLineOn, Text2dBounds},
    window::{PresentMode, WindowPlugin},
};

fn main() {
    let mut app = App::new();
    app.add_plugins(DefaultPlugins.set(WindowPlugin {
        primary_window: Some(Window {
            present_mode: PresentMode::AutoNoVsync,
            ..default()
        }),
        ..default()
    }))
    .add_plugin(FrameTimeDiagnosticsPlugin)
    .add_plugin(LogDiagnosticsPlugin::default())
    .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(Camera2dBundle::default());
    let mut text = Text {
        sections: vec![TextSection {
            value: "0123456789".repeat(10_000),
            style: TextStyle {
                font_size: 4.,
                color: Color::WHITE,
                ..default()
            },
        }],
        alignment: TextAlignment::Left,
        linebreak_behavior: BreakLineOn::AnyCharacter,
    };

    commands
        .spawn(NodeBundle {
            style: Style {
                flex_basis: Val::Percent(100.),
                align_items: AlignItems::Center,
                justify_content: JustifyContent::Center,
                ..default()
            },
            ..default()
        })
        .with_children(|commands| {
            commands.spawn(TextBundle {
                text: text.clone(),
                style: Style {
                    width: Val::Px(1000.),
                    ..Default::default()
                },
                ..Default::default()
            });
        });

    text.sections[0].style.color = Color::RED;

    commands.spawn(Text2dBundle {
        text,
        text_anchor: bevy::sprite::Anchor::Center,
        text_2d_bounds: Text2dBounds {
            size: Vec2::new(1000., f32::INFINITY),
        },
        ..Default::default()
    });
}

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