2D Rendering / 2D Gizmos

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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.

//! This example demonstrates Bevy's immediate mode drawing API intended for visual debugging.

use std::f32::consts::PI;

use bevy::prelude::*;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup)
        .add_systems(Update, (system, update_config))
        .run();
}

fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
    commands.spawn(Camera2dBundle::default());
    // text
    commands.spawn(TextBundle::from_section(
        "Hold 'Left' or 'Right' to change the line width",
        TextStyle {
            font: asset_server.load("fonts/FiraMono-Medium.ttf"),
            font_size: 24.,
            color: Color::WHITE,
        },
    ));
}

fn system(mut gizmos: Gizmos, time: Res<Time>) {
    let sin = time.elapsed_seconds().sin() * 50.;
    gizmos.line_2d(Vec2::Y * -sin, Vec2::splat(-80.), Color::RED);
    gizmos.ray_2d(Vec2::Y * sin, Vec2::splat(80.), Color::GREEN);

    // Triangle
    gizmos.linestrip_gradient_2d([
        (Vec2::Y * 300., Color::BLUE),
        (Vec2::new(-255., -155.), Color::RED),
        (Vec2::new(255., -155.), Color::GREEN),
        (Vec2::Y * 300., Color::BLUE),
    ]);

    gizmos.rect_2d(
        Vec2::ZERO,
        time.elapsed_seconds() / 3.,
        Vec2::splat(300.),
        Color::BLACK,
    );

    // The circles have 32 line-segments by default.
    gizmos.circle_2d(Vec2::ZERO, 120., Color::BLACK);
    // You may want to increase this for larger circles.
    gizmos.circle_2d(Vec2::ZERO, 300., Color::NAVY).segments(64);

    // Arcs default amount of segments is linearly interpolated between
    // 1 and 32, using the arc length as scalar.
    gizmos.arc_2d(Vec2::ZERO, sin / 10., PI / 2., 350., Color::ORANGE_RED);
}

fn update_config(mut config: ResMut<GizmoConfig>, keyboard: Res<Input<KeyCode>>, time: Res<Time>) {
    if keyboard.pressed(KeyCode::Right) {
        config.line_width += 5. * time.delta_seconds();
    }
    if keyboard.pressed(KeyCode::Left) {
        config.line_width -= 5. * time.delta_seconds();
    }
}