Bevy Sky Gradient

A simple and beautiful procedural sky shader for the Bevy game engine.

Features

• Skybox: Everything is rendered using skyboxes. Supports gradient coloring, sun, stars, and auroras.
• Day-Night Cycle: Animate the sky from sunrise to sunset and through the night. You can easily configure the duration of the cycle.
• Procedural Sun: A sun that moves across the sky, synchronized with the day-night cycle, casting a directional light in your scene.
• Stars & Auroras: As night falls, stars and procedural auroras will light up the sky.
• Modular by Design: Enable or disable features you don't need. If you want a static sky, you can disable the day-night cycle. If you don't need auroras, you can remove them to save performance.
• Easy Customization: Modify sky parameters at runtime to change its appearance dynamically.

Quick Start

Add the bevy_sky_gradient crate to your Cargo.toml:

[dependencies]
bevy_sky_gradient = "0.2.0"

Then, add the SkyPlugin to your app and add the SkyboxMagnetTag to your camera.

use bevy::prelude::*;
use bevy_sky_gradient::prelude::*;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        // Add the SkyPlugin with all features enabled
        .add_plugins(SkyPlugin::default())
        .add_systems(Startup, setup)
        .run();
}

fn setup(mut commands: Commands) {
    // Spawn a camera
    commands.spawn((
        Camera3dBundle {
            transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
            ..default()
        },
        // Add this tag to make the skybox follow the camera
        SkyboxMagnetTag,
    ));
}

Customization

bevy_sky_gradient is designed to be modular. You can easily enable, disable, or configure features using the SkyPlugin::builder().

SkyPlugin::builder()
  .set_sun_driver(SunDriverPlugin{
    sun_settings: SunSettings{ sun_color: vec4(1.0,1.0,0.0,1.0), ..default()}
    ..default()
  })
  .set_aurora(AuroraPlugin {
    aurora_settings: AuroraSettings {
      render_texture_percent: 0.25, // Render at 25% resolution
      ..default()
  },
  .set_cycle(SkyCyclePlugin::default())
  .set_gradient_driver(GradientDriverPlugin::default())
  .set_ambient_driver(AmbientDriverPlugin:::default())

}).build(),

Features Explained

• Sky Cycle (SkyCyclePlugin): This plugin introduces a timer that drives the day-night cycle. It controls the position of the sun and the color of the sky gradient. You can customize the length of the day, night, sunrise, and sunset via the SkyTimeSettings resource.

• Sun Driver (SunDriverPlugin): This plugin spawns a DirectionalLight entity and updates its position and intensity based on the time of day from the SkyCyclePlugin. It also updates the sun's appearance in the skybox shader.

• Aurora (AuroraPlugin): This plugin adds a beautiful procedural aurora effect to the night sky. The aurora is rendered to a separate texture for better performance and is then blended with the main skybox. You can adjust the render quality of the aurora via the AuroraSettings resource.

• Rendering to a Texture: For advanced use cases like screen-space fog or reflections, you can have the skybox render to a texture instead of directly to the screen. Use the .with_render_sky_to_texture() method on the SkyPluginBuilder.

Bevy support table

bevy	Bevy Sky Gradient
0.17	0.2.0
0.16	0.1.0

License

This project is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.