Bevy 3D lighting

When to use

Load this when a 3D scene needs lights. Materials stay on bevy-3d-materials. Spawn light entities; clustering and shadow extraction stay engine-owned.

ECS shape

• Module: bevy::light says it provides directional, point, and spot lights, plus light probes, atmosphere, volumetrics, and shadow configuration.
• Feature: bevy_light is described the same way on the crate feature list.
• PBR page names: DirectionalLightViewEntities, ExtractedDirectionalLight, ExtractedPointLight, ExtractedRectLight, GpuClusteredLight (point, spot, or rectangle), DistanceFog, LightProbePlugin, ContactShadows.
• Systems: light clustering and extraction are engine-owned. Gameplay only spawns light entities.

Light choice

Need	Spawn
Sun	DirectionalLight plus CascadeShadowConfig on one entity.
Local omni	PointLight (intensity in lumens, range in meters).
Cone	SpotLight with inner_angle and outer_angle in radians.
Distance haze	DistanceFog on the camera entity.
Local image-based lighting	LightProbe with EnvironmentMapLight cubemap handles.

bevy_solari is the experimental raytraced-lighting Cargo feature. These examples use the raster lights in bevy::light.

[dependencies]
bevy = "0.20"

use bevy::light::{
    CascadeShadowConfig, CascadeShadowConfigBuilder, DirectionalLightShadowMap, SunDisk,
};

fn spawn_sun(mut commands: Commands) {
    commands.insert_resource(DirectionalLightShadowMap { size: 4096 });
    let cascades: CascadeShadowConfig = CascadeShadowConfigBuilder {
        num_cascades: 4,
        minimum_distance: 0.1,
        first_cascade_far_bound: 10.0,
        maximum_distance: 500.0,
        overlap_proportion: 0.2,
    }
    .into();
    commands.spawn((
        DirectionalLight {
            illuminance: 10_000.0,
            shadow_maps_enabled: true,
            shadow_depth_bias: DirectionalLight::DEFAULT_SHADOW_DEPTH_BIAS,
            shadow_normal_bias: DirectionalLight::DEFAULT_SHADOW_NORMAL_BIAS,
            color: Color::srgb(1.0, 0.96, 0.9),
            ..default()
        },
        cascades,
        SunDisk::EARTH,
        Transform::from_rotation(Quat::from_euler(EulerRot::XYZ, -0.8, 0.4, 0.0)),
    ));
}

pub struct SunPlugin;

impl Plugin for SunPlugin {
    fn build(&self, app: &mut App) {
        app.add_systems(Startup, spawn_sun);
    }
}

fn spawn_local_lights(mut commands: Commands) {
    commands.spawn((
        PointLight {
            intensity: 800.0,
            range: 8.0,
            radius: 0.1,
            shadow_maps_enabled: false,
            color: Color::srgb(1.0, 0.65, 0.3),
            ..default()
        },
        Transform::from_xyz(2.0, 1.5, 0.0),
    ));
    commands.spawn((
        SpotLight {
            intensity: 4_000.0,
            range: 18.0,
            inner_angle: 0.2,
            outer_angle: 0.45,
            shadow_maps_enabled: true,
            color: Color::WHITE,
            ..default()
        },
        Transform::from_xyz(0.0, 2.2, 1.0).looking_at(Vec3::ZERO, Vec3::Y),
    ));
}

fn spawn_fog_camera(mut commands: Commands) {
    commands.spawn((
        Camera3d::default(),
        DistanceFog {
            color: Color::srgb(0.65, 0.7, 0.78),
            directional_light_color: Color::srgb(1.0, 0.9, 0.7),
            directional_light_exponent: 8.0,
            falloff: FogFalloff::Linear {
                start: 20.0,
                end: 90.0,
            },
        },
        Transform::from_xyz(0.0, 2.0, 10.0).looking_at(Vec3::ZERO, Vec3::Y),
    ));
}

fn orbit_sun(time: Res<Time>, mut suns: Query<&mut Transform, With<DirectionalLight>>) {
    for mut transform in &mut suns {
        transform.rotation = Quat::from_euler(
            EulerRot::XYZ,
            -std::f32::consts::FRAC_PI_2 + time.elapsed_secs() * 0.04,
            0.35,
            0.0,
        );
    }
}

fn keep_nearest_point_shadows(
    camera: Query<&GlobalTransform, With<Camera3d>>,
    mut lights: Query<(&GlobalTransform, &mut PointLight)>,
) {
    let Ok(view) = camera.single() else {
        return;
    };
    let origin = view.translation();
    let mut ranked: Vec<(f32, Mut<PointLight>)> = lights
        .iter_mut()
        .map(|(transform, light)| (transform.translation().distance(origin), light))
        .collect();
    ranked.sort_by(|a, b| a.0.total_cmp(&b.0));
    for (index, (_, light)) in ranked.iter_mut().enumerate() {
        light.shadow_maps_enabled = index < 4;
    }
}

pub struct LightingPlugin;

impl Plugin for LightingPlugin {
    fn build(&self, app: &mut App) {
        app.add_systems(Startup, (spawn_local_lights, spawn_fog_camera))
            .add_systems(Update, (orbit_sun, keep_nearest_point_shadows).chain());
    }
}

Expert Knowledge Delta

Target: Bevy 0.20+.

Core ECS types: Component, Resource, Query, Commands, Startup, Update, Fixed / FixedMain (bevy::time), .chain(), Plugin, DefaultPlugins, MinimalPlugins. Messages and observers are an ownership slot. See bevy-events-messaging for their APIs. Systems run in parallel unless .chain() orders the ones that conflict.

Who owns state

Piece	Owner	Who may mutate	Schedule
Data on one entity	Component	One system via Query	Update or FixedMain
One value for the whole app	Resource	One system	Startup to insert, then the schedule that reads it
Spawn	Commands	The spawning system	Startup for the initial world; later schedules for runtime spawn
Order that must not race	.chain()	The chained systems only	Same schedule
Plugin boundary	Plugin	build registers systems and resources	Before the app runs

Borrow rule: two systems that both mutably query the same component must be ordered (.chain()) or split so only one writes. Unrelated systems stay parallel. That is the ECS page rule, not a guess at a system-set API.

Decision

If you need	Do this	Do not
Per-entity data	Component + Query	One script that owns the whole actor
App-wide config or clock	Resource	Copy the value onto every entity
Stable simulation step	FixedMain and the Fixed clock	Tie simulation to raw frame Update
Startup spawn	Commands in Startup	Spawn from a render system
Cross-system notice that is not shared state	Message or observer slot in bevy-events-messaging	A new event type invented in this file
An API outside the documented set	Check the official docs first	A made-up crate or API

Load references/ecs-ownership.md for the ownership table.

NEVER

• Do not pin /0.20.0/ in docs URLs. WHY: links stay on latest; the 0.20 target is stated once in prose.

• Do not mutably query the same component from two unordered systems. WHY: the schedule runs systems in parallel unless .chain() orders them.

• Do not invent a physics, navigation, networking, or XR crate here. WHY: this skill only names documented Bevy crates and modules.

• No light-node types from another engine. WHY: a ported node API will not cluster, extract, or cast cascades the way bevy::light does.

• No foreign engine types in Bevy code. WHY: the schedule, queries, and light components only exist on Bevy entities.

• No invented APIs or unnamed third-party crates as the chosen solver. WHY: Bevy code stays idiomatic ECS and uses only documented Bevy APIs.

Reference

The library pin on bevy-master stays 0.20.0. Load references/ecs-ownership.md when deciding whether a light value is a component or a resource. Do not load it for material authoring.

Official Documentation

• Assets - Official asset catalog. No third-party crate was selected.
• Examples - Example tree on the latest branch.
• ECS - Component, systems, Query, Startup, Update, and .chain().
• Plugins - Plugin, DefaultPlugins, MinimalPlugins, and add_plugins.

Related Skills

Prerequisites

• bevy-master - Hub and schedules.
• bevy-ecs-composition - Components and systems.
• bevy-3d-materials - Lit surfaces.
• bevy-camera-systems - Camera the lights affect.

Complements

• bevy-3d-world-building - Place light entities in a level.

Downstream / consumers

• None yet.

Master

• bevy-master - Bevy router.