Lightmap is not updating

[kirillsurkov]

Bevy version

0.16.1

[Optional] Relevant system information

AdapterInfo { name: "NVIDIA RTX A3000 Laptop GPU", vendor: 4318, device: 9400, device_type: DiscreteGpu, driver: "NVIDIA", driver_info: "566.24", backend: Vulkan }

What you did

I tried to run this code:

use bevy::{
    asset::RenderAssetUsages,
    pbr::Lightmap,
    prelude::*,
    render::render_resource::{Extent3d, TextureDimension, TextureFormat},
};

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

fn setup(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    mut images: ResMut<Assets<Image>>,
) {
    let mut mesh: Mesh = Plane3d::new(Vec3::Y, 5.0 * Vec2::ONE).into();
    let uv_0 = mesh.attribute(Mesh::ATTRIBUTE_UV_0).unwrap().clone();
    mesh.insert_attribute(Mesh::ATTRIBUTE_UV_1, uv_0);

    let image = Image::new_fill(
        Extent3d {
            width: 1,
            height: 1,
            ..Default::default()
        },
        TextureDimension::D2,
        &[255, 255, 255, 255],
        TextureFormat::bevy_default(),
        RenderAssetUsages::all(),
    );

    commands.spawn((
        Mesh3d(meshes.add(mesh)),
        MeshMaterial3d(materials.add(StandardMaterial {
            lightmap_exposure: 250.0,
            ..Default::default()
        })),
        Transform::default(),
        Lightmap {
            image: images.add(image),
            ..Default::default()
        },
    ));

    commands.spawn((
        Camera3d::default(),
        Transform::from_xyz(-2.5, 4.5, 9.0).looking_at(Vec3::ZERO, Vec3::Y),
    ));
}

fn update_lightmap(
    lightmap: Single<&Lightmap>,
    time: Res<Time>,
    mut images: ResMut<Assets<Image>>,
) {
    let image = images.get_mut(&lightmap.image).unwrap();
    let brightness = time.elapsed_secs().sin() * 0.5 + 0.5;
    image
        .set_color_at(0, 0, Color::srgba(brightness, brightness, brightness, 1.0))
        .unwrap();
}

What went wrong

Plane lighting isn't updating