bevy_pbr 0.16.0-rc.4 - Panic on despawn of a Mesh that was/is in PointLight range outside of Camera view

[dekirisu]

Bevy version

bevy 0.16.0-rc.4

What you did

I'm not quite sure what the minimal setup for this is, but I could create an always crashing setup:

• A PointLight with shadow_enabled
• A Mesh with NoFrustumCulling
• A Camera moving away from the light

Then: Despawning the mesh after the camera moved some distance away.

Minimal code:

use bevy::{prelude::*, render::view::NoFrustumCulling};

const CAM_Y: f32 = 0.;
const ZOOM:  f32 = 30.;
const SPEED: f32 = 30.;

fn main(){
    let mut app = App::new();
    app .add_plugins(DefaultPlugins)
        .add_systems(Startup,startup)
        .add_systems(Update,( move_camera, despawn ))
        .run();
}

fn startup(
    mut cmd: Commands,
    mut ass: ResMut<Assets<Mesh>>,
    mut ase: ResMut<Assets<StandardMaterial>>
){
    cmd.spawn((
        Transform::from_xyz(0.,CAM_Y,ZOOM),
        Camera3d::default(),
    ));
     cmd.spawn((
        Mesh3d(ass.add(Cuboid::new(1.,1.,1.))),
        MeshMaterial3d(ase.add(Color::srgb(1.,0.,0.))),
        NoFrustumCulling
    ));
    cmd.spawn(PointLight{
         shadows_enabled: true,
         ..default()
     });
}

fn move_camera(
    mut query: Query<(&mut Transform,Has<Camera>),With<Camera>>,
    time: Res<Time>,
){
    for (mut t,_) in &mut query {
        t.translation.y += time.delta_secs() * SPEED;
    }
}

// despawn after 2 seconds
fn despawn(
    mut cmd: Commands,
    query: Query<Entity,With<Mesh3d>>,
    time: Res<Time>,
    mut delay: Local<f32>
){
    *delay += time.delta_secs();
    if *delay < 2. {return}
    for e in &query {
        cmd.entity(e).despawn();
    }
}

What went wrong

It always crashes here (on linux 6.13.8-arch1-1) :

thread 'Compute Task Pool (15)' panicked at ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bevy_pbr-0.16.0-rc.4/src/render/light.rs:1820:84:
called `Option::unwrap()` on a `None` value
Encountered a panic in system `bevy_pbr::render::light::specialize_shadows<bevy_pbr::pbr_material::StandardMaterial>`!

Additional information

• This DOES panic, even if the Mesh is moved far away from the light before the despawn

  • e.g.: after 1 sec: move mesh to Y:1000. | after 2 secs: despawn | => panic

• This DOESN'T panic when the camera is moving slower or is zoomed out more

  • e.g. set SPEED=15.; or ZOOM=200.;

• This DOESN'T panic when the light was never 'in view' of the Camera

  • e.g. set CAM_Y=50.;

• This DOESN'T panic when the Mesh doesn't have NoFrustumCulling

• This DIDN'T panic in bevy_pbr 0.16.0-rc.3

I believe there are more setups where this happens even without using NoFrustumCulling, but that's the only minimal one I could come up with.

Note: The panic is the same as in #18809 and may be related.