Fixes a crash when using deferred rendering but disabling the default
deferred lighting plugin.
# The Issue
The `ScreenSpaceReflectionsPlugin` references
`NodePbr::DeferredLightingPass`, which hasn't been added when
`PbrPlugin::add_default_deferred_lighting_plugin` is `false`.
This yields the following crash:
```
thread 'main' panicked at /Users/marius/Documents/dev/bevy/crates/bevy_render/src/render_graph/graph.rs:155:26:
InvalidNode(DeferredLightingPass)
stack backtrace:
0: rust_begin_unwind
at /rustc/90b35a6239c3d8bdabc530a6a0816f7ff89a0aaf/library/std/src/panicking.rs:665:5
1: core::panicking::panic_fmt
at /rustc/90b35a6239c3d8bdabc530a6a0816f7ff89a0aaf/library/core/src/panicking.rs:74:14
2: bevy_render::render_graph::graph::RenderGraph::add_node_edges
at /Users/marius/Documents/dev/bevy/crates/bevy_render/src/render_graph/graph.rs:155:26
3: <bevy_app::sub_app::SubApp as bevy_render::render_graph::app::RenderGraphApp>::add_render_graph_edges
at /Users/marius/Documents/dev/bevy/crates/bevy_render/src/render_graph/app.rs:66:13
4: <bevy_pbr::ssr::ScreenSpaceReflectionsPlugin as bevy_app::plugin::Plugin>::finish
at /Users/marius/Documents/dev/bevy/crates/bevy_pbr/src/ssr/mod.rs:234:9
5: bevy_app::app::App::finish
at /Users/marius/Documents/dev/bevy/crates/bevy_app/src/app.rs:255:13
6: bevy_winit::state::winit_runner
at /Users/marius/Documents/dev/bevy/crates/bevy_winit/src/state.rs:859:9
7: core::ops::function::FnOnce::call_once
at /Users/marius/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/function.rs:250:5
8: core::ops::function::FnOnce::call_once{{vtable.shim}}
at /Users/marius/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/function.rs:250:5
9: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
at /Users/marius/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/alloc/src/boxed.rs:2454:9
10: bevy_app::app::App::run
at /Users/marius/Documents/dev/bevy/crates/bevy_app/src/app.rs:184:9
11: bevy_deferred_test::main
at ./src/main.rs:9:5
12: core::ops::function::FnOnce::call_once
at /Users/marius/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/function.rs:250:5
```
### Minimal reproduction example:
```rust
use bevy::core_pipeline::prepass::{DeferredPrepass, DepthPrepass};
use bevy::pbr::{DefaultOpaqueRendererMethod, PbrPlugin, ScreenSpaceReflections};
use bevy::prelude::*;
fn main() {
App::new()
.add_plugins(DefaultPlugins.set(PbrPlugin {
add_default_deferred_lighting_plugin: false,
..default()
}))
.add_systems(Startup, setup)
.insert_resource(DefaultOpaqueRendererMethod::deferred())
.run();
}
/// set up a camera
fn setup(
mut commands: Commands
) {
// camera
commands.spawn((
Camera3d::default(),
Transform::from_xyz(-2.5, 4.5, 9.0).looking_at(Vec3::ZERO, Vec3::Y),
DepthPrepass,
DeferredPrepass,
ScreenSpaceReflections::default(),
));
}
```
# The Fix
When no node under the default lighting node's label exists, this label
isn't added to the SSR's graph node edges. It's good to keep the
SSRPlugin enabled, this way, users can plug in their own lighting
system, which I have successfully done on top of this PR.
# Workarounds
A current workaround for this issue is to re-use Bevy's
`NodePbr::DeferredLightingPass` as the label for your own custom
lighting pass node.
fcce3fb344