Bevy app with `pbr_transmission_textures` crashes on macOS/Metal after PCSS PR merge

[coreh]

Bevy version

417e6cc

Relevant system information

SystemInfo { os: "MacOS 15.0 ", kernel: "24.0.0", cpu: "Apple M1 Max", core_count: "10", memory: "32.0 GiB" }`
AdapterInfo { name: "Apple M1 Max", vendor: 0, device: 0, device_type: IntegratedGpu, driver: "", driver_info: "", backend: Metal }

What you did

cargo run --example 3d_scene --features pbr_transmission_textures

What went wrong

Resource limit exceeded: StageInfo { stage: Fragment, counters: ResourceData { buffers: 13, textures: 38, samplers: 17 }, pc_buffer: None, pc_limit: 0, sizes_buffer: Some(12), need_sizes_buffer: true, resources: {ResourceBinding { group: 0, binding: 0 }: BindTarget { buffer: Some(0), texture: None, sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 1 }: BindTarget { buffer: Some(1), texture: None, sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 2 }: BindTarget { buffer: None, texture: Some(0), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 3 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(0)), binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 4 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(1)), binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 5 }: BindTarget { buffer: None, texture: Some(1), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 6 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(2)), binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 7 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(3)), binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 8 }: BindTarget { buffer: Some(2), texture: None, sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 9 }: BindTarget { buffer: Some(3), texture: None, sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 10 }: BindTarget { buffer: Some(4), texture: None, sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 11 }: BindTarget { buffer: Some(5), texture: None, sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 12 }: BindTarget { buffer: Some(6), texture: None, sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 13 }: BindTarget { buffer: Some(7), texture: None, sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 15 }: BindTarget { buffer: Some(8), texture: None, sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 16 }: BindTarget { buffer: None, texture: Some(2), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 17 }: BindTarget { buffer: None, texture: Some(3), sampler: None, binding_array_size: Some(8), mutable: false }, ResourceBinding { group: 0, binding: 18 }: BindTarget { buffer: None, texture: Some(11), sampler: None, binding_array_size: Some(8), mutable: false }, ResourceBinding { group: 0, binding: 19 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(4)), binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 20 }: BindTarget { buffer: Some(9), texture: None, sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 21 }: BindTarget { buffer: None, texture: Some(19), sampler: None, binding_array_size: Some(8), mutable: false }, ResourceBinding { group: 0, binding: 22 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(5)), binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 23 }: BindTarget { buffer: None, texture: Some(27), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 24 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(6)), binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 29 }: BindTarget { buffer: None, texture: Some(28), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 0, binding: 30 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(7)), binding_array_size: None, mutable: false }, ResourceBinding { group: 1, binding: 0 }: BindTarget { buffer: Some(10), texture: None, sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 0 }: BindTarget { buffer: Some(11), texture: None, sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 1 }: BindTarget { buffer: None, texture: Some(29), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 2 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(8)), binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 3 }: BindTarget { buffer: None, texture: Some(30), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 4 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(9)), binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 5 }: BindTarget { buffer: None, texture: Some(31), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 6 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(10)), binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 7 }: BindTarget { buffer: None, texture: Some(32), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 8 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(11)), binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 9 }: BindTarget { buffer: None, texture: Some(33), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 10 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(12)), binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 11 }: BindTarget { buffer: None, texture: Some(34), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 12 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(13)), binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 15 }: BindTarget { buffer: None, texture: Some(35), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 16 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(14)), binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 17 }: BindTarget { buffer: None, texture: Some(36), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 18 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(15)), binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 19 }: BindTarget { buffer: None, texture: Some(37), sampler: None, binding_array_size: None, mutable: false }, ResourceBinding { group: 2, binding: 20 }: BindTarget { buffer: None, texture: None, sampler: Some(Resource(16)), binding_array_size: None, mutable: false }} }    
2024-09-21T03:11:45.569610Z ERROR log: Handling wgpu errors as fatal by default

Additional information

Looks like we're exceeding the limit on bindings. We might need to gate PCSS bindings on a feature flag, or change how we set up the bindings to only bind the actually used textures/samplers.

Edit: Looking a bit more into it, it looks like we're not hitting the texture limit. The limit is exclusively on samplers, maybe we can virtualize the samplers, as suggested here: google/filament#5788

[DGriffin91]

Note that on some platforms you have to use combined samplers and can't share. (WebGL?)

[mockersf]

Relevant limit on my m1: max_samplers_per_shader_stage: 16

It should crash on every gpu with the same or lower limit