Fix: Support RenderLayers filtering for Lights (Adoption of #23265) by kfc35 · Pull Request #23925 · bevyengine/bevy

kfc35 · 2026-04-22T02:15:03Z

Objective

Adoption of Fix: support RenderLayer filtering for lights #23265
Fixes Regression: RenderLayers do not work for Lights #23264

Solution

Copied and Pasted from original PR:

Added per-light packed render-layer masks (stored in unused high bits of existing light flags) and used them during shading.
Added a packed render-layer mask to mesh uniforms/input uniforms, propagated through GPU preprocess and meshlet resolve.
Forward PBR lighting now filters point/spot/directional lights by mesh_layers ∩ light_layers at fragment time.
Shadow specialization/queue now also filters by light-vs-mesh layers (not just camera-vs-mesh), so wrong-layer meshes no longer cast into a light’s shadow pass.

With this implementation, per-mesh/per-light filtering supports layers 0..=25 (26 layers total).

These 26 bits are packed into light flags starting at bit 6.
If a mesh/light uses layers outside that packed range, it falls back to permissive behavior for those cases (preserves previous behavior instead of breaking rendering).

Additional Note from Me: Updating to main was mostly painless. All the conflicts were in crates/bevy_pbr/src/render/light.rs, and I resolved to the best of my ability and understanding since mucking around in that same file for another rendering issue.

I’m not as well versed in the rendering side of things, so if you have a comment, you might have to explain it like I’m five. Hopefully there isn’t much to fix up… but if there is, lean towards being very specific for my sake please 🙏

Testing

from original author: Tested and confirmed working with: cargo run --example light_render_layers

from me: I double checked the example and it works the same as it did before I merged main and resolved conflicts.

Showcase

Video of `light_render_layers ` example

Screen.Recording.2026-04-23.at.5.27.27.PM.mov

github-actions · 2026-04-22T02:23:45Z

Your PR caused a change in the graphical output of an example or rendering test. This might be intentional, but it could also mean that something broke!
You can review it at https://pixel-eagle.com/project/B04F67C0-C054-4A6F-92EC-F599FEC2FD1D?filter=PR-23925

If it's expected, please add the M-Deliberate-Rendering-Change label.

If this change seems unrelated to your PR, you can consider updating your PR to target the latest main branch, either by rebasing or merging main into it.

github-actions · 2026-04-22T02:27:38Z

Your PR caused a change in the graphical output of an example or rendering test. This might be intentional, but it could also mean that something broke!
You can review it at https://pixel-eagle.com/project/B04F67C0-C054-4A6F-92EC-F599FEC2FD1D?filter=PR-23925

If it's expected, please add the M-Deliberate-Rendering-Change label.

If this change seems unrelated to your PR, you can consider updating your PR to target the latest main branch, either by rebasing or merging main into it.

kfc35 · 2026-04-22T02:48:09Z

RE PixelEagle: it was an expected change and c71c870 changes it back to normal.

github-actions · 2026-04-22T02:49:54Z

Your PR caused a change in the graphical output of an example or rendering test. This might be intentional, but it could also mean that something broke!
You can review it at https://pixel-eagle.com/project/B04F67C0-C054-4A6F-92EC-F599FEC2FD1D?filter=PR-23925

If it's expected, please add the M-Deliberate-Rendering-Change label.

If this change seems unrelated to your PR, you can consider updating your PR to target the latest main branch, either by rebasing or merging main into it.

pauliusuza · 2026-04-23T15:01:56Z

Looks great, thanks @kfc35 for taking this on

tychedelia

I'm not sure we should land this without also landing per-camera shadow maps as it may be confusing to users trying to make use of this feature.

tychedelia · 2026-04-23T21:53:45Z

    pub local_from_world_transpose_b: f32,
    pub flags: u32,
+    /// Packed render layer mask used for per-mesh light filtering in shaders.
+    pub render_layers: u32,


Am confused why we don't need padding here

tychedelia · 2026-04-23T21:54:41Z

    /// If the mesh has no morph targets, this is `u32::MAX`.
    pub morph_descriptor_index: u32,
+    /// Padding to preserve 16-byte alignment for POD casts.
+    pub pad: [u32; 3],


these can usually be gated with #[cfg(feature = "webgl2")] and SIXTEEN_BYTE_ALIGNMENT in teh shader.

…or InputUniform

pauliusuza and others added 7 commits March 8, 2026 13:21

Add RenderLayer example for Lights

7f17c16

Fix: support RenderLayer filtering for lights bevyengine#23264

d6bac8a

Merge branch 'main' into main

2180e5d

Merge branch 'main' of github.com:bevyengine/bevy into 23264_adoption

f33b14f

style: cargo fmt

959e603

refactor/fix: shorten light querying logic for render layers

e2cc157

docs: add comment about bits into code

247baf9

kfc35 added C-Bug An unexpected or incorrect behavior A-Rendering Drawing game state to the screen P-Regression Functionality that used to work but no longer does. Add a test for this! S-Needs-Review Needs reviewer attention (from anyone!) to move forward labels Apr 22, 2026

github-project-automation Bot added this to Rendering Apr 22, 2026

github-project-automation Bot moved this to Needs SME Triage in Rendering Apr 22, 2026

kfc35 added this to the 0.19 milestone Apr 22, 2026

style: cargo fmt

537237c

kfc35 added 2 commits April 21, 2026 22:41

fix: add render layers into mesh uniform in instance manager

b8461df

fix: renderlayers testbed light shines on all cubes

c71c870

kfc35 added 3 commits April 21, 2026 22:57

fix: ugh one more usage of MeshUniform::new

80a77ab

fix: use constructor for MeshUniform

7abdda6

style: get rid of unused use

3347a1b

alice-i-cecile added the D-Modest A "normal" level of difficulty; suitable for simple features or challenging fixes label Apr 22, 2026

alice-i-cecile requested a review from tychedelia April 22, 2026 18:33

alice-i-cecile added the X-Uncontroversial This work is generally agreed upon label Apr 22, 2026

alice-i-cecile requested a review from IceSentry April 23, 2026 18:42

alice-i-cecile reviewed Apr 23, 2026

View reviewed changes

Comment thread crates/bevy_pbr/src/render/light.rs Outdated

alice-i-cecile reviewed Apr 23, 2026

View reviewed changes

Comment thread crates/bevy_pbr/src/render/light.rs Outdated

alice-i-cecile reviewed Apr 23, 2026

View reviewed changes

Comment thread crates/bevy_pbr/src/render/light.rs Outdated

refactor: extract common logic for getting light render layers

05c4bc4

alice-i-cecile approved these changes Apr 23, 2026

View reviewed changes

kfc35 force-pushed the 23264_adoption branch from 39a01b1 to 2db215f Compare April 23, 2026 20:58

refactor: consolidate mask logic

2bb46aa

kfc35 force-pushed the 23264_adoption branch from 2db215f to 2bb46aa Compare April 23, 2026 21:02

tychedelia suggested changes Apr 23, 2026

View reviewed changes

kfc35 added S-Waiting-on-Author The author needs to make changes or address concerns before this can be merged and removed S-Needs-Review Needs reviewer attention (from anyone!) to move forward labels Apr 23, 2026

kfc35 force-pushed the 23264_adoption branch from 59d125a to 3b2d601 Compare April 24, 2026 01:29

kfc35 added S-Blocked This cannot move forward until something else changes and removed S-Waiting-on-Author The author needs to make changes or address concerns before this can be merged labels Apr 24, 2026

add webgl2 padding for MeshUniform, clarify why padding is that way f…

732ba38

…or InputUniform

kfc35 force-pushed the 23264_adoption branch from 3b2d601 to 732ba38 Compare April 24, 2026 02:02

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Fix: Support RenderLayers filtering for Lights (Adoption of #23265)#23925

Fix: Support RenderLayers filtering for Lights (Adoption of #23265)#23925
kfc35 wants to merge 16 commits intobevyengine:mainfrom
kfc35:23264_adoption

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