Add support for gaps in bind group layouts & update relevant validation by teoxoy · Pull Request #9034 · gfx-rs/wgpu

teoxoy · 2026-02-11T13:54:36Z

Connections
Fixes #4738.
Fixes #1489.
Fixes #7985.

Notable spec PRs:

Allow empty bindGroupLayouts in GPUPipelineLayoutDescriptor gpuweb/gpuweb#4946
maxBindGroupsPlusVertexBuffers and unbinding gpuweb/gpuweb#3938 (unbinding vertex buffers and the new limit are not part of this PR)

Description
Allows pipeline layouts to contain gaps in BGLs.
Updates draw/dispatch bind group validation.
Pipelines with shaders that have gaps in @group attributes will result in derived layouts that have gaps in their BGLs.
Updated .get_bind_group_layout() & .create_pipeline_layout() to be in line with the CTS since the spec is unclear, see:

Testing
Enabled new CTS tests.

Squash or Rebase?
Squash.

teoxoy · 2026-02-11T13:55:30Z

Actually, I should do the wgpu plumbing as well or else it's not correct to say that this PR closes all the issues listed in the description.

teoxoy · 2026-02-11T19:39:11Z

@cwfitzgerald you might want to give the wgpu changes a quick look, I had to add a new trait to be able to still support passing BGLs by reference instead of by optional references.

wgpu/src/api/device.rs

wgpu/src/api/pipeline_layout.rs

cwfitzgerald

I have to type something here as I didn't make a review, I made individual comments.

wgpu/src/api/pipeline_layout.rs

jimblandy

Follow-up request: assuming that we do change the PipelineLayoutDescriptor's bind_group_layouts to be a slice of Options as Connor and I requested:

This is a big breaking change, so the changelog entry needs to be quite prominent. It should probably just be the top thing on the list, so that people are unlikely to miss it.

andyleiserson

Sorry for the delay, I didn't realize you were still waiting for my review until I got the ping.

wgpu/src/api/device.rs

CHANGELOG.md

wgpu-core/src/command/bind.rs

wgpu-core/src/binding_model.rs

andyleiserson · 2026-02-25T03:47:14Z

wgpu-core/src/command/bind.rs

+            self.update_rebind_start_index(index);
+        }
+
+        pub fn clear(&mut self, index: usize) {


Does this need to update the start index?

In the case of setting and then clearing bind groups in a single pass/dispatch, it doesn't matter, because the bind group doesn't get set until the scope is finalized. But if the bind groups are carrying over from a previous pass/dispatch, do we need to clear it?

We don't have to clear bind groups at the wgpu-hal level since validation will ensure that the ones that have been cleared are not used.

I think we could do it for Vulkan (vkCmdBindDescriptorSets can take VK_NULL_HANDLE) and Metal (MTLComputeCommandEncoder's setX methods can take nullable resources) but I don't see a way to do it on D3D12 (ID3D12GraphicsCommandList's Set{Graphics,Compute}RootDescriptorTable & Set{Graphics,Compute}RootConstantBufferView methods don't seem to have nullable parameters).

Actually the fact that we don't clear bound resources is preexisting on Metal and D3D12 since they don't have a 1:1 mapping for bind groups. Resources that have been previously set by a previous bind group at indices higher than ones used by a newly set bind group won't get cleared/overwritten.

I don't think this is an issue though, it would be more work for the driver to clear them and more code for us to maintain. I think relying on (correct) validation is the way to go.

And allow unbinding in the web backend.

wgpu update for v29. I have tested on macos m1, m5, and windows. Linux testing is appreciated. - [x] before merge, naga_oil and dlss_wgpu need to be published, and the patches referencing their respective PRs removed from the workspace Cargo.toml ##### other PRs - naga_oil: bevyengine/naga_oil#134 - dlss_wgpu: bevyengine/dlss_wgpu#27 ##### Source of relevant changes - `Dx12Compiler::DynamicDxc` no longer has `max_shader_model` - gfx-rs/wgpu#8607 - `Dx12BackendOptions::force_shader_model` comes from: - gfx-rs/wgpu#8984 - Allow optional `RawDisplayHandle` in `InstanceDescriptor` - gfx-rs/wgpu#8012 - Add `GlDebugFns` option to disable OpenGL debug functions - gfx-rs/wgpu#8931 - Add a DX12 backend option to force a certain shader model - gfx-rs/wgpu#8984 - Migrate validation from maxInterStageShaderComponents to maxInterStageShaderVariables - gfx-rs/wgpu#8652 - gaps are now supported in bind group layouts - gfx-rs/wgpu#9034 - depth validation changed to option to match spec - gfx-rs/wgpu#8840 - SHADER_PRIMITIVE_INDEX is now PRIMITIVE_INDEX - gfx-rs/wgpu#9101 - Support for binding arrays of RT acceleration structures - gfx-rs/wgpu#8923 - Make HasDisplayHandle optional in WindowHandle - gfx-rs/wgpu#8782 - `QueueWriteBufferView` can no longer be dereferenced to `&mut [u8]`, so use `WriteOnly`. - gfx-rs/wgpu#9042 - ~bevy_mesh currently has an added dependency on `wgpu`, can we move `WriteOnly` to wgpu-types?~ (it is in wgpu-types now) - Change max_*_buffer_binding_size type to match WebGPU spec (u32 -> u64) - gfx-rs/wgpu#9146 - raw vulkan init `open_with_callback` takes Limits as argument now - gfx-rs/wgpu#8756 ## Known Issues There is currently one known issue with occlusion culling on macos, which we've decided to disable on macos by checking the limits we actually require. This makes it so that if wgpu releases a patch fix, bevy 0.19 users will benefit from occlusion culling re-enabling for them. <details><summary>More details</summary> On macos, the wpgu limits were changed to align with the spec and now put the early and late GPU occlusion culling `StorageBuffer` limit at 8, but we currently use 9. [Filed in wgpu repo](gfx-rs/wgpu#9287) ``` 2026-03-19T01:37:10.771117Z ERROR bevy_render::error_handler: Caught rendering error: Validation Error Caused by: In Device::create_bind_group_layout, label = 'build mesh uniforms GPU late occlusion culling bind group layout' Too many bindings of type StorageBuffers in Stage ShaderStages(COMPUTE), limit is 8, count was 9. Check the limit `max_storage_buffers_per_shader_stage` passed to `Adapter::request_device` ``` </details> solari working on wgpu 29: <img width="1282" height="752" alt="image" src="https://github.com/user-attachments/assets/4744faec-65c0-4a72-93e1-34a721fc26d8" /> --------- Co-authored-by: atlv <email@atlasdostal.com>

teoxoy force-pushed the null-bg-and-bgl branch from fb0314c to 1045b93 Compare February 11, 2026 13:57

cwfitzgerald assigned andyleiserson Feb 11, 2026

teoxoy force-pushed the null-bg-and-bgl branch from 597c663 to 525cf3f Compare February 11, 2026 19:33

cwfitzgerald self-assigned this Feb 11, 2026

cwfitzgerald reviewed Feb 11, 2026

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cwfitzgerald reviewed Feb 11, 2026

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cwfitzgerald requested changes Feb 11, 2026

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jimblandy requested changes Feb 12, 2026

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teoxoy force-pushed the null-bg-and-bgl branch from f9718a5 to a586412 Compare February 16, 2026 11:22

teoxoy requested review from cwfitzgerald and jimblandy February 16, 2026 11:48

teoxoy force-pushed the null-bg-and-bgl branch 2 times, most recently from 6d5f8e3 to 9efbd33 Compare February 16, 2026 12:19

teoxoy requested a review from andyleiserson February 23, 2026 10:49

andyleiserson approved these changes Feb 25, 2026

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teoxoy force-pushed the null-bg-and-bgl branch 3 times, most recently from 64555c9 to ad64484 Compare February 25, 2026 18:09

teoxoy added 2 commits February 25, 2026 19:11

[wgpu-core] add support for optional BG & BGL entries

a423853

[wgpu] allow gaps in bind group layouts

0dd1b33

And allow unbinding in the web backend.

teoxoy force-pushed the null-bg-and-bgl branch from ad64484 to d874963 Compare February 25, 2026 18:11

teoxoy added 3 commits February 25, 2026 19:14

adapt tests

c11333e

add changelog entry

22d2a68

[wgpu] remove generic from PipelineLayoutDescriptor

6f796e7

teoxoy force-pushed the null-bg-and-bgl branch from d874963 to 6f796e7 Compare February 25, 2026 18:14

teoxoy merged commit e114d2f into gfx-rs:trunk Feb 25, 2026
58 checks passed

teoxoy deleted the null-bg-and-bgl branch February 25, 2026 18:47

ChristopherBiscardi mentioned this pull request Mar 9, 2026

Wgpu 29 bevyengine/bevy#23277

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Add support for gaps in bind group layouts & update relevant validation#9034

Add support for gaps in bind group layouts & update relevant validation#9034
teoxoy merged 5 commits intogfx-rs:trunkfrom
teoxoy:null-bg-and-bgl

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teoxoy commented Feb 11, 2026 •

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