[windows]: adjusts uniform buffers to hit hlsl optimization by gaaclarke · Pull Request #188538 · flutter/flutter

gaaclarke · 2026-06-24T23:45:56Z

This removes the following class of HLSL warnings:

WARN: ProgramD3D.cpp:711 (rx::ProgramD3D::linkJobImpl): Uniform block 'FragInfo' will be slow to compile. See UniformBlockToStructuredBufferTranslation.md (https://shorturl.at/drFY7) for details.

By putting large uniform arrays into their own uniform buffer the HLSL compiler in ANGLE is able to optimize the compilation using a StructuredBuffer. This removes the warning about long compilation time.

testing: refactor, no logical change

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…ove HLSL compilation performance.

gaaclarke · 2026-06-24T23:49:18Z

This looks good, we need to do this for KernelSamples too.

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Code Review

This pull request refactors several shaders and their corresponding host-side rendering code to move large arrays (such as colors, stop pairs, and kernel samples) into dedicated uniform blocks, preventing size and alignment issues on certain graphics platforms. Feedback recommends passing the temporary returned by GenerateBlurInfo directly to LerpHackKernelSamples to enable copy elision and avoid copying a large struct.

walley892

LG as long as the goldens don't change

b-luk

LGTM. Just a couple of nits, which I'll leave up to you to decide if you think it's anything worth changing.

b-luk · 2026-06-29T17:23:35Z

  float coefficient;
 };

 /// A larger mirror of GaussianBlurPipeline::FragmentShader::KernelSamples.


This is no longer true. GaussianBlurPipeline::FragmentShader::KernelSamples no longer contains sample_count, so this struct is no longer a mirror of it.

I think the comment is still helpful despite that technicality since it convey's the relationship between them. I think it's better to keep it as-is.

b-luk · 2026-06-29T17:34:58Z

  KernelSample samples[kMaxKernelSize];
 };

+struct LerpHackResult {


I think this is badly named, and it makes the code a bit harder to follow. I don't know the best way to improve it, but I'd be in favor of even just removing it entirely and using a pair<int32_t, GaussianBlurPipeline::FragmentShader::KernelSamples>.

The name of the function that generates this is LerpHackKernelSamples. I wouldn't want to switch to unstructured data since we'd be losing named fields. It's common to have a struct declared for returning multiple values. We could name it LerpHackKernelSamplesResult to be more clear if you like. Dropping some of the name didn't seem to affect the readability I my eyes, let me know.

Maybe it's not exactly a naming issue. I think what makes it harder to follow is that we no longer have a single struct that directly represents the shader input. The behavior used to be:

GenerateBlurInfo() generates KernalSamples, which is an expanded version of the FragmentShader::KernelSamples shader input.

LerpHackKernelSamples() converts the expanded KernalSamples into the input FragmentShader::KernelSamples, which is bound to the shader.

So there's a single KernalSamples struct which directly maps to a single shader input.

Now it's:

GenerateBlurInfo() generates KernalSamples, which is an expanded version of (FragmentShader::FragInfo::sample_count + FragmentShader::KernelSamples).

LerpHackKernelSamples() converts KernalSamples into LerpHackResult, which is the non-expanded version of (FragmentShader::FragInfo::sample_count + FragmentShader::KernelSamples).

The two parts of LerpHackResult get split up to be bound to two different inputs in the shader.

We end up with two intermediate KernalSamples and LerpHackResult structs, and neither of them map directly to a shader input field.

I don't know a good way to clean this up, so I'm not blocking submission. The new version isn't super complex. Once you look at it enough you can see what's going on. But I think it does force the reader to juggle a bunch more types/fields/subfields in their head to understand the flow of data compared to the old version. And for many of the new fields it's not immediately clear/intuitive what they represent within the data flow.

yea, it's less clear, our hand was forced based on hlsl's requirements. It looks like c++26 will have std::inplace_vector which may clean this up a bit. We won't need the struct anymore after that.

auto-submit · 2026-06-29T18:19:23Z

autosubmit label was removed for flutter/flutter/188538, because - The status or check suite Linux linux_unopt has failed. Please fix the issues identified (or deflake) before re-applying this label.

b-luk · 2026-06-29T19:15:15Z

  KernelSample samples[kMaxKernelSize];
 };

+struct LerpHackResult {


Maybe it's not exactly a naming issue. I think what makes it harder to follow is that we no longer have a single struct that directly represents the shader input. The behavior used to be:

GenerateBlurInfo() generates KernalSamples, which is an expanded version of the FragmentShader::KernelSamples shader input.

LerpHackKernelSamples() converts the expanded KernalSamples into the input FragmentShader::KernelSamples, which is bound to the shader.

So there's a single KernalSamples struct which directly maps to a single shader input.

Now it's:

GenerateBlurInfo() generates KernalSamples, which is an expanded version of (FragmentShader::FragInfo::sample_count + FragmentShader::KernelSamples).

LerpHackKernelSamples() converts KernalSamples into LerpHackResult, which is the non-expanded version of (FragmentShader::FragInfo::sample_count + FragmentShader::KernelSamples).

The two parts of LerpHackResult get split up to be bound to two different inputs in the shader.

We end up with two intermediate KernalSamples and LerpHackResult structs, and neither of them map directly to a shader input field.

I don't know a good way to clean this up, so I'm not blocking submission. The new version isn't super complex. Once you look at it enough you can see what's going on. But I think it does force the reader to juggle a bunch more types/fields/subfields in their head to understand the flow of data compared to the old version. And for many of the new fields it's not immediately clear/intuitive what they represent within the data flow.

flutter-dashboard · 2026-06-29T20:39:40Z

CI had a failure that stopped further tests from running. We need to investigate to determine the root cause.

SHA at time of execution: 87c4efc.

Possible causes:

Configuration Changes: The .ci.yaml file might have been modified between the creation of this pull request and the start of this test run. This can lead to ci yaml validation errors.
Infrastructure Issues: Problems with the CI environment itself (e.g., quota) could have caused the failure.

A blank commit, or merging to head, will be required to resume running CI for this PR.

Error Details:

FormatException: ERROR: Linux test_ownership is a new builder added. it needs to be marked bringup: true
If ci.yaml wasn't changed, try `git fetch upstream && git merge upstream/master`

Stack trace:

#0      CiYaml._validate (package:cocoon_service/src/model/ci_yaml/ci_yaml.dart:395:7)
#1      new CiYaml (package:cocoon_service/src/model/ci_yaml/ci_yaml.dart:128:7)
#2      new CiYamlSet (package:cocoon_service/src/model/ci_yaml/ci_yaml.dart:48:23)
#3      CiYamlFetcher._getCiYaml (package:cocoon_service/src/service/scheduler/ci_yaml_fetcher.dart:124:12)
<asynchronous suspension>
#4      Scheduler.getPresubmitTargets (package:cocoon_service/src/service/scheduler.dart:1084:20)
<asynchronous suspension>
#5      Scheduler._getTestsForStage (package:cocoon_service/src/service/scheduler.dart:1368:14)
<asynchronous suspension>
#6      Scheduler._runCiTestingStage (package:cocoon_service/src/service/scheduler.dart:1408:30)
<asynchronous suspension>
#7      Scheduler.proceedToCiTestingStage (package:cocoon_service/src/service/scheduler.dart:1516:7)
<asynchronous suspension>
#8      Scheduler._closeSuccessfulEngineBuildStage (package:cocoon_service/src/service/scheduler.dart:1341:5)
<asynchronous suspension>
#9      Scheduler.processCheckRunCompleted (package:cocoon_service/src/service/scheduler.dart:1273:11)
<asynchronous suspension>
#10     PresubmitLuciSubscription.post (package:cocoon_service/src/request_handlers/presubmit_luci_subscription.dart:176:9)
<asynchronous suspension>
#11     RequestHandler.service (package:cocoon_service/src/request_handling/request_handler.dart:42:20)
<asynchronous suspension>
#12     SubscriptionHandler.service (package:cocoon_service/src/request_handling/subscription_handler.dart:134:5)
<asynchronous suspension>
#13     createServer.<anonymous closure> (package:cocoon_service/server.dart:448:7)
<asynchronous suspension>
#14     main.<anonymous closure>.<anonymous closure> (file:///app/app_dart/bin/gae_server.dart:187:9)
<asynchronous suspension>

auto-submit · 2026-06-29T21:54:22Z

autosubmit label was removed for flutter/flutter/188538, because - The status or check suite Linux linux_fuchsia_tests has failed. Please fix the issues identified (or deflake) before re-applying this label.

gaaclarke · 2026-06-29T23:12:35Z

this may benefit #188338

…#12081) Manual roll Flutter from 0c80830e465b to ca9f874f5284 (119 revisions) Manual roll requested by [email protected] flutter/flutter@0c80830...ca9f874 2026-06-30 [email protected] [tool] Don't require a Flutter compile task when staging jniLibs (flutter/flutter#188805) 2026-06-30 [email protected] [Impeller] Fix potential overflow when allocating buffers at the next power of two size (flutter/flutter#188742) 2026-06-30 [email protected] [Framework/Tool] Decouple preview theme imports (flutter/flutter#188176) 2026-06-30 [email protected] Add import of `dart:_js_interop_wasm` in sdk rewriter tool (flutter/flutter#188620) 2026-06-30 [email protected] Detach LLDB and print stack trace on process stop (flutter/flutter#188576) 2026-06-30 [email protected] [Linux] Fix FlCompositorOpenGL.pixels comment (flutter/flutter#188754) 2026-06-30 [email protected] [flutter_tools] Fix crash in flutter create when pubspec.yaml is empty (flutter/flutter#188385) 2026-06-30 [email protected] Roll Packages from 656ccaa to 274ed3e (23 revisions) (flutter/flutter#188792) 2026-06-30 [email protected] In AndroidImageGenerator, check that the destination pixel buffer has sufficient capacity for the decoded data (flutter/flutter#188752) 2026-06-30 [email protected] Roll pub packages (flutter/flutter#188773) 2026-06-30 [email protected] [Impeller] Add a flat VertexAttributeFormat for vertex inputs (flutter/flutter#188684) 2026-06-30 [email protected] Roll pub packages (flutter/flutter#188764) 2026-06-30 [email protected] Roll Dart SDK from 0cb483880b6b to e1bdb9ce3327 (2 revisions) (flutter/flutter#188763) 2026-06-29 [email protected] Handle 'no permissions' adb device state (flutter/flutter#187248) 2026-06-29 [email protected] [windows]: adjusts uniform buffers to hit hlsl optimization (flutter/flutter#188538) 2026-06-29 [email protected] Roll Skia from bfb7860cb9c7 to 71947c4110b0 (9 revisions) (flutter/flutter#188747) 2026-06-29 [email protected] ci: extract wait-for-engine-build logic into a reusable composite action (flutter/flutter#188748) 2026-06-29 [email protected] Provide guided migration logs when iOS app crashes on simulator (flutter/flutter#188736) 2026-06-29 [email protected] Revert "[flutter_tools] Track asset transformer dependencies for hot reload" (flutter/flutter#188751) 2026-06-29 [email protected] Migrate ABI splits to new AGP dsl (flutter/flutter#188369) 2026-06-29 [email protected] Add Impeller+OpenGLES startup benchmark for mokey (flutter/flutter#188495) 2026-06-29 [email protected] Increase macOS minimum supported version from 10.15 to 12 to support Xcode 27 (flutter/flutter#188520) 2026-06-29 [email protected] Moves test ownership validation to flutter/flutter (flutter/flutter#188655) 2026-06-29 [email protected] Add --flavor support for Windows desktop builds (flutter/flutter#187034) 2026-06-29 [email protected] Android_hardware_smoke_test: Enable pixel exact local file comparator to read goldens from flutter asset URI (flutter/flutter#188587) 2026-06-29 [email protected] [flutter_tools] Use DeviceHub.app for iOS simulator path on Xcode 27+ (flutter/flutter#187910) 2026-06-29 [email protected] Roll Skia from 111e7582d081 to bfb7860cb9c7 (2 revisions) (flutter/flutter#188731) 2026-06-29 [email protected] Use `revert` label instead of `revert_wf` (flutter/flutter#188639) 2026-06-29 [email protected] Properly await Dart Development Service shutdown with timeout (flutter/flutter#188387) 2026-06-29 [email protected] [flutter_tools] Track asset transformer dependencies for hot reload (flutter/flutter#187947) 2026-06-29 [email protected] [Tool] Tolerate malformed UTF-8 in process streaming decoders (flutter/flutter#188453) 2026-06-29 [email protected] [flutter_tools] Use new ddc modules in test (flutter/flutter#188240) 2026-06-29 [email protected] Roll Packages from c1f7d92 to 656ccaa (12 revisions) (flutter/flutter#188728) 2026-06-29 [email protected] Remove unused fields (flutter/flutter#188705) 2026-06-29 [email protected] Clear text input handler widget on view dispose (flutter/flutter#188701) 2026-06-29 [email protected] Free compositor in view renderer finalize to avoid use-after-free (flutter/flutter#188702) 2026-06-29 [email protected] [linux] Use GWeakRef in mock signal handler test helper (flutter/flutter#188700) 2026-06-29 [email protected] Fixing few related editing issues with LTR/RTL text (flutter/flutter#188503) 2026-06-29 [email protected] [Flutter GPU] Add Texture.fromImage to wrap a ui.Image texture (flutter/flutter#188605) 2026-06-29 [email protected] [Flutter GPU] Honor the enable argument in RenderPass.setDepthWriteEnable (flutter/flutter#188715) 2026-06-29 [email protected] Roll Skia from ba1942d8c3e1 to 111e7582d081 (1 revision) (flutter/flutter#188721) 2026-06-29 [email protected] Roll Skia from 587d8befe1ee to ba1942d8c3e1 (6 revisions) (flutter/flutter#188717) 2026-06-29 [email protected] Remove some refs to package:intl (flutter/flutter#188504) 2026-06-29 [email protected] [VPAT] Update a11y assessment app FAB example to announce value change when it's updated. (flutter/flutter#188466) ...

…flutter#12081) Manual roll Flutter from 0c80830e465b to ca9f874f5284 (119 revisions) Manual roll requested by [email protected] flutter/flutter@0c80830...ca9f874 2026-06-30 [email protected] [tool] Don't require a Flutter compile task when staging jniLibs (flutter/flutter#188805) 2026-06-30 [email protected] [Impeller] Fix potential overflow when allocating buffers at the next power of two size (flutter/flutter#188742) 2026-06-30 [email protected] [Framework/Tool] Decouple preview theme imports (flutter/flutter#188176) 2026-06-30 [email protected] Add import of `dart:_js_interop_wasm` in sdk rewriter tool (flutter/flutter#188620) 2026-06-30 [email protected] Detach LLDB and print stack trace on process stop (flutter/flutter#188576) 2026-06-30 [email protected] [Linux] Fix FlCompositorOpenGL.pixels comment (flutter/flutter#188754) 2026-06-30 [email protected] [flutter_tools] Fix crash in flutter create when pubspec.yaml is empty (flutter/flutter#188385) 2026-06-30 [email protected] Roll Packages from 656ccaa to 274ed3e (23 revisions) (flutter/flutter#188792) 2026-06-30 [email protected] In AndroidImageGenerator, check that the destination pixel buffer has sufficient capacity for the decoded data (flutter/flutter#188752) 2026-06-30 [email protected] Roll pub packages (flutter/flutter#188773) 2026-06-30 [email protected] [Impeller] Add a flat VertexAttributeFormat for vertex inputs (flutter/flutter#188684) 2026-06-30 [email protected] Roll pub packages (flutter/flutter#188764) 2026-06-30 [email protected] Roll Dart SDK from 0cb483880b6b to e1bdb9ce3327 (2 revisions) (flutter/flutter#188763) 2026-06-29 [email protected] Handle 'no permissions' adb device state (flutter/flutter#187248) 2026-06-29 [email protected] [windows]: adjusts uniform buffers to hit hlsl optimization (flutter/flutter#188538) 2026-06-29 [email protected] Roll Skia from bfb7860cb9c7 to 71947c4110b0 (9 revisions) (flutter/flutter#188747) 2026-06-29 [email protected] ci: extract wait-for-engine-build logic into a reusable composite action (flutter/flutter#188748) 2026-06-29 [email protected] Provide guided migration logs when iOS app crashes on simulator (flutter/flutter#188736) 2026-06-29 [email protected] Revert "[flutter_tools] Track asset transformer dependencies for hot reload" (flutter/flutter#188751) 2026-06-29 [email protected] Migrate ABI splits to new AGP dsl (flutter/flutter#188369) 2026-06-29 [email protected] Add Impeller+OpenGLES startup benchmark for mokey (flutter/flutter#188495) 2026-06-29 [email protected] Increase macOS minimum supported version from 10.15 to 12 to support Xcode 27 (flutter/flutter#188520) 2026-06-29 [email protected] Moves test ownership validation to flutter/flutter (flutter/flutter#188655) 2026-06-29 [email protected] Add --flavor support for Windows desktop builds (flutter/flutter#187034) 2026-06-29 [email protected] Android_hardware_smoke_test: Enable pixel exact local file comparator to read goldens from flutter asset URI (flutter/flutter#188587) 2026-06-29 [email protected] [flutter_tools] Use DeviceHub.app for iOS simulator path on Xcode 27+ (flutter/flutter#187910) 2026-06-29 [email protected] Roll Skia from 111e7582d081 to bfb7860cb9c7 (2 revisions) (flutter/flutter#188731) 2026-06-29 [email protected] Use `revert` label instead of `revert_wf` (flutter/flutter#188639) 2026-06-29 [email protected] Properly await Dart Development Service shutdown with timeout (flutter/flutter#188387) 2026-06-29 [email protected] [flutter_tools] Track asset transformer dependencies for hot reload (flutter/flutter#187947) 2026-06-29 [email protected] [Tool] Tolerate malformed UTF-8 in process streaming decoders (flutter/flutter#188453) 2026-06-29 [email protected] [flutter_tools] Use new ddc modules in test (flutter/flutter#188240) 2026-06-29 [email protected] Roll Packages from c1f7d92 to 656ccaa (12 revisions) (flutter/flutter#188728) 2026-06-29 [email protected] Remove unused fields (flutter/flutter#188705) 2026-06-29 [email protected] Clear text input handler widget on view dispose (flutter/flutter#188701) 2026-06-29 [email protected] Free compositor in view renderer finalize to avoid use-after-free (flutter/flutter#188702) 2026-06-29 [email protected] [linux] Use GWeakRef in mock signal handler test helper (flutter/flutter#188700) 2026-06-29 [email protected] Fixing few related editing issues with LTR/RTL text (flutter/flutter#188503) 2026-06-29 [email protected] [Flutter GPU] Add Texture.fromImage to wrap a ui.Image texture (flutter/flutter#188605) 2026-06-29 [email protected] [Flutter GPU] Honor the enable argument in RenderPass.setDepthWriteEnable (flutter/flutter#188715) 2026-06-29 [email protected] Roll Skia from ba1942d8c3e1 to 111e7582d081 (1 revision) (flutter/flutter#188721) 2026-06-29 [email protected] Roll Skia from 587d8befe1ee to ba1942d8c3e1 (6 revisions) (flutter/flutter#188717) 2026-06-29 [email protected] Remove some refs to package:intl (flutter/flutter#188504) 2026-06-29 [email protected] [VPAT] Update a11y assessment app FAB example to announce value change when it's updated. (flutter/flutter#188466) ...

gaaclarke added 2 commits June 24, 2026 16:05

Split out large uniform arrays into their own uniform buffers to impr…

5eb88eb

…ove HLSL compilation performance.

fixed preprocessor macros

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flutter-dashboard Bot added the CICD Run CI/CD label Jun 24, 2026

github-actions Bot added engine flutter/engine related. See also e: labels. e: impeller Impeller rendering backend issues and features requests labels Jun 24, 2026

migrated gaussian blur

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Comment thread engine/src/flutter/impeller/entity/contents/filters/gaussian_blur_filter_contents.cc Outdated

gemini feedback / removed type deduction

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gaaclarke requested review from b-luk and walley892 June 25, 2026 17:18

added some static checks to make sure we don't regress

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Merge branch 'master' into hlsl-structured-uniforms

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Roll Flutter from 0c80830e465b to 9c7a3b5baf84 (110 revisions) flutter/packages#12071

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gaaclarke mentioned this pull request Jun 30, 2026

regression: impeller windows transition caused startup regression #188338

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