[Flutter GPU] Add 2D texture array support by bdero · Pull Request #190036 · flutter/flutter

bdero · 2026-07-26T03:21:28Z

Related to #188776.

Adds 2D array texture support to Flutter GPU. TextureType.texture2DArray with a layerCount argument on GpuContext.createTexture creates the texture, Texture.overwrite and ColorAttachment.slice address each layer as a slice, and GpuContext.doesSupportTextureArrays reports availability. On the engine side, Capabilities::SupportsTextureArrays reports backend support, BlitPass::AddCopy validates slices against the texture type rather than a fixed cubemap bound, and the GLES backend gains buffer-to-array-layer blits. The capability reports false on GLES for now because shader bundles cannot carry an ES 3.0 shader variant yet, so user shaders there cannot sample arrays.

Pre-launch Checklist

I read the Contributor Guide and followed the process outlined there for submitting PRs.
I read the Tree Hygiene wiki page, which explains my responsibilities.
I read and followed the Flutter Style Guide and the C++, Objective-C, Java style guides.
I listed at least one issue that this PR fixes in the description above.
I added new tests to check the change I am making or feature I am adding, or the PR is test-exempt. See testing the engine for instructions on writing and running engine tests.
I updated/added relevant documentation (doc comments with ///).
I signed the CLA.
All existing and new tests are passing.

gemini-code-assist

Code Review

This pull request adds support for 2D array textures (TextureType::kTexture2DArray) to the Impeller GLES backend and exposes it to the Flutter GPU Dart API, enabling multi-layer texture allocation, uploading, and sampling. Feedback recommends explicitly casting variables to GLint and GLsizei in OpenGL calls to prevent narrowing conversion warnings, and replacing assert statements with standard expect assertions in Dart tests to ensure they execute across all build modes.

gaaclarke · 2026-07-27T18:18:55Z

@bdero how about this one too, ready to review?

bdero · 2026-07-29T01:36:32Z

ready to go now!

gaaclarke

Code looks good, testing looks good, design looks good. I just have a few notes.

gaaclarke · 2026-08-03T20:08:18Z

+        VALIDATION_LOG
+            << "2D array textures are not supported on this context.";
+        return false;


This seems like the sort of thing we should surface up to Dart. Can we add some TODO and file a follow up issue?

Resolved directly instead of deferring: GpuContext.createTexture now throws when a texture2DArray is requested but doesSupportTextureArrays is false, so callers get a clear error at creation rather than a failed upload. It reads the cached capability at creation time only, nothing on the draw path. This engine check stays as a backstop. No follow-up issue needed. (8cfb9ef)

gaaclarke · 2026-08-03T20:30:57Z

  desc.size = {width, height};
  desc.format = flutter::gpu::ToImpellerPixelFormat(format);
  desc.mip_count = static_cast<size_t>(mip_level_count);
+  desc.array_layer_count = static_cast<uint16_t>(layer_count);


fml_dcheck( layer_count <= uint16_max)

Done in a2fd5fa.

gaaclarke · 2026-08-03T20:32:33Z

@@ -0,0 +1 @@
+/Users/bdero/projects/flutter/flutter/engine/src/flutter/prebuilts


checked in on accident?

Yes, that was an accidental checkin of a local build symlink (the repo .gitignore only matches the prebuilts/ directory, not a symlink, so git add -A caught it). Removed. (d41651d)

gaaclarke

lgtm when passes ci

flutter-dashboard · 2026-09-06T20:15:02Z

This pull request executed golden file tests, but it has not been updated in a while (20+ days). Test results from Gold expire after as many days, so this pull request will need to be updated with a fresh commit in order to get results from Gold.

For more guidance, visit Writing a golden file test for package:flutter.

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.

gaaclarke

lgtm!

TextureType.texture2DArray plus a layerCount argument on GpuContext.createTexture create the texture, Texture.overwrite and ColorAttachment.slice address each layer as a slice, and GpuContext.doesSupportTextureArrays reports availability. Capabilities::SupportsTextureArrays reports backend support, BlitPass::AddCopy validates slices against the texture type rather than a fixed cubemap bound, and the GLES backend gains buffer-to-array-layer blits. The capability reports false on GLES for now because shader bundles cannot carry an ES 3.0 shader variant yet, so user shaders there cannot sample arrays.

GpuContext.createTexture now throws when a texture2DArray is requested but doesSupportTextureArrays is false, so callers get a clear error at creation instead of a failed upload later. The check reads a cached capability and runs only at creation, not on any draw path.

bdero · 2026-09-24T00:59:33Z

At the time of writing, Google testing has been stuck for 5 hours. 🤔

github-actions Bot added engine flutter/engine related. See also e: labels. e: impeller Impeller rendering backend issues and features requests flutter-gpu team-fluttergpu Owned by Flutter GPU team labels Jul 26, 2026

github-project-automation Bot added this to Flutter GPU Jul 26, 2026

github-project-automation Bot moved this to 🤔 Needs Triage in Flutter GPU Jul 26, 2026

bdero added the CICD Run CI/CD label Jul 26, 2026

bdero marked this pull request as ready for review July 26, 2026 04:43

gemini-code-assist Bot reviewed Jul 26, 2026

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Comment thread engine/src/flutter/impeller/renderer/backend/gles/blit_command_gles.cc

Comment thread engine/src/flutter/impeller/renderer/backend/gles/blit_command_gles.cc

Comment thread engine/src/flutter/testing/dart/gpu_test.dart

bdero requested a review from gaaclarke July 29, 2026 01:36

bdero mentioned this pull request Aug 1, 2026

2D texture array support bdero/flutter_scene#211

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gaaclarke reviewed Aug 3, 2026

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bdero force-pushed the bdero/flutter-gpu-texture-2d-array branch from b7870c1 to a2fd5fa Compare August 6, 2026 00:22

bdero added CICD Run CI/CD and removed CICD Run CI/CD labels Aug 6, 2026

gaaclarke self-requested a review August 17, 2026 18:19

gaaclarke previously approved these changes Aug 17, 2026

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bdero dismissed gaaclarke’s stale review via b03257e September 21, 2026 12:40

bdero force-pushed the bdero/flutter-gpu-texture-2d-array branch from 209fb5a to b03257e Compare September 21, 2026 12:40

bdero added CICD Run CI/CD and removed CICD Run CI/CD labels Sep 21, 2026

bdero force-pushed the bdero/flutter-gpu-texture-2d-array branch from b03257e to 78566dc Compare September 21, 2026 13:51

bdero added CICD Run CI/CD and removed CICD Run CI/CD labels Sep 21, 2026

bdero added the CICD Run CI/CD label Sep 23, 2026

bdero requested a review from gaaclarke September 23, 2026 17:53

gaaclarke approved these changes Sep 23, 2026

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bdero added CICD Run CI/CD and removed CICD Run CI/CD labels Sep 23, 2026

bdero added 6 commits September 23, 2026 12:19

Cast mip level and layer count in the GLES array texture uploads

7a6f628

Address review: DCHECK array layer count, TODO for Dart surfacing

eba2c5e

Format flutter_gpu_array_texture.frag with clang-format

a3e8fa9

Omit obvious local variable types in the array texture tests

916b679

bdero force-pushed the bdero/flutter-gpu-texture-2d-array branch from d488a58 to 916b679 Compare September 23, 2026 19:20

bdero added CICD Run CI/CD autosubmit Merge PR when tree becomes green via auto submit App and removed CICD Run CI/CD labels Sep 23, 2026

auto-submit Bot added this pull request to the merge queue Sep 24, 2026

Merged via the queue into flutter:master with commit 911600f Sep 24, 2026
29 checks passed

flutter-dashboard Bot removed the autosubmit Merge PR when tree becomes green via auto submit App label Sep 24, 2026

justinmc mentioned this pull request Sep 25, 2026

Flutter Notable Commits - 2026 #181433

Open

engine-flutter-autoroll mentioned this pull request Sep 25, 2026

Roll Flutter from 4fcd90be0045 to e20e5c3ca619 (188 revisions) flutter/packages#13017

Closed

bdero mentioned this pull request Sep 25, 2026

[flutter_gpu] Proposal: 2D array textures (TextureType.texture2DArray) #193367

Closed

		@@ -0,0 +1 @@
		/Users/bdero/projects/flutter/flutter/engine/src/flutter/prebuilts No newline at end of file

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bdero commented Jul 26, 2026

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