[Impeller] Cache GLES sampler configuration in RenderPassStateCache - #193922

…nd Track C

- Merge origin/master (including flutter#193922 SamplerStateCache) into
  wimp-track-b-gles3-state-dedup.
- Convert struct VertexAttribStateCache to class VertexAttribStateCache with
  private data members and encapsulated state-tracking methods matching the
  review style from flutter#193922 and flutter#193427.
- DelegateSamplerStateCache::IsTextureConfigured in BindAndConfigureTexture.

Roll Flutter from 4249ccbc18a3 to 426be968b5eb (44 revisions)

flutter/flutter@4249ccb...426be96

2026-10-14 [email protected] Allow color delta tolerance in in-memory fuzzy image comparator (flutter/flutter#193937)
2026-10-14 [email protected] [web] Drop stale composing range after text is replaced mid-composition (flutter/flutter#194096)
2026-10-14 [email protected] Roll Skia from 2a2bbea66844 to acde3755d2e2 (1 revision) (flutter/flutter#194376)
2026-10-14 [email protected] Roll Skia from 128c983b12de to 2a2bbea66844 (1 revision) (flutter/flutter#194371)
2026-10-14 [email protected] Roll Skia from 48a294ed4955 to 128c983b12de (3 revisions) (flutter/flutter#194353)
2026-10-14 [email protected] feat(flutter_tools): extract WebDebugConfig from DebuggingOptions (flutter/flutter#194312)
2026-10-14 [email protected] Roll Skia from ea6781c5b6d1 to 48a294ed4955 (2 revisions) (flutter/flutter#194349)
2026-10-14 [email protected] Include <vector> in Android proc_table.h. (flutter/flutter#194325)
2026-10-14 [email protected] Roll Dart SDK from 5933cb486b4a to 6b50116630d0 (28 revisions) (flutter/flutter#194341)
2026-10-14 [email protected] Move GLES3 instancing API entry points to FOR_EACH_IMPELLER_GLES3_PROC (flutter/flutter#194319)
2026-10-14 [email protected] feat(flutter_tools): extract AndroidGradleConfig and move toGradleConfig to AndroidBuildInfo (flutter/flutter#194016)
2026-10-14 [email protected] Roll Skia from ae297bec6012 to ea6781c5b6d1 (8 revisions) (flutter/flutter#194331)
2026-10-14 [email protected] [flutter_tools] Migrate gradle_errors and deferred_components_prebuild_validator away from globals (flutter/flutter#193649)
2026-10-14 [email protected] [Impeller] Cache GLES sampler configuration in RenderPassStateCache (flutter/flutter#193922)
2026-10-14 [email protected] Roll pub packages (flutter/flutter#194332)
2026-10-13 [email protected] [tool] Migrate RunCommand to modular dependency injection (flutter/flutter#190791)
2026-10-13 [email protected] Include `engine/src/flutter/.ci.yaml` in quarterly `goldctl` checklist (flutter/flutter#194316)
2026-10-13 [email protected] [flutter_tools] Remove the last AMD module system support (flutter/flutter#193607)
2026-10-13 [email protected] Roll Skia from 8b3394a60654 to ae297bec6012 (5 revisions) (flutter/flutter#194310)
2026-10-13 [email protected] [web] Remove the a11y placeholder only after the gesture ends (flutter/flutter#194109)
2026-10-13 [email protected] Upgrade goldctl to the latest version (flutter/flutter#193932)
2026-10-13 [email protected] [flutter_tools] Lazily initialize AndroidStudio validation and optimize candidate selection (flutter/flutter#191968)
2026-10-13 [email protected] [flutter_tools] Clean up outdated widget preview TODOs and refactor static state (flutter/flutter#189437)
2026-10-13 [email protected] Roll Skia from e5b5db6d0d6f to 8b3394a60654 (2 revisions) (flutter/flutter#194306)
2026-10-13 [email protected] Redistribute TESTOWNERS for Android team (flutter/flutter#193861)
2026-10-13 [email protected] feat(flutter_tools): introduce Test and Drive specification objects (flutter/flutter#194017)
2026-10-13 [email protected] [Impeller] Keep the aspect ratio when shrinking images to the max texture size (flutter/flutter#194010)
2026-10-13 [email protected] [flutter tool] preserve inherited `DASH__SUPPRESS_ANALYTICS=true` for sub-tools (flutter/flutter#194261)
2026-10-13 [email protected] Roll Packages from d8d9e97 to a1ed23c (9 revisions) (flutter/flutter#194302)
2026-10-13 [email protected] Use PE/COFF AOT snapshots for Windows x64 (flutter/flutter#187594)
2026-10-13 [email protected] Fix Expansible crash when PageStorage holds a non-bool value (flutter/flutter#192195)
2026-10-13 [email protected] Roll Skia from ffeccb3ca58a to e5b5db6d0d6f (1 revision) (flutter/flutter#194297)
2026-10-13 [email protected] Explain why initState() is too early to depend on an inherited widget (flutter/flutter#192727)
2026-10-13 [email protected] Refactor TestPlatformDispatcher (flutter/flutter#192747)
2026-10-13 [email protected] Roll Skia from 3de0984208ec to ffeccb3ca58a (2 revisions) (flutter/flutter#194291)
2026-10-13 [email protected] Roll Skia from 0580c2b780f6 to 3de0984208ec (2 revisions) (flutter/flutter#194281)
2026-10-13 [email protected] Roll Skia from f641d55e07a8 to 0580c2b780f6 (3 revisions) (flutter/flutter#194275)
2026-10-13 [email protected] Roll Skia from 0e5d8d1be81b to f641d55e07a8 (1 revision) (flutter/flutter#194266)
2026-10-13 [email protected] Scaffold view metrics overrides (flutter/flutter#192764)
2026-10-13 [email protected] [web] Add SemanticsRole.listBox and SemanticsRole.option (flutter/flutter#192971)
2026-10-13 [email protected] Pin mac_unopt to macOS 15 (flutter/flutter#194254)
2026-10-13 [email protected] Roll pub packages (flutter/flutter#194257)
2026-10-12 [email protected] Roll Skia from 17f6986c226c to 0e5d8d1be81b (4 revisions) (flutter/flutter#194249)
2026-10-12 [email protected] Make DisplayLists' use of DlPaint, SkPaint, and impeller::Paint agree on the default isAntiAlias (flutter/flutter#193939)

If this roll has caused a breakage, revert this CL and set the roller
...

…lutter#193922)

### Rationale

Split out from flutter#193427 per
@gaaclarke's review feedback.

OpenGL ES does not expose standalone sampler objects on the paths used
by `SamplerGLES`; instead, `SamplerGLES::ConfigureBoundTexture` emits up
to 5 `glTexParameteri` calls (`GL_TEXTURE_MIN_FILTER`,
`GL_TEXTURE_MAG_FILTER`, `GL_TEXTURE_MAX_LEVEL`, `GL_TEXTURE_WRAP_S`,
`GL_TEXTURE_WRAP_T`) plus optional `GL_TEXTURE_MAX_ANISOTROPY_EXT` on
the bound GL texture object every time a texture is bound for a draw
call. On glyph-atlas-heavy and tiled scenes (`bouncy@128`, `grid@1000`),
hundreds or thousands of consecutive draw calls sample the same texture
with an identical `SamplerDescriptor`, issuing up to `12,258` redundant
`glTexParameteri`/`glTexParameterf` calls per frame after
flutter#193427.

Within a render pass, non-wrapped `TextureGLES` instances own an
immutable `UniqueHandleGLES` (`HandleGLES`) and immutable
`TextureDescriptor` / `mip_count`. Caching the last configured
`SamplerDescriptor::ToKey` per `HandleGLES` in `SamplerStateCache`
inside `RenderPassStateCache` (alongside `BlendStateCache`,
`StencilStateCache`, and `DepthStateCache`) skips redundant
`glTexParameter*` calls across draws and pipelines within the pass
without storing mutable cached state on `TextureGLES`.

### Summary of Changes

-
[`engine/src/flutter/impeller/renderer/backend/gles/texture_gles.h`](https://github.com/kevmoo/flutter/blob/f9f4ba51255/engine/src/flutter/impeller/renderer/backend/gles/texture_gles.h):
Add a read-only `const HandleGLES& GetHandle() const` accessor matching
`PipelineGLES::GetProgramHandle()`.
-
[`engine/src/flutter/impeller/renderer/backend/gles/buffer_bindings_gles.h`](https://github.com/kevmoo/flutter/blob/f9f4ba51255/engine/src/flutter/impeller/renderer/backend/gles/buffer_bindings_gles.h)
&
[`engine/src/flutter/impeller/renderer/backend/gles/buffer_bindings_gles.cc`](https://github.com/kevmoo/flutter/blob/f9f4ba51255/engine/src/flutter/impeller/renderer/backend/gles/buffer_bindings_gles.cc):
Add `struct SamplerStateCache` (`absl::flat_hash_map<HandleGLES,
uint64_t, HandleGLES::Hash, HandleGLES::Equal> configured_samplers;` +
`ConfigureBoundTexture(...)`) and pass an optional `SamplerStateCache*`
into `BufferBindingsGLES::BindUniformData` and
`BufferBindingsGLES::BindTextures`. Wrapped external textures
(`IsWrapped()`) bypass the cache so external callers mutating raw GL
texture parameters are unaffected.
-
[`engine/src/flutter/impeller/renderer/backend/gles/render_pass_gles.cc`](https://github.com/kevmoo/flutter/blob/f9f4ba51255/engine/src/flutter/impeller/renderer/backend/gles/render_pass_gles.cc):
Add `SamplerStateCache sampler;` to `RenderPassStateCache` and pass
`&state_cache.sampler` into `vertex_desc_gles->BindUniformData(...)`.
-
[`engine/src/flutter/impeller/renderer/backend/gles/buffer_bindings_gles_unittests.cc`](https://github.com/kevmoo/flutter/blob/f9f4ba51255/engine/src/flutter/impeller/renderer/backend/gles/buffer_bindings_gles_unittests.cc):
Add
`BufferBindingsGLESTest.SkipsRedundantSamplerConfigurationOnSameTexture`
covering repeated binds with an identical sampler descriptor,
re-configuration when the sampler descriptor changes, cross-pipeline
deduplication/invalidation via a shared `SamplerStateCache`, and cache
bypass for wrapped external textures (`TextureGLES::WrapTexture`).

### Flow / Surface Delta

#### 1. Deterministic WebGL2 Call-Count Reductions (`0%` Variance)

Measured on top of merged flutter#193427
(`origin/master` @ `a554b8ac180` vs. `daad7727f54` across steady-state
frames):

| Workload (`1280x720`, `wimp_st`) | Metric | Pre-Change
(post-`flutter#193427`) | Post-Change | Absolute Delta | Delta (%) | Reduction
|
| :--- | :--- | :---: | :---: | :---: | :---: | :--- |
| **`bouncy` (`128` nodes, `441` draws, `247` textured)** |
`glTexParameteri` + `glTexParameterf` / frame | `1,482` (`1,235` +
`247`) | `~6` (`1` per pass) | `-1,476` | **`-99.6%`** | **Deduplicated
per pass** |
| | Total GL calls / frame | `7,827` | `6,336` | `-1,491` | **`-19.0%`**
| **`1.24x` fewer calls** (`-52.2%` / `2.09x` cumulative w/ `flutter#193427`) |
| **`grid` (`100` nodes, `660` draws, `245` textured)** |
`glTexParameteri` + `glTexParameterf` / frame | `1,470` (`1,225` +
`245`) | `~6` (`1` per pass) | `-1,464` | **`-99.6%`** | **Deduplicated
per pass** |
| | Total GL calls / frame | `10,674` | `9,213` | `-1,461` |
**`-13.7%`** | **`1.16x` fewer calls** |
| **`grid` (`1000` nodes, `5,908` draws, `2,043` textured)** |
`glTexParameteri` + `glTexParameterf` / frame | `12,258` (`10,215` +
`2,043`) | `~6` (`1` per pass) | `-12,252` | **`-99.95%`** |
**Deduplicated per pass** |
| | Total GL calls / frame | `93,669` | `81,285` | `-12,384` |
**`-13.2%`** | **`1.15x` fewer calls** (`-47.4%` / `1.90x` cumulative w/
`flutter#193427`) |

In `100us` V8/Wasm CPU profiling of the `DedicatedWorker` raster thread
on `grid@1000` (`--profile --no-strip-wasm`), redundant
`glTexParameteri` (`9.75 ms` Wasm self-time + `19.76 ms` JS binding) and
`glTexParameterf` (`12.80 ms` JS binding) accounted for **`42.31 ms`
(`2.09%` of total active worker CPU time)** across a `2.02s`
steady-state window.

#### 2. Hardware WebGL2 `rasterTimeMs` A/B (`AMD Radeon 780M`, `n=5`
Interleaved ABBA Pairs)

Measured on headed Chrome 154 (`ANGLE (AMD, AMD Radeon 780M Graphics
(radeonsi phoenix ACO), OpenGL ES 3.2)`, `--disable-gpu-vsync
--disable-frame-rate-limit`, `10` samples/run × `5` interleaved ABBA
pairs per arm):

| Workload (`1280x720`, `wimp_st`) | Pre-Change (`a554b8ac180`) |
Post-Change (`daad7727f54`) | Absolute Delta | Delta (%) | Speedup |
| :--- | :---: | :---: | :---: | :---: | :---: |
| **`bouncy` (`64` nodes)** | `1.412 ms` | `1.382 ms` | `-0.030 ms` |
`-2.15%` | `1.02x` |
| **`bouncy` (`128` nodes)** | `1.842 ms` | `1.756 ms` | `-0.086 ms` |
**`-4.66%`** | **`1.05x`** |
| **`grid` (`100` nodes)** | `1.783 ms` | `1.727 ms` | `-0.057 ms` |
**`-3.17%`** | **`1.03x`** |
| **`grid` (`1000` nodes)** | `16.385 ms` | `15.996 ms` | `-0.389 ms` |
**`-2.37%`** | **`1.02x`** |

**How much to trust these numbers:**
- **Call counts (Table 1) are exact (`0%` run-to-run variance)**: Every
frame deterministically eliminates `1,464`–`12,252` redundant
`glTexParameter*` calls across the boundary.
- **Wall-clock `rasterTimeMs` (Table 2) has a `~1.2%–2.0%` run-to-run
noise floor**:
- **`bouncy@128` (`-4.66%`)** and **`grid@100` (`-3.17%`)** clear the
noise floor consistently (`5/5` interleaved Post runs beat Pre).
- **`grid@1000` (`-2.37%`, `-0.39 ms`)** sits just above the
`~1.5%–2.0%` noise floor (`4/5` pairs faster) and aligns with the
`2.09%` worker CPU profile share of `glTexParameter*` when `5,908` draw
calls dominate frame time.
- **`bouncy@64` (`-2.15%`, `-0.03 ms`)** is inside the noise floor at
`<1.5 ms` frame times and should be treated as flat/within noise.

### Verification

- Built and ran `host_debug_unopt:impeller_unittests
--gtest_filter="*BufferBindingsGLES*:*RenderPassGLES*:*SamplerGLES*:*TextureGLES*"`
locally (`37/37` passed, including
`BufferBindingsGLESTest.SkipsRedundantSamplerConfigurationOnSameTexture`).
- Built `wasm_release:skwasm/wimp.js` and verified both deterministic
WebGL2 call counts and `n=5` interleaved hardware WebGL2 `rasterTimeMs`
medians (`AMD Radeon 780M`) in Chrome 154 via `flutter-wasm-compare`.

Related to flutter#192147
Towards flutter#174980

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responsibilities.
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we expect every widget to implement].
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- [x] I listed at least one issue that this PR fixes in the description
above.
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`///`).
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linked a website documentation issue or PR in [flutter/website] (or
verified none is needed).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
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