Bump JsRuntimeHost for File/FileReader polyfill (re-enables 19 GLTF/OBJ tests) by bkaradzic-microsoft · Pull Request #1706 · BabylonJS/BabylonNative

bkaradzic-microsoft · 2026-05-18T16:35:30Z

Re-enables the 19 GLTF/OBJ serializer round-trip tests that fail under BN today because the runtime is missing File and FileReader. Babylon.js code paths (new File([blob], 'scene.glb') followed by LoadAssetContainerAsync(file, scene), which internally reads via FileReader.readAsArrayBuffer) need both APIs to work.

The actual polyfill lives in JsRuntimeHost (bkaradzic-microsoft/JsRuntimeHost @ 670084e5), next to Polyfills/Blob/. That's the architecturally correct home — File and FileReader are standard WHATWG web APIs in the same category as the existing XMLHttpRequest / URL / WebSocket / TextDecoder / AbortController polyfills hosted there, and File is layered directly on top of Blob. Hosting them there means every JsRuntimeHost consumer (BN and any other embedder) gets them.

Addresses @bghgary's review: "this should be a proper C++ polyfill under Polyfills/ so every consumer gets it, not a Playground-only JS script".

This PR (BN-side) is intentionally tiny:

CMakeLists.txt — bump JsRuntimeHost GIT_TAG to 670084e5 and temporarily point GIT_REPOSITORY at the bkaradzic-microsoft/JsRuntimeHost fork until the upstream JsRuntimeHost PR is merged. Will be re-pinned to a BabylonJS/JsRuntimeHost commit before this PR merges.
Apps/Playground/Shared/AppContext.cpp — Babylon::Polyfills::File::Initialize(env) immediately after Blob::Initialize(env). The old LoadScript("app:///Scripts/file_polyfill.js") line is gone.
Apps/Playground/CMakeLists.txt — drops file_polyfill.js from SCRIPTS, links the new JsRuntimeHost File target into the Playground binary.
Apps/Playground/Scripts/file_polyfill.js — deleted (308 lines of JS subsumed by the C++ polyfill in JsRuntimeHost).
Apps/Playground/Scripts/config.json — re-enables 19 affected tests; adds excludedGraphicsApis: ["OpenGL"] to 5 GLTF Serializer tests (KHR gpu instancing + 4 Camera variants) for OpenGL-specific backend issues unrelated to this polyfill.

Verified: 19/19 affected tests pass on Win32 D3D11 Release headless without --include-excluded (indices 208-216, 219-226, 275-276). Remaining 9 (in the same family) fail with separate root causes — tracked separately.

Landing sequence

✅ Push JsRuntimeHost work to fork branch + this BN PR (← here, validating CI against fork branch).
⏳ Open PR to BabylonJS/JsRuntimeHost adding Polyfills/File/ once BN CI is green here.
⏳ After the JsRuntimeHost PR merges, re-pin this BN PR's GIT_REPOSITORY / GIT_TAG back to BabylonJS/JsRuntimeHost at the merged SHA.
⏳ Merge this BN PR.

Series landing context

This PR is one of 7 splits from the proven CI-green combined preview in draft PR #1702 (see #1702 for the full intended end-state and verified CI run 26044922430).

Note: the original split included an 8th PR (#1709, ES2020+ -> ES2019 syntax-repair polyfill for Chakra). It was closed in favour of investigating @babel/standalone properly (#1711).

Recommended landing order

Tier 1 - parallel-reviewable, no source conflicts:

Fix ExternalTexture_OpenGL throw-stubs to avoid MSVC C4702 under /WX #1703 - ExternalTexture C4702 build fix
Document accurate root cause for post-#1695 pixel-diff fallouts #1704 - config.json reason rewrites (5 entries)
Document accurate root cause for 17 subtle pixel-diff tests #1705 - config.json reason rewrites (17 entries)

Tier 2 - sequential, each touches Apps/Playground/CMakeLists.txt SCRIPTS list + Apps/Playground/Shared/AppContext.cpp LoadScript order; rebase the next branch after the previous merges:

Bump JsRuntimeHost for File/FileReader polyfill (re-enables 19 GLTF/OBJ tests) #1706 - File/FileReader polyfill (JsRuntimeHost bump + Playground wiring; largest test impact: 19 re-enables)
Add fetch() polyfill over XMLHttpRequest for Playground #1707 - fetch polyfill
Add DOM globals polyfill + native AbortController for Playground #1708 - DOM globals + native AbortController + Android CMake link
Add cubemap auto-expand polyfill for Playground (re-enables 7 PBR tests) #1710 - Cubemap auto-expand polyfill (loaded after babylon.max.js)

Reference policy reminder

Reference PNGs across all 7 PRs come from Babylon.js; never re-baked by BN. Combined diff: 0 PNGs.

BabylonNative's native JsRuntimeHost ships a Blob C++ ObjectWrap but no File constructor or FileReader. Several Babylon.js serializer round-trip tests (GLTF/OBJ export then re-load) use new File([blob], 'scene.glb') and rely on the loader's FilesInputStore path that internally invokes FileReader.readAsArrayBuffer. Without these the tests fail with ReferenceError: 'File' is not defined / 'FileReader' is not defined. Adds a self-detecting JS polyfill that: - no-ops on runtimes that already expose File/FileReader (V8, JSC may) - no-ops when the native Blob polyfill is missing - decorates a native Blob with name/lastModified to produce a File (deliberately without setPrototypeOf - pivoting the napi ObjectWrap prototype strips its bound instance methods on Chakra) - implements FileReader on top of Blob.arrayBuffer() with readAsArrayBuffer, readAsText, readAsDataURL, readAsBinaryString and the standard event surface (onload/onerror/onloadend, addEventListener/removeEventListener) Hooked into Playground via SCRIPTS in Apps/Playground/CMakeLists.txt and loaded from AppContext.cpp before ammo.js / babylon.max.js. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Re-enables tests at indices 208-216, 219-226, 275, 276 in Apps/Playground/Scripts/config.json (GLTF Serializer round-trip variants and OBJ Stanford Bunny round-trip in both handednesses), which were previously excluded with "Pixel comparison fails (more than 20% pixels differ)" or "File API not available" reasons. The actual root cause was the missing File/FileReader globals, now addressed in the previous commit. All 19 tests verified passing via headless Playground runner without --include-excluded. Updates reasons for tests that still fail with the polyfill present: - idx 217 (Draco mesh compression): Draco loader uses 'utf8' encoding name which Babylon Native's TextDecoder polyfill rejects (only 'utf-8' OK) - idx 277, 278 (glTF to OBJ round trip): hangs on Win32 Chakra D3D11 Remaining still-excluded entries (218, 227-230, 420, 421) keep their existing pixel-diff reasons; they are unrelated to the File polyfill. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Linux JSC and GCC CI runners (OpenGL backend) hit a 3.4% pixel diff (8097/240000 px) on this test that does not appear on the D3D11 backend. The test was re-enabled by the file-api branch because it passes on Win32 D3D11, but the OpenGL backend has a separate rendering issue that is out of scope for the File API polyfill work. Mark the test excludedGraphicsApis=[OpenGL] so it still runs on D3D11/D3D12/Metal/ Vulkan and stays skipped on OpenGL. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Same pattern as KHR gpu instancing: the Camera serializer roundtrip test diverges on the OpenGL backend (Linux JSC and GCC CI runners, ~21% pixel diff with the rendered clear color showing through where the geometry should be) but passes on D3D11. Exclude on OpenGL while we figure out the backend-specific issue. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

CI continues to surface the same OpenGL-only rendering issue on every test using playgroundId #O0M0J9#25 (the Camera serializer roundtrip): - left-handed (already excluded last round) - right-handed (failed this round, ~50K px diff) - left-handed, round trip twice - right-handed, round trip twice All share the same scene and codepath. Mark the remaining 3 with excludedGraphicsApis=[OpenGL] preemptively so we stop iterating one test at a time on this same failure mode. Tests still run on D3D11/ D3D12/Metal/Vulkan. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds a JS-side File / FileReader polyfill to Babylon Native’s Playground so GLTF serializer/loader round-trip tests can run under the BN JS runtime again.

Changes:

Introduces file_polyfill.js implementing File (as a decorated native Blob) and a Promise-backed FileReader.
Loads the polyfill early in Playground startup and includes it in the CMake scripts bundle.
Re-enables previously excluded serializer-related tests and refines exclusions/reasons for known backend issues.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 7 comments.

File	Description
Apps/Playground/Shared/AppContext.cpp	Loads the new File API polyfill before other scripts.
Apps/Playground/Scripts/file_polyfill.js	Adds minimal `File` + `FileReader` implementations on top of the native `Blob`.
Apps/Playground/Scripts/config.json	Re-enables many tests; adds targeted OpenGL exclusions and updates a few “reason” strings.
Apps/Playground/CMakeLists.txt	Ensures the new polyfill script is packaged with existing Playground scripts.

FileReader changes: - abort() now invalidates the in-flight read via a monotonic `_readId` token; the .then continuation in startRead() captures the token and early-returns if it has moved on, so a late-resolving arrayBuffer() promise can no longer clobber state or dispatch a phantom `load` after a user-initiated abort. - readAsText now prefers TextDecoder first and falls back to a chunked String.fromCharCode.apply + Array.join path. The previous code built a byte-by-byte `s += c` string and then often discarded it; for multi-MB GLTF JSON this was the most expensive path in the polyfill. - dispatchEvent(event) routes through the existing internal dispatch() helper so on* handlers and addEventListener listeners actually fire for the event type, instead of returning true and dropping the event. Config change: - Rewrite the Draco/utf8 reason text to scope the limitation correctly: it is BN's TextDecoder (no WHATWG label normalization) that rejects `utf8`, not Web TextDecoder in general. Refs PR BabylonJS#1706. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

ryantrem

Should we not just add File support to the actual native Blob polyfill?

bghgary

[Reviewed by Copilot on behalf of @bghgary]

File and FileReader are standard web APIs that Babylon.js code paths depend on (GLTF serializer round-trip). This should be a proper C++ polyfill under Polyfills/ so every consumer gets it, not a Playground-only JS script.

Per-test PIL-composite triage of all 17 ``subtle pixel-diff`` tests. None of them are deterministic-cosmetic (no re-bakes possible - all show real visible regressions). Updates the `reason` field in `Apps/Playground/Scripts/config.json` for 17 tests with accurate symptom descriptions, classifying into recurring root-cause clusters: - 9 GUI green->red color regressions (idx 160, 174, 175, 196, 197, 370, 402, 566, 587) - 4 OpenPBR analytic-lights right-column red rendering (580, 584, 587, 592) - 1 instanced billboard foliage red (169) - 1 LineEdgesRenderer extra red lines (179) - 1 Background blur red splotches (602) - 1 Clip planes GUI sliders red (182) - 1 Instanced Bones edge-AA (256, borderline) **No source changes, no test re-enables, no PNGs.** Metadata-only correction so the issue tracker reflects actionable root causes. --- ## Landing context This PR is one of **7 splits** from the proven CI-green combined preview in **draft PR #1702** (see [#1702](#1702) for the full intended end-state and verified CI run [26044922430](https://github.com/BabylonJS/BabylonNative/actions/runs/26044922430)). > Note: the original split included an 8th PR (#1709, ES2020+ -> ES2019 syntax-repair polyfill for Chakra). It was closed in favour of investigating `@babel/standalone` properly (#1711). ### Recommended landing order **Tier 1 - parallel-reviewable, no source conflicts:** 1. #1703 - ExternalTexture C4702 build fix 2. #1704 - config.json `reason` rewrites (5 entries) 3. #1705 - config.json `reason` rewrites (17 entries) **Tier 2 - sequential, each touches `Apps/Playground/CMakeLists.txt` SCRIPTS list + `Apps/Playground/Shared/AppContext.cpp` LoadScript order; rebase the next branch after the previous merges:** 4. #1706 - File/Blob/FileReader polyfill (largest test impact: 19 re-enables) 5. #1707 - fetch polyfill 6. #1708 - DOM globals + native AbortController + Android CMake link 7. #1710 - Cubemap auto-expand polyfill (loaded after babylon.max.js) ### Reference policy reminder Reference PNGs across all 7 PRs come from Babylon.js; never re-baked by BN. Combined diff: **0 PNGs**.

Per-test triage of 5 post-#1695 pixel-diff fallouts. Updates the `reason` field in `Apps/Playground/Scripts/config.json` for 3 entries to name the real BN rendering regression instead of generic "Pixel comparison fails": - idx 363 SSR2 - SSR not rendering wet floor. - idx 369 Sprites Pixel Perfect - sprite alpha-blending broken. - idx 395 soft-transparent-shadows - soft-shadow filter precision degraded. **No source changes, no test re-enables, no PNGs.** Metadata-only correction so the issue tracker reflects actionable root causes for follow-up engineering work. --- ## Landing context This PR is one of **7 splits** from the proven CI-green combined preview in **draft PR #1702** (see [#1702](#1702) for the full intended end-state and verified CI run [26044922430](https://github.com/BabylonJS/BabylonNative/actions/runs/26044922430)). > Note: the original split included an 8th PR (#1709, ES2020+ -> ES2019 syntax-repair polyfill for Chakra). It was closed in favour of investigating `@babel/standalone` properly (#1711). ### Recommended landing order **Tier 1 - parallel-reviewable, no source conflicts:** 1. #1703 - ExternalTexture C4702 build fix 2. #1704 - config.json `reason` rewrites (5 entries) 3. #1705 - config.json `reason` rewrites (17 entries) **Tier 2 - sequential, each touches `Apps/Playground/CMakeLists.txt` SCRIPTS list + `Apps/Playground/Shared/AppContext.cpp` LoadScript order; rebase the next branch after the previous merges:** 4. #1706 - File/Blob/FileReader polyfill (largest test impact: 19 re-enables) 5. #1707 - fetch polyfill 6. #1708 - DOM globals + native AbortController + Android CMake link 7. #1710 - Cubemap auto-expand polyfill (loaded after babylon.max.js) ### Reference policy reminder Reference PNGs across all 7 PRs come from Babylon.js; never re-baked by BN. Combined diff: **0 PNGs**.

@bghgary

Addresses @bghgary's review on BabylonJS#1706: File and FileReader are standard WHATWG web APIs that Babylon.js code paths depend on (GLTF serializer round-trip uses `new File([blob], 'scene.glb')` then `LoadAssetContainerAsync` which internally reads via `FileReader.readAsArrayBuffer`). The polyfills now live in JsRuntimeHost (next to `Polyfills/Blob/`) so every JsRuntimeHost consumer gets them, not just BabylonNative. The JsRuntimeHost-side change is at bkaradzic-microsoft/JsRuntimeHost@670084e5 ("Add File / FileReader polyfill"). This temporarily points BabylonNative's FetchContent at that fork branch; once the upstream JsRuntimeHost PR lands, we will re-pin to the merged commit on BabylonJS/JsRuntimeHost. Babylon Native side: - `CMakeLists.txt`: bump JsRuntimeHost GIT_TAG to `670084e5` and point GIT_REPOSITORY at the bkaradzic-microsoft fork until the upstream JsRuntimeHost PR is merged. - `Apps/Playground/Shared/AppContext.cpp`: include `<Babylon/Polyfills/File.h>` and call `Babylon::Polyfills::File::Initialize(env)` immediately after `Blob::Initialize(env)`. The old `LoadScript("app:///Scripts/ file_polyfill.js")` line is gone. - `Apps/Playground/CMakeLists.txt`: drop `file_polyfill.js` from SCRIPTS, link the new JsRuntimeHost `File` target into the Playground binary. - `Apps/Playground/Scripts/file_polyfill.js`: deleted (308 lines of JS subsumed by the C++ polyfill in JsRuntimeHost). Verified by running the GLTF/OBJ serializer round-trip tests that this PR re-enables (indices 208-216, 219-226, 275-276): 19/19 pass on Win32 D3D11 Release headless. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

@bghgary

Addresses @bghgary's review on BabylonJS#1706: File and FileReader are standard WHATWG web APIs that Babylon.js code paths depend on (GLTF serializer round-trip uses `new File([blob], 'scene.glb')` then `LoadAssetContainerAsync` which internally reads via `FileReader.readAsArrayBuffer`). The polyfills now live in JsRuntimeHost (next to `Polyfills/Blob/`) so every JsRuntimeHost consumer gets them, not just BabylonNative. The JsRuntimeHost-side change is at bkaradzic-microsoft/JsRuntimeHost@670084e5 ("Add File / FileReader polyfill"). This temporarily points BabylonNative's FetchContent at that fork branch; once the upstream JsRuntimeHost PR lands, we will re-pin to the merged commit on BabylonJS/JsRuntimeHost. Babylon Native side: - `CMakeLists.txt`: bump JsRuntimeHost GIT_TAG to `670084e5` and point GIT_REPOSITORY at the bkaradzic-microsoft fork until the upstream JsRuntimeHost PR is merged. - `Apps/Playground/Shared/AppContext.cpp`: include `<Babylon/Polyfills/File.h>` and call `Babylon::Polyfills::File::Initialize(env)` immediately after `Blob::Initialize(env)`. The old `LoadScript("app:///Scripts/ file_polyfill.js")` line is gone. - `Apps/Playground/CMakeLists.txt`: drop `file_polyfill.js` from SCRIPTS, link the new JsRuntimeHost `File` target into the Playground binary. - `Apps/Playground/Scripts/file_polyfill.js`: deleted (308 lines of JS subsumed by the C++ polyfill in JsRuntimeHost). Verified by running the GLTF/OBJ serializer round-trip tests that this PR re-enables (indices 208-216, 219-226, 275-276): 19/19 pass on Win32 D3D11 Release headless. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Implements `File` and `FileReader` as Napi::ObjectWrap-based polyfills, matching the rest of `JsRuntimeHost/Polyfills/`. Lives next to `Blob` because `File` is layered directly on top of `Blob` (delegates byte storage to the global `Blob` constructor, then decorates the instance with `name` / `lastModified`). Why JsRuntimeHost: `File` and `FileReader` are standard WHATWG web APIs in the same category as the existing `XMLHttpRequest`, `URL`, `WebSocket`, `TextDecoder`, `AbortController`, etc. polyfills. Hosting them here means every JsRuntimeHost embedder (BabylonNative and others) gets them for free, rather than each consumer reimplementing. Polyfills/File/: - File: Napi::ObjectWrap that delegates byte storage to the native Blob polyfill (constructs an inner Blob via the global constructor so it stays in lockstep with whatever Blob the runtime exposes) and layers `name` / `lastModified` on top. size/type/arrayBuffer/text/ bytes forward to the inner Blob. - FileReader: full ObjectWrap with readAsArrayBuffer / readAsText / readAsDataURL / readAsBinaryString, addEventListener / removeEventListener / dispatchEvent, on{load,error,loadstart, loadend,progress,abort} handler slots, EMPTY/LOADING/DONE state constants, and abort() honored via a monotonic readId token so a late-resolving arrayBuffer() promise can't dispatch a phantom load after the user aborted. The single base64 call site (readAsDataURL) uses an inlined RFC 4648 encoder to avoid pulling in a third-party dep just for this polyfill. - Initialize() is self-detecting: no-op when globalThis.File already exists, and no-op when globalThis.Blob is missing (so Blob::Initialize must run first - documented in Readme.md). Wiring: - CMakeLists.txt: new `JSRUNTIMEHOST_POLYFILL_FILE` option (ON by default), placed next to the existing `_BLOB` / `_PERFORMANCE` options. - Polyfills/CMakeLists.txt: `if(JSRUNTIMEHOST_POLYFILL_FILE) add_subdirectory(File) endif()` between Blob and Performance. Verified end-to-end via BabylonNative's GLTF/OBJ serializer round-trip tests (BabylonJS/BabylonNative#1706): 19/19 pass on Win32 D3D11 Release headless (test indices 208-216, 219-226, 275-276). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

@bghgary

Addresses @bghgary's review on BabylonJS#1706: File and FileReader are standard WHATWG web APIs that Babylon.js code paths depend on (GLTF serializer round-trip uses `new File([blob], 'scene.glb')` then `LoadAssetContainerAsync` which internally reads via `FileReader.readAsArrayBuffer`). The polyfills now live in JsRuntimeHost (next to `Polyfills/Blob/`) so every JsRuntimeHost consumer gets them, not just BabylonNative. The JsRuntimeHost-side change is at bkaradzic-microsoft/JsRuntimeHost@670084e5 ("Add File / FileReader polyfill"). This temporarily points BabylonNative's FetchContent at that fork branch; once the upstream JsRuntimeHost PR lands, we will re-pin to the merged commit on BabylonJS/JsRuntimeHost. Babylon Native side: - `CMakeLists.txt`: bump JsRuntimeHost GIT_TAG to `670084e5` and point GIT_REPOSITORY at the bkaradzic-microsoft fork until the upstream JsRuntimeHost PR is merged. - `Apps/Playground/Shared/AppContext.cpp`: include `<Babylon/Polyfills/File.h>` and call `Babylon::Polyfills::File::Initialize(env)` immediately after `Blob::Initialize(env)`. The old `LoadScript("app:///Scripts/ file_polyfill.js")` line is gone. - `Apps/Playground/CMakeLists.txt`: drop `file_polyfill.js` from SCRIPTS, link the new JsRuntimeHost `File` target into the Playground binary. - `Apps/Playground/Scripts/file_polyfill.js`: deleted (308 lines of JS subsumed by the C++ polyfill in JsRuntimeHost). Verified by running the GLTF/OBJ serializer round-trip tests that this PR re-enables (indices 208-216, 219-226, 275-276): 19/19 pass on Win32 D3D11 Release headless. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

@bghgary

Addresses @bghgary's review on BabylonJS#1706: File and FileReader are standard WHATWG web APIs that Babylon.js code paths depend on (GLTF serializer round-trip uses `new File([blob], 'scene.glb')` then `LoadAssetContainerAsync` which internally reads via `FileReader.readAsArrayBuffer`). The polyfills now live in JsRuntimeHost (next to `Polyfills/Blob/`) so every JsRuntimeHost consumer gets them, not just BabylonNative. The JsRuntimeHost-side change is at bkaradzic-microsoft/JsRuntimeHost@670084e5 ("Add File / FileReader polyfill"). This temporarily points BabylonNative's FetchContent at that fork branch; once the upstream JsRuntimeHost PR lands, we will re-pin to the merged commit on BabylonJS/JsRuntimeHost. Babylon Native side: - `CMakeLists.txt`: bump JsRuntimeHost GIT_TAG to `670084e5` and point GIT_REPOSITORY at the bkaradzic-microsoft fork until the upstream JsRuntimeHost PR is merged. - `Apps/Playground/Shared/AppContext.cpp`: include `<Babylon/Polyfills/File.h>` and call `Babylon::Polyfills::File::Initialize(env)` immediately after `Blob::Initialize(env)`. The old `LoadScript("app:///Scripts/ file_polyfill.js")` line is gone. - `Apps/Playground/CMakeLists.txt`: drop `file_polyfill.js` from SCRIPTS, link the new JsRuntimeHost `File` target into the Playground binary. - `Apps/Playground/Scripts/file_polyfill.js`: deleted (308 lines of JS subsumed by the C++ polyfill in JsRuntimeHost). Verified by running the GLTF/OBJ serializer round-trip tests that this PR re-enables (indices 208-216, 219-226, 275-276): 19/19 pass on Win32 D3D11 Release headless. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

The File polyfill was previously shipped as a JS shim (Apps/Playground/Scripts/file_polyfill.js, ~308 lines) and registered via LoadScript from AppContext. Per review on PR BabylonJS#1706 it now lives as a proper C++ polyfill in JsRuntimeHost alongside Blob, URL, WebSocket, XMLHttpRequest, etc., so every JsRuntimeHost consumer gets File / FileReader -- not only the Playground. This change: * Bumps the JsRuntimeHost FetchContent pin to the commit that adds Polyfills/File + unit tests. * Calls Babylon::Polyfills::File::Initialize(env) right after Babylon::Polyfills::Blob::Initialize(env) in AppContext. * Drops the file_polyfill.js shim and its LoadScript call. * Links the new File polyfill target in both the desktop and Android Playground CMakeLists. Re-enables 19 GLTF / OBJ tests that previously depended on the JS shim (208-216, 219-226, 275-276). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…1703) Fixes MSVC C4702 (unreachable code) under `/WX` in `Plugins/ExternalTexture/Source/ExternalTexture_OpenGL.cpp` so the OpenGL TU builds cleanly without the project-wide `/wd4702` workaround. ## What changed `Plugins/ExternalTexture/Source/ExternalTexture_OpenGL.cpp` keeps the unimplemented `Impl` stubs as `throw std::runtime_error{"not implemented"}` (so callers get an unambiguous diagnostic matching every other backend's unimplemented path) and wraps the `#include "ExternalTexture_Shared.h"` line in `#pragma warning(push)/(disable: 4702)/(pop)`. The shared dispatchers instantiated by that include unconditionally call the stubs, so MSVC's flow analysis flags the dispatcher's post-call code as unreachable; the pragma suppresses C4702 only for the dispatcher code instantiated in this translation unit. Any other code in this file is still subject to `/WX` C4702 enforcement. `Plugins/ExternalTexture/CMakeLists.txt` - drop the `/wd4702` target compile option, which previously silenced C4702 across the whole target. ## Alternatives considered - **`[[noreturn]]` on the stubs**: MSVC propagates "never returns" through the shared dispatcher, which flags *more* post-call statements as unreachable. Tried and rejected (it made the warning worse). - **TU-wide `/wd4702` via `target_compile_options`**: silences any future legitimate C4702 elsewhere in the same TU, defeating `/WX`. The current localized `#pragma warning(push/pop)` block keeps the rest of the TU under `/WX` enforcement. - **Replacing the throws with inert return-default stubs**: changes product behaviour (callers would silently receive a null texture instead of a clear "not implemented" error) to work around a compiler warning. Rejected on principle. ## Verified Clean under Debug + Release + RelWithDebInfo on OpenGL (`win32-gl`, `GRAPHICS_API=OpenGLWindowsDevOnly`) and D3D11 (`win32`). --- ## Landing context This PR is one of **7 splits** from the proven CI-green combined preview in **draft PR #1702** (see [#1702](#1702) for the full intended end-state and verified CI run [26044922430](https://github.com/BabylonJS/BabylonNative/actions/runs/26044922430)). > Note: the original split included an 8th PR (#1709, ES2020+ -> ES2019 syntax-repair polyfill for Chakra). It was closed in favour of investigating `@babel/standalone` properly (#1711). ### Recommended landing order **Tier 1 - parallel-reviewable, no source conflicts:** 1. #1703 - ExternalTexture C4702 build fix 2. #1704 - config.json `reason` rewrites (5 entries) 3. #1705 - config.json `reason` rewrites (17 entries) **Tier 2 - sequential, each touches `Apps/Playground/CMakeLists.txt` SCRIPTS list + `Apps/Playground/Shared/AppContext.cpp` LoadScript order; rebase the next branch after the previous merges:** 4. #1706 - File/Blob/FileReader polyfill (largest test impact: 19 re-enables) 5. #1707 - fetch polyfill 6. #1708 - DOM globals + native AbortController + Android CMake link 7. #1710 - Cubemap auto-expand polyfill (loaded after babylon.max.js) ### Reference policy reminder Reference PNGs across all 7 PRs come from Babylon.js; never re-baked by BN. Combined diff: **0 PNGs**. --------- Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

bkaradzic-microsoft and others added 5 commits May 15, 2026 20:58

Copilot AI review requested due to automatic review settings May 18, 2026 16:35

bkaradzic-microsoft requested review from CedricGuillemet, bghgary and ryantrem May 18, 2026 16:42

Copilot AI reviewed May 18, 2026

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Copilot started reviewing on behalf of bkaradzic-microsoft May 18, 2026 17:37 View session

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bghgary requested changes May 21, 2026

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bkaradzic-microsoft changed the title ~~Add File/Blob/FileReader polyfill for Playground (re-enables 19 GLTF tests)~~ File/FileReader C++ polyfill (re-enables 19 GLTF/OBJ tests) May 26, 2026

bkaradzic-microsoft force-pushed the weekend/tpc-1582-file-api branch from 18d0b82 to 93d7053 Compare May 26, 2026 18:04

bkaradzic-microsoft changed the title ~~File/FileReader C++ polyfill (re-enables 19 GLTF/OBJ tests)~~ Bump JsRuntimeHost for File/FileReader polyfill (re-enables 19 GLTF/OBJ tests) May 26, 2026

bkaradzic-microsoft force-pushed the weekend/tpc-1582-file-api branch from 93d7053 to 8644cf5 Compare May 26, 2026 18:07

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bkaradzic-microsoft mentioned this pull request May 26, 2026

Add File / FileReader polyfill BabylonJS/JsRuntimeHost#169

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bkaradzic-microsoft force-pushed the weekend/tpc-1582-file-api branch from 7cfdd7b to 7395246 Compare May 27, 2026 00:01

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Bump JsRuntimeHost for File/FileReader polyfill (re-enables 19 GLTF/OBJ tests)#1706

Bump JsRuntimeHost for File/FileReader polyfill (re-enables 19 GLTF/OBJ tests)#1706
bkaradzic-microsoft wants to merge 7 commits into
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bkaradzic-microsoft commented May 18, 2026 •

edited

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bkaradzic-microsoft commented May 18, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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bkaradzic-microsoft commented May 18, 2026 •

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