Restore NativeDraco free-function compatibility exports

[bkaradzic-microsoft]

Summary

• restore _native.decodeDracoMesh and _native.encodeDracoMesh as compatibility entry points
• retain the grouped _native.DracoCodec.Decode, Encode, and Version API
• cover cross-export encode/decode round trips and identical malformed-input error propagation
• update the NativeDraco API documentation

Compatibility scope

BabylonNative's unchanged stock runtime bundle is babylonjs 9.21.2. That bundle does not contain either native Draco feature probe. I also checked the published babylonjs and @babylonjs/core packages at 9.21.2 and at the current 9.26.0 release; neither contains _native.decodeDracoMesh or _native.encodeDracoMesh.

These exports therefore prepare NativeDraco for the Babylon.js native decoder/encoder interface without claiming that a released Babylon.js version currently selects this path. The signatures match that interface: synchronous decode returns { indices, attributes, totalVertices }, and synchronous encode returns { data: Int8Array, attributeIds }.

No dependency pin, lockfile, scene, reference, gate, or exclusion changed.

Validation

Configured and built with NativeDraco enabled:

cmake -S . -B build\win32 -G "Visual Studio 17 2022" -A x64 -DGRAPHICS_API=D3D11 -DBABYLON_NATIVE_PLUGIN_NATIVEXR=OFF -DBABYLON_NATIVE_PLUGIN_NATIVEDRACO=ON
npm run build  # Apps\UnitTests\JavaScript, before the native copy/build
cmake --build build\win32 --target UnitTests --config Release -- /m:2 /verbosity:minimal

Negative control on unchanged exports with the new regression tests:

UnitTests.exe --gtest_filter=JavaScript.All
63 passing, 10 pending, 2 failing

The failures explicitly reported the missing compatibility function and showed that its missing-function TypeError did not match the grouped decoder's native malformed-input error.

After the export change:

UnitTests.exe --gtest_filter=JavaScript.All
65 passing, 10 pending
[ PASSED ] JavaScript.All

This is API/unit coverage against stock pinned assets; no stock visual-test outcome is claimed because the released bundle does not probe these entry points.

[Copilot]

🟢 Approval recommended

The reviewed changes are covered by passing regression tests and documentation updates.

Pull request overview

Restores NativeDraco free-function compatibility exports while retaining the grouped DracoCodec API.

Changes:

• Adds decodeDracoMesh and encodeDracoMesh.
• Adds cross-export round-trip and error-propagation tests.
• Updates NativeDraco documentation and declarations.

File summaries

File	Description
Plugins/NativeDraco/Source/NativeDraco.cpp	Registers compatibility exports.
Plugins/NativeDraco/README.md	Documents both API forms.
Plugins/NativeDraco/Include/Babylon/Plugins/NativeDraco.h	Updates API comments.
Apps/UnitTests/JavaScript/src/tests.javaScript.all.ts	Adds compatibility tests.
Apps/UnitTests/JavaScript/dist/tests.javaScript.all.js	Updates compiled tests.

Review details

• Files reviewed: 4/5 changed files
• Comments generated: 0
• Review effort level: Lite

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[Copilot]

🟢 Approval recommended

No unresolved issues remain, and the exports, documentation, and regression coverage are included.

Review details

• Files reviewed: 4/5 changed files
• Comments generated: 0 new
• Review effort level: Lite