[compat-sync] Back NullEngine with Lite headless engine + add RawTexture3D

[babylon-compat-sync]

Automated sync of @babylonjs/lite-compat against the latest Babylon.js and Babylon Lite changes,
produced by the update-compat-layer skill.

Synced against BJS commit: fe3f8210e9def4da065ec4ee2b2ef07e5afff63b

Validation (run independently by the pipeline)

• ✅ compat unit tests
• ✅ compat typecheck

Changed files

• ackages/babylon-lite-compat/COMPAT-STATUS.md
• packages/babylon-lite-compat/README.md
• packages/babylon-lite-compat/src/engine/engine.ts
• packages/babylon-lite-compat/src/index.ts
• packages/babylon-lite-compat/src/scene/scene.ts
• packages/babylon-lite-compat/src/textures/textures.ts
• packages/babylon-lite-compat/tests/null-engine.test.ts
• packages/babylon-lite/src/engine/null-engine.ts
• packages/babylon-lite-compat/tests/raw-texture-3d.test.ts

Validation passed. Please review the wrapper changes and the updated COMPAT-STATUS.md before merging.

Opened as a draft by the compat-sync pipeline. Review and mark ready when satisfied.

[bjsplat]

Lab - Static Site

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_{Build 20260704.1 - merge @ 92b0f1f}

[Copilot]

Pull request overview

Syncs @babylonjs/lite-compat to the referenced Babylon.js commit by replacing the compat NullEngine stub with Babylon Lite’s real headless engine path, and adds a compat RawTexture3D wrapper backed by Lite’s createTexture3DFromPixels.

Changes:

• Back compat NullEngine/headless Scene with Babylon Lite’s createNullEngine + stepScene, using defaultRenderTask: false for deviceless simulation.
• Add compat RawTexture3D (construction, getters, update, whenReadyAsync) and export it from the compat entrypoint.
• Add/extend compat tests for the headless engine stepping path and RawTexture3D argument coercion/forwarding.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
packages/babylon-lite/src/engine/null-engine.ts	Ensures headless engine contexts have _renderingContexts so scene disposal/unregister paths are safe.
packages/babylon-lite-compat/src/engine/engine.ts	Switches compat NullEngine to Lite createNullEngine + stepScene and updates headless run loop semantics.
packages/babylon-lite-compat/src/scene/scene.ts	Replaces the prior headless SceneContext stub with a real Lite scene context using defaultRenderTask: false, and always disposes via disposeScene.
packages/babylon-lite-compat/src/textures/textures.ts	Adds RawTexture3D wrapper and the helper that coerces raw data to RGBA bytes for Lite upload.
packages/babylon-lite-compat/src/index.ts	Re-exports RawTexture3D from the compat public surface.
packages/babylon-lite-compat/README.md	Updates supported texture surface list to include RawTexture3D.
packages/babylon-lite-compat/COMPAT-STATUS.md	Updates sync SHA/date and marks NullEngine and RawTexture3D support status/details.
packages/babylon-lite-compat/tests/null-engine.test.ts	Adds assertions proving headless scenes are Lite-driven and stepped via stepScene (observables + delta).
packages/babylon-lite-compat/tests/raw-texture-3d.test.ts	Adds unit coverage for RawTexture3D forwarding, coercion, getters, update, and readiness behavior.

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[bjsplat]

Bundle Size Changes

Decreases

Package	Current	Master	Change
Scene 146 — PBR Geometry Renderer (Sponza) scene146	65 KB	112 KB	-47 KB

Sizes rounded to nearest KB. Run pnpm build:bundle-scenes locally to verify.

[bjsplat]

Lab - Static Site

Open deployed site

_{Build 20260706.14 - merge @ 208ca35}