Add Spark splat dynamic lighting and line-based point helper

[querielo]

Summary

Add dynamic Spark lighting support for Gaussian splats and switch point light helper rendering to line geometry (no wireframe mesh).

Screen.Recording.2026-06-05.at.00.28.08.mp4

Why

• Splats needed to react to scene lights.
• Point/spot behavior needed better parity with standard materials.
• Point light helper should avoid wireframe rendering.

Lighting Behavior

• PointLight + SpotLight supported for splats.
• SpotLight uses cone + range clipping.
• PointLight tuned dimmer for splats with softer falloff.
• Ambient/Directional mapping stays opt-in.
• Runtime-only lights skipped unless explicitly enabled.

Performance

• Scan-based light/splat discovery (scanIntervalMs).
• Reduced per-frame allocations in bridge.
• Fast path: no per-frame sync when no visible splats.

Validation

• Typecheck passed.
• Focused eslint passed.
• Runtime probes passed for:
  • spot cone orientation
  • point vs spot SDF composition
  • hidden-parent visibility handling
  • no-splat fast path

Risk / Notes

• Scan interval can add small propagation delay for new/removed lights/splats.
• Set scene.userData.rendering.splat.lighting.scanIntervalMs = 0 for immediate updates.

[Copilot]

Pull request overview

Note

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

Introduces a Spark dynamic lighting bridge that converts Three.js scene lights into Spark SDF-based lighting edits, wires it into the main renderer lifecycle, and updates helpers/loader behavior to support the new lighting workflow.

Changes:

• Added SparkSceneLightingBridge to scan scene lights and drive Spark SplatEdit/SplatEditSdf instances.
• Integrated lighting bridge creation/update/disposal into EffectRenderer.
• Updated VolumePointLightHelper implementation and made loaded splats editable.

Reviewed changes

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

File	Description
client/packages/editor-oss/src/render/SparkLightingBridge.ts	New bridge that maps Three lights to Spark lighting SDF edits and manages lifecycle.
client/packages/editor-oss/src/render/EffectRenderer.js	Creates/updates/disposes the lighting bridge during renderer init/render/cleanup.
client/packages/editor-oss/src/helper/light/VolumePointLightHelper.js	Replaces PointLightHelper inheritance with a custom LineSegments-based helper.
client/packages/editor-oss/src/assets/js/loaders/SparkGaussianSplatLoader.ts	Loads splats as editable to support downstream edits/lighting workflows.

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