PointLight/SpotLight: Deprecate distance parameter, auto-compute from intensity and decay.

[mrdoob]

Description

The distance parameter was redundant - it can be derived from the physically-based intensity and decay values. This simplifies the API and ensures consistency between visual range and actual light falloff.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	355.12 84.44	355.12 84.44	+0 B +0 B
WebGPU	616.54 171.12	616.54 171.12	+0 B +0 B
WebGPU Nodes	615.14 170.85	615.14 170.85	+0 B +0 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

	Before	After	Diff
WebGL	487.3 119.32	487.3 119.32	+0 B +0 B
WebGPU	687.29 186.66	687.72 186.75	+426 B +90 B
WebGPU Nodes	637.13 173.88	637.56 173.97	+426 B +88 B

[mrdoob]

Improved PointLightHelper while I was at it.

Screen.Recording.2025-12-13.at.17.16.29.mov

[mrdoob]

Seems like distance was yet another parameter that was affecting PBR accuracy.
The fall-off in RoomEnvironment was not correct and that "leaked" into all the examples that used it.