ColorUtils: Add setKelvin().

[Nedunchezhiyan-M]

Related issue: N/A

Description

Adds setKelvin( color, kelvin ) to a new examples/jsm/utils/ColorUtils.js module — converts a color temperature (1000K–40000K) to an approximate sRGB color using Tanner Helland's well-known algorithm.

Follows the suggestion from code review to place this in utils/ rather than core, using the same named-function module pattern as GeometryUtils, SceneUtils, etc.

import * as ColorUtils from 'three/addons/utils/ColorUtils.js';

const light = new THREE.PointLight();
ColorUtils.setKelvin( light.color, 3200 ); // tungsten studio light

Input is clamped to [1000, 40000]K. Output is passed through setRGB( r, g, b, SRGBColorSpace ) for correct color management.

Changes

• examples/jsm/utils/ColorUtils.js — new module with setKelvin()
• test/unit/addons/utils/ColorUtils.tests.js — unit tests (all pass, 0 failures)
• test/unit/three.addons.unit.js — registers the new test file

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	361.21 85.78	361.21 85.78	+0 B +0 B
WebGPU	637.48 177.06	637.48 177.06	+0 B +0 B
WebGPU Nodes	635.59 176.76	635.59 176.76	+0 B +0 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	493.58 120.42	493.91 120.62	+335 B +201 B
WebGPU	709.22 191.88	709.55 192.05	+335 B +174 B
WebGPU Nodes	658.44 179.17	658.77 179.35	+335 B +183 B