three.js/examples/jsm/nodes/display/ColorAdjustmentNode.js

import TempNode from '../core/TempNode.js';
import { ShaderNode, vec3, mat3, add, sub, mul, max, div, float, mix, cos, sin, atan2, sqrt, luminance } from '../shadernode/ShaderNodeBaseElements.js';

const saturationNode = new ShaderNode( ( { color, adjustment } ) => {

	return mix( luminance( color ), color, adjustment );

} );

const vibranceNode = new ShaderNode( ( { color, adjustment } ) => {

	const average = div( add( color.r, color.g, color.b ), 3.0 );

	const mx = max( color.r, max( color.g, color.b ) );
	const amt = mul( sub( mx, average ), mul( - 3.0, adjustment ) );

	return mix( color.rgb, vec3( mx ), amt );

} );

const hueNode = new ShaderNode( ( { color, adjustment } ) => {

	const RGBtoYIQ = mat3( 0.299, 0.587, 0.114, 0.595716, - 0.274453, - 0.321263, 0.211456, - 0.522591, 0.311135 );
	const YIQtoRGB = mat3( 1.0, 0.9563, 0.6210, 1.0, - 0.2721, - 0.6474, 1.0, - 1.107, 1.7046 );

	const yiq = mul( RGBtoYIQ, color );

	const hue = add( atan2( yiq.z, yiq.y ), adjustment );
	const chroma = sqrt( add( mul( yiq.z, yiq.z ), mul( yiq.y, yiq.y ) ) );

	return mul( YIQtoRGB, vec3( yiq.x, mul( chroma, cos( hue ) ), mul( chroma, sin( hue ) ) ) );

} );

class ColorAdjustmentNode extends TempNode {

	constructor( method, colorNode, adjustmentNode = float( 1 ) ) {

		super( 'vec3' );

		this.method = method;

		this.colorNode = colorNode;
		this.adjustmentNode = adjustmentNode;

	}

	construct() {

		const { method, colorNode, adjustmentNode } = this;

		const callParams = { color: colorNode, adjustment: adjustmentNode };

		let outputNode = null;

		if ( method === ColorAdjustmentNode.SATURATION ) {

			outputNode = saturationNode.call( callParams );

		} else if ( method === ColorAdjustmentNode.VIBRANCE ) {

			outputNode = vibranceNode.call( callParams );

		} else if ( method === ColorAdjustmentNode.HUE ) {

			outputNode = hueNode.call( callParams );

		} else {

			console.error( `${ this.type }: Method "${ this.method }" not supported!` );

		}

		return outputNode;

	}

}

ColorAdjustmentNode.SATURATION = 'saturation';
ColorAdjustmentNode.VIBRANCE = 'vibrance';
ColorAdjustmentNode.HUE = 'hue';

export default ColorAdjustmentNode;