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

import { TempNode } from '../core/TempNode.js';
import { FunctionNode } from '../core/FunctionNode.js';
import { LuminanceNode } from './LuminanceNode.js';

function ColorAdjustmentNode( rgb, adjustment, method ) {

	TempNode.call( this, 'v3' );

	this.rgb = rgb;
	this.adjustment = adjustment;

	this.method = method || ColorAdjustmentNode.SATURATION;

}

ColorAdjustmentNode.Nodes = ( function () {

	var hue = new FunctionNode( [
		'vec3 hue(vec3 rgb, float adjustment) {',

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

		'	vec3 yiq = RGBtoYIQ * rgb;',

		'	float hue = atan(yiq.z, yiq.y) + adjustment;',
		'	float chroma = sqrt(yiq.z * yiq.z + yiq.y * yiq.y);',

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

		'}'
	].join( '\n' ) );

	var saturation = new FunctionNode( [
		// Algorithm from Chapter 16 of OpenGL Shading Language
		'vec3 saturation(vec3 rgb, float adjustment) {',

		'	vec3 intensity = vec3( luminance( rgb ) );',

		'	return mix( intensity, rgb, adjustment );',

		'}'
	].join( '\n' ), [ LuminanceNode.Nodes.luminance ] ); // include LuminanceNode function

	var vibrance = new FunctionNode( [
		// Shader by Evan Wallace adapted by @lo-th
		'vec3 vibrance(vec3 rgb, float adjustment) {',

		'	float average = (rgb.r + rgb.g + rgb.b) / 3.0;',

		'	float mx = max(rgb.r, max(rgb.g, rgb.b));',
		'	float amt = (mx - average) * (-3.0 * adjustment);',

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

		'}'
	].join( '\n' ) );

	return {
		hue: hue,
		saturation: saturation,
		vibrance: vibrance
	};

} )();

ColorAdjustmentNode.SATURATION = 'saturation';
ColorAdjustmentNode.HUE = 'hue';
ColorAdjustmentNode.VIBRANCE = 'vibrance';
ColorAdjustmentNode.BRIGHTNESS = 'brightness';
ColorAdjustmentNode.CONTRAST = 'contrast';

ColorAdjustmentNode.prototype = Object.create( TempNode.prototype );
ColorAdjustmentNode.prototype.constructor = ColorAdjustmentNode;
ColorAdjustmentNode.prototype.nodeType = 'ColorAdjustment';
ColorAdjustmentNode.prototype.hashProperties = [ 'method' ];

ColorAdjustmentNode.prototype.generate = function ( builder, output ) {

	var rgb = this.rgb.build( builder, 'v3' ),
		adjustment = this.adjustment.build( builder, 'f' );

	switch ( this.method ) {

		case ColorAdjustmentNode.BRIGHTNESS:

			return builder.format( '( ' + rgb + ' + ' + adjustment + ' )', this.getType( builder ), output );

			break;

		case ColorAdjustmentNode.CONTRAST:

			return builder.format( '( ' + rgb + ' * ' + adjustment + ' )', this.getType( builder ), output );

			break;

	}

	var method = builder.include( ColorAdjustmentNode.Nodes[ this.method ] );

	return builder.format( method + '( ' + rgb + ', ' + adjustment + ' )', this.getType( builder ), output );

};

ColorAdjustmentNode.prototype.copy = function ( source ) {

	TempNode.prototype.copy.call( this, source );

	this.rgb = source.rgb;
	this.adjustment = source.adjustment;
	this.method = source.method;

	return this;

};

ColorAdjustmentNode.prototype.toJSON = function ( meta ) {

	var data = this.getJSONNode( meta );

	if ( ! data ) {

		data = this.createJSONNode( meta );

		data.rgb = this.rgb.toJSON( meta ).uuid;
		data.adjustment = this.adjustment.toJSON( meta ).uuid;
		data.method = this.method;

	}

	return data;

};

export { ColorAdjustmentNode };