three.js/src/math/ColorManagement.js

import { SRGBColorSpace, LinearSRGBColorSpace, DisplayP3ColorSpace, LinearDisplayP3ColorSpace, Rec709Primaries, P3Primaries, SRGBTransfer, LinearTransfer, NoColorSpace, } from '../constants.js';
import { Matrix3 } from './Matrix3.js';

/**
 * Matrices converting P3 <-> Rec. 709 primaries, without gamut mapping
 * or clipping. Based on W3C specifications for sRGB and Display P3,
 * and ICC specifications for the D50 connection space. Values in/out
 * are _linear_ sRGB and _linear_ Display P3.
 *
 * Note that both sRGB and Display P3 use the sRGB transfer functions.
 *
 * Reference:
 * - http://www.russellcottrell.com/photo/matrixCalculator.htm
 */

const LINEAR_SRGB_TO_LINEAR_DISPLAY_P3 = /*@__PURE__*/ new Matrix3().set(
	0.8224621, 0.177538, 0.0,
	0.0331941, 0.9668058, 0.0,
	0.0170827, 0.0723974, 0.9105199,
);

const LINEAR_DISPLAY_P3_TO_LINEAR_SRGB = /*@__PURE__*/ new Matrix3().set(
	1.2249401, - 0.2249404, 0.0,
	- 0.0420569, 1.0420571, 0.0,
	- 0.0196376, - 0.0786361, 1.0982735
);

/**
 * Defines supported color spaces by transfer function and primaries,
 * and provides conversions to/from the Linear-sRGB reference space.
 */
const COLOR_SPACES = {
	[ LinearSRGBColorSpace ]: {
		transfer: LinearTransfer,
		primaries: Rec709Primaries,
		toReference: ( color ) => color,
		fromReference: ( color ) => color,
	},
	[ SRGBColorSpace ]: {
		transfer: SRGBTransfer,
		primaries: Rec709Primaries,
		toReference: ( color ) => color.convertSRGBToLinear(),
		fromReference: ( color ) => color.convertLinearToSRGB(),
	},
	[ LinearDisplayP3ColorSpace ]: {
		transfer: LinearTransfer,
		primaries: P3Primaries,
		toReference: ( color ) => color.applyMatrix3( LINEAR_DISPLAY_P3_TO_LINEAR_SRGB ),
		fromReference: ( color ) => color.applyMatrix3( LINEAR_SRGB_TO_LINEAR_DISPLAY_P3 ),
	},
	[ DisplayP3ColorSpace ]: {
		transfer: SRGBTransfer,
		primaries: P3Primaries,
		toReference: ( color ) => color.convertSRGBToLinear().applyMatrix3( LINEAR_DISPLAY_P3_TO_LINEAR_SRGB ),
		fromReference: ( color ) => color.applyMatrix3( LINEAR_SRGB_TO_LINEAR_DISPLAY_P3 ).convertLinearToSRGB(),
	},
};

const SUPPORTED_WORKING_COLOR_SPACES = new Set( [ LinearSRGBColorSpace, LinearDisplayP3ColorSpace ] );

export const ColorManagement = {

	enabled: true,

	_workingColorSpace: LinearSRGBColorSpace,

	get workingColorSpace() {

		return this._workingColorSpace;

	},

	set workingColorSpace( colorSpace ) {

		if ( ! SUPPORTED_WORKING_COLOR_SPACES.has( colorSpace ) ) {

			throw new Error( `Unsupported working color space, "${ colorSpace }".` );

		}

		this._workingColorSpace = colorSpace;

	},

	convert: function ( color, sourceColorSpace, targetColorSpace ) {

		if ( this.enabled === false || sourceColorSpace === targetColorSpace || ! sourceColorSpace || ! targetColorSpace ) {

			return color;

		}

		const sourceToReference = COLOR_SPACES[ sourceColorSpace ].toReference;
		const targetFromReference = COLOR_SPACES[ targetColorSpace ].fromReference;

		return targetFromReference( sourceToReference( color ) );

	},

	fromWorkingColorSpace: function ( color, targetColorSpace ) {

		return this.convert( color, this._workingColorSpace, targetColorSpace );

	},

	toWorkingColorSpace: function ( color, sourceColorSpace ) {

		return this.convert( color, sourceColorSpace, this._workingColorSpace );

	},

	getPrimaries: function ( colorSpace ) {

		return COLOR_SPACES[ colorSpace ].primaries;

	},

	getTransfer: function ( colorSpace ) {

		if ( colorSpace === NoColorSpace ) return LinearTransfer;

		return COLOR_SPACES[ colorSpace ].transfer;

	},

};


export function SRGBToLinear( c ) {

	return ( c < 0.04045 ) ? c * 0.0773993808 : Math.pow( c * 0.9478672986 + 0.0521327014, 2.4 );

}

export function LinearToSRGB( c ) {

	return ( c < 0.0031308 ) ? c * 12.92 : 1.055 * ( Math.pow( c, 0.41666 ) ) - 0.055;

}