three.js/src/math/Color.js

import { clamp, euclideanModulo, lerp } from './MathUtils.js';
import { ColorManagement, SRGBToLinear, LinearToSRGB } from './ColorManagement.js';
import { SRGBColorSpace } from '../constants.js';
import { warn } from '../utils.js';

const _colorKeywords = { 'aliceblue': 0xF0F8FF, 'antiquewhite': 0xFAEBD7, 'aqua': 0x00FFFF, 'aquamarine': 0x7FFFD4, 'azure': 0xF0FFFF,
	'beige': 0xF5F5DC, 'bisque': 0xFFE4C4, 'black': 0x000000, 'blanchedalmond': 0xFFEBCD, 'blue': 0x0000FF, 'blueviolet': 0x8A2BE2,
	'brown': 0xA52A2A, 'burlywood': 0xDEB887, 'cadetblue': 0x5F9EA0, 'chartreuse': 0x7FFF00, 'chocolate': 0xD2691E, 'coral': 0xFF7F50,
	'cornflowerblue': 0x6495ED, 'cornsilk': 0xFFF8DC, 'crimson': 0xDC143C, 'cyan': 0x00FFFF, 'darkblue': 0x00008B, 'darkcyan': 0x008B8B,
	'darkgoldenrod': 0xB8860B, 'darkgray': 0xA9A9A9, 'darkgreen': 0x006400, 'darkgrey': 0xA9A9A9, 'darkkhaki': 0xBDB76B, 'darkmagenta': 0x8B008B,
	'darkolivegreen': 0x556B2F, 'darkorange': 0xFF8C00, 'darkorchid': 0x9932CC, 'darkred': 0x8B0000, 'darksalmon': 0xE9967A, 'darkseagreen': 0x8FBC8F,
	'darkslateblue': 0x483D8B, 'darkslategray': 0x2F4F4F, 'darkslategrey': 0x2F4F4F, 'darkturquoise': 0x00CED1, 'darkviolet': 0x9400D3,
	'deeppink': 0xFF1493, 'deepskyblue': 0x00BFFF, 'dimgray': 0x696969, 'dimgrey': 0x696969, 'dodgerblue': 0x1E90FF, 'firebrick': 0xB22222,
	'floralwhite': 0xFFFAF0, 'forestgreen': 0x228B22, 'fuchsia': 0xFF00FF, 'gainsboro': 0xDCDCDC, 'ghostwhite': 0xF8F8FF, 'gold': 0xFFD700,
	'goldenrod': 0xDAA520, 'gray': 0x808080, 'green': 0x008000, 'greenyellow': 0xADFF2F, 'grey': 0x808080, 'honeydew': 0xF0FFF0, 'hotpink': 0xFF69B4,
	'indianred': 0xCD5C5C, 'indigo': 0x4B0082, 'ivory': 0xFFFFF0, 'khaki': 0xF0E68C, 'lavender': 0xE6E6FA, 'lavenderblush': 0xFFF0F5, 'lawngreen': 0x7CFC00,
	'lemonchiffon': 0xFFFACD, 'lightblue': 0xADD8E6, 'lightcoral': 0xF08080, 'lightcyan': 0xE0FFFF, 'lightgoldenrodyellow': 0xFAFAD2, 'lightgray': 0xD3D3D3,
	'lightgreen': 0x90EE90, 'lightgrey': 0xD3D3D3, 'lightpink': 0xFFB6C1, 'lightsalmon': 0xFFA07A, 'lightseagreen': 0x20B2AA, 'lightskyblue': 0x87CEFA,
	'lightslategray': 0x778899, 'lightslategrey': 0x778899, 'lightsteelblue': 0xB0C4DE, 'lightyellow': 0xFFFFE0, 'lime': 0x00FF00, 'limegreen': 0x32CD32,
	'linen': 0xFAF0E6, 'magenta': 0xFF00FF, 'maroon': 0x800000, 'mediumaquamarine': 0x66CDAA, 'mediumblue': 0x0000CD, 'mediumorchid': 0xBA55D3,
	'mediumpurple': 0x9370DB, 'mediumseagreen': 0x3CB371, 'mediumslateblue': 0x7B68EE, 'mediumspringgreen': 0x00FA9A, 'mediumturquoise': 0x48D1CC,
	'mediumvioletred': 0xC71585, 'midnightblue': 0x191970, 'mintcream': 0xF5FFFA, 'mistyrose': 0xFFE4E1, 'moccasin': 0xFFE4B5, 'navajowhite': 0xFFDEAD,
	'navy': 0x000080, 'oldlace': 0xFDF5E6, 'olive': 0x808000, 'olivedrab': 0x6B8E23, 'orange': 0xFFA500, 'orangered': 0xFF4500, 'orchid': 0xDA70D6,
	'palegoldenrod': 0xEEE8AA, 'palegreen': 0x98FB98, 'paleturquoise': 0xAFEEEE, 'palevioletred': 0xDB7093, 'papayawhip': 0xFFEFD5, 'peachpuff': 0xFFDAB9,
	'peru': 0xCD853F, 'pink': 0xFFC0CB, 'plum': 0xDDA0DD, 'powderblue': 0xB0E0E6, 'purple': 0x800080, 'rebeccapurple': 0x663399, 'red': 0xFF0000, 'rosybrown': 0xBC8F8F,
	'royalblue': 0x4169E1, 'saddlebrown': 0x8B4513, 'salmon': 0xFA8072, 'sandybrown': 0xF4A460, 'seagreen': 0x2E8B57, 'seashell': 0xFFF5EE,
	'sienna': 0xA0522D, 'silver': 0xC0C0C0, 'skyblue': 0x87CEEB, 'slateblue': 0x6A5ACD, 'slategray': 0x708090, 'slategrey': 0x708090, 'snow': 0xFFFAFA,
	'springgreen': 0x00FF7F, 'steelblue': 0x4682B4, 'tan': 0xD2B48C, 'teal': 0x008080, 'thistle': 0xD8BFD8, 'tomato': 0xFF6347, 'turquoise': 0x40E0D0,
	'violet': 0xEE82EE, 'wheat': 0xF5DEB3, 'white': 0xFFFFFF, 'whitesmoke': 0xF5F5F5, 'yellow': 0xFFFF00, 'yellowgreen': 0x9ACD32 };

const _hslA = { h: 0, s: 0, l: 0 };
const _hslB = { h: 0, s: 0, l: 0 };

function hue2rgb( p, q, t ) {

	if ( t < 0 ) t += 1;
	if ( t > 1 ) t -= 1;
	if ( t < 1 / 6 ) return p + ( q - p ) * 6 * t;
	if ( t < 1 / 2 ) return q;
	if ( t < 2 / 3 ) return p + ( q - p ) * 6 * ( 2 / 3 - t );
	return p;

}

/**
 * A Color instance is represented by RGB components in the linear <i>working
 * color space</i>, which defaults to `LinearSRGBColorSpace`. Inputs
 * conventionally using `SRGBColorSpace` (such as hexadecimals and CSS
 * strings) are converted to the working color space automatically.
 *
 * ```js
 * // converted automatically from SRGBColorSpace to LinearSRGBColorSpace
 * const color = new THREE.Color().setHex( 0x112233 );
 * ```
 * Source color spaces may be specified explicitly, to ensure correct conversions.
 * ```js
 * // assumed already LinearSRGBColorSpace; no conversion
 * const color = new THREE.Color().setRGB( 0.5, 0.5, 0.5 );
 *
 * // converted explicitly from SRGBColorSpace to LinearSRGBColorSpace
 * const color = new THREE.Color().setRGB( 0.5, 0.5, 0.5, SRGBColorSpace );
 * ```
 * If THREE.ColorManagement is disabled, no conversions occur. For details,
 * see <i>Color management</i>. Iterating through a Color instance will yield
 * its components (r, g, b) in the corresponding order. A Color can be initialised
 * in any of the following ways:
 * ```js
 * //empty constructor - will default white
 * const color1 = new THREE.Color();
 *
 * //Hexadecimal color (recommended)
 * const color2 = new THREE.Color( 0xff0000 );
 *
 * //RGB string
 * const color3 = new THREE.Color("rgb(255, 0, 0)");
 * const color4 = new THREE.Color("rgb(100%, 0%, 0%)");
 *
 * //X11 color name - all 140 color names are supported.
 * //Note the lack of CamelCase in the name
 * const color5 = new THREE.Color( 'skyblue' );
 * //HSL string
 * const color6 = new THREE.Color("hsl(0, 100%, 50%)");
 *
 * //Separate RGB values between 0 and 1
 * const color7 = new THREE.Color( 1, 0, 0 );
 * ```
 */
class Color {

	/**
	 * Constructs a new color.
	 *
	 * Note that standard method of specifying color in three.js is with a hexadecimal triplet,
	 * and that method is used throughout the rest of the documentation.
	 *
	 * @param {(number|string|Color)} [r] - The red component of the color. If `g` and `b` are
	 * not provided, it can be hexadecimal triplet, a CSS-style string or another `Color` instance.
	 * @param {number} [g] - The green component.
	 * @param {number} [b] - The blue component.
	 */
	constructor( r, g, b ) {

		/**
		 * This flag can be used for type testing.
		 *
		 * @type {boolean}
		 * @readonly
		 * @default true
		 */
		this.isColor = true;

		/**
		 * The red component.
		 *
		 * @type {number}
		 * @default 1
		 */
		this.r = 1;

		/**
		 * The green component.
		 *
		 * @type {number}
		 * @default 1
		 */
		this.g = 1;

		/**
		 * The blue component.
		 *
		 * @type {number}
		 * @default 1
		 */
		this.b = 1;

		return this.set( r, g, b );

	}

	/**
	 * Sets the colors's components from the given values.
	 *
	 * @param {(number|string|Color)} [r] - The red component of the color. If `g` and `b` are
	 * not provided, it can be hexadecimal triplet, a CSS-style string or another `Color` instance.
	 * @param {number} [g] - The green component.
	 * @param {number} [b] - The blue component.
	 * @return {Color} A reference to this color.
	 */
	set( r, g, b ) {

		if ( g === undefined && b === undefined ) {

			// r is THREE.Color, hex or string

			const value = r;

			if ( value && value.isColor ) {

				this.copy( value );

			} else if ( typeof value === 'number' ) {

				this.setHex( value );

			} else if ( typeof value === 'string' ) {

				this.setStyle( value );

			}

		} else {

			this.setRGB( r, g, b );

		}

		return this;

	}

	/**
	 * Sets the colors's components to the given scalar value.
	 *
	 * @param {number} scalar - The scalar value.
	 * @return {Color} A reference to this color.
	 */
	setScalar( scalar ) {

		this.r = scalar;
		this.g = scalar;
		this.b = scalar;

		return this;

	}

	/**
	 * Sets this color from a hexadecimal value.
	 *
	 * @param {number} hex - The hexadecimal value.
	 * @param {string} [colorSpace=SRGBColorSpace] - The color space.
	 * @return {Color} A reference to this color.
	 */
	setHex( hex, colorSpace = SRGBColorSpace ) {

		hex = Math.floor( hex );

		this.r = ( hex >> 16 & 255 ) / 255;
		this.g = ( hex >> 8 & 255 ) / 255;
		this.b = ( hex & 255 ) / 255;

		ColorManagement.colorSpaceToWorking( this, colorSpace );

		return this;

	}

	/**
	 * Sets this color from RGB values.
	 *
	 * @param {number} r - Red channel value between `0.0` and `1.0`.
	 * @param {number} g - Green channel value between `0.0` and `1.0`.
	 * @param {number} b - Blue channel value between `0.0` and `1.0`.
	 * @param {string} [colorSpace=ColorManagement.workingColorSpace] - The color space.
	 * @return {Color} A reference to this color.
	 */
	setRGB( r, g, b, colorSpace = ColorManagement.workingColorSpace ) {

		this.r = r;
		this.g = g;
		this.b = b;

		ColorManagement.colorSpaceToWorking( this, colorSpace );

		return this;

	}

	/**
	 * Sets this color from RGB values.
	 *
	 * @param {number} h - Hue value between `0.0` and `1.0`.
	 * @param {number} s - Saturation value between `0.0` and `1.0`.
	 * @param {number} l - Lightness value between `0.0` and `1.0`.
	 * @param {string} [colorSpace=ColorManagement.workingColorSpace] - The color space.
	 * @return {Color} A reference to this color.
	 */
	setHSL( h, s, l, colorSpace = ColorManagement.workingColorSpace ) {

		// h,s,l ranges are in 0.0 - 1.0
		h = euclideanModulo( h, 1 );
		s = clamp( s, 0, 1 );
		l = clamp( l, 0, 1 );

		if ( s === 0 ) {

			this.r = this.g = this.b = l;

		} else {

			const p = l <= 0.5 ? l * ( 1 + s ) : l + s - ( l * s );
			const q = ( 2 * l ) - p;

			this.r = hue2rgb( q, p, h + 1 / 3 );
			this.g = hue2rgb( q, p, h );
			this.b = hue2rgb( q, p, h - 1 / 3 );

		}

		ColorManagement.colorSpaceToWorking( this, colorSpace );

		return this;

	}

	/**
	 * Sets this color from a CSS-style string. For example, `rgb(250, 0,0)`,
	 * `rgb(100%, 0%, 0%)`, `hsl(0, 100%, 50%)`, `#ff0000`, `#f00`, or `red` ( or
	 * any [X11 color name]{@link https://en.wikipedia.org/wiki/X11_color_names#Color_name_chart} -
	 * all 140 color names are supported).
	 *
	 * @param {string} style - Color as a CSS-style string.
	 * @param {string} [colorSpace=SRGBColorSpace] - The color space.
	 * @return {Color} A reference to this color.
	 */
	setStyle( style, colorSpace = SRGBColorSpace ) {

		function handleAlpha( string ) {

			if ( string === undefined ) return;

			if ( parseFloat( string ) < 1 ) {

				warn( 'Color: Alpha component of ' + style + ' will be ignored.' );

			}

		}


		let m;

		if ( m = /^(\w+)\(([^\)]*)\)/.exec( style ) ) {

			// rgb / hsl

			let color;
			const name = m[ 1 ];
			const components = m[ 2 ];

			switch ( name ) {

				case 'rgb':
				case 'rgba':

					if ( color = /^\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*(?:,\s*(\d*\.?\d+)\s*)?$/.exec( components ) ) {

						// rgb(255,0,0) rgba(255,0,0,0.5)

						handleAlpha( color[ 4 ] );

						return this.setRGB(
							Math.min( 255, parseInt( color[ 1 ], 10 ) ) / 255,
							Math.min( 255, parseInt( color[ 2 ], 10 ) ) / 255,
							Math.min( 255, parseInt( color[ 3 ], 10 ) ) / 255,
							colorSpace
						);

					}

					if ( color = /^\s*(\d+)\%\s*,\s*(\d+)\%\s*,\s*(\d+)\%\s*(?:,\s*(\d*\.?\d+)\s*)?$/.exec( components ) ) {

						// rgb(100%,0%,0%) rgba(100%,0%,0%,0.5)

						handleAlpha( color[ 4 ] );

						return this.setRGB(
							Math.min( 100, parseInt( color[ 1 ], 10 ) ) / 100,
							Math.min( 100, parseInt( color[ 2 ], 10 ) ) / 100,
							Math.min( 100, parseInt( color[ 3 ], 10 ) ) / 100,
							colorSpace
						);

					}

					break;

				case 'hsl':
				case 'hsla':

					if ( color = /^\s*(\d*\.?\d+)\s*,\s*(\d*\.?\d+)\%\s*,\s*(\d*\.?\d+)\%\s*(?:,\s*(\d*\.?\d+)\s*)?$/.exec( components ) ) {

						// hsl(120,50%,50%) hsla(120,50%,50%,0.5)

						handleAlpha( color[ 4 ] );

						return this.setHSL(
							parseFloat( color[ 1 ] ) / 360,
							parseFloat( color[ 2 ] ) / 100,
							parseFloat( color[ 3 ] ) / 100,
							colorSpace
						);

					}

					break;

				default:

					warn( 'Color: Unknown color model ' + style );

			}

		} else if ( m = /^\#([A-Fa-f\d]+)$/.exec( style ) ) {

			// hex color

			const hex = m[ 1 ];
			const size = hex.length;

			if ( size === 3 ) {

				// #ff0
				return this.setRGB(
					parseInt( hex.charAt( 0 ), 16 ) / 15,
					parseInt( hex.charAt( 1 ), 16 ) / 15,
					parseInt( hex.charAt( 2 ), 16 ) / 15,
					colorSpace
				);

			} else if ( size === 6 ) {

				// #ff0000
				return this.setHex( parseInt( hex, 16 ), colorSpace );

			} else {

				warn( 'Color: Invalid hex color ' + style );

			}

		} else if ( style && style.length > 0 ) {

			return this.setColorName( style, colorSpace );

		}

		return this;

	}

	/**
	 * Sets this color from a color name. Faster than {@link Color#setStyle} if
	 * you don't need the other CSS-style formats.
	 *
	 * For convenience, the list of names is exposed in `Color.NAMES` as a hash.
	 * ```js
	 * Color.NAMES.aliceblue // returns 0xF0F8FF
	 * ```
	 *
	 * @param {string} style - The color name.
	 * @param {string} [colorSpace=SRGBColorSpace] - The color space.
	 * @return {Color} A reference to this color.
	 */
	setColorName( style, colorSpace = SRGBColorSpace ) {

		// color keywords
		const hex = _colorKeywords[ style.toLowerCase() ];

		if ( hex !== undefined ) {

			// red
			this.setHex( hex, colorSpace );

		} else {

			// unknown color
			warn( 'Color: Unknown color ' + style );

		}

		return this;

	}

	/**
	 * Returns a new color with copied values from this instance.
	 *
	 * @return {Color} A clone of this instance.
	 */
	clone() {

		return new this.constructor( this.r, this.g, this.b );

	}

	/**
	 * Copies the values of the given color to this instance.
	 *
	 * @param {Color} color - The color to copy.
	 * @return {Color} A reference to this color.
	 */
	copy( color ) {

		this.r = color.r;
		this.g = color.g;
		this.b = color.b;

		return this;

	}

	/**
	 * Copies the given color into this color, and then converts this color from
	 * `SRGBColorSpace` to `LinearSRGBColorSpace`.
	 *
	 * @param {Color} color - The color to copy/convert.
	 * @return {Color} A reference to this color.
	 */
	copySRGBToLinear( color ) {

		this.r = SRGBToLinear( color.r );
		this.g = SRGBToLinear( color.g );
		this.b = SRGBToLinear( color.b );

		return this;

	}

	/**
	 * Copies the given color into this color, and then converts this color from
	 * `LinearSRGBColorSpace` to `SRGBColorSpace`.
	 *
	 * @param {Color} color - The color to copy/convert.
	 * @return {Color} A reference to this color.
	 */
	copyLinearToSRGB( color ) {

		this.r = LinearToSRGB( color.r );
		this.g = LinearToSRGB( color.g );
		this.b = LinearToSRGB( color.b );

		return this;

	}

	/**
	 * Converts this color from `SRGBColorSpace` to `LinearSRGBColorSpace`.
	 *
	 * @return {Color} A reference to this color.
	 */
	convertSRGBToLinear() {

		this.copySRGBToLinear( this );

		return this;

	}

	/**
	 * Converts this color from `LinearSRGBColorSpace` to `SRGBColorSpace`.
	 *
	 * @return {Color} A reference to this color.
	 */
	convertLinearToSRGB() {

		this.copyLinearToSRGB( this );

		return this;

	}

	/**
	 * Returns the hexadecimal value of this color.
	 *
	 * @param {string} [colorSpace=SRGBColorSpace] - The color space.
	 * @return {number} The hexadecimal value.
	 */
	getHex( colorSpace = SRGBColorSpace ) {

		ColorManagement.workingToColorSpace( _color.copy( this ), colorSpace );

		return Math.round( clamp( _color.r * 255, 0, 255 ) ) * 65536 + Math.round( clamp( _color.g * 255, 0, 255 ) ) * 256 + Math.round( clamp( _color.b * 255, 0, 255 ) );

	}

	/**
	 * Returns the hexadecimal value of this color as a string (for example, 'FFFFFF').
	 *
	 * @param {string} [colorSpace=SRGBColorSpace] - The color space.
	 * @return {string} The hexadecimal value as a string.
	 */
	getHexString( colorSpace = SRGBColorSpace ) {

		return ( '000000' + this.getHex( colorSpace ).toString( 16 ) ).slice( - 6 );

	}

	/**
	 * Converts the colors RGB values into the HSL format and stores them into the
	 * given target object.
	 *
	 * @param {{h:number,s:number,l:number}} target - The target object that is used to store the method's result.
	 * @param {string} [colorSpace=ColorManagement.workingColorSpace] - The color space.
	 * @return {{h:number,s:number,l:number}} The HSL representation of this color.
	 */
	getHSL( target, colorSpace = ColorManagement.workingColorSpace ) {

		// h,s,l ranges are in 0.0 - 1.0

		ColorManagement.workingToColorSpace( _color.copy( this ), colorSpace );

		const r = _color.r, g = _color.g, b = _color.b;

		const max = Math.max( r, g, b );
		const min = Math.min( r, g, b );

		let hue, saturation;
		const lightness = ( min + max ) / 2.0;

		if ( min === max ) {

			hue = 0;
			saturation = 0;

		} else {

			const delta = max - min;

			saturation = lightness <= 0.5 ? delta / ( max + min ) : delta / ( 2 - max - min );

			switch ( max ) {

				case r: hue = ( g - b ) / delta + ( g < b ? 6 : 0 ); break;
				case g: hue = ( b - r ) / delta + 2; break;
				case b: hue = ( r - g ) / delta + 4; break;

			}

			hue /= 6;

		}

		target.h = hue;
		target.s = saturation;
		target.l = lightness;

		return target;

	}

	/**
	 * Returns the RGB values of this color and stores them into the given target object.
	 *
	 * @param {Color} target - The target color that is used to store the method's result.
	 * @param {string} [colorSpace=ColorManagement.workingColorSpace] - The color space.
	 * @return {Color} The RGB representation of this color.
	 */
	getRGB( target, colorSpace = ColorManagement.workingColorSpace ) {

		ColorManagement.workingToColorSpace( _color.copy( this ), colorSpace );

		target.r = _color.r;
		target.g = _color.g;
		target.b = _color.b;

		return target;

	}

	/**
	 * Returns the value of this color as a CSS style string. Example: `rgb(255,0,0)`.
	 *
	 * @param {string} [colorSpace=SRGBColorSpace] - The color space.
	 * @return {string} The CSS representation of this color.
	 */
	getStyle( colorSpace = SRGBColorSpace ) {

		ColorManagement.workingToColorSpace( _color.copy( this ), colorSpace );

		const r = _color.r, g = _color.g, b = _color.b;

		if ( colorSpace !== SRGBColorSpace ) {

			// Requires CSS Color Module Level 4 (https://www.w3.org/TR/css-color-4/).
			return `color(${ colorSpace } ${ r.toFixed( 3 ) } ${ g.toFixed( 3 ) } ${ b.toFixed( 3 ) })`;

		}

		return `rgb(${ Math.round( r * 255 ) },${ Math.round( g * 255 ) },${ Math.round( b * 255 ) })`;

	}

	/**
	 * Adds the given HSL values to this color's values.
	 * Internally, this converts the color's RGB values to HSL, adds HSL
	 * and then converts the color back to RGB.
	 *
	 * @param {number} h - Hue value between `0.0` and `1.0`.
	 * @param {number} s - Saturation value between `0.0` and `1.0`.
	 * @param {number} l - Lightness value between `0.0` and `1.0`.
	 * @return {Color} A reference to this color.
	 */
	offsetHSL( h, s, l ) {

		this.getHSL( _hslA );

		return this.setHSL( _hslA.h + h, _hslA.s + s, _hslA.l + l );

	}

	/**
	 * Adds the RGB values of the given color to the RGB values of this color.
	 *
	 * @param {Color} color - The color to add.
	 * @return {Color} A reference to this color.
	 */
	add( color ) {

		this.r += color.r;
		this.g += color.g;
		this.b += color.b;

		return this;

	}

	/**
	 * Adds the RGB values of the given colors and stores the result in this instance.
	 *
	 * @param {Color} color1 - The first color.
	 * @param {Color} color2 - The second color.
	 * @return {Color} A reference to this color.
	 */
	addColors( color1, color2 ) {

		this.r = color1.r + color2.r;
		this.g = color1.g + color2.g;
		this.b = color1.b + color2.b;

		return this;

	}

	/**
	 * Adds the given scalar value to the RGB values of this color.
	 *
	 * @param {number} s - The scalar to add.
	 * @return {Color} A reference to this color.
	 */
	addScalar( s ) {

		this.r += s;
		this.g += s;
		this.b += s;

		return this;

	}

	/**
	 * Subtracts the RGB values of the given color from the RGB values of this color.
	 *
	 * @param {Color} color - The color to subtract.
	 * @return {Color} A reference to this color.
	 */
	sub( color ) {

		this.r = Math.max( 0, this.r - color.r );
		this.g = Math.max( 0, this.g - color.g );
		this.b = Math.max( 0, this.b - color.b );

		return this;

	}

	/**
	 * Multiplies the RGB values of the given color with the RGB values of this color.
	 *
	 * @param {Color} color - The color to multiply.
	 * @return {Color} A reference to this color.
	 */
	multiply( color ) {

		this.r *= color.r;
		this.g *= color.g;
		this.b *= color.b;

		return this;

	}

	/**
	 * Multiplies the given scalar value with the RGB values of this color.
	 *
	 * @param {number} s - The scalar to multiply.
	 * @return {Color} A reference to this color.
	 */
	multiplyScalar( s ) {

		this.r *= s;
		this.g *= s;
		this.b *= s;

		return this;

	}

	/**
	 * Linearly interpolates this color's RGB values toward the RGB values of the
	 * given color. The alpha argument can be thought of as the ratio between
	 * the two colors, where `0.0` is this color and `1.0` is the first argument.
	 *
	 * @param {Color} color - The color to converge on.
	 * @param {number} alpha - The interpolation factor in the closed interval `[0,1]`.
	 * @return {Color} A reference to this color.
	 */
	lerp( color, alpha ) {

		this.r += ( color.r - this.r ) * alpha;
		this.g += ( color.g - this.g ) * alpha;
		this.b += ( color.b - this.b ) * alpha;

		return this;

	}

	/**
	 * Linearly interpolates between the given colors and stores the result in this instance.
	 * The alpha argument can be thought of as the ratio between the two colors, where `0.0`
	 * is the first and `1.0` is the second color.
	 *
	 * @param {Color} color1 - The first color.
	 * @param {Color} color2 - The second color.
	 * @param {number} alpha - The interpolation factor in the closed interval `[0,1]`.
	 * @return {Color} A reference to this color.
	 */
	lerpColors( color1, color2, alpha ) {

		this.r = color1.r + ( color2.r - color1.r ) * alpha;
		this.g = color1.g + ( color2.g - color1.g ) * alpha;
		this.b = color1.b + ( color2.b - color1.b ) * alpha;

		return this;

	}

	/**
	 * Linearly interpolates this color's HSL values toward the HSL values of the
	 * given color. It differs from {@link Color#lerp} by not interpolating straight
	 * from one color to the other, but instead going through all the hues in between
	 * those two colors. The alpha argument can be thought of as the ratio between
	 * the two colors, where 0.0 is this color and 1.0 is the first argument.
	 *
	 * @param {Color} color - The color to converge on.
	 * @param {number} alpha - The interpolation factor in the closed interval `[0,1]`.
	 * @return {Color} A reference to this color.
	 */
	lerpHSL( color, alpha ) {

		this.getHSL( _hslA );
		color.getHSL( _hslB );

		const h = lerp( _hslA.h, _hslB.h, alpha );
		const s = lerp( _hslA.s, _hslB.s, alpha );
		const l = lerp( _hslA.l, _hslB.l, alpha );

		this.setHSL( h, s, l );

		return this;

	}

	/**
	 * Sets the color's RGB components from the given 3D vector.
	 *
	 * @param {Vector3} v - The vector to set.
	 * @return {Color} A reference to this color.
	 */
	setFromVector3( v ) {

		this.r = v.x;
		this.g = v.y;
		this.b = v.z;

		return this;

	}

	/**
	 * Transforms this color with the given 3x3 matrix.
	 *
	 * @param {Matrix3} m - The matrix.
	 * @return {Color} A reference to this color.
	 */
	applyMatrix3( m ) {

		const r = this.r, g = this.g, b = this.b;
		const e = m.elements;

		this.r = e[ 0 ] * r + e[ 3 ] * g + e[ 6 ] * b;
		this.g = e[ 1 ] * r + e[ 4 ] * g + e[ 7 ] * b;
		this.b = e[ 2 ] * r + e[ 5 ] * g + e[ 8 ] * b;

		return this;

	}

	/**
	 * Returns `true` if this color is equal with the given one.
	 *
	 * @param {Color} c - The color to test for equality.
	 * @return {boolean} Whether this bounding color is equal with the given one.
	 */
	equals( c ) {

		return ( c.r === this.r ) && ( c.g === this.g ) && ( c.b === this.b );

	}

	/**
	 * Sets this color's RGB components from the given array.
	 *
	 * @param {Array<number>} array - An array holding the RGB values.
	 * @param {number} [offset=0] - The offset into the array.
	 * @return {Color} A reference to this color.
	 */
	fromArray( array, offset = 0 ) {

		this.r = array[ offset ];
		this.g = array[ offset + 1 ];
		this.b = array[ offset + 2 ];

		return this;

	}

	/**
	 * Writes the RGB components of this color to the given array. If no array is provided,
	 * the method returns a new instance.
	 *
	 * @param {Array<number>} [array=[]] - The target array holding the color components.
	 * @param {number} [offset=0] - Index of the first element in the array.
	 * @return {Array<number>} The color components.
	 */
	toArray( array = [], offset = 0 ) {

		array[ offset ] = this.r;
		array[ offset + 1 ] = this.g;
		array[ offset + 2 ] = this.b;

		return array;

	}

	/**
	 * Sets the components of this color from the given buffer attribute.
	 *
	 * @param {BufferAttribute} attribute - The buffer attribute holding color data.
	 * @param {number} index - The index into the attribute.
	 * @return {Color} A reference to this color.
	 */
	fromBufferAttribute( attribute, index ) {

		this.r = attribute.getX( index );
		this.g = attribute.getY( index );
		this.b = attribute.getZ( index );

		return this;

	}

	/**
	 * This methods defines the serialization result of this class. Returns the color
	 * as a hexadecimal value.
	 *
	 * @return {number} The hexadecimal value.
	 */
	toJSON() {

		return this.getHex();

	}

	*[ Symbol.iterator ]() {

		yield this.r;
		yield this.g;
		yield this.b;

	}

}

const _color = /*@__PURE__*/ new Color();

/**
 * A dictionary with X11 color names.
 *
 * Note that multiple words such as Dark Orange become the string 'darkorange'.
 *
 * @static
 * @type {Object}
 */
Color.NAMES = _colorKeywords;

export { Color };