下面是将HEX颜色值分别更改为红色，绿色，蓝色的Javascript代码。

R = hexToR("#FFFFFF");
G = hexToG("#FFFFFF");
B = hexToB("#FFFFFF");

function hexToR(h) {return parseInt((cutHex(h)).substring(0,2),16)}
function hexToG(h) {return parseInt((cutHex(h)).substring(2,4),16)}
function hexToB(h) {return parseInt((cutHex(h)).substring(4,6),16)}
function cutHex(h) {return (h.charAt(0)=="#") ? h.substring(1,7):h}

当你在3D环境中工作时(webGL, ThreeJS)，你有时需要为网格的不同面创建3个值，基本的一个(主色)，一个浅一点的和一个深一点的:

material.color.set( 0x660000, 0xff0000, 0xff6666 ); // red cube

我们可以从主RBG颜色创建这3个值:255,0,0

function rgbToHex(rgb) { 
  var hex = Number(rgb).toString(16);
  if (hex.length < 2) {
       hex = "0" + hex;
  }
  return hex;
};

function convertToHex(r,g,b) { 

    var fact = 100;  // contrast 
    var code = '0x';

    // main color
    var r_hexa = rgbToHex(r);
    var g_hexa = rgbToHex(g);
    var b_hexa = rgbToHex(b);

    // lighter
    var r_light = rgbToHex(Math.floor(r+((1-(r/255))*fact)));
    var g_light = rgbToHex(Math.floor(g+((1-(g/255))*fact)));
    var b_light = rgbToHex(Math.floor(b+((1-(b/255))*fact)));

    // darker
    var r_dark = rgbToHex(Math.floor(r-((r/255)*(fact*1.5)))); // increase contrast
    var g_dark = rgbToHex(Math.floor(g-((g/255)*(fact*1.5))));
    var b_dark = rgbToHex(Math.floor(b-((b/255)*(fact*1.5))));

    var hexa = code+r_hexa+g_hexa+b_hexa;
    var light = code+r_light+g_light+b_light;
    var dark = code+r_dark+g_dark+b_dark;

    console.log('HEXs -> '+dark+" + "+hexa+" + "+light)

    var colors = [dark, hexa, light]; 
    return colors;

}

在你的ThreeJS代码中简单地写:

var material = new THREE.MeshLambertMaterial();
var c = convertToHex(255,0,0); // red cube needed
material.color.set( Number(c[0]), Number(c[1]), Number(c[2]) );

结果:

//                                 dark      normal     light
convertToHex(255,255,255) HEXs -> 0x696969 + 0xffffff + 0xffffff
convertToHex(255,0,0) HEXs -> 0x690000 + 0xff0000 + 0xff6464
convertToHex(255,127,0) HEXs -> 0x690000 + 0xff0000 + 0xff6464
convertToHex(100,100,100) HEXs -> 0x292929 + 0x646464 + 0xa0a0a0
convertToHex(10,10,10) HEXs -> 0x040404 + 0x0a0a0a + 0x6a6a6a

hexToRgb的另一个版本:

function hexToRgb(hex) {
    var bigint = parseInt(hex, 16);
    var r = (bigint >> 16) & 255;
    var g = (bigint >> 8) & 255;
    var b = bigint & 255;

    return r + "," + g + "," + b;
}

编辑:3/28/2017 这是另一种似乎更快的方法

function hexToRgbNew(hex) {
  var arrBuff = new ArrayBuffer(4);
  var vw = new DataView(arrBuff);
  vw.setUint32(0,parseInt(hex, 16),false);
  var arrByte = new Uint8Array(arrBuff);

  return arrByte[1] + "," + arrByte[2] + "," + arrByte[3];
}

编辑:8/11/2017 经过更多测试后，上面的新方法并没有更快:(。虽然这是一种有趣的替代方式。

这个代码片段将十六进制转换为rgb, rgb转换为十六进制。

视图演示

function hexToRgb(str) { 
    if ( /^#([0-9a-f]{3}|[0-9a-f]{6})$/ig.test(str) ) { 
        var hex = str.substr(1);
        hex = hex.length == 3 ? hex.replace(/(.)/g, '$1$1') : hex;
        var rgb = parseInt(hex, 16);               
        return 'rgb(' + [(rgb >> 16) & 255, (rgb >> 8) & 255, rgb & 255].join(',') + ')';
    } 

    return false; 
}

function rgbToHex(red, green, blue) {
    var out = '#';

    for (var i = 0; i < 3; ++i) {
        var n = typeof arguments[i] == 'number' ? arguments[i] : parseInt(arguments[i]);

        if (isNaN(n) || n < 0 || n > 255) {
            return false;
        }

        out += (n < 16 ? '0' : '') + n.toString(16);
    }
    return out
}

R = HexToR("#FFFFFF");
G = HexToG("#FFFFFF");
B = HexToB("#FFFFFF");

function HexToR(h) {return parseInt((cutHex(h)).substring(0,2),16)}
function HexToG(h) {return parseInt((cutHex(h)).substring(2,4),16)}
function HexToB(h) {return parseInt((cutHex(h)).substring(4,6),16)}
function cutHex(h) {return (h.charAt(0)=="#") ? h.substring(1,7):h}

使用这些函数来实现没有任何问题的结果。：）

以下是我的看法:

function rgbToHex(red, green, blue) {
  const rgb = (red << 16) | (green << 8) | (blue << 0);
  return '#' + (0x1000000 + rgb).toString(16).slice(1);
}

function hexToRgb(hex) {
  const normal = hex.match(/^#([0-9a-f]{2})([0-9a-f]{2})([0-9a-f]{2})$/i);
  if (normal) return normal.slice(1).map(e => parseInt(e, 16));

  const shorthand = hex.match(/^#([0-9a-f])([0-9a-f])([0-9a-f])$/i);
  if (shorthand) return shorthand.slice(1).map(e => 0x11 * parseInt(e, 16));

  return null;
}