RGBToString = function (r, g, b, a, prefix)
{
    if (a === undefined) { a = 255; }
    if (prefix === undefined) { prefix = '#'; }

    if (prefix === '#')
    {
        return '#' + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1, 7);
    }
    else
    {
        return '0x' + ComponentToHex(a) + ComponentToHex(r) + ComponentToHex(g) + ComponentToHex(b);
    }
}
Converts the color values into an HTML compatible color string, prefixed with either `#` or `0x`.

@function Phaser.Display.Color.RGBToString
@since 3.0.0

@param {number} r - The red color value. A number between 0 and 255.
@param {number} g - The green color value. A number between 0 and 255.
@param {number} b - The blue color value. A number between 0 and 255.
@param {number} [a=255] - The alpha value. A number between 0 and 255.
@param {string} [prefix=#] - The prefix of the string. Either `#` or `0x`.

@return {string} A string-based representation of the color values.