NormalX = function (line)
{
    return Math.cos(Angle(line) - MATH_CONST.TAU);
}
Returns the x component of the normal vector of the given line.

@function Phaser.Geom.Line.NormalX
@since 3.0.0

@param {Phaser.Geom.Line} line - The Line object to get the normal value from.

@return {number} The x component of the normal vector of the line.