code: function (scale) {
              scale = me.Math.clamp(scale, 0, 1);
              this.glArray[0] *= scale;
              this.glArray[1] *= scale;
              this.glArray[2] *= scale;
  
              return this;
          }
docs: Darken this color value by 0..1
  @name darken
  @memberOf me.Color
  @function
  @param {Number} scale
  @return {me.Color} Reference to this object for method chaining