setToGradientColorMapWhiteColor(color) {
    if (!cc.colorEqual(this._toGradientColorMapWhiteColor, color)) {
      this._toGradientColorMapWhiteColor = color;
      this._gradientMapDirty = true;
    }
  }
Sets the current Gradient Color Map TO white color point.
@param     {cc.Color}     color   The color to set for this value.