StandardMaterialBaseIsPreMultipliedAlphaColor Property

When IsPreMultipliedAlphaColor is true (false by default) and Opacity is less then 1, then the color components of the DiffuseColor are already multiplied with alpha value to produce pre-multiplied colors. When false, then non-premultiplied color is converted in pre-multiplied color when this is required by the shader. Default value is false.

public bool IsPreMultipliedAlphaColor { get; set; }