System.Int32. An Int32 value to replace with transparent black, or 0 to disable the color key. This is always a 32-bit ARGB color that is independent of the source image format. Alpha is significant, and usually should be set to FF for opaque color keys. For example, for opaque black, the value is equal to 0xFF000000.
Remarks
Writing to any surface except the "zero" level surface of the volume texture does not cause the dirty rectangle to be updated. If FromFile is called and the texture is not already dirty (which is unlikely under normal usage scenarios), the application must explicitly call VolumeTexture.AddDirtyBox on the volume texture.