Microsoft.DirectX.Direct3D.CubeMapFace. A CubeMapFace value that identifies the face where the dirty region will be added. Omitting the sig_CubeMapFace_Rectangle parameter indicates that the dirty region should expand to cover the full face.
For performance reasons, dirty regions are recorded only for level 0 of a texture. For sublevels, it is assumed that the corresponding (scaled) rectangle or box is also dirty. Dirty regions are automatically recorded when CubeTexture.LockRectangle is called without LockFlags.NoDirtyUpdate or LockFlags.ReadOnly.