x1 (object/medium) is unclear/murky/obfuscating/(at least somewhat/semi-)opaque/impeding/with obstacle/fogs with regard to transmission x2
Do not use for "befuddling"/"confusing". A solar-style eclipse could be so characterized (in which case medium x1 is the solid body of Luna or another significant object); an eclipse caused by a significant physical object blocking the viewing of another (from yet another) by physically intervening (being positioned betwixt them).