One does not say the Sh’ma in the presence of urine, feces or nakedness; based on the text “. . .that He see no unseemly thing in thee” (Deut. 23:15). Nakedness includes seeing someone through a glass. One’s own nakedness can be covered by water (although it cannot be fetid - but it should be stirred up).
An interesting conversation questioning if it is permissible in that instance if “the heart sees his nakedness” – (I like that image of the heart seeing.) Some permit, some not. What if the “heel sees his nakedness”? Raba says it is permitted – and it is his reason that interests me: because “the Torah was not given to the ministering angels.” That is to say, we are human and you cannot make things so stringent that we would have to be an angel (without a body?) to be fully compliant.
But how can we apply Raba’s principle? How do we balance the ideal with the reality? Aiming for angelic perfection while realizing that we are limited by our humanity? The Torah wasn’t given to or for those of angelic perfection – it is a tool for us all, as flawed humans, to make ourselves strive for something more. We don't wallow or excuse the shallow flesh-based reality, but we don't deride ourselves for our humanness either. I like that image of being suspended between heaven and earth - we are more than the animals and less than the angels and our two-sided nature pulls us in both directions. Torah is our tool to keep us focused in the right direction.