Glass material in GIMP

[Ofnuts]

Not impossible; but the difficulty with reflections is that except in very few and quite artificial cases you cannot create the reflection from the object you have in direct sight because the reflection shows you a different angle (if you take someone in front of a mirror, in direct sight you see that person's front but on the mirror you see that persons' back). The reflection of something that is off-screen is a mlot easier