frostClamp property
How far the copy of the content showing through the frost may stray from the cloud on one side, as a fraction of full scale before frostOpacity is applied; 0 (the default) leaves both sides free.
Positive holds it from going darker than the cloud by more than this,
negative from going lighter. That is the asymmetry of the native
material: through the light glass a black stripe is a flat pale band
and a white one a narrow bright hump, so dark detail reads bolder and
light detail finer, and through the dark glass the reverse. Light
measures 0.4, dark -0.45.
Implementation
final double frostClamp;