Sharp where it touches the glass.

THE SYSTEM BEHIND THE SURFACE

Inside Frost Glass.

An etched pane scatters every ray that crosses it into a narrow cone, so what it shows of an object is blurred in proportion to the object's distance behind the glass: a leaf pressed against it is crisp to the veins, a leaf a hand's width back is a soft shadow, and the open light beyond has no edges at all. The shader gives every leaf and stem its own depth and convolves each shape with a Gaussian of that depth's width in closed form (the normal CDF of its signed distance), so blur is exact per shape rather than a post-process. Thin parts lose contrast first as the kernel outgrows them, which is why the monstera's slits and windows vanish long before the blade. Wind rocks each stem at its own rate and tips the blade toward and away from the pane, so leaves drift in and out of focus. The etched face also returns some room light as a milky veil and catches light in its pits; unetched clear lines cut through the frost, and through them the same leaves are seen sharp. The pointer presses what is beneath it flat to the glass. Behind the pane can stand the monstera, or autumn leaves falling past the glass in a loop: maple, oak and birch, each coloured as it turns, gliding side to side like a pendulum and tilting into each swing, some turning over so their width comes and goes, and drifting toward or away from the pane so that one crossing close to the glass sharpens for a moment.

It does not blur the page behind the canvas or any HTML: the plant and the light are procedural. Shapes are drawn back to front in a fixed order, so two leaves crossing in depth do not swap. There is no condensation, no ice crystal growth and no refraction of the frame; patterned (pebbled or reeded) obscure glass is a different surface.

No published timing sample. Profile this effect on your target devices.