Ripple

The traditional waved comb displaces each line of the bath sideways by a sine of its position. In the ripple frame (rotatable by ripple_angle):

$$x_{src} = x - A\,\sin(k\,y + \varphi),\qquad y_{src} = y .$$

A = amount (CC 102), ramped in so the shear is seen growing; k = wavelength (CC 103), φ = the frame angle; b switches live shimmer (0) to a baked pass (1).open full size ↗

Invariants

• A pure shear. Each horizontal line translates rigidly; the Jacobian is 1 identically at any amplitude, so the map never folds and is never sub-stepped.
• A commutative group at fixed $(k, \varphi)$. Applying $\Delta A$ per frame composes additively, so an LFO that breathes $A$ up and back to zero leaves the field bitwise unchanged. Changing $k$ or $\varphi$ between passes breaks commutativity and bakes residue in — and that residue is marbling, the waved-comb feathering. The boundary is deliberate and documented.
• Two insertion points, one switch (ripple_bake). Live (0): the ripple displaces the ink sampling coordinate at composite time — a view effect; nothing accumulates, the water shimmers and stills. Bake (1): a real deformation pass, delta-driven like the pinch. The washi grain never ripples (paper is screen-locked) and the paper dip always samples the un-rippled field — the print is what touches the water; the shimmer is surface motion.

The same ramp with b = 1, baked: each step is a real deformation pass, delta-driven, and the comb stays in the ink — drag A back to 0 and the live shimmer above would still; this one keeps what it laid down.open full size ↗

Ownership

• Per-note pitch bend with bend_mode = 1. The intent is subtle vibrato: a note’s bend wobble shimmers the water instead of wiggling its drop. The drop holds; one consumer owns the note bend, and the switch is clean both ways (the glide target is untouched in mode 1, so switching back never emits a stale-delta tine). The master bend keeps its shear tine in both modes.
• The amount is the bend’s distance from centre: $A = |\text{semitones}| / 6$, clamped — a ±0.5-semitone vibrato breathes about 8 %; last-writer-wins across voices, smoothed like every global control. So the water stills itself: bend re-centres → amount 0; the last note releases → amount 0; a 1→0 mode flip zeroes the residual.
• Bend-driven bake is permanent by design. The emitted pass phase drifts with activity ($\varphi \mathrel{+}= |\Delta A| / A_{max} \cdot 1.5$ rad, wrapped), so an excursion never retraces exactly: each vibrato cycle lays a slightly shifted comb, a feathered record that accumulates like glide tines, while the dynamic still stills. CC-driven bake keeps $\varphi$ fixed — the pure composing-back property, preserved for the regression gate.
• CC 102 / CC 103 — an external amount handle (sharing the slot, last-writer-wins) and the wavelength, a flavour control resting mid-range; the strip’s assignable wheels and the desktop’s settings window take them. On the tablets the Ripple toggle selects bend_mode = 1 and ripple_bake = 1 together; desktop keeps a manual live/bake override.