World-unit wave height (half peak-to-trough).
Wavelength in world units. Drives the dispersion frequency sqrt(g*k).
Choppiness in [0, 1]; 0 = flat sinusoid, ~0.9 = sharp peaks / flat troughs.
OptionalphaseConstant phase offset, in radians. Use to de-correlate same-direction waves.
xz plane unit vector — host should normalize; shader re-normalizes too.