ocean_wake

The disturbance field — what happens to the water when something moves through it. Wakes, splashes, impacts and swimmers all come from the same mechanism.

It integrates the 2-D wave equation on a grid, so a disturbance PROPAGATES: a hull pushing the surface down leaves a depression that spreads as a ring, the rings from successive frames overlap into a trail, and two wakes crossing interfere the way water does. None of that is authored — it falls out of the equation, which is why this is simulated rather than stamped along a path.

The grid follows the ocean, so each step resamples the previous field through the origin it was written against; that is what keeps a disturbance where it was made in the world while the grid slides under the viewer. Height, velocity and foam travel in one field so a single resample carries all three.

The integration clamps its own Courant number rather than trusting the caller's wave speed and timestep — a hitched frame must not be able to blow the field up.