ocean_probe

Resamples every cascade onto one small grid that the CPU reads back, so gameplay can ask where the water is without stalling a frame on the full simulation.

Dispatched once per cascade: the first overwrites the grid, the rest add to it. xyz is the summed displacement in metres and w the strongest folding, so a caller can also ask whether the water at a point is breaking.

The swell bank is deliberately absent — it is analytic and longer than the tile this grid covers, so ocean.module evaluates it directly on the CPU instead.