Perhaps this has already been discussed (I've read a few discussions on water displacement near the coast), but I wonder if it would be possible to somehow get the depth (Get Altitude?)and 'transfer' this to the waterplane with a certain displacement. It would in theory be possible to raise the water level at certain depths (waterlevel minus 1, waterlevel minus 2, etc) , and lower at others (with a little overall displacement to roughen the water). Not physically correct maybe, but perhaps good enough to get the idea of coastal wave displacement.
Foam slightly behind or on top of the upward displacement might also be done this way, perhaps???
I am awfully terrible at maths (one of my greater frustrations when studying biology), as you can probably see in the attached screendump of my feeble attempt at functions to get foam at certain depths. Can anybody shed some light on a better approach?
---Dune