Detect Edges of Mesh (DepthFade?) in Masked Material

Hi, we’re making a paper-based game and as such we are trying to create water with a paper feel to it. Currently we’ve got this:

3611-water.png

Now what I want is, to create “foam” (white edges) along the sides of the mesh and, if at all possible also around whatever object that might pass through the water. I was thinking of using the DepthFade to determine this, but apparenly this can only be used with Transparent (or PostProcess) materials. Is there any other way to determine these factors? OuO