Add a CTexmap - but have the map affected by the refraction in the water?

[DPS]

I have faked some caustics by mapping a texture to a riverbed - but ideally I don't want to bake them in.

I tried adding to the Ctexmap but the refractions are ignored.

Also would be handy if I could render a RAW lighting pass that also respected the water. So I could mask out the caustics in the shadows, in post.

[maru]

I am not sure if I understand the issue correctly (better description + some screenshots, renders, etc would be appreciated!), but maybe plugging the fake caustics into the self illumination slot of the riverbed material would be a solution here?