So, I've written a pretty nice water shader that translates a white to black gradient into animated water foam. What I need to do next is to add a soft white halo around any actors or floating objects in the water. My first thought was to use some particles, capture them with an overhead camera, and then project the captured particles back down onto the surface of the water. I can do this using a projector easily enough, but in that case the projected halo does not translate into ripples the same way my shoreline does, and it makes the lighting inconsistent besides. What I would like to do is be able to get that projected texture back into the shader so I can add the results before the shoreline translation is performed, but I can't for the life of me figure out a way to do this to get the placements consistent. The camera that captures the particles is attached positionally to the water plane. I assign UV coordinates to each vertex of the water plane whenever it shifts in order to keep the texture's placement consistent, but I haven't done anything with other UV channels yet. I'm thinking I should be able to use uv2 to work this out, and it's entirely possible I'm missing something obvious, but it's just escaping me at the moment. Any suggestions welcome. Simple gradient mask in the water marks where foam/ripples should appear. This is where I need to work. Shoreline gradient converted into foam/ripples. Showing the macro structure of the scene setup. Snapshot with particles and resulting effect visible; the effect just isn't lined up in the right place.