Shader for the water in the sea surrounding the island, and in smaller water ponds. Deep water is not accessible by the player (they can't swim), but we can consider shallow ponds in which they can walk. Needs support for water moving up and down, and some kind of foam (that can be turned off for ponds?). Even though it would still be toon-like, it can be a different shader than the one used for toon objects. For instance, it doesn't need to support additional lights, baking, etc.