We don’t think we’ll be adding real water physics after all. We’ve tried with Bullet Physics btHfFluid like in HeightFieldFluidDemo, but performance is really slow with this. 1 frame per second is not cool at all.
The best solution would probably be something like detecting whether an object is inside a water mesh and send a message about it. The graphics or some other component will then receive this message and enable fog.
We don’t really like the idea of cheating with water but it seems no other solution gives the same good performance with so many meshes.