Underwater Volumetric Fog Experiments (Patreon)

I've been doing some experiments to see if underwater fog would be useful in Retroquad.

Keeping the underwater fog constrained to the liquid volumes helps players perceive the underwater fog as a property of the liquid itself, indicating how much water there still is ahead. This improved perception of depth is good for the gameplay.

However, this impression is only achieved if the fog is thick enough, and thick volumetric fog looks very bad in dark areas. So, in the general case the effect must be toned down a lot to not become distracting, which kills the intended impression.

The best approach should be to make the underwater volumetric fog effect opt-in for map authors. This way the effect would only be used when the author specifically define all of its parameters to ensure that it works as intended. For all other maps, it's better to keep it off.

Right now the volumetric clipping of the underwater fog is just a hack, and it only works when the view is inside of the liquids. The experiments have shown that clipping it when in the outside is also needed; that's more complicated, but I'll look into it.

And the impact on the framerate isn't negligible, but it's acceptable.

So, while it's still not guaranteed that this effect will be part of the engine, there are some good chances.