its time to have a chat #gamedev and #indiedev
its time for us to talk about water, and how your in game water looks good, but is wrong
(this may become a safety talk, kk, just a heads up)

but its time to talk about turbulent water, rapids, and how water actually moves

this thread will focus on rivers cause thats what i know, ANYWAY

lets start with flow, in general rivers dont have uniform depth, deeper parts will move faster, and sallower parts move slower

this is becasue of everyones friend friction, and also explains river errosion

so what happens if we shove something in the way?

as water moves around and past our obstacle, we form an eddy.
this is an area where the water is moving back UP the river to fillin the empty space behind the rock. This can create a spot of calm in the middle of the rapid

but what happens if that object is under the water? or the water drops REAL fast?

then you end up with a hydraluic or stopper, these are parts of a rapid where the water hits the bottom of the river and comes back up, recurculating back on itself, creating a kinda pillow look

here you can see how the water drops significantly in a short time, and then is forced down and onto the bottom and bouced back up, forming a stationary wall/pillow of water where the water recurculates

heres and example of each of these
the paddler can transfer their speed around up and then back out, because the eddy's flow direction is back up the river.

and the final moment you see the paddler have to move through a stopper, the water moving back towards them slowing a bit

so last but not least, we have the boil, this occours when a fast moving current hits a feature underwater (some times DEEP) and sends water back UP to the surface, these features arent super common, but create a kind of messy and undulating look to water

so why is this important? (its not)

well realism is fake, rivers and rapids specifically are not chaotic (unless flooded) they have features, shapes and move in very predictable way

eddys and stoppers are both important parts of how to safely cross and move aorund rivers

but i do want ot highlight some things here, and talk about river safety while i have ur eyes

rapids are incredible and fun, but also can be dangerous, so if your ever in/around one, please follow this advice

-if you are swimming, keep your feet up, and dont EVER stand in the main flow (your feet can get trapped, and the water keep you under)

-dont try to swim against the current, float until you spot and eddy, and THEN swim to it

-never, ever, NEVER swim in a flooded river! deep water can look safe, but be incredibly fast

-if there is a tree in a river stay away from it. They are very dangerous, and can catch you with the force of water moving through them

-rocks are you friend

AIGHT thats all for now, ask Q's if you have em, i love talking about rivers and boats, and I want to see more if not accurate, more accurate water movement from games

(the thing to remember is that water has energy and momentum, so it bouces and has friction!)