I need some ideas on a good way to place particles for a waterfall system. For a single waterfall, the answer is simple. I would choose a random point along a line segment spanning the top of the waterfall, and have the particle start there with the appropriate force vectors etc.
Here's the difficult part: There could be quite a few waterfalls on screen at one time, and all of them would have different widths although I can use a finite set of widths (like small, medium, large river). I would like to ensure that there would be a direct relationship between the number of particles on a waterfall and it's width, so that a wide river has more particles spawn there at a given time than a narrow river, but in a way that is visually (mathematically?) proportional and consistent.
I've already went down a few rabbit holes trying devise some overall weighted random choice across differing line segments, but that involves looping through everything and is probably not feasible. I would like to hear how other people would handle the problem.