Showing off a particle engine I made.. Well, more sparks than particles - I'm building another to handle bitmap image particles.
Anyway, the idea was to be able to have a large amount of particle sprays without causing much lag, and I think I succeeded. Oh, they had to look cool, too, and be easy to customize.
Click to make a particle spray of random colour, density, speed, thickness, decay rate, uniformity and rotational uniformity
Also included in the engine but not showed in this demo is the ability to shape the sprays - eg if it was supposed to illustrate a bullet hitting a wall, the spray could be told to only shoot particles away from the wall, and not through it.