Instead of keeping track of one global time value, use multiple bounded low-frequency oscillators. This will keep working for an unlimited amount of time.

This was causing a compiler warning

https://code.google.com/p/nanoflann/

From nanoflann-1.1.7

Tested on MIPS OpenWRT router

This gives us opportunities to improve performance, since particles have a finite distance over which they
provide a contribution to the scene. This also includes kernel function and its derivative for use by subclasses.

It was too easy to accidentally use the integer version before. Now it's convenient to sample from floats or a Vec2.

Now you can include these without changing the header path at all

This would cause the algorithm to get stuck forever

This Effect can layer on other effects to keep their brightness within a particular range

This gives effects global information about the frame, before and after rendering pixels. This
can make some effects more convenient to write, and it allows effects to keep track of global per-pixel
data if they need to.