Replace `percent` with something more credible

[semibran]

The current implementation of percent happens to be copied from a certain answer on StackOverflow.

function percent(seed) {
  var x = sin(seed) * 0xFFFFFF
  return x - floor(x)
}

While this algorithm is quite fast and works well for small projects, it'd be great to see this function replaced with something more credible (i.e. some PRNG with its own Wikipedia article).

[jamen]

There is Mersenne Twister which is a "a well tested and fairly robust RNG with a huge orbit and excellent performance" (according to this SO post), but the algorithm in the article went over my head. 😩

[jamen]

Another interesting one mentioned is Lehmer RNG which looks simple to implement. Maybe even using Emscripten? 😮