eevee

"""Perlin noise implementation."""
# Licensed under ISC
from itertools import product
import math
import random


def smoothstep(t):
    """Smooth curve with a zero derivative at 0 and 1, making it useful for
    interpolating.

mfuerstenau

  ZigZag-Encoding
  ---------------
  
  Maps negative values to positive values while going back and
  forth (0 = 0, -1 = 1, 1 = 2, -2 = 3, 2 = 4, -3 = 5, 3 = 6 ...)

  (i >> bitlength-1) ^ (i << 1)

  with "i" being the number to be encoded, "^" being
  XOR-operation and ">>" would be arithemtic shifting-operation

Reedbeta

# Simulator for depth comparison error (i.e. z-fighting)
# Nathan Reed, June 2015
# Written for Python 3.4; requires numpy

import math
import numpy as np
import optparse

# Parse command-line options
parser = optparse.OptionParser()

badboy

Original link: http://www.concentric.net/~Ttwang/tech/inthash.htm
Taken from: http://web.archive.org/web/20071223173210/http://www.concentric.net/~Ttwang/tech/inthash.htm
Reformatted using pandoc

Integer Hash Function

Thomas Wang, Jan 1997

last update Mar 2007