Type: perlin :: Pattern Double

perlin produces 1D Perlin (smooth) noise. It works like rand but smoothly moves between random values each cycle.

For example, you can smoothly and randomly change speed:

d1 $ sound "bd*32" # speed (perlin + 0.5)

The perlin function produces a new random value to move to every cycle. If you want a new random value to be generated more or less frequently, you can use fast or slow, respectively:

d1 $ sound "bd*32" # speed (fast 4 $ perlin + 0.5)
d1 $ sound "bd*32" # speed (slow 4 $ perlin + 0.5)

perlinWith

perlinWith allows you to specify a pattern as input to generate random values instead of using the default cycle count:

d1 $ s "arpy*32" # cutoff (perlinWith (saw * 4) * 2000)

perlin2

perlin2 creates 2D noise by allowing you to specify a custom pattern as a second dimension (cycle number remains as the first dimension):

d1 $ s "bd*32" # speed (perlin2 (sine*4) + 1)

perlin2With

perlin2With is the same as perlinWith except allows you to provide two functions for 2D noise:

d1
 $ s "[arpy*32]"
 # lpf (range 60 5000 $ perlin2With (cosine*2) (sine*2))
 # lpq 0.3