noise()

Returns random numbers that can be tuned to feel organic.

Values returned by random() and randomGaussian() can change by large amounts between function calls. By contrast, values returned by noise() can be made "smooth". Calls to noise() with similar inputs will produce similar outputs. noise() is used to create textures, motion, shapes, terrains, and so on. Ken Perlin invented noise() while animating the original Tron film in the 1980s.

The version of noise in L5 varies from p5.js and Processing. It returns simplex noise for 2 and 3 input arguments. Simplex noise is an algorithm designed in 2001 by Ken Perlin to address limitations in his classic noise function, notably relating to speed, complexity and higher order dimensions.

noise() always returns values between 0 and 1. It returns the same value for a given input while a sketch is running. noise() produces different results each time a sketch runs. The noiseSeed() function can be used to generate the same sequence of Perlin noise values each time a sketch runs.

The character of the noise can be adjusted by scaling the inputs. noise() interprets inputs as coordinates. The sequence of noise values will be smoother when the input coordinates are closer.

The version of noise() with one parameter computes noise values in one dimension. This dimension can be thought of as space, as in noise(x), or time, as in noise(t).

The version of noise() with two parameters computes noise values in two dimensions. These dimensions can be thought of as space, as in noise(x, y), or space and time, as in noise(x, t).

The version of noise() with three parameters computes noise values in three dimensions. These dimensions can be thought of as space, as in noise(x, y, z), or space and time, as in noise(x, y, t). Note that the version of noise() that takes 3 parameters actually computes the original Perlin noise algorithm, not Simplex.

Examples

function setup()
  size(100, 100)

  describe('A black dot moves randomly on a gray square.')
end

function draw()
  background(200)

  -- Calculate the coordinates.
  local x = 100 * noise(0.005 * frameCount)
  local y = 100 * noise(0.005 * frameCount + 10000)

  -- Draw the point.
  strokeWeight(5)
  point(x, y)
end

function setup() 
  size(100, 100)

  describe('A black dot moves randomly on a gray square.')
end

function draw() 
  background(200)

  -- Set the noise level and scale.
  local noiseLevel = 100
  local noiseScale = 0.005

  -- Scale the input coordinate.
  local nt = noiseScale * frameCount

  -- Compute the noise values.
  local x = noiseLevel * noise(nt)
  local y = noiseLevel * noise(nt + 10000);

  -- Draw the point.
  strokeWeight(5)
  point(x, y)
end

function setup() 
  size(100, 100)

  describe('A hilly terrain drawn in gray against a black sky.')
end

function draw() 
  -- Set the noise level and scale.
  local noiseLevel = 100
  local noiseScale = 0.02

  -- Scale the input coordinate.
  local x = frameCount
  local nx = noiseScale * x

  -- Compute the noise value.
  local y = noiseLevel * noise(nx)

  -- Draw the line.
  line(x, 0, x, y)
end

function setup() 
  size(100, 100)

  describe('A calm sea drawn in gray against a black sky.')
end

function draw() 
  background(200)

  -- Set the noise level and scale.
  local noiseLevel = 100;
  local noiseScale = 0.002

  -- Iterate from left to right.
  for x = 1,width do
    -- Scale the input coordinates.
    local nx = noiseScale * x
    local nt = noiseScale * frameCount

    -- Compute the noise value.
    local y = noiseLevel * noise(nx, nt)

    -- Draw the line.
    line(x, 0, x, y)
  end
end

function setup() 
  size(100, 100)

  background(200)

  -- Set the noise level and scale.
  local noiseLevel = 255
  local noiseScale = 0.01

  -- Iterate from top to bottom.
  for y=1,height do
    -- Iterate from left to right.
    for x = 0,width do
      -- Scale the input coordinates.
      local nx = noiseScale * x
      local ny = noiseScale * y

      -- Compute the noise value.
      local c = noiseLevel * noise(nx, ny)

      -- Draw the point.
      stroke(c)
      point(x, y)
    end
  end

  describe('A gray cloudy pattern.')
end

function setup() 
  size(100, 100)

  describe('A gray cloudy pattern that changes.')
end

function draw() 
  -- Set the noise level and scale.
  local noiseLevel = 255
  local noiseScale = 0.009

  -- Iterate from top to bottom.
  for y=1,height do
    -- Iterate from left to right.
    for x=1,width do
      -- Scale the input coordinates.
      local nx = noiseScale * x
      local ny = noiseScale * y
      local nt = noiseScale * frameCount

      -- Compute the noise value.
      local c = noiseLevel * noise(nx, ny, nt)

      -- Draw the point.
      stroke(c)
      point(x, y)
    end
  end
end

Syntax

noise(x, [y])

Parameters

Parameter
x	Number: x-coordinate in noise space.
y	Number: y-coordinate in noise space.
z	Number: z-coordinate in noise space.

Returns

Number: Simplex noise value at specified coordinates.

Related

• random()
• randomGaussian()