#### Name

### noise()

#### Description

Returns the Perlin noise value at specified coordinates. Perlin noise is a
random sequence generator producing a more natural, harmonic succession of
numbers than that of the standard **random()** function. It was
developed by Ken Perlin in the 1980s and has been used in graphical
applications to generate procedural textures, shapes, terrains, and other
seemingly organic forms.

In contrast to the **random()** function, Perlin noise is defined in an
infinite n-dimensional space, in which each pair of coordinates corresponds
to a fixed semi-random value (fixed only for the lifespan of the program).
The resulting value will always be between 0.0 and 1.0. Processing can
compute 1D, 2D and 3D noise, depending on the number of coordinates given.
The noise value can be animated by moving through the noise space, as
demonstrated in the first example above. The 2nd and 3rd dimensions can
also be interpreted as time.

The actual noise structure is similar to that of an audio signal, in
respect to the function's use of frequencies. Similar to the concept of
harmonics in physics, Perlin noise is computed over several octaves which
are added together for the final result.

Another way to adjust the character of the resulting sequence is the scale
of the input coordinates. As the function works within an infinite space,
the value of the coordinates doesn't matter as such; only the
*distance* between successive coordinates is important (such as when
using **noise()** within a loop). As a general rule, the smaller the
difference between coordinates, the smoother the resulting noise sequence.
Steps of 0.005-0.03 work best for most applications, but this will differ
depending on use.

There have been debates over the accuracy of the implementation of noise in
Processing. For clarification, it's an implementation of "classic Perlin
noise" from 1983, and not the newer "simplex noise" method from 2001.

#### Examples

`float xoff = 0.0; void draw() { background(204); xoff = xoff + .01; float n = noise(xoff) * width; line(n, 0, n, height); }`

`float noiseScale = 0.02; void draw() { background(0); for (int x=0; x < width; x++) { float noiseVal = noise((mouseX+x)*noiseScale, mouseY*noiseScale); stroke(noiseVal*255); line(x, mouseY+noiseVal*80, x, height); } }`

#### Syntax

`noise(x)`

`noise(x, y)`

`noise(x, y, z)`

#### Parameters

`x`

`(float)`

x-coordinate in noise space`y`

`(float)`

y-coordinate in noise space`z`

`(float)`

z-coordinate in noise space

#### Return

`float`

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