p5.func

Function generators for p5.js

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p5.func

Function Generators for p5.js

R. Luke DuBois (dubois@nyu.edu)
Integrated Digital Media / Brooklyn Experimental Media Center
NYU Tandon School of Engineering

Shiffman, it’s pronounced funk.

p5.func is a p5 extension that provides new objects and utilities for function generation in the time, frequency, and spatial domains. You might find this module useful for everything from plotting animation paths to generating procedural graphics to designing signal processing algorithms.

p5.func contains five new objects:

The library also contains a number of utility functions for p5:

Quite a bit of this code is adapted from other sources, notably:

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Examples

p5.Gen Example (direct evaluation)

var g = new p5.Gen(); // function generator object

// evaluate the value 20% (0.2) into a wavetable 
// defined by harmonic strengths 1., 0.5, and 0.3:
g.harmonics(0.2, [1.0, 0.5, 0.3]); // 1.0686135667536483

// evaluate the value halfway (0.5) into a breakpoint function 
// rising from 0 to 1 then falling to 0:
g.bpf(0.5, [0, 0, 1, 1, 2, 0]); // 1.

// evaluate the value 3/4ths (0.75) into a hamming window function:
g.window(0.75, "hamming"); // 0.5400000000000001

p5.Gen Example (array filling)

var g = new p5.Gen(); // function generator object

// assign 'foo' to a 512-point Array containing the wavetable 
// defined by harmonic strengths 1., 0.5, and 0.3:
var foo = g.fillArray("harmonics", 512, [1.0, 0.5, 0.3]);

// assign 'bar' to a 1000-point Float32Array containing a 
// single sine wave:
var bar = g.fillFloat32Array("waveform", 1000, "sine");

// assign 100 points of low-weighted random numbers to 
// the Float64Array 'biz':
var biz = g.fillFloat64Array("random", 100, "low");

console.log(foo); // print
fplot(foo, "color: red; font-size:9px;"); // plot
console.log(bar); // print
fplot(bar, "color: green; font-size:9px;"); // plot
console.log(biz); // print
fplot(biz, "color: blue; font-size:9px;"); // plot

p5.Ease Example (direct evaluation)

var e = new p5.Ease(); // easing function object
e.listAlgos(); // return an array listing all the algorithms

// calculate the value halfway (0.5) through 
// the 'circularIn' easing function:
e.circularIn(0.5); // 0.1339745962155614

// calculate the value a quarter (0.25) through 
// the 'doubleCircularOgee' function with a coefficient of 0.5:
e.doubleCircularOgee(0.25, 0.5); // 0.4330127018922193

p5.Ease Example (array filling)

var e = new p5.Ease(); // easing function object

// assign 'foo' to a 10-point Array filled with 
// a "doubleQuadraticBezie" easing function:
var foo = e.fillArray("doubleQuadraticBezier", 10);

// assign 'bar' to a 100-point Float32Array filled with 
// a "smoothStep" easing function:
var bar = e.fillFloat32Array("smoothStep", 100);

// assign a 1000-point "doubleCircularSigmoid" with 
// a coefficient of 0.8 to the Float64Array 'biz':
var biz = e.fillFloat64Array("doubleCircularSigmoid", 1000, 0.8);

console.log(foo); // print
fplot(foo, "color: red; font-size:9px;"); // plot
console.log(bar); // print
fplot(bar, "color: green; font-size:9px;"); // plot
console.log(biz); // print
fplot(biz, "color: blue; font-size:9px;"); // plot

p5.ArrayEval Example

var a = new p5.ArrayEval(); // array evaluation object

// 10-point 'normal map' (0 to 1):
var foo = a.eval('u', 10); 

// 20x20 two-dimensional signed normal map (-1 to 1):
var bar = a.eval2d(['su', 'sv'], 20, 20); 

// 8x8x8 array with a volumetric distance function:
var biz = a.eval3d('sqrt(su*su+sv*sv+sw*sw)', 8, 8, 8); 

console.log(foo); // print
console.log(bar); // print
console.log(biz); // print

p5.Filt Example

// filter object with math calibrated to a 60Hz sampling rate:
var f = new p5.Filt(60); 
// lowpass filter with a cutoff frequency of 3Hz and a Q of 0.7:
f.set("lowpass", 3, 0.7); 

var ip = new Array(100); // input array
var op = new Array(100); // output array

for(let i = 0;i<100;i++)
{
 ip[i] = random(-1, 1); // random input
 op[i] = f.tick(ip[i]); // smoothed (lowpassed) output
}

console.log(ip); // print
fplot(ip, "color: red; font-size:9px;"); // plot
console.log(op); // print
fplot(op, "color: blue; font-size:9px;"); // plot

p5.FastFourierTransform Example

// 512-point FFT calibrated to a 60Hz sampling rate:
var fft = new p5.FastFourierTransform(512, 60); 
var g = new p5.Gen(); // function generator object

var ip = g.fillArray("waveform", 512, "saw"); // input array
fft.forward(ip); // compute FFT

var op = fft.spectrum; // output array (256 points of magnitude)
console.log(op); // print
fplot(op, "color: green; font-size:9px;"); // plot

More Examples

Reference

p5.Gen

methods

p5.Ease

methods

For all easing functions, x is 0 to 1. Method returns f(x). Some methods have optional arguments: n is order for exponential / stepping functions; a, b, c, and d are coefficients.

p5.ArrayEval

methods

p5.Filt

constructor

methods

p5.FastFourierTransform

constructor

methods

properties

Misc. Functions