RandomBand

a band of dots jittered by random, which is jagged, and the mouse re-rolls it

Run

swift run --package-path Examples Example-Randomness-RandomBand

Source

Examples/Randomness/RandomBand/Sketch.swift

//  Ported from the p5.js sketch week-1/random (MIT) in
//  https://github.com/eaviles/rtp-sfpc-f21-p5 — itself a p5 port of Zach
//  Lieberman's openFrameworks sample for the RTP class at SFPC, Fall 2021
//  (https://github.com/ofZach/RTP_SFPC_F21). Reworked for Ollin's API.

import Ollin

/// A dot per column across the canvas, each jittered vertically by
/// `random(-amplitude, amplitude)` — a rough, uncorrelated band, every dot
/// independent of its neighbors. `randomSeed(mouseX)` holds the scatter steady for
/// a given cursor position, so sliding the mouse re-rolls it. The smooth
/// counterpart is `NoiseWave` — the two together are the classic random-vs-noise
/// comparison.
@main
final class RandomBand: Sketch {
    override func setup() {
        noStroke()
    }

    override func draw() {
        background(.black)
        randomSeed(Int(mouseX))
        let amplitude = height / 8        // dots jitter within ⅛ of the height
        for i in 0..<Int(width) {
            drawCircle(Double(i), height / 2 + random(-amplitude, amplitude), 2 * scale)
        }
    }
}