mirror of
https://github.com/osmarks/website
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158 lines
6.9 KiB
HTML
158 lines
6.9 KiB
HTML
---
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title: FractalArt
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slug: fractalart
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description: A somewhat unperformant generator for pleasant watercolor-y "fractalart" images. Ported from a Haskell implementation by "TomSmeets".
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---
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<style>
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.controls input, .controls button { border: 1px solid black; padding: 0.2em; }
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#fractalart { display: flex; align-items: flex-start; flex-wrap: wrap; }
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#status { font-style: italic; }
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#info { padding-top: 0.5em; font-size: 0.8em; }
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#out { image-rendering: crisp-edges; }
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</style>
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<div id="fractalart">
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<canvas id="out" width=512 height=512></canvas>
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<table class="controls">
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<tr><td>Lightness:</td><td><input id="lightness" type="number" max="1" min="0" step="0.01" value="0.6"></td></tr>
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<tr><td>Saturation:</td><td><input id="saturation" type="number" max="1" min="0" step="0.01" value="1.0"></td></tr>
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<tr><td>Hue:</td><td><input id="hue" type="number" max="360" min="0" step="1" value="0"></td><td>(or random: <input type="checkbox" checked id="hue-random">)</td></tr>
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<tr><td>Variance:</td><td><input id="variance" type="number" min="0" step="0.25" value="4"></td></tr>
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<tr><td>Bias:</td><td><input id="bias" type="number" step="0.25" value="0"></td></td></tr>
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<tr><td>Render Size:</td><td><input id="width" type="number" step="16" value="512"></td></td></tr>
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<tr><td><button id="generate">Generate</button></td></tr>
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<tr><td colspan="4" id="status"></td></tr>
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<tr><td colspan="4"><div id="info">
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<a href="https://github.com/TomSmeets/FractalArt/">FractalArt</a> for JS.<br>
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If this is too slow try my <a href="https://github.com/osmarks/random-stuff/tree/master/fractalart-rs">Rust port</a>.<br>
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This is all contained in one HTML file, so you can save it locally if you want.
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</div></td></tr>
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</table>
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</div>
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<script id="fractalart-code">
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// harvested from github somewhere
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function hslToRgb(h, s, l) {
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var r, g, b;
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if (s == 0) {
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r = g = b = l; // achromatic
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} else {
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function hue2rgb(p, q, t) {
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if (t < 0) t += 1;
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if (t > 1) t -= 1;
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if (t < 1/6) return p + (q - p) * 6 * t;
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if (t < 1/2) return q;
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if (t < 2/3) return p + (q - p) * (2/3 - t) * 6;
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return p;
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}
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var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
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var p = 2 * l - q;
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r = hue2rgb(p, q, h + 1/3);
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g = hue2rgb(p, q, h);
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b = hue2rgb(p, q, h - 1/3);
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}
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return [ r * 255, g * 255, b * 255 ];
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}
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const randRange = x => Math.floor(Math.random() * x)
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// main fractalart logic
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// todo: WASM (there is already a perfectly good Rust version...) or just actually optimize this
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const run = (im, { hue, saturation, lightness, variance, bias }) => {
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const set = (x, y, offset, value) => { im.data[(y * im.width + x) * 4 + offset] = value }
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const get = (x, y, offset) => im.data[(y * im.width + x) * 4 + offset]
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const boundcheck = (x, y) => x >= 0 && y >= 0 && x < im.width && y < im.height
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const ringAt = (x, y, l) => {
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let out = []
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for (let n = -l; n <= l; n++) {
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out.push([n + x, l + y])
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out.push([n + x, -l + y])
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}
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for (let n = 1 - l; n <= l; n++) {
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out.push([l + x, n + y])
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out.push([-l + x, n + y])
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}
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return out.filter(([x, y]) => boundcheck(x, y))
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}
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const modColorChannel = x => Math.min(Math.max(Math.floor(x + (Math.random() * (variance * 2 + 1)) - variance + bias), 0), 255)
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const startX = randRange(im.width)
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const startY = randRange(im.height)
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const iterations = Math.max(startX, im.width - 1 - startX, startY, im.height - 1 - startY)
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const [sR, sG, sB] = hslToRgb(hue, saturation, lightness)
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set(startX, startY, 0, Math.floor(sR))
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set(startX, startY, 1, Math.floor(sG))
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set(startX, startY, 2, Math.floor(sB))
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set(startX, startY, 3, 255)
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for (let iteration = 1; iteration <= iterations; iteration++) {
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for (const [x, y] of ringAt(startX, startY, iteration)) {
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const possibleColors = []
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for (const [ax, ay] of ringAt(x, y, 1)) {
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if (get(ax, ay, 3)) {
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possibleColors.push([get(ax, ay, 0), get(ax, ay, 1), get(ax, ay, 2)])
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}
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}
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const [chosenR, chosenG, chosenB] = possibleColors[randRange(possibleColors.length)]
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set(x, y, 0, modColorChannel(chosenR))
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set(x, y, 1, modColorChannel(chosenG))
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set(x, y, 2, modColorChannel(chosenB))
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set(x, y, 3, 255)
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}
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}
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postMessage(im)
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}
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const readInput = name => document.getElementById(name).value
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// detect if not running on webworker
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if ("document" in self) {
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const statusDisplay = document.querySelector("#status")
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let status = "Idle"
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let startTime = null
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const updateStatus = s => {
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if (statusDisplay.firstChild) { statusDisplay.removeChild(statusDisplay.firstChild) }
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statusDisplay.appendChild(document.createTextNode(s))
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status = s
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}
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const canv = document.querySelector("#out")
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// TODO things
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canv.style.width = canv.style.height = Math.min(512, window.innerWidth - 16) + "px"
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const ctx = canv.getContext("2d")
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const source = `
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${document.querySelector("#fractalart-code").innerHTML}
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onmessage = e => run(e.data[0], e.data[1])
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`
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// be nice to foolish single threaded browsers
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// offload to worker thread
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const worker = new Worker(URL.createObjectURL(new Blob([source], {type: 'application/javascript'})))
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worker.onmessage = e => {
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const im = e.data
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canv.width = canv.height = im.width
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ctx.putImageData(im, 0, 0)
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updateStatus(`Idle (${Date.now() - startTime}ms)`)
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}
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worker.onerror = e => {
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console.warn(e)
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updateStatus(e.message)
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}
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const generate = () => {
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if (status !== "Working") {
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updateStatus("Working")
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startTime = Date.now()
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const size = parseInt(readInput("width"))
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worker.postMessage([ctx.createImageData(size, size), {
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hue: document.getElementById("hue-random").checked ? Math.random() : parseFloat(readInput("hue")),
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saturation: parseFloat(readInput("saturation")),
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lightness: parseFloat(readInput("lightness")),
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variance: parseFloat(readInput("variance")),
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bias: parseFloat(readInput("bias"))
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}])
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}
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}
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document.querySelector("#generate").addEventListener("click", generate)
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generate()
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}
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</script> |