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Diffstat (limited to 'src/_posts/2021-05-28-viz-5.md')
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diff --git a/src/_posts/2021-05-28-viz-5.md b/src/_posts/2021-05-28-viz-5.md deleted file mode 100644 index ea2f9e9..0000000 --- a/src/_posts/2021-05-28-viz-5.md +++ /dev/null @@ -1,306 +0,0 @@ ---- -title: >- - Visualization 5 -description: >- - Seeing double. -series: viz -tags: tech art ---- - -<script type="text/javascript"> - -function randn(n) { - return Math.floor(Math.random() * n); -} - -const w = 100; -const h = 50; - -const maxNewElsPerTick = 10; -const deathThresh = 10; - -class Canvas { - constructor(canvasDOM) { - this.dom = canvasDOM; - this.ctx = canvasDOM.getContext("2d"); - - // expand canvas element's width to match parent. - this.dom.width = this.dom.parentElement.offsetWidth; - - // rectSize must be an even number or the pixels don't display nicely. - this.rectSize = Math.floor(this.dom.width / w /2) * 2; - - this.dom.width = w * this.rectSize; - this.dom.height = h * this.rectSize; - } - - rectSize() { - return Math.floor(this.dom.width / w); - } -} - -class Layer { - constructor(newEl) { - this.els = {}; - this.diff = {}; - this.newEl = newEl; - } - - _normCoord(coord) { - if (typeof coord !== 'string') coord = JSON.stringify(coord); - return coord; - } - - get(coord) { - return this.els[this._normCoord(coord)]; - } - - getAll() { - return Object.values(this.els); - } - - set(coord, el) { - this.diff[this._normCoord(coord)] = {action: "set", coord: coord, ...el}; - } - - unset(coord) { - this.diff[this._normCoord(coord)] = {action: "unset"}; - } - - applyDiff() { - for (const coordStr in this.diff) { - const el = this.diff[coordStr]; - delete this.diff[coordStr]; - - if (el.action == "set") { - delete el.action; - this.els[coordStr] = el; - } else { - delete this.els[coordStr]; - } - } - } - - update(state) { - // Apply diff from previous update first. The diff can't be applied last - // because it needs to be present during the draw phase. - this.applyDiff(); - - const allEls = this.getAll().sort(() => Math.random() - 0.5); - - if (allEls.length == 0) { - this.set([w/2, h/2], this.newEl([])); - } - - let newEls = 0; - for (const el of allEls) { - const nCoord = randEmptyNeighboringCoord(this, el.coord); - if (!nCoord) continue; // el has no empty neighboring spots - - const nEl = this.newEl(neighboringElsOf(this, nCoord)) - nEl.tick = state.tick; - this.set(nCoord, nEl); - - newEls++; - if (newEls >= maxNewElsPerTick) break; - } - - for (const el of allEls) { - const nEls = neighboringElsOf(this, el.coord); - if (state.tick - el.tick - (nEls.length * deathThresh) >= deathThresh) this.unset(el.coord); - } -} - - draw(canvas) { - for (const coordStr in this.diff) { - const el = this.diff[coordStr]; - const coord = JSON.parse(coordStr); - - if (el.action == "set") { - canvas.ctx.fillStyle = `hsl(${el.h}, ${el.s}, ${el.l})`; - canvas.ctx.fillRect( - coord[0]*canvas.rectSize, coord[1]*canvas.rectSize, - canvas.rectSize, canvas.rectSize, - ); - - } else { - canvas.ctx.clearRect( - coord[0]*canvas.rectSize, coord[1]*canvas.rectSize, - canvas.rectSize, canvas.rectSize, - ); - } - } - } -} - -const neighbors = [ - [-1, -1], [0, -1], [1, -1], - [-1, 0], /* [0, 0], */ [1, 0], - [-1, 1], [0, 1], [1, 1], -]; - -function neighborsOf(coord) { - return neighbors.map((n) => { - let nX = coord[0]+n[0]; - let nY = coord[1]+n[1]; - nX = (nX + w) % w; - nY = (nY + h) % h; - return [nX, nY]; - }); -} - -function randEmptyNeighboringCoord(layer, coord) { - const neighbors = neighborsOf(coord).sort(() => Math.random() - 0.5); - for (const nCoord of neighbors) { - if (!layer.get(nCoord)) return nCoord; - } - return null; -} - -function neighboringElsOf(layer, coord) { - const neighboringEls = []; - for (const nCoord of neighborsOf(coord)) { - const el = layer.get(nCoord); - if (el) neighboringEls.push(el); - } - return neighboringEls; -} - -const drift = 30; -function mkNewEl(l) { - return (nEls) => { - const s = "100%"; - if (nEls.length == 0) { - return { - h: randn(360), - s: s, - l: l, - }; - } - - // for each h (which can be considered as degrees around a circle) break the h - // down into x and y vectors, and add those up separately. Then find the angle - // between those two resulting vectors, and that's the "average" h value. - let x = 0; - let y = 0; - nEls.forEach((el) => { - const hRad = el.h * Math.PI / 180; - x += Math.cos(hRad); - y += Math.sin(hRad); - }); - - let h = Math.atan2(y, x); - h = h / Math.PI * 180; - - // apply some random drift, normalize - h += (Math.random() * drift * 2) - drift; - h = (h + 360) % 360; - - return { - h: h, - s: s, - l: l, - }; - } -} - -class Universe { - constructor(canvasesByClass, layersByClass) { - this.canvasesByClass = canvasesByClass; - this.state = { - tick: 0, - layers: layersByClass, - }; - } - - update() { - this.state.tick++; - Object.values(this.state.layers).forEach((layer) => layer.update(this.state)); - } - - draw() { - for (const layerName in this.state.layers) { - if (!this.canvasesByClass[layerName]) return; - this.canvasesByClass[layerName].forEach((canvas) => { - this.state.layers[layerName].draw(canvas); - }); - } - } -} - -</script> - -<style> - -.canvasContainer { - display: grid; - margin-bottom: 2rem; - text-align: center; -} - -canvas { - border: 1px dashed #AAA; - width: 100%; - grid-area: 1/1/2/2; -} - -</style> - -<div class="canvasContainer"> - <canvas class="layer1"></canvas> - <canvas class="layer2"></canvas> -</div> - -<div class="row"> - <div class="columns six"> - <div class="canvasContainer"><canvas class="layer1"></canvas></div> - </div> - <div class="columns six"> - <div class="canvasContainer"><canvas class="layer2"></canvas></div> - </div> -</div> - -This visualization combines two distinct layers, each of them borrowing their -behavior from [Visualization 4][viz4]. Neither layer has any effect on the -other, one is merely super-imposed on top of the other in the top canvas. You -can see each layer individually in the two lower canvases. - -Despite their not affecting each other, the code is set up so that each layer -_could_ be affected by the other. This will likely be explored more in a future -post. - -[viz4]: {% post_url 2021-05-26-viz-4 %} - -<script> - -const canvasesByClass = {}; -[...document.getElementsByTagName("canvas")].forEach((canvasDOM) => { - - const canvas = new Canvas(canvasDOM); - canvasDOM.classList.forEach((name) => { - if (!canvasesByClass[name]) canvasesByClass[name] = []; - canvasesByClass[name].push(canvas); - }) -}); - - -const universe = new Universe(canvasesByClass, { - "layer1": new Layer(mkNewEl("90%")), - "layer2": new Layer(mkNewEl("50%")), -}); - -const requestAnimationFrame = - window.requestAnimationFrame || - window.mozRequestAnimationFrame || - window.webkitRequestAnimationFrame || - window.msRequestAnimationFrame; - -function doTick() { - universe.update(); - universe.draw(); - requestAnimationFrame(doTick); -} - -doTick(); - -</script> |