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author | Brian Picciano <mediocregopher@gmail.com> | 2021-07-31 11:35:39 -0600 |
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committer | Brian Picciano <mediocregopher@gmail.com> | 2021-07-31 11:35:39 -0600 |
commit | f1998c321a4eec6d75b58d84aa8610971bf21979 (patch) | |
tree | a90783eb296cc50e1c48433f241624f26b99be27 /static/src/_posts/2021-05-26-viz-4.md | |
parent | 03a35dcc38b055f15df160bd300969e3b703d4b1 (diff) |
move static files into static sub-dir, refactor nix a bit
Diffstat (limited to 'static/src/_posts/2021-05-26-viz-4.md')
-rw-r--r-- | static/src/_posts/2021-05-26-viz-4.md | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/static/src/_posts/2021-05-26-viz-4.md b/static/src/_posts/2021-05-26-viz-4.md new file mode 100644 index 0000000..cd6054a --- /dev/null +++ b/static/src/_posts/2021-05-26-viz-4.md @@ -0,0 +1,213 @@ +--- +title: >- + Visualization 4 +description: >- + Birth, death, and colors. +series: viz +tags: tech art +--- + +<canvas id="canvas" style="padding-bottom: 2rem;" width="100%" height="100%"></canvas> + +This visualization is a conglomeration of ideas from all the previous ones. On +each tick up to 20 new pixels are generated. The color of each new pixel is +based on the average color of its neighbors, plus some random drift. + +Each pixel dies after a certain number of ticks, `N`. A pixel's life can be +extended by up to `8N` ticks, one for each neighbor it has which is still alive. +This mechanism accounts for the strange behavior which is seen when the +visualization first loads, but also allows for more coherent clusters of pixels +to hold together as time goes on. + +The asteroid rule is also in effect in this visualization, so the top row and +bottom row pixels are neighbors of each other, and similarly for the rightmost +and leftmost column pixels. + +<script type="text/javascript"> + +function randn(n) { + return Math.floor(Math.random() * n); +} + +const canvas = document.getElementById("canvas"); +const parentWidth = canvas.parentElement.offsetWidth; + +const rectSize = Math.floor(parentWidth /100 /2) *2; // must be even number +console.log("rectSize", rectSize); + +canvas.width = parentWidth - rectSize - (parentWidth % rectSize); +canvas.height = canvas.width * 0.75; +canvas.height -= canvas.height % rectSize; +const ctx = canvas.getContext("2d"); + +const w = (canvas.width / rectSize) - 1; +const h = (canvas.height / rectSize) - 1; + +class Elements { + constructor() { + this.els = {}; + this.diff = {}; + } + + _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"}; + } + + drawDiff(ctx) { + for (const coordStr in this.diff) { + const el = this.diff[coordStr]; + const coord = JSON.parse(coordStr); + + if (el.action == "set") { + ctx.fillStyle = `hsl(${el.h}, ${el.s}, ${el.l})`; + } else { + ctx.fillStyle = `#FFF`; + } + + ctx.fillRect(coord[0]*rectSize, coord[1]*rectSize, rectSize, rectSize); + } + } + + 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]; + } + } + } +} + +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(els, coord) { + const neighbors = neighborsOf(coord).sort(() => Math.random() - 0.5); + for (const nCoord of neighbors) { + if (!els.get(nCoord)) return nCoord; + } + return null; +} + +function neighboringElsOf(els, coord) { + const neighboringEls = []; + for (const nCoord of neighborsOf(coord)) { + const el = els.get(nCoord); + if (el) neighboringEls.push(el); + } + return neighboringEls; +} + +const drift = 30; +function newEl(nEls) { + + // 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: "100%", + l: "50%", + }; +} + +const requestAnimationFrame = + window.requestAnimationFrame || + window.mozRequestAnimationFrame || + window.webkitRequestAnimationFrame || + window.msRequestAnimationFrame; + +const els = new Elements(); + +const maxNewElsPerTick = 20; +const deathThresh = 20; + +let tick = 0; +function doTick() { + tick++; + + const allEls = els.getAll().sort(() => Math.random() - 0.5); + + if (allEls.length == 0) { + els.set([w/2, h/2], { + h: randn(360), + s: "100%", + l: "50%", + }); + } + + let newEls = 0; + for (const el of allEls) { + const nCoord = randEmptyNeighboringCoord(els, el.coord); + if (!nCoord) continue; // el has no empty neighboring spots + + const nEl = newEl(neighboringElsOf(els, nCoord)) + nEl.tick = tick; + els.set(nCoord, nEl); + + newEls++; + if (newEls >= maxNewElsPerTick) break; + } + + for (const el of allEls) { + const nEls = neighboringElsOf(els, el.coord); + if (tick - el.tick - (nEls.length * deathThresh) >= deathThresh) els.unset(el.coord); + } + + els.drawDiff(ctx); + els.applyDiff(); + requestAnimationFrame(doTick); +} +requestAnimationFrame(doTick); + +</script> |