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stipple.js
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stipple.js
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importScripts('helpers.js', 'external/rhill-voronoi-core.min.js', 'external/stackblur.min.js')
postMessage(['sliders', defaultControls.concat([
{label: 'Max Stipples', value: 2000, min: 500, max: 10000},
{label: 'Max Iterations', value: 30, min:2, max:200},
{label: 'Min dot size', value: 2, min: 0.5, max: 8, step:0.1, noRestart:true},
{label: 'Dot size range', value: 4, min: 0, max: 20, step:0.1, noRestart:true},
{label: 'TSP Art', type:'checkbox', noRestart:true},
{label: 'Stipple type', type:'select', options:['Circles', 'Spirals', 'Hexagons', 'Pentagrams', 'Snowflakes'], noRestart:true},
])]);
// TODO
// noRestart on max iterations change?
// TSP termination could do with improvement
(function(){
var particles, config, pixData, pixelCache =[];
onmessage = function(e) {
if (!particles) {
[ config, pixData ] = e.data;
render()
} else {
Object.assign(config, e.data[0])
redraw( config['TSP Art'] )
}
}
function makeAsync(f) {
return new Promise(resolve => setTimeout(() => resolve(f()), 0) )
}
function getPixel(x,y){
return pixelCache[Math.floor(x)][Math.floor(y)]
}
function redraw(tsp){
if (tsp) {
postLines(particles)
} else {
let minsize = config['Min dot size'], scale = config['Dot size range']/255;
let points=[]
switch (config['Stipple type']) {
case 'Spirals':
for (let p in particles) {
let theta=0, r=getPixel(particles[p].x,particles[p].y)*scale + minsize, spiral=[]
while (r>=0.1) {
spiral.push( [particles[p].x + r*Math.cos(theta), particles[p].y + r*Math.sin(theta)] )
theta+=0.5
if (theta>6.3) r-=0.1 //do one full loop before spiraling in
}
points.push(spiral)
}
postLines(points)
break;
case 'Hexagons': {
let s60 = Math.sin(60*Math.PI/180), c60 = 0.5
for (let p in particles) {
let x=particles[p].x, y=particles[p].y
let r=getPixel(x,y)*scale + minsize
let hex = [ [x+r,y], [x+r*c60,y-r*s60], [x-r*c60, y-r*s60], [x-r, y], [x-r*c60, y+r*s60], [x+r*c60,y+r*s60], [x+r,y] ]
points.push(hex)
}
postLines(points)
} break;
case 'Pentagrams':
let px = [], py = []
for (let p=0;p<360;p+=360/5) {
px.push( Math.sin(p*Math.PI/180))
py.push(Math.cos(p*Math.PI/180) )
}
for (let p in particles) {
let x=particles[p].x, y=particles[p].y
let r=getPixel(x,y)*scale + minsize
points.push( [
[x+r*px[0],y+r*py[0]],
[x+r*px[3],y+r*py[3]],
[x+r*px[1],y+r*py[1]],
[x+r*px[4],y+r*py[4]],
[x+r*px[2],y+r*py[2]],
[x+r*px[0],y+r*py[0]],
])
}
postLines(points)
break;
case 'Snowflakes': {
let s60 = Math.sin(60*Math.PI/180), c60 = 0.5
for (let p in particles) {
let x=particles[p].x, y=particles[p].y
let r=getPixel(x,y)*scale + minsize
points.push([ [x-r,y] , [x+r,y] ])
points.push([ [x+r*c60,y+r*s60] , [x-r*c60,y-r*s60] ])
points.push([ [x-r*c60,y+r*s60] , [x+r*c60,y-r*s60] ])
}
postLines(points)
} break;
default: //circles
for (let p in particles)
particles[p].r=getPixel(particles[p].x,particles[p].y)*scale + minsize
postCircles(particles)
}
}
}
async function render() {
await makeAsync(()=> StackBlur.imageDataRGB(pixData, 0,0,config.width,config.height, 1) )
const getPixelSlow = pixelProcessor(config, pixData)
for (let x=0;x<config.width;x++) {
pixelCache[x]=[]
for (let y=0;y<config.height;y++)
pixelCache[x][y] = getPixelSlow(x,y)
}
const maxParticles = config['Max Stipples']
const border = 6;
particles = Array(maxParticles), i=0;
while ( i < maxParticles ) {
x=Math.random()*(config.width-border*2)+border;
y=Math.random()*(config.height-border*2)+border;
z = getPixel( x , y )
if (Math.random()*255 <= z)
particles[i++]={x,y}
}
var voronoi = new Voronoi();
var diagram=null
var bbox = {xl:border, xr:config.width-border, yt:border, yb:config.height-border}
for (let k=0;k<config['Max Iterations'];k++){
postMessage(['msg', "Iteration "+k]);
voronoi.recycle(diagram)
await makeAsync(()=> diagram = voronoi.compute(particles, bbox))
await makeAsync(()=>{
for (let c = 0; c< maxParticles; c++) {
let edgePixels = []
let halfedges = diagram.cells[c].halfedges;
if (halfedges.length==0) continue
let v = halfedges[0].getStartpoint()
let sx = v.x
let sy = v.y;
let dx,ex,ey;
// Walk around the perimeter of the cell marking the boundary pixels
// No need for full bressenham since we'll be scanning across anyway
for (i of halfedges){
v = i.getEndpoint()
ex = v.x
ey = v.y
dx = (ex-sx) / (ey-sy)
if (sy == ey) {
edgePixels.push([Math.round(sx),Math.round(sy)])
} else if (sy<ey) {
while (sy < ey) {
edgePixels.push([Math.round(sx),Math.round(sy)])
sy++
sx += dx
}
} else {
while (sy > ey) {
edgePixels.push([Math.round(sx),Math.round(sy)])
sy--
sx -= dx
}
}
sy=ey
sx=ex
}
// create lookup addressed by Y coord
let byY ={}
for (i of edgePixels){
if (byY[i[1]]) byY[i[1]].push(i[0])
else byY[i[1]] = [i[0]]
}
// scanlines
let xSum=0, ySum=0, dSum = 0;
for (let ny in byY) {
let y = Number(ny)
for (let x = Math.min(...byY[ny]); x<= Math.max(...byY[ny]); x++){
let z = 0.001 + getPixel(x,y)
xSum += z*x
ySum += z*y
dSum += z
}
}
if (dSum>0) {
xSum /= dSum
ySum /= dSum
}
particles[c].x = Math.max(border,Math.min(xSum, config.width-border))
particles[c].y = Math.max(border,Math.min(ySum, config.height-border))
}
});
redraw(0)
}
postMessage(['msg', "Route optimization"]);
function distance(p1,p2){
let dx = p1.x-p2.x
let dy = p1.y-p2.y
return dx*dx+dy*dy
}
function swapParticles(p1,p2){
let temp = particles[p1]
particles[p1]=particles[p2]
particles[p2]=temp
}
await makeAsync(()=>{
for (i=1; i< maxParticles; i++){
let closest = 0, mindist = 1e99
for (let j=i; j<maxParticles; j++) {
let d = distance(particles[j], particles[i-1])
if (d < mindist) {
closest = j
mindist=d
}
}
swapParticles(i,closest)
}
})
// 2-opt optimization
let numSwaps=100
let terminate = 2000/maxParticles
while (numSwaps>terminate) {
redraw(1)
await makeAsync(()=>{
numSwaps*=0.9
for (i=0;i<1e6;i++) {
let iA = Math.floor(Math.random()*(maxParticles-1))
let iB = Math.floor(Math.random()*(maxParticles-1))
if (Math.abs(iA-iB)<2) continue
if (iB<iA) {
let temp = iB
iB=iA
iA = temp
}
let dA = distance( particles[iA], particles[iA+1] )
+ distance( particles[iB], particles[iB+1] )
let dB = distance( particles[iA], particles[iB])
+ distance( particles[iA+1], particles[iB+1])
if (dB<dA) {
// reverse tour between a1 and b0
let high = iB, low = iA+1
while (high>low) {
swapParticles(low, high)
high--
low++
}
numSwaps++
}
}
})
postMessage(['msg', `Optimizing route... [${numSwaps.toFixed(2)}]`]);
}
redraw(config['TSP Art'])
postMessage(['msg', "Done"]);
}
})();