function run(inputs, controls) { const { seed, growth } = controls; if (!Number.isInteger(seed) || seed < 1 || seed > 9999 || !Number.isInteger(growth) || growth < 3 || growth > 25) { throw new Error('Use a seed from 1 to 9999 and 3 to 25 rounds of growth.'); } const feet = [[-3,-3,0],[3,-3,0],[3,3,0],[-3,3,0]]; const groundReturn = (foot, direction) => Array.from({length:13},(_,i)=>{ const angle=(i-6)*Math.PI/12; const offset=.24*Math.sin(angle); return [foot[0]+offset*direction[0],foot[1]+offset*direction[1],.24*(1-Math.cos(angle))]; }); const supports = [ [[-2.86,-2.89,.82],[-2.69,-2.72,1.84],[-2.47,-2.53,2.58]], [[2.48,-2.63,2.64],[2.72,-2.98,1.83],[2.94,-3.23,.64], ...groundReturn(feet[1],[0,1]),[2.99,-2.74,.68],[2.95,-2.61,1.59],[2.84,-2.36,2.58]], [[2.75,2.38,2.77],[3.03,2.70,1.68],[3.22,2.96,.63], ...groundReturn(feet[2],[-1,0]),[2.74,2.99,.64],[2.57,2.94,1.7],[2.36,2.81,2.62]], [[-2.46,2.55,2.67],[-2.74,2.76,1.82],[-2.90,2.91,.79]], ]; const bows = [[0,1.42,3.35],[-2.65,0,4.35],[0,-1.55,3.84]]; const trace = inputs?.capture ? [] : null; const clamp = (x,a,b) => Math.max(a,Math.min(b,x)); const add = (a,b) => a.map((x,i)=>x+b[i]); const sub = (a,b) => a.map((x,i)=>x-b[i]); const scale = (a,s) => a.map(x=>x*s); const mix = (a,b,t) => a.map((x,i)=>x+(b[i]-x)*t); const dot = (a,b) => a.reduce((sum,x,i)=>sum+x*b[i],0); const cross = (a,b) => [a[1]*b[2]-a[2]*b[1],a[2]*b[0]-a[0]*b[2],a[0]*b[1]-a[1]*b[0]]; const length = a => Math.hypot(...a); const unit = a => scale(a,1/Math.max(1e-8,length(a))); // Give each seed the same small initial line and its own growth tendency. let state = seed; const random = () => ((state = (Math.imul(state,1664525) + 1013904223) >>> 0) / 4294967296); const bands = bows.map((bow,index) => { const a=supports[index].at(-1), b=supports[index+1][0]; return Array.from({length:10},(_,i)=>{ const t=i/9; const p=mix(mix(a,bow,t),mix(bow,b,t),t); return { p, rate: .7+.6*random(), twist: random()-.5 }; }); }); function skeleton() { return [feet[0], ...supports[0], ...bands[0].slice(1,-1).map(n=>n.p), ...supports[1], ...bands[1].slice(1,-1).map(n=>n.p), ...supports[2], ...bands[2].slice(1,-1).map(n=>n.p), ...supports[3], feet[3]]; } const remember = () => { if(trace) trace.push(skeleton()); }; function grow() { for (const band of bands) { // Add points to the stretches under the most tension. Nothing assigns a return or a lane. const priorities=band.slice(1).map((b,i)=>{ const a=band[i]; return {i, weight: length(sub(b.p,a.p))*(a.rate+b.rate)/2}; }).sort((a,b)=>b.weight-a.weight || a.i-b.i); const split=new Set(priorities.slice(0,4).map(edge=>edge.i)); for(let i=band.length-2;i>=0;i--){ if(!split.has(i)) continue; const a=band[i], b=band[i+1]; const centre=mix(a.p,b.p,.5); const tangent=unit(sub(b.p,a.p)); const side=unit(cross(tangent,[0,0,1])); const twist=.55*(a.twist+b.twist)+.42*(random()-.5); const p=add(centre,add(scale(side,twist*.15),[0,0,.10*(random()-.5)])); band.splice(i+1,0,{p,rate:clamp((a.rate+b.rate)/2+.20*(random()-.5),.7,1.3),twist}); } } } function relax() { const nodes=bands.flatMap((band,lane)=>band.map((node,i)=>({node,lane,i,edge:i===0||i===band.length-1}))); const forces=nodes.map(({node,lane,i,edge})=>{ if(edge) return [0,0,0]; const band=bands[lane], p=node.p, previous=band[i-1].p, next=band[i+1].p; const links=[previous,next].map(neighbour=>{ const d=sub(neighbour,p); return scale(unit(d),.18*(length(d)-.64)); }); const bend=scale(sub(mix(previous,next,.5),p),.16); const ceiling=.012*(2.77+.30*lane+.16*node.twist-p[2]); return add(add(add(links[0],links[1]),bend),[0,0,ceiling]); }); const interactionRadius=.99; const byX=nodes.map(({node},index)=>({x:node.p[0],index})).sort((a,b)=>a.x-b.x); const neighbours=nodes.map(()=>[]); // Index local pairs by x, then apply the forces in the original node order. for(let i=0;ii-j)){ const right=nodes[b]; if(left.edge&&right.edge || left.lane===right.lane&&right.i-left.i<3) continue; const q=right.node.p; const dy=y-q[1],dz=z-q[2]; if(Math.abs(dy)>=interactionRadius||Math.abs(dz)>=interactionRadius) continue; const difference=[x-q[0],dy,dz]; const distance=length(difference); if(distance>=interactionRadius || distance<1e-8) continue; const push=scale(difference,.25*(interactionRadius-distance)/distance); if(!left.edge) forces[a]=add(forces[a],push); if(!right.edge) forces[b]=sub(forces[b],push); } } nodes.forEach(({node,edge},i)=>{ if(edge) return; const [x,y,z]=add(node.p,forces[i]); node.p=[clamp(x,-2.78,2.78),clamp(y,-2.78,2.78),clamp(z,2.36,4.26)]; }); } remember(); for(let round=0;roundMath.sqrt(length(v))); const tangentIn=add(sub(scale(sub(b,a),dt1/dt0),scale(sub(c,a),dt1/(dt0+dt1))),sub(c,b)); const tangentOut=add(sub(sub(c,b),scale(sub(d,b),dt1/(dt1+dt2))),scale(sub(d,c),dt1/dt2)); const count=Math.max(2,Math.ceil(length(sub(c,b))/.14)); for(let j=1;j<=count;j++){ const t=j/count; const u=t*t, w=u*t; const p=b.map((v,k)=>(2*w-3*u+1)*v+(w-2*u+t)*tangentIn[k]+ (3*u-2*w)*c[k]+(w-u)*tangentOut[k]); curve.push(j===count?c:[p[0],p[1],Math.max(0,p[2])]); } } if(trace) return { curve, trace }; // Sweep one circular section in a parallel-transport frame. const radius = 0.050; const sides = 10; const vertices = []; const faces = [Array.from({length:sides},(_,j)=>sides-1-j)]; let normal=[0,1,0]; for(let i=0;iNumber(v.toFixed(5)))); if(i){ const a=(i-1)*sides+j, b=(i-1)*sides+(j+1)%sides; faces.push([a,b,b+sides,a+sides]); } } } const last=vertices.length-sides; faces.push(Array.from({length:sides},(_,j)=>last+j)); return { version:2, units:'metres', objects:[{type:'MESH',name:'One continuous tube',color:'#253de8',vertices,faces}] }; }