/*
title: Brownian Snotite Walky Chromies
files:
head
pointlist
point
../point_src/stage.js
mouse
dragging
stroke
---
228 colour creatures (28 large, 200 half-sized and slower) seek similar hues, blend on contact, and merge with close matches.
Drag them into each other to play genetic matchmaker. Big creatures that go 800 frames without merging burst into a random number of differently sized, random-coloured offspring while conserving mass.
*/
class MainStage extends Stage {
canvas = 'playspace'
randomGenes() {
return {
aggression: Math.random(),
fear: Math.random(),
speed: .55 + Math.random() * 1.1,
turnRate: .025 + Math.random() * .24
}
}
inheritGenes(parent, other, weight=1) {
const genes = {}
for (const key of ['aggression','fear','speed','turnRate']) {
const center = other ? parent[key]*weight + other[key]*(1-weight) : parent[key]
const variation = key==='speed' ? .12 : key==='turnRate' ? .025 : .09
const lo = key==='speed' ? .35 : key==='turnRate' ? .012 : 0
const hi = key==='speed' ? 2 : key==='turnRate' ? .38 : 1
genes[key] = Math.max(lo,Math.min(hi,center+(Math.random()+Math.random()-1)*variation))
}
return genes
}
mounted() {
this.points = new PointList()
const cx = this.canvas.width / 2, cy = this.canvas.height / 2
for (let i = 0; i < 28; i++) {
const a = i * Math.PI * 2 / 28, r = 95 + (i % 6) * 25
const p = new Point({x: cx + Math.cos(a)*r, y: cy + Math.sin(a)*r, radius: 4})
p.genes = this.randomGenes()
p.hue = Math.floor(Math.random()*12)*30
p.vx = (Math.random()-.5)*2
p.vy = (Math.random()-.5)*2
p.mass = 1
p.speedScale = 1
p.cool = 0
p.hunger = 0
this.points.push(p)
}
// Two hundred half-sized, slower wanderers scattered throughout the stage.
for (let i = 0; i < 200; i++) {
const p = new Point({
x: 8 + Math.random() * Math.max(1, this.canvas.width - 16),
y: 8 + Math.random() * Math.max(1, this.canvas.height - 16),
radius: 2
})
p.genes = this.randomGenes()
p.hue = Math.floor(Math.random() * 12) * 30
p.vx = (Math.random() - .5) * .8
p.vy = (Math.random() - .5) * .8
p.mass = .25
p.cool = 0
p.speedScale = .45
this.points.push(p)
}
this.dragging.add(...this.points)
}
hueDiff(a,b) {
const d = Math.abs(a-b)%360
return Math.min(d, 360-d)
}
mixHue(a,b) {
const x = Math.cos(a*Math.PI/180)+Math.cos(b*Math.PI/180)
const y = Math.sin(a*Math.PI/180)+Math.sin(b*Math.PI/180)
return (Math.atan2(y,x)*180/Math.PI+360)%360
}
step() {
const ps = this.points
const width = this.canvas.width, height = this.canvas.height
for (const p of ps) {
if (p.cool > 0) p.cool--
p.hunger = (p.hunger || 0) + 1
let friend = null, best = Infinity
let threat = null, threatScore = 0
for (const q of ps) {
if (p === q) continue
const dx=q.x-p.x, dy=q.y-p.y
const dist=Math.hypot(dx,dy)||.001
const hue=this.hueDiff(p.hue,q.hue)
const danger = (q.radius / Math.max(1,p.radius)) * (q.genes ? q.genes.aggression : .5)
const range = 18 + p.radius * 4 + 50*p.genes.fear
if (danger > .45 && dist < range) {
const intensity = (range-dist)/range * danger
if (intensity > threatScore) {threatScore=intensity;threat=q}
}
const score = hue*3 + dist*.12
if (score < best) {best=score; friend=q}
// Gently repel neighbours so the screen stays lively.
const personalSpace = 20 + p.radius + q.radius
if (dist < personalSpace && dist > 0) {
const force = (personalSpace-dist)/personalSpace*.13 * p.speedScale * (1+.6*p.genes.fear)
p.vx -= dx/dist*force
p.vy -= dy/dist*force
}
}
if (friend) {
const dx=friend.x-p.x, dy=friend.y-p.y
const dist=Math.hypot(dx,dy)||1
const chase = .055*p.speedScale*(.35+1.5*p.genes.aggression)
p.vx += dx/dist*chase
p.vy += dy/dist*chase
}
if(threat && threat !== p) {
const dx=p.x-threat.x,dy=p.y-threat.y
const d=Math.hypot(dx,dy)||1
const flee=.14*p.genes.fear*threatScore*p.speedScale
p.vx+=dx/d*flee;p.vy+=dy/d*flee
}
p.vx += (Math.random()-.5)*.08*p.speedScale
p.vy += (Math.random()-.5)*.08*p.speedScale
p.vx *= .97; p.vy *= .97
const speed=Math.hypot(p.vx,p.vy)
const limit = 2.3 * p.speedScale * p.genes.speed
if(speed>limit) {p.vx*=limit/speed; p.vy*=limit/speed}
// Gene-limited steering: smooth, individual turns.
if (Math.hypot(p.vx,p.vy) > .03) {
const target=Math.atan2(p.vy,p.vx)
if (!Number.isFinite(p.radians)) p.radians=target
const delta=Math.atan2(Math.sin(target-p.radians),Math.cos(target-p.radians))
p.radians+=Math.max(-p.genes.turnRate,Math.min(p.genes.turnRate,delta))
const magnitude=Math.hypot(p.vx,p.vy)
p.vx=Math.cos(p.radians)*magnitude
p.vy=Math.sin(p.radians)*magnitude
}
p.x+=p.vx; p.y+=p.vy
// Toroidal screen wrap. Reset the visual tail at the seam so it
// doesn't draw a long line across the canvas.
let wrapped = false
if(p.x < -p.radius) {p.x=width+p.radius;wrapped=true}
if(p.x > width+p.radius) {p.x=-p.radius;wrapped=true}
if(p.y < -p.radius) {p.y=height+p.radius;wrapped=true}
if(p.y > height+p.radius) {p.y=-p.radius;wrapped=true}
if(wrapped) p.tail = null
}
const gone = new Set()
for (let i=0;i
= a.radius+b.radius)continue
const difference=this.hueDiff(a.hue,b.hue)
if(difference < 18 && ps.length-gone.size>3) {
const total=a.mass+b.mass
a.x=(a.x*a.mass+b.x*b.mass)/total
a.y=(a.y*a.mass+b.y*b.mass)/total
a.vx=(a.vx*a.mass+b.vx*b.mass)/total
a.vy=(a.vy*a.mass+b.vy*b.mass)/total
a.radians=Math.atan2(a.vy,a.vx)
a.hue=this.mixHue(a.hue,b.hue)
a.genes=this.inheritGenes(a.genes,b.genes,a.mass/total)
a.mass=total
a.speedScale=(a.speedScale*(total-b.mass)+b.speedScale*b.mass)/total
a.radius=Math.min(17,4*Math.sqrt(total))
a.cool=25
a.hunger=0
gone.add(b)
} else {
const blended=this.mixHue(a.hue,b.hue)
a.hue=(a.hue*.7+blended*.3)%360
b.hue=(b.hue*.7+blended*.3)%360
a.cool=b.cool=22
const nx=dx/(dist||1),ny=dy/(dist||1)
a.vx-=nx*.7*a.speedScale;a.vy-=ny*.7*a.speedScale
b.vx+=nx*.7*b.speedScale;b.vy+=ny*.7*b.speedScale
}
}
}
// Starved adults burst into a random number of unequal pieces.
// Offspring masses sum to the parent's mass (last takes the remainder).
const newborns = []
let population = ps.length - gone.size
for (const p of ps) {
if (gone.has(p) || p.mass < 1.5 || p.hunger < 800) continue
const maxPieces = Math.min(7, Math.floor(p.mass / .25), 400 - population + 1)
if (maxPieces < 2) continue
const count = 2 + Math.floor(Math.random() * (maxPieces - 1))
const weights = Array.from({length: count}, () => .3 + Math.random() * 2)
const weightSum = weights.reduce((a,b) => a+b,0)
let remaining = p.mass
const baseAngle = Math.random() * Math.PI * 2
const offspring = []
for (let i = 0; i < count; i++) {
const childMass = i === count - 1 ? remaining : p.mass * weights[i] / weightSum
remaining -= childMass
// Radius represents mass, not a mass deduction.
const childRadius = Math.max(1, Math.min(17, 4 * Math.sqrt(childMass)))
const theta = baseAngle + i * 2 * Math.PI / count
const offset = p.radius + childRadius + 2
const child = new Point({
x: Math.max(childRadius, Math.min(width-childRadius, p.x + Math.cos(theta)*offset)),
y: Math.max(childRadius, Math.min(height-childRadius, p.y + Math.sin(theta)*offset)),
radius: childRadius
})
child.genes = this.inheritGenes(p.genes)
child.mass = childMass
child.hue = Math.random() * 360
child.vx = p.vx + Math.cos(theta) * .7
child.vy = p.vy + Math.sin(theta) * .7
child.speedScale = Math.max(.45, p.speedScale * .85)
child.cool = 45
child.hunger = 0
child.radians = Math.atan2(child.vy, child.vx)
offspring.push(child)
}
gone.add(p)
newborns.push(...offspring)
population += count - 1
}
if(gone.size || newborns.length) {
// Keep the surviving Point objects and re-register dragging.
const survivors=Array.from(ps).filter(p=>!gone.has(p))
this.points=new PointList(...survivors, ...newborns)
this.dragging.add(...newborns)
}
}
updateTail(p) {
const count=7, spacing=Math.max(1.1,p.radius*.48)
if(!p.tail) {
const angle=p.radians||0
p.tail=Array.from({length:count},(_,i)=>({x:p.x-Math.cos(angle)*spacing*(i+1),y:p.y-Math.sin(angle)*spacing*(i+1)}))
p.swimPhase=Math.random()*Math.PI*2
}
const v=Math.hypot(p.vx,p.vy)
p.swimPhase+=.09+Math.min(.22,v*.055)
let leader=p
const angle=p.radians||0
for(let i=0;i