moire-pattern/index.html at main · cairn-code/moire-pattern · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
<title>Moiré</title>
<link href="https://fonts.googleapis.com/css2?family=Inter:wght@300;500&display=swap" rel="stylesheet">
<style>
*{margin:0;padding:0;box-sizing:border-box}
body{background:#0a0a0f;overflow:hidden;font-family:'Inter',sans-serif;cursor:crosshair;-webkit-tap-highlight-color:transparent;user-select:none}
canvas{display:block}
.title{position:fixed;top:50%;left:50%;transform:translate(-50%,-50%);color:rgba(255,255,255,.55);font-size:clamp(1.4rem,4vw,2.4rem);font-weight:300;letter-spacing:.5em;text-transform:uppercase;z-index:10;transition:opacity 2s;pointer-events:none}
.hint{position:fixed;top:calc(50% + 2.5rem);left:50%;transform:translateX(-50%);color:rgba(255,255,255,.2);font-size:.72rem;font-weight:300;letter-spacing:.18em;z-index:10;transition:opacity 2s;pointer-events:none}
.mode-lbl{position:fixed;top:1.4rem;left:50%;transform:translateX(-50%);color:rgba(255,255,255,.18);font-size:.6rem;font-weight:300;letter-spacing:.25em;text-transform:uppercase;z-index:10;pointer-events:none}
.controls{position:fixed;bottom:2rem;left:50%;transform:translateX(-50%);display:flex;gap:.5rem;z-index:10}
.btn{background:rgba(255,255,255,.03);border:1px solid rgba(255,255,255,.07);color:rgba(255,255,255,.35);padding:.4rem .9rem;font-family:'Inter',sans-serif;font-size:.65rem;letter-spacing:.12em;text-transform:uppercase;cursor:pointer;transition:all .3s;border-radius:2px}
.btn:hover{background:rgba(255,255,255,.08);color:rgba(255,255,255,.7)}
.btn.on{background:rgba(255,255,255,.09);color:rgba(255,255,255,.85);border-color:rgba(255,255,255,.18)}
.speed-lbl{position:fixed;bottom:4.5rem;left:50%;transform:translateX(-50%);color:rgba(255,255,255,.15);font-size:.55rem;letter-spacing:.15em;z-index:10;pointer-events:none}
</style>
</head>
<body>
<canvas id="c"></canvas>
<div class="title" id="title">Moiré</div>
<div class="hint" id="hint">move to shift the pattern</div>
<div class="mode-lbl" id="ml">circles</div>
<div class="speed-lbl" id="sl">scroll to change density</div>
<div class="controls">
<button class="btn on" data-m="circles">circles</button>
<button class="btn" data-m="lines">lines</button>
<button class="btn" data-m="radial">radial</button>
<button class="btn" data-m="grid">grid</button>
</div>
<script>
const $=s=>document.querySelector(s);
const C=$('#c'),X=C.getContext('2d');
let w,h,mx,my,tx,ty,time=0,mode='circles',touched=false,spacing=6;

function resize(){
  w=C.width=innerWidth;h=C.height=innerHeight;
  mx=tx=w/2;my=ty=h/2;
}
addEventListener('resize',resize);resize();

function onInput(x,y){
  tx=x;ty=y;
  if(!touched){touched=true;$('#title').style.opacity='.06';$('#hint').style.opacity='0';$('#sl').style.opacity='0';}
}
addEventListener('mousemove',e=>onInput(e.clientX,e.clientY));
addEventListener('touchmove',e=>{e.preventDefault();onInput(e.touches[0].clientX,e.touches[0].clientY)},{passive:false});
addEventListener('touchstart',e=>{e.preventDefault();onInput(e.touches[0].clientX,e.touches[0].clientY)},{passive:false});

addEventListener('wheel',e=>{
  e.preventDefault();
  spacing=Math.max(3,Math.min(20,spacing+Math.sign(e.deltaY)));
},{passive:false});

document.querySelectorAll('.btn').forEach(b=>{
  b.addEventListener('click',()=>{
    document.querySelectorAll('.btn').forEach(x=>x.classList.remove('on'));
    b.classList.add('on');mode=b.dataset.m;$('#ml').textContent=mode;
  });
});

function circles(cx,cy,hue){
  const mr=Math.sqrt(w*w+h*h);
  for(let r=spacing;r<mr;r+=spacing){
    X.beginPath();X.arc(cx,cy,r,0,Math.PI*2);
    X.strokeStyle='hsla('+(r*.25+hue)%360+',55%,52%,.18)';
    X.lineWidth=.7;X.stroke();
  }
}

function lines(cx,cy,ang,hue){
  X.save();X.translate(cx,cy);X.rotate(ang);
  const n=Math.ceil(Math.sqrt(w*w+h*h)/spacing);
  for(let i=-n;i<=n;i++){
    X.beginPath();X.moveTo(i*spacing,-h);X.lineTo(i*spacing,h);
    X.strokeStyle='hsla('+(Math.abs(i)*1.5+hue)%360+',55%,52%,.18)';
    X.lineWidth=.7;X.stroke();
  }
  X.restore();
}

function radial(cx,cy,hue,rot){
  X.save();X.translate(cx,cy);X.rotate(rot);
  const mr=Math.sqrt(w*w+h*h),n=90;
  for(let i=0;i<n;i++){
    const a=(i/n)*Math.PI*2;
    X.beginPath();X.moveTo(0,0);
    X.lineTo(Math.cos(a)*mr,Math.sin(a)*mr);
    X.strokeStyle='hsla('+(i*4+hue)%360+',55%,52%,.14)';
    X.lineWidth=.7;X.stroke();
  }
  X.restore();
}

function grid(cx,cy,hue){
  const gap=spacing*2.5,sz=Math.max(1.5,gap*.2);
  const cols=Math.ceil(w/gap)+4,rows=Math.ceil(h/gap)+4;
  const sx=cx-(cols/2)*gap,sy=cy-(rows/2)*gap;
  for(let r=0;r<rows;r++){
    for(let c=0;c<cols;c++){
      const x=sx+c*gap,y=sy+r*gap;
      const d=Math.sqrt((c-cols/2)**2+(r-rows/2)**2);
      X.fillStyle='hsla('+(d*6+hue)%360+',55%,52%,.45)';
      X.fillRect(x-sz/2,y-sz/2,sz,sz);
    }
  }
}

function frame(){
  const cx=w/2,cy=h/2;

  // auto-drift before interaction
  if(!touched){tx=cx+Math.cos(time*.4)*60;ty=cy+Math.sin(time*.55)*60;}

  // smooth follow
  mx+=(tx-mx)*.045;my+=(ty-my)*.045;
  const ox=cx+(mx-cx)*.55,oy=cy+(my-cy)*.55;

  X.fillStyle='#0a0a0f';X.fillRect(0,0,w,h);
  X.globalCompositeOperation='lighter';

  const h1=(time*12)%360,h2=(h1+180)%360;

  switch(mode){
    case'circles':circles(cx,cy,h1);circles(ox,oy,h2);break;
    case'lines':lines(cx,cy,0,h1);lines(ox,oy,.025+Math.sin(time*.4)*.018,h2);break;
    case'radial':radial(cx,cy,h1,0);radial(ox,oy,h2,time*.08);break;
    case'grid':grid(cx,cy,h1);grid(ox,oy,h2);break;
  }

  X.globalCompositeOperation='source-over';
  time+=.007;
  requestAnimationFrame(frame);
}
frame();
</script>
</body>
</html>