loftmorph/index.html at main · hbehrensj/loftmorph · 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">
<title>Morph Preview — convex cross-sections</title>
<style>
  :root { --bg:#14171c; --panel:#1c2129; --line:#2b323d; --ink:#e6e9ee; --dim:#8b96a5; --x:#5db0ff; --y:#ffa95d; }
  * { box-sizing:border-box; }
  html,body { margin:0; height:100%; background:var(--bg); color:var(--ink);
    font:13px/1.5 ui-monospace, "SF Mono", Menlo, Consolas, monospace; overflow:hidden; }
  #app { display:flex; height:100%; }
  #view { flex:1; position:relative; }
  canvas { display:block; }
  #panel { width:296px; background:var(--panel); border-left:1px solid var(--line);
    padding:16px 18px 14px; overflow-y:auto; }
  h1 { font-size:13px; letter-spacing:.04em; text-transform:uppercase; color:var(--dim); margin:0 0 6px; font-weight:600; }
  .group { font-size:11px; letter-spacing:.03em; text-transform:uppercase; color:var(--dim);
    margin:16px 0 8px; padding-bottom:4px; border-bottom:1px solid var(--line); }
  select { width:100%; background:var(--bg); color:var(--ink); border:1px solid var(--line);
    border-radius:4px; padding:6px 8px; font:inherit; margin-bottom:10px; }
  .ctrl { margin-bottom:11px; }
  .ctrl.dis { opacity:.35; }
  .ctrl label { display:flex; justify-content:space-between; margin-bottom:5px; }
  .ctrl.x label .val { color:var(--x); } .ctrl.y label .val { color:var(--y); } .ctrl label .val { color:var(--ink); }
  input[type=range] { width:100%; }
  .ctrl.x input { accent-color:var(--x); } .ctrl.y input { accent-color:var(--y); } .ctrl input { accent-color:var(--ink); }
  .row { display:flex; align-items:center; gap:8px; margin:10px 0 4px; color:var(--dim); }
  #profile { width:100%; background:var(--bg); border:1px solid var(--line); border-radius:4px; }
  .cap { color:var(--dim); font-size:11px; margin:14px 0 2px; }
  .legend { display:flex; gap:14px; font-size:11px; color:var(--dim); margin:6px 0 4px; }
  .legend i { display:inline-block; width:10px; height:3px; margin-right:5px; vertical-align:middle; }
  .note { color:var(--dim); font-size:11px; line-height:1.6; margin-top:6px; }
  .note b { color:var(--ink); font-weight:600; }
  button#export { width:100%; margin-top:16px; padding:10px; background:var(--x); color:#0b1017;
    border:none; border-radius:5px; font:inherit; font-weight:600; letter-spacing:.02em; cursor:pointer; }
  button#export:hover { filter:brightness(1.08); }
  #meshinfo { color:var(--dim); font-size:11px; margin-top:7px; text-align:center; }
</style>
<script type="importmap">
{ "imports": {
  "three": "https://unpkg.com/three@0.160.0/build/three.module.js",
  "three/addons/": "https://unpkg.com/three@0.160.0/examples/jsm/"
}}
</script>
</head>
<body>
<div id="app">
  <div id="view"></div>
  <div id="panel">
    <h1>Morph preview</h1>

    <div class="group">Bottom cross-section</div>
    <select id="bottom">
      <option value="rect" selected>Rectangle</option>
      <option value="oval">Oval</option>
      <option value="tri">Triangle</option>
      <option value="pent">Pentagon</option>
      <option value="hex">Hexagon</option>
    </select>
    <div class="ctrl x" id="w-bX"><label>Size X <span class="val" id="v-bX">20</span></label><input type="range" id="bX" min="2" max="100" step="1" value="20"></div>
    <div class="ctrl y" id="w-bY"><label>Size Y <span class="val" id="v-bY">20</span></label><input type="range" id="bY" min="2" max="100" step="1" value="20"></div>
    <div class="ctrl"   id="w-bRot"><label>Rotation° <span class="val" id="v-bRot">0</span></label><input type="range" id="bRot" min="-180" max="180" step="1" value="0"></div>

    <div class="group">Top cross-section</div>
    <select id="top">
      <option value="oval" selected>Oval</option>
      <option value="rect">Rectangle</option>
      <option value="tri">Triangle</option>
      <option value="pent">Pentagon</option>
      <option value="hex">Hexagon</option>
    </select>
    <div class="ctrl x" id="w-tX"><label>Size X <span class="val" id="v-tX">20</span></label><input type="range" id="tX" min="2" max="100" step="1" value="20"></div>
    <div class="ctrl y" id="w-tY"><label>Size Y <span class="val" id="v-tY">20</span></label><input type="range" id="tY" min="2" max="100" step="1" value="20"></div>
    <div class="ctrl"   id="w-tRot"><label>Rotation° <span class="val" id="v-tRot">0</span></label><input type="range" id="tRot" min="-180" max="180" step="1" value="0"></div>

    <div class="group">Body</div>
    <div class="ctrl"><label>Height <span class="val" id="v-height">40</span></label><input type="range" id="height" min="2" max="200" step="1" value="40"></div>
    <div class="ctrl"><label>Segments <span class="val" id="v-segments">48</span></label><input type="range" id="segments" min="8" max="128" step="1" value="48"></div>
    <div class="ctrl"><label>Layers <span class="val" id="v-layers">40</span></label><input type="range" id="layers" min="2" max="100" step="1" value="40"></div>

    <div class="row"><input type="checkbox" id="wire"><label for="wire" style="margin:0;color:var(--dim)">Wireframe</label></div>

    <button id="export">⬇ Export STL</button>
    <div id="meshinfo"></div>

    <div class="cap">Bounding half-extent vs height</div>
    <div class="legend"><span><i style="background:var(--x)"></i>X</span><span><i style="background:var(--y)"></i>Y</span></div>
    <canvas id="profile" width="260" height="140"></canvas>
    <div class="note">Both ends blend with <b>smootherstep</b>, so the envelope leaves the base and meets the top with a flat tangent — no crease. Matching corner counts are auto-aligned to the least-twist rotation; unmatched corners fall back to a direct radial correspondence.</div>
  </div>
</div>

<script type="module">
import * as THREE from 'three';
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';

/* ---- SHARED MATH (mirror of generate_morph_stl.py) ---- */
const NGON={tri:3,pent:5,hex:6};
function smootherstep(t){ if(t<0)t=0; else if(t>1)t=1; return t*t*t*(t*(t*6-15)+10); }
function rot2(x,y,r){ const c=Math.cos(r),s=Math.sin(r); return [x*c-y*s, x*s+y*c]; }

function basePoint(kind,a,X,Y){
  if(kind==='oval') return [X*Math.cos(a), Y*Math.sin(a)];
  if(kind==='rect'){ const c=Math.cos(a),d=Math.sin(a),m=Math.max(Math.abs(c)/X,Math.abs(d)/Y); return [c/m,d/m]; }
  const n=NGON[kind], R=X, ap=R*Math.cos(Math.PI/n), step=2*Math.PI/n, alpha0=Math.PI/2+Math.PI/n;
  let d=a-alpha0; d=((d+Math.PI/n)%step+step)%step - Math.PI/n;
  const r=ap/Math.cos(d);
  return [r*Math.cos(a), r*Math.sin(a)];
}
function baseCorners(kind,X,Y){
  if(kind==='oval') return [];
  if(kind==='rect'){ const a0=Math.atan2(Y,X); return [a0,Math.PI-a0,Math.PI+a0,2*Math.PI-a0]; }
  const n=NGON[kind], out=[]; for(let k=0;k<n;k++) out.push(Math.PI/2+2*Math.PI*k/n); return out;
}
function shapePoint(kind,a,X,Y,rot){ const [x,y]=basePoint(kind,a-rot,X,Y); return rot2(x,y,rot); }
function shapeCorners(kind,X,Y,rot){ return baseCorners(kind,X,Y).map(c=>c+rot); }

// Best non-crossing correspondence between the two ends' corners: tries every
// rotational offset, picks the one minimizing total angular mismatch (DP over
// a circular subsequence alignment). Corners that can't be paired (unequal
// corner counts) fall back to the old shared-angle sampling for that corner.
function bestMatching(bc,tc){
  const TWO=2*Math.PI;
  const circDist=(a,b)=>{ let d=Math.abs(a-b)%TWO; if(d>Math.PI) d=TWO-d; return d; };
  const nb=bc.length, nt=tc.length;
  const swap=nb>nt;
  const small=swap?tc:bc, large=swap?bc:tc;
  const m=small.length, M=large.length;
  if(M===0) return [];
  let bestCost=Infinity, bestMatchOf=new Array(M).fill(-1);
  for(let r=0;r<M;r++){
    const largeR=Array.from({length:M},(_,k)=>large[(r+k)%M]);
    const dp=Array.from({length:m+1},()=>new Array(M+1).fill(Infinity));
    const choice=Array.from({length:m+1},()=>new Array(M+1).fill(0));
    for(let j=0;j<=M;j++) dp[0][j]=0;
    for(let i=1;i<=m;i++){
      for(let j=1;j<=M;j++){
        let val=dp[i][j-1], c=0;
        const mv=dp[i-1][j-1]+circDist(small[i-1],largeR[j-1])**2;
        if(mv<val){ val=mv; c=1; }
        dp[i][j]=val; choice[i][j]=c;
      }
    }
    const cost=dp[m][M];
    if(cost<bestCost){
      const matchOfR=new Array(M).fill(-1);
      let i=m, j=M;
      while(i>0 && j>0){ if(choice[i][j]===1){ matchOfR[j-1]=i-1; i--; j--; } else j--; }
      const matchOf=new Array(M).fill(-1);
      for(let k=0;k<M;k++) matchOf[(r+k)%M]=matchOfR[k];
      bestCost=cost; bestMatchOf=matchOf;
    }
  }
  const anchors=[];
  for(let k=0;k<M;k++){
    const largeAngle=large[k], si=bestMatchOf[k];
    const smallAngle= si>=0 ? small[si] : largeAngle;
    anchors.push(swap
      ? {aBottom:largeAngle, aTop:smallAngle, aKey:largeAngle}
      : {aBottom:smallAngle, aTop:largeAngle, aKey:largeAngle});
  }
  return anchors;
}
function buildAngles(bottomC,topC,segments){
  const TWO=2*Math.PI;
  const norm=arr=>{
    const a=arr.map(c=>((c%TWO)+TWO)%TWO).sort((p,q)=>p-q);
    const eps=1e-6, out=[];
    for(const v of a){ if(!out.length || Math.abs(v-out[out.length-1])>eps) out.push(v); }
    if(out.length>=2 && Math.abs((out[0]+TWO)-out[out.length-1])<eps) out.pop();
    return out;
  };
  const bc=norm(bottomC), tc=norm(topC);
  const anchors=bestMatching(bc,tc);
  if(!anchors.length){
    const n=Math.max(3,Math.round(segments)), out=[];
    for(let i=0;i<n;i++){ const a=TWO*i/n; out.push({aBottom:a,aTop:a}); }
    return out;
  }
  const m=anchors.length, total=Math.max(Math.round(segments),m), fill=total-m;
  const arcs=[]; let s=0;
  for(let i=0;i<m;i++){ const lo=anchors[i].aKey, hi=(i===m-1)?anchors[0].aKey+TWO:anchors[i+1].aKey; arcs.push(hi-lo); s+=hi-lo; }
  const base=[], frac=[]; let used=0;
  for(let i=0;i<m;i++){ const ex=fill*arcs[i]/s, f=Math.floor(ex); base.push(f); frac.push(ex-f); used+=f; }
  const order=[...Array(m).keys()].sort((p,q)=>frac[q]-frac[p]);
  for(let i=0;i<fill-used;i++) base[order[i]]++;
  const angles=[];
  for(let i=0;i<m;i++){
    const a0=anchors[i], nxt=anchors[(i+1)%m];
    const loB=a0.aBottom, hiB=(i===m-1)?nxt.aBottom+TWO:nxt.aBottom;
    const loT=a0.aTop,    hiT=(i===m-1)?nxt.aTop+TWO:nxt.aTop;
    angles.push({aBottom:loB, aTop:loT});
    for(let k=1;k<=base[i];k++){
      angles.push({ aBottom:loB+(hiB-loB)*k/(base[i]+1), aTop:loT+(hiT-loT)*k/(base[i]+1) });
    }
  }
  return angles;
}
function ringAt(u,P,angles){
  const b=smootherstep(u), z=P.height*u, ring=[];
  for(const a of angles){
    const [bx,by]=shapePoint(P.bottom,a.aBottom,P.bX,P.bY,P.bRot);
    const [tx,ty]=shapePoint(P.top,   a.aTop,   P.tX,P.tY,P.tRot);
    ring.push([bx*(1-b)+tx*b, by*(1-b)+ty*b, z]);
  }
  return ring;
}
/* ------------------------------------------------------- */

function buildGeometry(P){
  const positions=[], indices=[];
  const push=v=>{ positions.push(v[0],v[1],v[2]); return positions.length/3-1; };
  const bc=shapeCorners(P.bottom,P.bX,P.bY,P.bRot), tc=shapeCorners(P.top,P.tX,P.tY,P.tRot);
  const angles=buildAngles(bc,tc,P.segments);
  const seg=angles.length, lay=Math.round(P.layers);

  const grid=[];
  for(let L=0;L<=lay;L++) grid.push(ringAt(L/lay,P,angles).map(push));
  for(let L=0;L<lay;L++){
    for(let i=0;i<seg;i++){
      const j=(i+1)%seg;
      const a=grid[L][i], b=grid[L][j], c=grid[L+1][j], d=grid[L+1][i];
      indices.push(a,b,d, b,c,d);
    }
  }
  const bottom=ringAt(0,P,angles).map(push), cBot=push([0,0,0]);
  for(let i=0;i<seg;i++){ const j=(i+1)%seg; indices.push(cBot,bottom[j],bottom[i]); }
  const top=ringAt(1,P,angles).map(push), cTop=push([0,0,P.height]);
  for(let i=0;i<seg;i++){ const j=(i+1)%seg; indices.push(cTop,top[i],top[j]); }

  const g=new THREE.BufferGeometry();
  g.setAttribute('position', new THREE.Float32BufferAttribute(positions,3));
  g.setIndex(indices); g.computeVertexNormals();
  return g;
}

const view=document.getElementById('view');
const scene=new THREE.Scene(); scene.background=new THREE.Color(0x14171c);
const camera=new THREE.PerspectiveCamera(45,1,0.1,5000); camera.up.set(0,0,1);
const renderer=new THREE.WebGLRenderer({antialias:true}); view.appendChild(renderer.domElement);
const controls=new OrbitControls(camera, renderer.domElement); controls.enableDamping=true;

scene.add(new THREE.HemisphereLight(0xffffff,0x30343c,0.9));
const key=new THREE.DirectionalLight(0xffffff,1.1); key.position.set(1,-1.4,2); scene.add(key);
const grid=new THREE.GridHelper(300,30,0x2b323d,0x22272f); grid.rotation.x=Math.PI/2; scene.add(grid);

const mat=new THREE.MeshStandardMaterial({color:0x9fb4c8, metalness:0.1, roughness:0.55, side:THREE.DoubleSide});
let mesh=new THREE.Mesh(new THREE.BufferGeometry(), mat); scene.add(mesh);

const P={bottom:'rect',bX:20,bY:20,bRot:0, top:'oval',tX:20,tY:20,tRot:0, height:40,segments:48,layers:40};

function syncEnabled(){
  // Y is unused for polygons; grey it out.
  const poly=k=>k==='tri'||k==='pent'||k==='hex';
  document.getElementById('w-bY').classList.toggle('dis', poly(P.bottom));
  document.getElementById('bY').disabled=poly(P.bottom);
  document.getElementById('w-tY').classList.toggle('dis', poly(P.top));
  document.getElementById('tY').disabled=poly(P.top);
}
function rebuild(){
  mesh.geometry.dispose();
  mesh.geometry=buildGeometry(P);
  mesh.material.wireframe=document.getElementById('wire').checked;
  controls.target.set(0,0,P.height/2);
  drawProfile();
  updateInfo();
}
function updateInfo(){
  const g=mesh.geometry; g.computeBoundingBox(); const bb=g.boundingBox;
  const tris=(g.index?g.index.count:g.attributes.position.count)/3;
  const w=(bb.max.x-bb.min.x), d=(bb.max.y-bb.min.y), h=(bb.max.z-bb.min.z);
  document.getElementById('meshinfo').textContent =
    `${tris.toLocaleString()} triangles · ${w.toFixed(0)}×${d.toFixed(0)}×${h.toFixed(0)} mm`;
}

// Binary STL straight from the live geometry (same winding/normals as the Python exporter).
function geometryToSTL(geo){
  const pos=geo.attributes.position, idx=geo.index;
  const nTri=(idx?idx.count:pos.count)/3;
  const buf=new ArrayBuffer(84+nTri*50), dv=new DataView(buf);
  const label="morph preview STL"; for(let i=0;i<label.length;i++) dv.setUint8(i,label.charCodeAt(i));
  dv.setUint32(80,nTri,true);
  let off=84;
  const V=i=>[pos.getX(i),pos.getY(i),pos.getZ(i)];
  for(let t=0;t<nTri;t++){
    const a=idx?idx.getX(t*3):t*3, b=idx?idx.getX(t*3+1):t*3+1, c=idx?idx.getX(t*3+2):t*3+2;
    const va=V(a), vb=V(b), vc=V(c);
    const ux=vb[0]-va[0],uy=vb[1]-va[1],uz=vb[2]-va[2], vx=vc[0]-va[0],vy=vc[1]-va[1],vz=vc[2]-va[2];
    let nx=uy*vz-uz*vy, ny=uz*vx-ux*vz, nz=ux*vy-uy*vx; const L=Math.hypot(nx,ny,nz)||1;
    dv.setFloat32(off,nx/L,true); dv.setFloat32(off+4,ny/L,true); dv.setFloat32(off+8,nz/L,true); off+=12;
    for(const v of [va,vb,vc]){ dv.setFloat32(off,v[0],true); dv.setFloat32(off+4,v[1],true); dv.setFloat32(off+8,v[2],true); off+=12; }
    dv.setUint16(off,0,true); off+=2;
  }
  return buf;
}
function exportSTL(){
  const blob=new Blob([geometryToSTL(mesh.geometry)],{type:'model/stl'});
  const url=URL.createObjectURL(blob), a=document.createElement('a');
  a.href=url; a.download=`morph_${P.bottom}-${P.top}_h${Math.round(P.height)}.stl`;
  document.body.appendChild(a); a.click(); a.remove();
  setTimeout(()=>URL.revokeObjectURL(url),1000);
}
function frameCamera(){
  const d=Math.max(P.bX,P.bY,P.tX,P.tY,P.height)*2.6;
  camera.position.set(d,-d,d*0.75); controls.target.set(0,0,P.height/2); controls.update();
}

const pc=document.getElementById('profile'), px=pc.getContext('2d');
function extentAt(u){
  const b=smootherstep(u); let mx=0,my=0;
  for(let k=0;k<120;k++){
    const a=2*Math.PI*k/120;
    const [bx,by]=shapePoint(P.bottom,a,P.bX,P.bY,P.bRot);
    const [tx,ty]=shapePoint(P.top,a,P.tX,P.tY,P.tRot);
    const x=Math.abs(bx*(1-b)+tx*b), y=Math.abs(by*(1-b)+ty*b);
    if(x>mx)mx=x; if(y>my)my=y;
  }
  return [mx,my];
}
function drawProfile(){
  const W=pc.width,H=pc.height,pad=14,cx=W/2;
  px.clearRect(0,0,W,H);
  const N=64; let maxExt=1;
  const data=[]; for(let k=0;k<=N;k++){ const e=extentAt(k/N); data.push(e); maxExt=Math.max(maxExt,e[0],e[1]); }
  const sx=(W/2-pad)/maxExt;
  const X=e=>cx+e*sx, Y=u=>H-pad-u*(H-2*pad);
  px.strokeStyle='#2b323d'; px.lineWidth=1; px.beginPath(); px.moveTo(cx,Y(0)); px.lineTo(cx,Y(1)); px.stroke();
  function curve(ci,color){
    px.strokeStyle=color; px.lineWidth=2;
    for(const s of [1,-1]){ px.beginPath();
      for(let k=0;k<=N;k++){ const x=X(s*data[k][ci]), y=Y(k/N); k?px.lineTo(x,y):px.moveTo(x,y); } px.stroke(); }
  }
  curve(0, getComputedStyle(document.body).getPropertyValue('--x').trim()||'#5db0ff');
  curve(1, getComputedStyle(document.body).getPropertyValue('--y').trim()||'#ffa95d');
  px.fillStyle='#8b96a5'; px.font='10px monospace';
  px.fillText('top',cx+6,Y(1)+2); px.fillText('bottom',cx+6,Y(0)-4);
}

['bottom','top'].forEach(id=>{
  document.getElementById(id).addEventListener('change',e=>{ P[id]=e.target.value; syncEnabled(); rebuild(); });
});
[['bX','bX'],['bY','bY'],['bRot','bRot'],['tX','tX'],['tY','tY'],['tRot','tRot'],['height','height'],['segments','segments'],['layers','layers']]
.forEach(([id,key])=>{
  const el=document.getElementById(id), out=document.getElementById('v-'+id);
  el.addEventListener('input',()=>{ out.textContent=el.value;
    P[key] = (key==='bRot'||key==='tRot') ? (+el.value)*Math.PI/180 : +el.value;
    rebuild();
  });
});
document.getElementById('wire').addEventListener('change',()=>{ mesh.material.wireframe=document.getElementById('wire').checked; });
document.getElementById('export').addEventListener('click', exportSTL);

function resize(){ const w=view.clientWidth,h=view.clientHeight; renderer.setSize(w,h); renderer.setPixelRatio(devicePixelRatio); camera.aspect=w/h; camera.updateProjectionMatrix(); }
window.addEventListener('resize',resize);

syncEnabled(); resize(); frameCamera(); rebuild();
(function loop(){ requestAnimationFrame(loop); controls.update(); renderer.render(scene,camera); })();
</script>
</body>
</html>