Function tourRoute

packages/webapp/components/world/engine/world.js:10334–10366

()

   of the map rather than by rank or by index, so the route is a lap of the
   realm and not a zigzag across it — and closed, so the tour never ends. */
function tourRoute(){
  const live=(OPEN?OPEN.list:W.quarters).filter(x=>(OPEN?x.town:x.island));
  if(!live.length)return null;
  let cx=0,cz=0;
  for(const x of live){ cx+=x.x; cz+=x.z; }
  cx/=live.length; cz/=live.length;
  const ring=[...live].sort((a,b)=>
    Math.atan2(a.z-cz,a.x-cx)-Math.atan2(b.z-cz,b.x-cx));
  const pts=[];
  for(const x of ring){
    const R=spec(Math.max(1,x.level||1)).radius;
    /* Just off the rim and just over the roofline. A route through the middle
       of a town at spire height is a route through the spires; one high enough
       to clear everything is a map, and you can already read the map from
       outside. Skimming the outer edge is the one altitude where the place has
       a scale — you pass the towers rather than looking down on them. */
    const off=R*0.95+2;
    const a=Math.atan2(x.z-cz,x.x-cx);
    pts.push(new THREE.Vector3(x.x+Math.cos(a)*off,
                               (x.baseY||0)+R*0.5+4.5,
                               x.z+Math.sin(a)*off));
  }
  /* One waypoint is not a loop and two is a line you fly back and forth along;
     both come out as a degenerate curve, so pad them into a circle. */
  if(pts.length<3){
    const p=pts[0], r=Math.max(12,Math.hypot(p.x-cx,p.z-cz));
    pts.length=0;
    for(let i=0;i<5;i++){ const a=i/5*TAU;
      pts.push(new THREE.Vector3(cx+Math.cos(a)*r,p?p.y:12,cz+Math.sin(a)*r)); }
  }
  const curve=new THREE.CatmullRomCurve3(pts,true,'catmullrom',0.4);
  return {curve,len:curve.getLength()};
}

function possess(b,host){
  if(POV.bird)return;