Function buildFalls

packages/webapp/components/world/engine/world.js:1806–1842

(P,drop)

}

function buildFalls(P,drop){
  const g=new THREE.Group();
  const w=0.9;
  /* Two crossed sheets: a single plane vanishes to a line whenever the camera
     swings to face it edge-on, which on a free iso view is a quarter of all
     headings. */
  const sheetMat=mat(P.water,{opacity:0.45,flat:false,rough:0.1,
    emissive:P.water,ei:P.liquidGlow??0.3,side:THREE.DoubleSide});
  for(const rot of [0,Math.PI/2]){
    const sheet=meshOf(new THREE.PlaneGeometry(w,drop),sheetMat,false,false);
    sheet.position.y=-drop/2; sheet.rotation.y=rot; g.add(sheet);
  }
  const spray=P.kit==='forge'?P.lavaHot:0xFFFFFF;
  for(let i=0;i<4;i++){
    const u=(i+1)/4;
    const puff=meshOf(new THREE.IcosahedronGeometry(0.3+u*0.55,0),
      mat(spray,{opacity:0.22*(1-u*0.7),flat:false}),false,false);
    puff.position.y=-drop*u; puff.scale.y=0.7; g.add(puff);
  }
  /* Own material per streak. Sharing one cached glow meant seven streaks all
     wrote `.opacity` on the same material every frame and the falls strobed
     instead of falling. */
  for(let i=0;i<6;i++){
    const sm=new THREE.MeshStandardMaterial({color:spray,emissive:spray,
      emissiveIntensity:0.8,roughness:0.35,transparent:true,opacity:0.75});
    const st=meshOf(new THREE.BoxGeometry(0.07,0.5,0.03),sm,false,false);
    const off=i/6, xo=(i/6-0.5)*w*0.8;
    st.userData.tick=t=>{
      const u=(t*0.55+off)%1;
      st.position.set(xo,-u*drop,0.02);
      st.scale.y=0.6+u*1.4;
      sm.opacity=0.75*(1-u*0.8);
    };
    g.add(st); animated.push(st);
  }
  return g;
}

/* -------------------------------------------- building off the rim, and life */
/* The platform braced off the rim. It was ONE builder for all six realms —