*len]; }; DeformFrame.prototype.local3=function(p2){ return new T.Vector3(p2[0],p2[1],0); }; /* clamp a driven corner: reachable + linkage limits vs opposite corner */ DeformFrame.prototype.clampCorner=function(k){ var L=this.L, P=this.pos, o=OPP[k]; var t=P[k], r=this.rest[k]; /* stay near home: max reach 1.35*L from rest */ var dx=t[0]-r[0], dy=t[1]-r[1], d=Math.sqrt(dx*dx+dy*dy), maxR=1.35*L; if(d>maxR){ t=[r[0]+dx/d*maxR, r[1]+dy/d*maxR]; } /* linkage: |XY| within [0.35, 2L-0.02] */ var Y=P[o]; var dxy=vdist(t,Y), maxD=2*L-0.02, minD=0.35; if(dxy>maxD){ var s=maxD/dxy; t=[Y[0]+(t[0]-Y[0])*s, Y[1]+(t[1]-Y[1])*s]; } else if(dxy1e-9){ var s2=minD/dxy; t=[Y[0]+(t[0]-Y[0])*s2, Y[1]+(t[1]-Y[1])*s2]; } P[k]=t; }; /* solve the linkage: driven corners pinned, adjacents on rigid circles */ DeformFrame.prototype.solve=function(){ var L=this.L, P=this.pos, D=this.driven; var keys=Object.keys(D).filter(function(k){return D[k];}); if(!keys.length) return; var self=this; keys.forEach(function(k){ self.clampCorner(k); }); /* solve each driven corner's opposite pair */ var done={}; keys.forEach(function(k){ var o=OPP[k]; var tag=kmaxD){ /* pull both back symmetrically toward their midpoint */ var mx=(P[k][0]+P[o][0])/2, my=(P[k][1]+P[o][1])/2; var ux=(P[k][0]-mx)/d, uy=(P[k][1]-my)/d; P[k]=[mx+ux*maxD/2, my+uy*maxD/2]; P[o]=[mx-ux*maxD/2, my-uy*maxD/2]; } var adj=ADJ[k]; var nB=circleInt(P[k],L,P[o],L,P[adj[0]]); var nD=circleInt(P[k],L,P[o],L,P[adj[1]]); /* keep branches apart: assign each solved point to nearest previous */ if(nB&&nD){ var dBB=vdist(nB,P[adj[0]])+vdist(nD,P[adj[1]]); var dBX=vdist(nB,P[adj[1]])+vdist(nD,P[adj[0]]); if(dBX1.35||r2>1.35; if(isDiamond&&!this.diamondTold){ this.diamondTold=true; try{ codeStatus('diamond — edges rigid, joints flexed. that is a block, not a rope.'); }catch(e){} } if(!isDiamond) this.diamondTold=false; }; DeformFrame.prototype.reset=function(){ var h=this.L/2, self=this; this.pos={A:[h,h],B:[-h,h],C:[-h,-h],D:[h,-h]}; this.driven={}; this.grabs={}; this.diamondTold=false; this.corners.forEach(function(k){ self.ropeVec[k]=self.restOut(k,0.62); }); this.updateMeshes(); }; /* re-aim every mesh from 2D state */ var _up=new T.Vector3(0,1,0), _dir=new T.Vector3(), _mid=new T.Vector3(), _p1=new T.Vector3(), _p2=new T.Vector3(); function aimCyl(mesh,a,b){ _p1.set(a.x,a.y,a.z); _p2.set(b.x,b.y,b.z); _dir.subVectors(_p2,_p1); var len=_dir.length()||0.0001; _mid.addVectors(_p1,_p2).multiplyScalar(0.5); mesh.position.copy(_mid); mesh.quaternion.setFromUnitVectors(_up,_dir.normalize()); mesh.scale.set(1,len,1); } DeformFrame.prototype.updateMeshes=function(){ var self=this; var P3={}; this.corners.forEach(function(k){ P3[k]=self.local3(self.pos[k]); }); /* edges */ [['A','B'],['B','C'],['C','D'],['D','A']].forEach(function(pr){ aimCyl(self.edgeMesh[pr[0]+pr[1]], P3[pr[0]], P3[pr[1]]); }); /* joints */ this.corners.forEach(function(k){ self.jointMesh[k].position.copy(P3[k]); }); /* handles + ropes */ this.corners.forEach(function(k){ var hp=new T.Vector3(P3[k].x+self.ropeVec[k][0], P3[k].y+self.ropeVec[k][1], 0); self.handleMesh[k].position.copy(hp); self.handleMesh[k].lookAt(self.group.localToWorld(hp.clone())); aimCyl(self.ropeMesh[k], P3[k], hp); }); }; /* ---------------- anchor stake visual ---------------- */ function buildAnchorStake(){ var g=new T.Group(); var post=new T.Mesh(new T.CylinderGeometry(0.09,0.12,1,10),STEEL_MAT); g.add(post); g.userData.post=post; var tip=new T.Mesh(new T.ConeGeometry(0.14,0.5,10),STEEL_MAT); tip.rotation.x=Math.PI; g.add(tip); g.userData.tip=tip; var ring=new T.Mesh(new T.TorusGeometry(0.2,0.05,10,20),GOLD_MAT); g.add(ring); g.userData.ring=ring; return g; } /* ---------------- demo state ---------------- */ var demo=null; /* {group, anchored:DeformFrame, free:DeformFrame, stake, title} */ var raycaster=new T.Raycaster(); var ndc=new T.Vector2(); var planeTmp=new T.Plane(); var activeTouches={}; /* touchId -> {frame, corner, ropeVecAtGrab:[x,y], lastLocal:[x,y]} */ function groundYAt(rx,rz){ try{ if(typeof fortifiedGroundY==='function') return fortifiedGroundY(rx,rz); }catch(e){} return 0.3; } function status(m){ try{ codeStatus(m); }catch(