NavigationInfo{ type "EXAMINE" }
  
  PROTO SplinePositionInterpolator[
   eventIn SFFloat set_fraction
   eventOut SFVec3f value_changed
   field SFInt32 num 3
   field SFBool loop TRUE
   field MFFloat key []
   field MFVec3f keyValue [] ]{
  DEF Root Transform{ children[
   Shape{ appearance Appearance{ material Material{ emissiveColor 1 1 1 } }
   geometry DEF spline IndexedLineSet{ coord DEF spCoord Coordinate{} } }
  ]}
  DEF PosInt PositionInterpolator{
   set_fraction IS set_fraction
   value_changed IS value_changed
  }
  Script{
   field SFInt32 num IS num
   field SFBool loop IS loop
   field MFFloat key IS key
   field MFVec3f val IS keyValue
   field SFNode Root USE Root
   field SFNode spline USE spline
   field SFNode spCoord USE spCoord
   field SFNode PosInt USE PosInt
   directOutput TRUE
  url ["javascript:
  function initialize() { 
   n = key.length;
   str = 'PROTO M[ field SFVec3f trans 0 0 0]{'+
    'Transform{ translation IS trans children['+
    'Shape{ appearance Appearance{ material Material{ diffuseColor 1 1 0}}'+
    'geometry Sphere{ radius .1 }}]}}';
   for (i= 0; i< n; i++) str += ' M{ trans '+val[i]+' }';
   Root.addChildren = Browser.createVrmlFromString(str);
   if( loop ){ del0 = val[1].subtract(val[n-2]).divide(4); val[n] = val[1];}
   else{ del0 = val[1].subtract(val[0]).divide(4); val[n] = val[n-1];}
   p = new MFVec3f(); p.length = (n-1)*num+1;
   c = new MFInt32(); c.length = (n-1)*num+1;
   k = new MFFloat(); k.length = (n-1)*num+1;
   st = 1/num; t = 0; kt = 0;
   for (j= 0; j< n-1; j++){
    del1 = val[j+2].subtract(val[j]).divide(4);
    delK = (key[j+1]-key[j])/num;
    for (i= 0; i< num; i++){
     u = i*st;  u1 = 1-u; u12 = u1*u1; u2 = u*u;
     b0 = u1*u12; b1 = 3*u*u12; b2 = 3*u2*u1; b3 = u*u2;
     p[t]=val[j].multiply(b0).add( val[j].add(del0).multiply(b1) )
      .add( val[j+1].subtract(del1).multiply(b2) ).add(val[j+1].multiply(b3));
     k[t] = kt; kt += delK;
     c[t] = t++;}
    del0 = del1;}
   p[t] = val[n-1]; c[t] = t; k[t] = 1;
   spCoord.set_point = p;
   spline.set_coordIndex = c;
   PosInt.set_keyValue = p;
   PosInt.set_key = k;
  }
  "]}
  }
  
  DEF splInt SplinePositionInterpolator{ #loop FALSE
   key [0 .25 .5 .75 1] keyValue [0 -2 0,2 0 0,0 2 0,-2 0 0,0 -2 0]
  }
  DEF Model Transform{ children[ Shape{
   appearance Appearance{ material Material{ diffuseColor 1 1 1 } }
   geometry Box{size .5 .1 .5} }
  ]}
  DEF TS TimeSensor{ cycleInterval 10 loop TRUE}
  
  ROUTE TS.fraction_changed TO splInt.set_fraction
  ROUTE splInt.value_changed TO Model.set_translation