#VRML V2.0 utf8  SplinePositionInterpolator Demo, Evgeny Demidov, 31 March 2001

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