#VRML V2.0 utf8  Flight Interpolator, Evgeny Demidov, 4 April 2001

NavigationInfo{ type "EXAMINE" }
Viewpoint {position 0 2 8 description "Start"}

PROTO FlyInterpolator[
 eventIn SFFloat set_fraction
 eventOut SFVec3f position_changed
 eventOut SFRotation orientation_changed
 field SFInt32 num 3
 field SFFloat alpha 4
 field SFBool loop TRUE
 field MFFloat key []
 field MFFloat phi []
 field MFVec3f keyValue [] ]{
DEF PosInt PositionInterpolator{
 set_fraction IS set_fraction
 value_changed IS position_changed
}
DEF OrInt OrientationInterpolator{
 set_fraction IS set_fraction
 value_changed IS orientation_changed
}
Script{
 field SFInt32 num IS num
 field SFBool loop IS loop
 field MFFloat key IS key
 field MFVec3f val IS keyValue
 field SFFloat alpha IS alpha
 field MFFloat phi IS phi
 field SFNode PosInt USE PosInt
 field SFNode OrInt USE OrInt
 directOutput TRUE
url ["javascript:
function initialize() { 
 n = key.length;
 p = new MFVec3f(); p.length = (n-1)*num+1;
 k = new MFFloat(); k.length = (n-1)*num+1;
 ind = new MFInt32(); ind.length = (n-1)*num+1;
 r = new MFFloat(); r.length = (n-1)*num+1;
 if( loop ){ del0 = val[1].subtract(val[n-2]).divide(alpha); val[n] = val[1];}
 else{ del0 = val[1].subtract(val[0]).divide(alpha); val[n] = val[n-1];}
 st = 1/num; t = 0; kt = 0; rt = phi[0];
 for (j= 0; j< n-1; j++){
  del1 = val[j+2].subtract(val[j]).divide(alpha);
  delK = (Math.abs(key[j+1])-Math.abs(key[j]))/num;
  delR = (phi[j+1]-phi[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;
   if (key[j+1] < 0) ind[t] = -1; else ind[t] = 1;
   kt += delK;
   r[t] = rt; rt += delR;
   t++;}
  del0 = del1;}
 p[t] = val[n-1]; k[t] = kt; ind[t] = 1; r[t] = rt;
 PosInt.set_keyValue = p;
 PosInt.set_key = k;
 rot = new MFRotation(); rot.length = (n-1)*num+1;
 M = new VrmlMatrix(); M1 = new VrmlMatrix();
 O = new SFVec3f(0,0,0);
 Rx = new SFVec3f(1,0,0); Ry = new SFVec3f(0,1,0); Rz = new SFVec3f(0,0,1);
 dum = new SFVec3f(0,0,0);
 for (i= 0; i< t; i++){
  norm = p[i+1].subtract(p[i]).normalize();
  th = Math.asin(norm.y);
  if (norm.x == 0) ph = 0;
  else ph = -Math.atan(norm.z / norm.x);
  if (norm.x < 0)
   if( ind[i] < 0) th = 3.1415 - th; else ph += 3.1415;
  ri = new SFRotation(Rx, r[i]);
  M1.setTransform(O, ri );
  ri = new SFRotation(Rz, th);
  M.setTransform(O, ri );
  M = M.multLeft(M1);
  ri = new SFRotation(Ry, ph);
  M1.setTransform(O, ri );
  M = M1.multLeft(M);
  M.getTransform(dum, ri);
  rot[i] = ri;
 }
 rot[t] = rot[0];
 OrInt.set_keyValue = rot;
 OrInt.set_key = k;
}
"]}
}

DEF FlyInt FlyInterpolator{ #loop FALSE
 num 7
 keyValue [0 0 -2,2 0 0,0 0 2,-2 0 0,0 0 -2,
 2 2 -2, 0 4 -2, -2 2 -2, 0 0 -2]
 phi [0 0 0 0 0  0 0 0 0]
 key [0 .125 .25 .375 .5 -.625 -.75 -.875 -1]
}
DEF TS TimeSensor{ cycleInterval 20 loop TRUE}

DEF Model Transform{ children[
 Shape{ appearance Appearance{ material Material{ diffuseColor 1 1 1 } }
 geometry Box{size .3 .05 .6} }
]}

ROUTE TS.fraction_changed TO FlyInt.set_fraction
ROUTE FlyInt.position_changed TO Model.set_translation
ROUTE FlyInt.orientation_changed TO Model.set_rotation