void sbox(uint8_t which, const uint32_t in[4], uint32_t out[4])
{
uint32_t a[4];
uint32_t b[4];
uint32_t c[4];
uint32_t d[4];
perm(in, a);
s_hat(which, a, b);
t_hat(b, c);
perm_inv(c, d);
trans_inv(d, out);
}
//_____________________________________________________________________________
bool THaSpectrometerDetector::CalcTrackIntercept(THaTrack* theTrack,
Double_t& t, Double_t& xcross,
Double_t& ycross)
{
// projects a given track on to the plane of the detector
// xcross and ycross are the x and y coords of this intersection
// t is the distance from the origin of the track to the given plane.
//
// If a hit is NOT found, then t, xcross, and ycross are unchanged.
TVector3 t0( theTrack->GetX(), theTrack->GetY(), 0.0 );
Double_t norm = TMath::Sqrt(1.0 + theTrack->GetTheta()*theTrack->GetTheta() +
theTrack->GetPhi()*theTrack->GetPhi());
TVector3 t_hat( theTrack->GetTheta()/norm, theTrack->GetPhi()/norm, 1.0/norm );
TVector3 v;
if( !IntersectPlaneWithRay( fXax, fYax, fOrigin, t0, t_hat, t, v ))
return false;
v -= fOrigin;
xcross = v.Dot(fXax);
ycross = v.Dot(fYax);
return true;
}
