#include "math.h"
void VECT( float *X, float *Y, float *Z);
void attid( float TS, float U1, float U2, float *X, float *Z, float *DIR)
{
float UX, UY, S[3], E[3], P2[3], PA[3][3], DRA[3], ALF, BET, TGA, TGB, G;
float CG, SG, AX, UU, SX1, CX1, SX2, CX2;
register int i, j;
UU = (float) atan((double) 1.) / 45.;
UX = UU * U1;   UY = UU * U2;
DRA[0] = (float) cos((double) UX);
DRA[1] = (float) ( sin((double) UX) * cos((double) UY) );
DRA[2] = (float) ( sin((double) UX) * sin((double) UY) );
SX1 = (float) sin( (double) ( X[10] * TS ) );
CX1 = (float) cos( (double) ( X[10] * TS ) );
SX2 = (float) sin( (double) ( X[11] * TS ) );
CX2 = (float) cos( (double) ( X[11] * TS ) );
ALF = X[0] + X[1] * SX1 + X[2] * CX1 + X[3] * SX2 + X[4] * CX2;
BET = X[5] + X[6] * SX1 + X[7] * CX1 + X[8] * SX2 + X[9] * CX2;
ALF = ALF * UU; BET = BET * UU;
TGA= (float) ( tan((double)ALF) );
TGB= (float) ( tan((double)BET) );
S[0] = 1./ (float) sqrt( (double) (1. + TGA*TGA + TGB*TGB ) );
S[1] = TGA * S[0];
S[2] = TGB * S[0];
G= Z[0] + Z[1] * TS;
CG = (float) cos( (double) G );
SG = (float) sin( (double) G );
AX= S[1] * CG + S[2] * SG;
E[0] = - AX / (float) sqrt( (double) ( AX * AX + S[0] * S[0]) );
E[1] = (float) sqrt( (double) (1. - E[0] * E[0] ) ) * CG;
E[2] = (float) sqrt( (double) (1.-  E[0] * E[0] ) ) * SG;
VECT( E, S, P2 );
for(i=0; i<3; i++) {
      PA[0][i] = S[i];
      PA[1][i] = P2[i];
      PA[2][i] = E[i];
}
for(i=0; i<3; i++) DIR[i] = 0.0;
for(i=0; i<3; i++) for( j=0; j<3; j++ ) DIR[i] = DIR[i] + PA[i][j] * DRA[j];
}
void VECT( float *X, float *Y, float *Z)
{
register int i;
float ZZ;
Z[0] = X[1] * Y[2] - Y[1] * X[2];
Z[1] = X[2] * Y[0] - X[0] * Y[2];
Z[2] = X[0] * Y[1] - X[1] * Y[0];
ZZ = (float) sqrt( (double) (Z[0]*Z[0]+Z[1]*Z[1]+Z[2]*Z[2]) );
for ( i=0; i<3; i++ ) Z[i] = Z[i] / ZZ;
}