7 double lx = m_wpos[0] - m_wpos[3];
8 double ly = m_wpos[1] - m_wpos[4];
9 double lz = m_wpos[2] - m_wpos[5];
11 double xhit = (z - m_wpos[2]) * lx / lz + m_wpos[0];
12 double yhit = (z - m_wpos[2]) * ly / lz + m_wpos[1];
14 double r = sqrt( (xhit * xhit) + (yhit * yhit) );
15 double phi = asin(yhit / r);
17 if(xhit < 0) phi =
PI - phi;
18 if(phi < 0) phi +=
PI2;