How to get the mouse cursor coordinates in UCS?

BOOL filterMouse(MSG *pMsg)

{

 if( pMsg->message == WM_MOUSEMOVE )

{

  acedDwgPoint cpt;

  ads_point ptDCS, norm;

  AcGePoint3d  origin;

  AcGeVector3d e0, e1, e2;

  AcGeMatrix3d  matUcs2Wcs, matWcs2Ucs;

 

  // 1: Get the Mouse coords in DCS

  //

 

  CPoint cPnt (pMsg->lParam) ;

  acedCoordFromPixelToWorld (cPnt, cpt) ;

  ads_point_set ( cpt, ptDCS );

 

  // 2: Transform the DCS point to UCS isomatric view

  //

  ads_point result;

  struct resbuf fromrb, torb;

 

  fromrb.restype = RTSHORT;

  fromrb.resval.rint = 2; // DCS

 

 

  torb.restype = RTSHORT;

  torb.resval.rint = 1; // UCS 

 

 

  // disp == 0 indicates that pt is a point: 

  acedTrans(ptDCS, &fromrb, &torb, FALSE, result);

 

  // 3: Project the UCS point to the XY plan of UCS

  //

  struct resbuf rbview;

  ads_getvar( _T("viewdir"), &rbview );

  ads_point_set( rbview.resval.rpoint, norm );

 

 

  AcGePlane thePlane; // The default constructor creates XY plan.

 

  AcGePoint3d  pntInUCS( result[X], result[Y], result[Z] );

  AcGeVector3d vecViewdir( norm [X], norm [Y], norm [Z] );

  AcGePoint3d resPnt = pntInUCS.project (thePlane, vecViewdir);

 

  // 4: Print the result

  //

  ads_printf ( _T("\nMouse in Ucs-resPnt %f, %f, %f"), 

   resPnt[X],resPnt[Y], resPnt[Z] );

}

 else if( pMsg->message ==WM_LBUTTONDOWN)

{

  acedRemoveFilterWinMsg(filterMouse);

}

 return FALSE; // continue

}