//===========================================================================
// Copyright (C) 1998, 2000-2007, 2010, 2011, 2012 SINTEF ICT, Applied
// Mathematics, Norway.
//
// This file is part of GoTools
//
// This program is free software; you can redistribute it and/or          
// modify it under the terms of the GNU General Public License            
// as published by the Free Software Foundation version 2 of the License. 
//
// This program is distributed in the hope that it will be useful,        
// but WITHOUT ANY WARRANTY; without even the implied warranty of         
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the          
// GNU General Public License for more details.                           
//
// You should have received a copy of the GNU General Public License      
// along with this program; if not, see <http://www.gnu.org/licenses>
//
// Contact information: E-mail: tor.dokken@sintef.no                      
// SINTEF ICT, Department of Applied Mathematics,                         
// P.O. Box 124 Blindern,                                                 
// 0314 Oslo, Norway.                                                     
//
// Other licenses are also available for this software, notably licenses
// for:
// - Building commercial software.                                        
// - Building software whose source code you wish to keep private.        
//===========================================================================

#include "sisl-copyright.h"

#define S1452

#include "sislP.h"

#if defined(SISLNEEDPROTOTYPES)
void s1452(SISLSurf *ps, double aepsge, double aoffset, SISLSurf **rs,
	   int *jstat)
#else
void s1452(ps,aepsge,aoffset,rs,jstat)
     SISLSurf   *ps;
     double aepsge;
     double aoffset;
     SISLSurf   **rs;
     int    *jstat;
#endif
/*
*********************************************************************
*
*********************************************************************
*
* PURPOSE    : To create a B-spline approximating the offset surface of
*              a B-spline surface.
*
*
*
* INPUT      : ps     - The input B-spline surface.
*              aepsge - Maximal deviation allowed between true offset surface
*                       and the approximated offset surface.
*              aoffset- The offset distance.
*                       If idim=2 a positive signe on this value put the
*                       offset on the side of the positive normal vector,
*                       and a negative sign puts the offset on the sign
*                       of the negative normal vector.
*                       If idim=3 the offset is determined by the cross
*                       product of the tangent vector and the anorm vector.
*                       The offset distance is multiplied by this vector.
*
* OUTPUT     :
*              jstat  - status messages
*                                         > 0      : warning
*                                         = 0      : ok
*                                         < 0      : error
*              rs     - Pointer the approximated offset surface
*
* METHOD     : The 4 edge curves of the surface are extracted. Offset curves
*              of these 4 edge curves are approximated and a common
*              basis for the two pairs of opposite offset curves is calculated.
*              Vertices are recomputed.
*
* EXAMPLE OF USE:
*
*
* REFERENCES :
*
*
*-
* CALLS      : s1365     - This routine is performing the actual computation
*                          The existence of the current routine is for
*                          historical reasons.
*
* WRITTEN BY : Vibeke Skytt, SINTEF, 0394.
*
*********************************************************************
*/
{
  int kstat = 0;     /* Local status variable.                           */
  int kpos = 0;      /* Position of error.                               */
  int kdim = ps->idim;  /* Dimension of geometry space.                  */
  double tmax = (double)0;  /* Dummy.                                    */

  /* Compute offset surface. */

   s1365(ps, aoffset, aepsge, tmax, kdim, rs, &kstat);
   if (kstat < 0) goto error;

  /* Surface approximated. */

  *jstat = kstat;
  goto out;

  /* Error in lower level routine.  */

  error : *jstat = kstat;
  s6err("s1452",*jstat,kpos);
  goto out;

  out: return;
}
