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/*
* Copyright (C) 1998, 2000-2007, 2010, 2011, 2012, 2013 SINTEF ICT,
* Applied Mathematics, Norway.
*
* Contact information: E-mail: tor.dokken@sintef.no
* SINTEF ICT, Department of Applied Mathematics,
* P.O. Box 124 Blindern,
* 0314 Oslo, Norway.
*
* This file is part of SISL.
*
* SISL is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* SISL 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public
* License along with SISL. If not, see
* <http://www.gnu.org/licenses/>.
*
* In accordance with Section 7(b) of the GNU Affero General Public
* License, a covered work must retain the producer line in every data
* file that is created or manipulated using SISL.
*
* Other Usage
* You can be released from the requirements of the license by purchasing
* a commercial license. Buying such a license is mandatory as soon as you
* develop commercial activities involving the SISL library without
* disclosing the source code of your own applications.
*
* This file may be used in accordance with the terms contained in a
* written agreement between you and SINTEF ICT.
*/
#include "sisl-copyright.h"
/*
*
* $Id: s1361.c,v 1.2 2001-03-19 15:58:47 afr Exp $
*
*/
#define S1361
#include "sislP.h"
#if defined(SISLNEEDPROTOTYPES)
void
s1361(double epnt1[],double epnt2[],int idim,
double gmidd[],double gmtang[],int *jstat)
#else
void s1361(epnt1,epnt2,idim,gmidd,gmtang,jstat)
double epnt1[];
double epnt2[];
int idim;
double gmidd[];
double gmtang[];
int *jstat;
#endif
/*
*********************************************************************
*
* PURPOSE : To determint if the shape described by the input, points,
* tangents, curvatures and radius of curvature when used
* for making an Hermit segment, have a shape close to
* a circular arc.
*
* INPUT : epnt1 - Start point with tangent, curvature and radius
* of curvature.
* epnt2 - End point with tangent, curvature and radius
* of curvature.
* idim - The dimension of the space the point lie in
* gmidd - The middle point of the Bezier segement
* gmtang - The tangent at the middle of the Bezier segment
*
*
* OUTPUT : jstat - Status variable
* 0 - Shape not acceptabel
* 1 - Shape acceptable
*
* METHOD :
*
* WRITTEN BY : Tor Dokken, SI, Oslo, Norway. 18. Oct 1988
* UJK, October 1990, Included test for negative curvature.
*********************************************************************
*/
{
double tang1,tang2; /* Tangent lengths */
double tscal1,tscal2; /* The cosine of an angle */
double ta1,ta2; /* An angle */
double tlength; /* The length of a vector */
double tdiff; /* Difference between two numbers */
double tdist; /* Distance between points */
double tv2,tv3; /* Vertex compnents */
int ki; /* Variable in loop */
int kstat; /* Local status variable */
/* Find angle between tangents of epnt1 and epnt2, we assume that
the tangents are normalized */
tscal1 = s6scpr(epnt1+idim,epnt2+idim,idim);
if (tscal1 >= DZERO)
tscal1 = MIN((double)1.0,tscal1);
else
tscal1 = MAX((double)-1.0,tscal1);
ta1 = acos(tscal1);
if (fabs(ta1) < ANGULAR_TOLERANCE) ta1 = DZERO;
/* Make distance between epnt1 and epnt2 */
tdist = s6dist(epnt1,epnt2,idim);
/* Make tangent lengths for start and end points */
if (DNEQUAL(ta1,DZERO))
{
/* Make tangents based on radius of curvature */
tang1 = s1325(epnt1[3*idim],ta1);
tang2 = s1325(epnt2[3*idim],ta1);
}
/* Make sure that the tangent does not explode due to numeric errors, and
make a controlled tangent when the radius is zero or almost zero */
/* UJK, October 90, must include the case negative curvature */
if (DEQUAL(ta1,DZERO) || tang1 > tdist || epnt1[3*idim] <= DZERO)
tang1 = tdist/(double)3.0;
if (DEQUAL(ta1,DZERO) || tang2 > tdist || epnt2[3*idim] <= DZERO)
tang2 = tdist/(double)3.0;
/* We now know the Bezier polygon of the Hermit curve. Make angles
between line 1 and 2 and between line 2 and 3. Make length of line 3
*/
tscal1 = DZERO;
tscal2 = DZERO;
tlength = DZERO;
for (ki=0;ki<idim;ki++)
{
/* Make difference between second and third vertex, and accumulte
scalar products between polygon lines */
tv2 = epnt1[ki] + tang1*epnt1[ki+idim];
tv3 = epnt2[ki] - tang2*epnt2[ki+idim];
tdiff = tv3 - tv2 ;
tlength += tdiff*tdiff;
tscal1 += tdiff*epnt1[ki+idim];
tscal2 += tdiff*epnt2[ki+idim];
/* Make midpoint and tangent at midpoint */
gmidd[ki] = (epnt1[ki] + (double)3.0*(tv2+tv3) + epnt2[ki])/(double)8.0;
gmtang[ki] = (epnt2[ki] + tv3 - tv2 - epnt1[ki])/(double)8.0;
}
tlength = sqrt(tlength);
if (DEQUAL(tlength,DZERO)) tlength = (double)1.0;
tscal1 = tscal1/tlength;
tscal2 = tscal2/tlength;
if (tscal1 >= DZERO)
tscal1 = MIN((double)1.0,tscal1);
else
tscal1 = MAX((double)-1.0,tscal1);
if (tscal2 >= DZERO)
tscal2 = MIN((double)1.0,tscal2);
else
tscal2 = MAX((double)-1.0,tscal2);
ta1 = acos(tscal1);
ta2 = acos(tscal2);
/* Normalize tangent at midpoint */
(void)s6norm(gmtang,idim,gmtang,&kstat);
/* Make total angular change of polygon */
ta1 = fabs(ta1) + fabs(ta2);
/* If total angular change is greater than PI/3 or the length is greater
than 0.45 x the distance don't accept. The last condition make sure
that the middle span in the polygon is less that what we get when
we have a 90 circular arc. The first condition makes sure that the
polygon direction is not oscillating too much*/
if (ta1 > (double)1.0 || tlength > (double)0.45*tdist)
*jstat = 0;
else
*jstat = 1;
}
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