1 /*
2 * Copyright (C) 1998, 2000-2007, 2010, 2011, 2012, 2013 SINTEF ICT,
3 * Applied Mathematics, Norway.
4 *
5 * Contact information: E-mail: tor.dokken@sintef.no
6 * SINTEF ICT, Department of Applied Mathematics,
7 * P.O. Box 124 Blindern,
8 * 0314 Oslo, Norway.
9 *
10 * This file is part of SISL.
11 *
12 * SISL is free software: you can redistribute it and/or modify
13 * it under the terms of the GNU Affero General Public License as
14 * published by the Free Software Foundation, either version 3 of the
15 * License, or (at your option) any later version.
16 *
17 * SISL is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Affero General Public License for more details.
21 *
22 * You should have received a copy of the GNU Affero General Public
23 * License along with SISL. If not, see
24 * <http://www.gnu.org/licenses/>.
25 *
26 * In accordance with Section 7(b) of the GNU Affero General Public
27 * License, a covered work must retain the producer line in every data
28 * file that is created or manipulated using SISL.
29 *
30 * Other Usage
31 * You can be released from the requirements of the license by purchasing
32 * a commercial license. Buying such a license is mandatory as soon as you
33 * develop commercial activities involving the SISL library without
34 * disclosing the source code of your own applications.
35 *
36 * This file may be used in accordance with the terms contained in a
37 * written agreement between you and SINTEF ICT.
38 */
39
40 #include "sisl-copyright.h"
41
42 /*
43 *
44 * $Id: s1617.c,v 1.2 2001-03-19 15:58:52 afr Exp $
45 *
46 */
47
48
49 #define S1617
50
51 #include "sislP.h"
52
53 #if defined(SISLNEEDPROTOTYPES)
s1617(double epoint[],int inbpnt,int idim,int eptyp[],double aepsge,double econic[],double estart[],double etang[],double estop[],double * ashape,int * jstat)54 void s1617(double epoint[], int inbpnt, int idim, int eptyp[],
55 double aepsge, double econic[],
56 double estart[], double etang[], double estop[],
57 double *ashape, int *jstat)
58 #else
59 void s1617(epoint, inbpnt, idim, eptyp, aepsge, econic,
60 estart, etang, estop, ashape, jstat)
61 double epoint[];
62 int inbpnt;
63 int idim;
64 int eptyp[];
65 double aepsge;
66 double econic[];
67 double estart[];
68 double etang[];
69 double estop[];
70 double *ashape;
71 int *jstat;
72 #endif
73 /*
74 *************************************************************************
75 *
76 * PURPOSE: To produce interpolation conditions to interpolate the
77 * conic curve described by Epoint, Eptyp and Econic.
78 *
79 * INPUT:
80 * Epoint - The points/tangents describing the conic.
81 * Inbpnt - No. of points/tangents in the epoint array.
82 * Idim - The dimension of the space in which the points lie.
83 * Eptyp - Type indicator for the points/tangents :
84 * 1 - Ordinary point.
85 * 2 - Knuckle point. (Is treated as an ordinary point.)
86 * 3 - Tangent to next point.
87 * 4 - Tangent to prior point.
88 * Aepsge - The geometry reolution.
89 * Econic - The conic coefficients of the points in the Epoint array.
90 *
91 * Output:
92 * Estart - Start-point of conic segment.
93 * Etang - Intersection point of tangents from start- and endpoint.
94 * Estop - End-point of conic segment.
95 * Ashape - Shape factor.
96 * Jstat - Status variable.
97 *
98 * Method:
99 * The conics are classified into ellipses, parabolas and hyperbolas.
100 * The description of the arc by the output type of parameters is produced.
101 *-
102 * Calls: s1619,s6err.
103 *
104 * Written by: A.M. Ytrehus, si Oslo, Oct.91.
105 * After FORTRAN, (P1617), written by: T. Dokken SI.
106 *****************************************************************
107 */
108 {
109 int kk, kp;
110 double ta11, ta12, ta13, ta22, ta23, ta33;
111 double td13, td23, td33, tda;
112 double tshape;
113 int ktyp;
114 int kstat = 0;
115 int kpos = 0;
116
117 *jstat = 0;
118
119
120 /* Initiate variables. */
121
122 ta11 = econic[0];
123 ta12 = econic[1];
124 ta13 = econic[3]; /* ? */
125 ta22 = econic[2]; /* ? */
126 ta23 = econic[4];
127 ta33 = econic[5];
128
129
130 /* Calculate determinants. */
131
132 td13 = ta12 * ta23 - ta22 * ta13;
133 td23 = ta11 * ta23 - ta12 * ta13;
134 td33 = ta11 * ta22 - ta12 * ta12;
135 tda = ta13 * td13 - ta23 * td23 + ta33 * td33;
136
137
138 /* Discussion of the conic. */
139
140 if (DEQUAL(tda + (double) 1.0, (double) 1.0))
141 {
142 /* Degenerate conic. Produce straight line. */
143
144 *jstat = 1;
145 goto out;
146 }
147
148 /* Decide if ellipse, parabola or hyperbola. */
149
150 if (td33 > (double) 0.0)
151 {
152 /* Ellipse, decide if imaginary or real. */
153
154 if (tda * ta11 > (double) 0.0)
155 {
156 /* Imaginary ellipse. Produce straight line. */
157
158 *jstat = 1;
159 goto out;
160 }
161 else
162 {
163 /* Real eelipse. */
164
165 ktyp = 2;
166 }
167 }
168 else
169 {
170 /* Parabola or hyperbola. */
171
172 if (td33 < (double) 0.0)
173 {
174 /* Hyperbola. */
175
176 ktyp = 4;
177 }
178 else
179 {
180 /* Parabola. */
181
182 ktyp = 3;
183 }
184 }
185
186
187 /* Find rational description of conic. */
188
189 s1619 (epoint, inbpnt, idim, eptyp, econic, ktyp,
190 etang, &tshape, &kstat);
191 if (kstat < 0)
192 goto error;
193 if (kstat == 1)
194 {
195 /* Create straight line. */
196
197 *jstat = 1;
198 goto out;
199 }
200
201 kk = idim * (inbpnt - 1);
202
203 for (kp = 0; kp < idim; kp++)
204 {
205 estart[kp] = epoint[kp];
206 estop[kp] = epoint[kk + kp];
207 }
208
209 *ashape = tshape;
210
211 goto out;
212
213
214 /* Error in lower level routine. */
215
216 error:
217 *jstat = kstat;
218 s6err ("s1617", *jstat, kpos);
219 goto out;
220
221 out:
222
223 return;
224 }
225