src/gen/replmarks.c

#ifndef lint
static const char RCSid[] = "$Id: replmarks.c,v 2.18 2021/02/12 00:53:56 greg Exp $";
#endif
/*
 * Replace markers in Radiance scene description with objects or instances.
 *
 *      Created:        17 Feb 1991     Greg Ward
 */

#include <stdlib.h>
#include <ctype.h>
#include <math.h>
#include <stdio.h>

#include "platform.h"
#include "rtio.h"
#include "paths.h"
#include "fvect.h"

#ifdef  M_PI
#define  PI             ((double)M_PI)
#else
#define  PI             3.14159265358979323846
#endif

#define  MAXVERT        6       /* maximum number of vertices for markers */
#define  MAXMARK        128     /* maximum number of markers */

#define  USE_XFORM      1       /* use !xform inline command */
#define  USE_INSTANCE   2       /* use instance primitive */
#define  USE_MESH       3       /* use mesh primitive */

typedef struct {
        short   beg, end;               /* beginning and ending vertex */
        float   len2;                   /* length squared */
}  EDGE;                        /* a marker edge */

struct mrkr {
        char    *modout;                /* output modifier */
        double  mscale;                 /* scale by this to get unit */
        char    *modin;                 /* input modifier indicating marker */
        char    *objname;               /* output object file or octree */
        int     usetype;                /* one of USE_* above */
}  marker[MAXMARK+1];           /* array of markers */
int     nmarkers = 0;           /* number of markers */

int     expand;                 /* expand commands? */

char    *progname;

static void convert(char *name, FILE *fin);
static void cvcomm(char *fname, FILE *fin);
static void cvobject(char *fname, FILE *fin);
static void replace(char *fname, struct mrkr *m, char *mark, FILE *fin);
static int edgecmp(const void *e1, const void *e2);
static int buildxf(char *xf, double markscale, FILE *fin);
static int addrot(char *xf, FVECT xp, FVECT yp, FVECT zp);


int
main(
        int     argc,
        char    *argv[]
)
{
        FILE    *fp;
        int     i, j;

        progname = argv[0];
        i = 1;
        while (i < argc && argv[i][0] == '-') {
                do {
                        switch (argv[i][1]) {
                        case 'i':
                                marker[nmarkers].usetype = USE_INSTANCE;
                                marker[nmarkers].objname = argv[++i];
                                break;
                        case 'I':
                                marker[nmarkers].usetype = USE_MESH;
                                marker[nmarkers].objname = argv[++i];
                                break;
                        case 'x':
                                marker[nmarkers].usetype = USE_XFORM;
                                marker[nmarkers].objname = argv[++i];
                                break;
                        case 'e':
                                expand = 1;
                                break;
                        case 'm':
                                marker[nmarkers].modout = argv[++i];
                                break;
                        case 's':
                                marker[nmarkers].mscale = atof(argv[++i]);
                                break;
                        default:
                                goto userr;
                        }
                        if (++i >= argc)
                                goto userr;
                } while (argv[i][0] == '-');
                if (marker[nmarkers].objname == NULL)
                        goto userr;
                if (nmarkers >= MAXMARK) {
                        fprintf(stderr, "%s: too many markers\n", progname);
                        return 1;
                }
                marker[nmarkers++].modin = argv[i++];
                marker[nmarkers].mscale = marker[nmarkers-1].mscale;
        }
        if (nmarkers == 0)
                goto userr;
                                        /* simple header */
        putchar('#');
        for (j = 0; j < i; j++) {
                putchar(' ');
                fputs(argv[j], stdout);
        }
        putchar('\n');
        if (i == argc)
                convert("<stdin>", stdin);
        else
                for ( ; i < argc; i++) {
                        if ((fp = fopen(argv[i], "r")) == NULL) {
                                perror(argv[i]);
                                exit(1);
                        }
                        convert(argv[i], fp);
                        fclose(fp);
                }
        return 0;
userr:
        fprintf(stderr,
"Usage: %s [-e][-s size][-m modout] {-x objfile|-i octree|-I mesh} modname .. [file ..]\n",
                progname);
        return 1;
}


void
convert(                /* replace marks in a stream */
        char    *name,
        register FILE   *fin
)
{
        register int    c;

        while ((c = getc(fin)) != EOF) {
                if (isspace(c))                         /* blank */
                        continue;
                if (c == '#') {                         /* comment */
                        putchar(c);
                        do {
                                if ((c = getc(fin)) == EOF)
                                        return;
                                putchar(c);
                        } while (c != '\n');
                } else if (c == '!') {                  /* command */
                        ungetc(c, fin);
                        cvcomm(name, fin);
                } else {                                /* object */
                        ungetc(c, fin);
                        cvobject(name, fin);
                }
        }
}


void
cvcomm(         /* convert a command */
        char    *fname,
        FILE    *fin
)
{
        FILE    *pin;
        char    buf[512], *fgetline();

        fgetline(buf, sizeof(buf), fin);
        if (expand) {
                if ((pin = popen(buf+1, "r")) == NULL) {
                        fprintf(stderr,
                        "%s: (%s): cannot execute \"%s\"\n",
                                        progname, fname, buf);
                        exit(1);
                }
                convert(buf, pin);
                if (pclose(pin) != 0) {
                        fprintf(stderr,
                        "%s: (%s): bad status from \"%s\"\n",
                                        progname, fname, buf);
                        exit(1);
                }
        } else
                printf("\n%s\n", buf);
}


void
cvobject(               /* convert an object */
        char    *fname,
        FILE    *fin
)
{
        extern char     *fgetword();
        char    buf[128], typ[16], nam[128];
        int     i, n;
        register int    j;

        if (fgetword(buf, sizeof(buf), fin) == NULL ||
                        fgetword(typ, sizeof(typ), fin) == NULL ||
                        fgetword(nam, sizeof(nam), fin) == NULL)
                goto readerr;
        if (!strcmp(typ, "polygon"))
                for (j = 0; j < nmarkers; j++)
                        if (!strcmp(buf, marker[j].modin)) {
                                replace(fname, &marker[j], nam, fin);
                                return;
                        }
        putchar('\n'); fputword(buf, stdout);
        printf(" %s ", typ);
        fputword(nam, stdout); putchar('\n');
        if (!strcmp(typ, "alias")) {            /* alias special case */
                if (fgetword(buf, sizeof(buf), fin) == NULL)
                        goto readerr;
                putchar('\t'); fputword(buf, stdout); putchar('\n');
                return;
        }
        for (i = 0; i < 3; i++) {               /* pass along arguments */
                if (fscanf(fin, "%d", &n) != 1)
                        goto readerr;
                printf("%d", n);
                for (j = 0; j < n; j++) {
                        if (fgetword(buf, sizeof(buf), fin) == NULL)
                                goto readerr;
                        if (j%3 == 0)
                                putchar('\n');
                        putchar('\t');
                        fputword(buf, stdout);
                }
                putchar('\n');
        }
        return;
readerr:
        fprintf(stderr, "%s: (%s): read error for %s \"%s\"\n",
                        progname, fname, typ, nam);
}


void
replace(                /* replace marker */
        char    *fname,
        register struct mrkr    *m,
        char    *mark,
        FILE    *fin
)
{
        int     n;
        char    buf[256];

        buf[0] = '\0';                  /* bug fix thanks to schorsch */
        if (m->usetype == USE_XFORM) {
                sprintf(buf, "xform -n %s", mark);
                if (m->modout != NULL)
                        sprintf(buf+strlen(buf), " -m %s", m->modout);
                if (buildxf(buf+strlen(buf), m->mscale, fin) < 0)
                        goto badxf;
                sprintf(buf+strlen(buf), " %s", m->objname);
                if (expand) {
                        fflush(stdout);
                        system(buf);
                } else
                        printf("\n!%s\n", buf);
        } else {
                if ((n = buildxf(buf, m->mscale, fin)) < 0)
                        goto badxf;
                printf("\n%s %s %s\n",
                                m->modout==NULL?"void":m->modout,
                                m->usetype==USE_INSTANCE?"instance":"mesh",
                                mark);
                printf("%d %s%s\n0\n0\n", n+1, m->objname, buf);
        }
        return;
badxf:
        fprintf(stderr, "%s: (%s): bad arguments for marker \"%s\"\n",
                        progname, fname, mark);
        exit(1);
}


int
edgecmp(                        /* compare two edges, descending order */
        const void *e1,
        const void *e2
)
{
        if (((EDGE*)e1)->len2 > ((EDGE*)e2)->len2)
                return(-1);
        if (((EDGE*)e1)->len2 < ((EDGE*)e2)->len2)
                return(1);
        return(0);
}


int
buildxf(                /* build transform for marker */
        register char   *xf,
        double  markscale,
        FILE    *fin
)
{
        static FVECT    vlist[MAXVERT];
        static EDGE     elist[MAXVERT];
        FVECT   xvec, yvec, zvec;
        double  xlen;
        int     n;
        register int    i;
        /*
         * Read and sort vectors:  longest is hypotenuse,
         *      second longest is x' axis,
         *      third longest is y' axis (approximate),
         *      other vectors are ignored.
         * It is an error if the x' and y' axes do
         *      not share a common vertex (their origin).
         */
        if (fscanf(fin, "%*d %*d %d", &n) != 1)
                return(-1);
        if (n%3 != 0)
                return(-1);
        n /= 3;
        if (n < 3 || n > MAXVERT)
                return(-1);
                                        /* sort edges in descending order */
        for (i = 0; i < n; i++) {
                if (fscanf(fin, "%lf %lf %lf", &vlist[i][0],
                                &vlist[i][1], &vlist[i][2]) != 3)
                        return(-1);
                if (i) {
                        elist[i].beg = i-1;
                        elist[i].end = i;
                        elist[i].len2 = dist2(vlist[i-1],vlist[i]);
                }
        }
        elist[0].beg = n-1;
        elist[0].end = 0;
        elist[0].len2 = dist2(vlist[n-1],vlist[0]);
        qsort(elist, n, sizeof(EDGE), edgecmp);
                                        /* find x' and y' */
        if (elist[1].end == elist[2].beg || elist[1].end == elist[2].end) {
                i = elist[1].beg;
                elist[1].beg = elist[1].end;
                elist[1].end = i;
        }
        if (elist[2].end == elist[1].beg) {
                i = elist[2].beg;
                elist[2].beg = elist[2].end;
                elist[2].end = i;
        }
        if (elist[1].beg != elist[2].beg)
                return(-1);             /* x' and y' not connected! */
        for (i = 0; i < 3; i++) {
                xvec[i] = vlist[elist[1].end][i] - vlist[elist[1].beg][i];
                yvec[i] = vlist[elist[2].end][i] - vlist[elist[2].beg][i];
        }
        if ((xlen = normalize(xvec)) == 0.0)
                return(-1);
        fcross(zvec, xvec, yvec);
        if (normalize(zvec) == 0.0)
                return(-1);
        fcross(yvec, zvec, xvec);
        n = 0;                          /* start transformation... */
        if (markscale > 0.0) {          /* add scale factor */
                sprintf(xf, " -s %f", xlen*markscale);
                n += 2;
                while (*xf) ++xf;
        }
                                        /* add rotation */
        n += addrot(xf, xvec, yvec, zvec);
        while (*xf) ++xf;
                                        /* add translation */
        n += 4;
        sprintf(xf, " -t %f %f %f", vlist[elist[1].beg][0],
                        vlist[elist[1].beg][1], vlist[elist[1].beg][2]);
        return(n);                      /* all done */
}


int
addrot(         /* compute rotation (x,y,z) => (xp,yp,zp) */
        register char   *xf,
        FVECT xp,
        FVECT yp,
        FVECT zp
)
{
        int     n;
        double  theta;

        if (yp[2]*yp[2] + zp[2]*zp[2] < 2.*FTINY*FTINY) {
                /* Special case for X' along Z-axis */
                theta = -atan2(yp[0], yp[1]);
                sprintf(xf, " -ry %f -rz %f",
                                xp[2] < 0.0 ? 90.0 : -90.0,
                                theta*(180./PI));
                return(4);
        }
        n = 0;
        theta = atan2(yp[2], zp[2]);
        if (!FABSEQ(theta,0.0)) {
                sprintf(xf, " -rx %f", theta*(180./PI));
                while (*xf) ++xf;
                n += 2;
        }
        theta = Asin(-xp[2]);
        if (!FABSEQ(theta,0.0)) {
                sprintf(xf, " -ry %f", theta*(180./PI));
                while (*xf) ++xf;
                n += 2;
        }
        theta = atan2(xp[1], xp[0]);
        if (!FABSEQ(theta,0.0)) {
                sprintf(xf, " -rz %f", theta*(180./PI));
                /* while (*xf) ++xf; */
                n += 2;
        }
        return(n);
}
Revision:	2.19
Committed:	Tue Apr 22 04:45:25 2025 UTC (2 weeks, 3 days ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.18:	+7 -2 lines
Log Message:	fix: Added check to return value of pclose() in several tools
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.19	static const char RCSid[] = "$Id: replmarks.c,v 2.18 2021/02/12 00:53:56 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* Replace markers in Radiance scene description with objects or instances.
6			*
7			* Created: 17 Feb 1991 Greg Ward
8			*/
9
10	greg	2.5	#include <stdlib.h>
11	greg	1.1	#include <ctype.h>
12			#include <math.h>
13	schorsch	2.7	#include <stdio.h>
14	greg	1.1
15	schorsch	2.7	#include "platform.h"
16	schorsch	2.9	#include "rtio.h"
17	greg	2.17	#include "paths.h"
18	greg	1.1	#include "fvect.h"
19
20			#ifdef M_PI
21	gregl	2.4	#define PI ((double)M_PI)
22	greg	1.1	#else
23			#define PI 3.14159265358979323846
24			#endif
25
26			#define MAXVERT 6 /* maximum number of vertices for markers */
27	greg	2.13	#define MAXMARK 128 /* maximum number of markers */
28	greg	1.1
29	greg	2.11	#define USE_XFORM 1 /* use !xform inline command */
30			#define USE_INSTANCE 2 /* use instance primitive */
31			#define USE_MESH 3 /* use mesh primitive */
32
33	greg	1.1	typedef struct {
34			short beg, end; /* beginning and ending vertex */
35			float len2; /* length squared */
36			} EDGE; /* a marker edge */
37
38	greg	2.2	struct mrkr {
39			char modout; / output modifier */
40			double mscale; /* scale by this to get unit */
41			char modin; / input modifier indicating marker */
42			char objname; / output object file or octree */
43	greg	2.11	int usetype; /* one of USE_* above */
44	greg	2.13	} marker[MAXMARK+1]; /* array of markers */
45	greg	2.2	int nmarkers = 0; /* number of markers */
46	greg	1.1
47	greg	2.2	int expand; /* expand commands? */
48	greg	1.1
49			char *progname;
50
51	schorsch	2.9	static void convert(char name, FILE fin);
52			static void cvcomm(char fname, FILE fin);
53			static void cvobject(char fname, FILE fin);
54			static void replace(char fname, struct mrkr m, char mark, FILE fin);
55			static int edgecmp(const void e1, const void e2);
56			static int buildxf(char xf, double markscale, FILE fin);
57			static int addrot(char *xf, FVECT xp, FVECT yp, FVECT zp);
58	greg	1.1
59	schorsch	2.9
60			int
61			main(
62			int argc,
63			char *argv[]
64			)
65	greg	1.1	{
66			FILE *fp;
67			int i, j;
68
69			progname = argv[0];
70	greg	2.2	i = 1;
71			while (i < argc && argv[i][0] == '-') {
72			do {
73			switch (argv[i][1]) {
74			case 'i':
75	greg	2.11	marker[nmarkers].usetype = USE_INSTANCE;
76			marker[nmarkers].objname = argv[++i];
77			break;
78			case 'I':
79			marker[nmarkers].usetype = USE_MESH;
80	greg	2.2	marker[nmarkers].objname = argv[++i];
81			break;
82			case 'x':
83	greg	2.11	marker[nmarkers].usetype = USE_XFORM;
84	greg	2.2	marker[nmarkers].objname = argv[++i];
85			break;
86			case 'e':
87			expand = 1;
88			break;
89			case 'm':
90			marker[nmarkers].modout = argv[++i];
91			break;
92			case 's':
93			marker[nmarkers].mscale = atof(argv[++i]);
94			break;
95			default:
96			goto userr;
97			}
98			if (++i >= argc)
99			goto userr;
100			} while (argv[i][0] == '-');
101			if (marker[nmarkers].objname == NULL)
102			goto userr;
103	greg	2.13	if (nmarkers >= MAXMARK) {
104			fprintf(stderr, "%s: too many markers\n", progname);
105			return 1;
106			}
107	greg	2.2	marker[nmarkers++].modin = argv[i++];
108			marker[nmarkers].mscale = marker[nmarkers-1].mscale;
109			}
110			if (nmarkers == 0)
111	greg	1.1	goto userr;
112			/* simple header */
113			putchar('#');
114			for (j = 0; j < i; j++) {
115			putchar(' ');
116			fputs(argv[j], stdout);
117			}
118			putchar('\n');
119			if (i == argc)
120			convert("<stdin>", stdin);
121			else
122			for ( ; i < argc; i++) {
123			if ((fp = fopen(argv[i], "r")) == NULL) {
124			perror(argv[i]);
125			exit(1);
126			}
127			convert(argv[i], fp);
128			fclose(fp);
129			}
130	schorsch	2.9	return 0;
131	greg	1.1	userr:
132			fprintf(stderr,
133	greg	2.11	"Usage: %s [-e][-s size][-m modout] {-x objfile\|-i octree\|-I mesh} modname .. [file ..]\n",
134	greg	1.1	progname);
135	schorsch	2.9	return 1;
136	greg	1.1	}
137
138
139	schorsch	2.9	void
140			convert( /* replace marks in a stream */
141			char *name,
142			register FILE *fin
143			)
144	greg	1.1	{
145			register int c;
146
147			while ((c = getc(fin)) != EOF) {
148			if (isspace(c)) /* blank */
149			continue;
150			if (c == '#') { /* comment */
151			putchar(c);
152			do {
153			if ((c = getc(fin)) == EOF)
154			return;
155			putchar(c);
156			} while (c != '\n');
157			} else if (c == '!') { /* command */
158			ungetc(c, fin);
159			cvcomm(name, fin);
160			} else { /* object */
161			ungetc(c, fin);
162			cvobject(name, fin);
163			}
164			}
165			}
166
167
168	schorsch	2.9	void
169			cvcomm( /* convert a command */
170			char *fname,
171			FILE *fin
172			)
173	greg	1.1	{
174	schorsch	2.8	FILE *pin;
175	greg	1.1	char buf[512], *fgetline();
176
177			fgetline(buf, sizeof(buf), fin);
178			if (expand) {
179			if ((pin = popen(buf+1, "r")) == NULL) {
180			fprintf(stderr,
181			"%s: (%s): cannot execute \"%s\"\n",
182			progname, fname, buf);
183			exit(1);
184			}
185			convert(buf, pin);
186	greg	2.19	if (pclose(pin) != 0) {
187			fprintf(stderr,
188			"%s: (%s): bad status from \"%s\"\n",
189			progname, fname, buf);
190			exit(1);
191			}
192	greg	1.1	} else
193			printf("\n%s\n", buf);
194			}
195
196
197	schorsch	2.9	void
198			cvobject( /* convert an object */
199			char *fname,
200			FILE *fin
201			)
202	greg	1.1	{
203	greg	2.6	extern char *fgetword();
204	greg	1.1	char buf[128], typ[16], nam[128];
205	greg	2.2	int i, n;
206			register int j;
207	greg	1.1
208	greg	2.14	if (fgetword(buf, sizeof(buf), fin) == NULL \|\|
209			fgetword(typ, sizeof(typ), fin) == NULL \|\|
210			fgetword(nam, sizeof(nam), fin) == NULL)
211	greg	1.1	goto readerr;
212	greg	2.2	if (!strcmp(typ, "polygon"))
213			for (j = 0; j < nmarkers; j++)
214			if (!strcmp(buf, marker[j].modin)) {
215			replace(fname, &marker[j], nam, fin);
216			return;
217			}
218	greg	2.14	putchar('\n'); fputword(buf, stdout);
219			printf(" %s ", typ);
220			fputword(nam, stdout); putchar('\n');
221	greg	1.1	if (!strcmp(typ, "alias")) { /* alias special case */
222	greg	2.14	if (fgetword(buf, sizeof(buf), fin) == NULL)
223	greg	1.1	goto readerr;
224	greg	2.14	putchar('\t'); fputword(buf, stdout); putchar('\n');
225	greg	1.1	return;
226			}
227			for (i = 0; i < 3; i++) { /* pass along arguments */
228			if (fscanf(fin, "%d", &n) != 1)
229			goto readerr;
230			printf("%d", n);
231			for (j = 0; j < n; j++) {
232	greg	2.5	if (fgetword(buf, sizeof(buf), fin) == NULL)
233	greg	1.1	goto readerr;
234			if (j%3 == 0)
235			putchar('\n');
236	greg	2.5	putchar('\t');
237			fputword(buf, stdout);
238	greg	1.1	}
239			putchar('\n');
240			}
241			return;
242			readerr:
243			fprintf(stderr, "%s: (%s): read error for %s \"%s\"\n",
244			progname, fname, typ, nam);
245			}
246
247
248	schorsch	2.9	void
249			replace( /* replace marker */
250			char *fname,
251			register struct mrkr *m,
252			char *mark,
253			FILE *fin
254			)
255	greg	1.1	{
256			int n;
257			char buf[256];
258
259	greg	2.5	buf[0] = '\0'; /* bug fix thanks to schorsch */
260	greg	2.11	if (m->usetype == USE_XFORM) {
261	greg	2.10	sprintf(buf, "xform -n %s", mark);
262	greg	2.2	if (m->modout != NULL)
263			sprintf(buf+strlen(buf), " -m %s", m->modout);
264			if (buildxf(buf+strlen(buf), m->mscale, fin) < 0)
265	greg	1.1	goto badxf;
266	greg	2.2	sprintf(buf+strlen(buf), " %s", m->objname);
267	greg	1.1	if (expand) {
268			fflush(stdout);
269			system(buf);
270			} else
271			printf("\n!%s\n", buf);
272			} else {
273	greg	2.2	if ((n = buildxf(buf, m->mscale, fin)) < 0)
274	greg	1.1	goto badxf;
275	greg	2.11	printf("\n%s %s %s\n",
276			m->modout==NULL?"void":m->modout,
277			m->usetype==USE_INSTANCE?"instance":"mesh",
278			mark);
279	greg	2.2	printf("%d %s%s\n0\n0\n", n+1, m->objname, buf);
280	greg	1.1	}
281			return;
282			badxf:
283			fprintf(stderr, "%s: (%s): bad arguments for marker \"%s\"\n",
284			progname, fname, mark);
285			exit(1);
286			}
287
288
289	schorsch	2.9	int
290			edgecmp( /* compare two edges, descending order */
291			const void *e1,
292			const void *e2
293			)
294	greg	1.1	{
295	schorsch	2.9	if (((EDGE)e1)->len2 > ((EDGE)e2)->len2)
296	greg	1.1	return(-1);
297	schorsch	2.9	if (((EDGE)e1)->len2 < ((EDGE)e2)->len2)
298	greg	1.1	return(1);
299			return(0);
300			}
301
302
303			int
304	schorsch	2.9	buildxf( /* build transform for marker */
305			register char *xf,
306			double markscale,
307			FILE *fin
308			)
309	greg	1.1	{
310			static FVECT vlist[MAXVERT];
311			static EDGE elist[MAXVERT];
312			FVECT xvec, yvec, zvec;
313			double xlen;
314			int n;
315			register int i;
316			/*
317			* Read and sort vectors: longest is hypotenuse,
318			* second longest is x' axis,
319			* third longest is y' axis (approximate),
320			* other vectors are ignored.
321			* It is an error if the x' and y' axes do
322			* not share a common vertex (their origin).
323			*/
324			if (fscanf(fin, "%d %d %d", &n) != 1)
325			return(-1);
326			if (n%3 != 0)
327			return(-1);
328			n /= 3;
329			if (n < 3 \|\| n > MAXVERT)
330			return(-1);
331			/* sort edges in descending order */
332			for (i = 0; i < n; i++) {
333			if (fscanf(fin, "%lf %lf %lf", &vlist[i][0],
334			&vlist[i][1], &vlist[i][2]) != 3)
335			return(-1);
336			if (i) {
337			elist[i].beg = i-1;
338			elist[i].end = i;
339			elist[i].len2 = dist2(vlist[i-1],vlist[i]);
340			}
341			}
342			elist[0].beg = n-1;
343			elist[0].end = 0;
344			elist[0].len2 = dist2(vlist[n-1],vlist[0]);
345			qsort(elist, n, sizeof(EDGE), edgecmp);
346			/* find x' and y' */
347			if (elist[1].end == elist[2].beg \|\| elist[1].end == elist[2].end) {
348			i = elist[1].beg;
349			elist[1].beg = elist[1].end;
350			elist[1].end = i;
351			}
352			if (elist[2].end == elist[1].beg) {
353			i = elist[2].beg;
354			elist[2].beg = elist[2].end;
355			elist[2].end = i;
356			}
357			if (elist[1].beg != elist[2].beg)
358			return(-1); /* x' and y' not connected! */
359			for (i = 0; i < 3; i++) {
360			xvec[i] = vlist[elist[1].end][i] - vlist[elist[1].beg][i];
361			yvec[i] = vlist[elist[2].end][i] - vlist[elist[2].beg][i];
362			}
363			if ((xlen = normalize(xvec)) == 0.0)
364			return(-1);
365			fcross(zvec, xvec, yvec);
366			if (normalize(zvec) == 0.0)
367			return(-1);
368			fcross(yvec, zvec, xvec);
369			n = 0; /* start transformation... */
370			if (markscale > 0.0) { /* add scale factor */
371			sprintf(xf, " -s %f", xlen*markscale);
372			n += 2;
373	greg	2.5	while (*xf) ++xf;
374	greg	1.1	}
375			/* add rotation */
376			n += addrot(xf, xvec, yvec, zvec);
377	greg	2.5	while (*xf) ++xf;
378	greg	1.1	/* add translation */
379			n += 4;
380			sprintf(xf, " -t %f %f %f", vlist[elist[1].beg][0],
381			vlist[elist[1].beg][1], vlist[elist[1].beg][2]);
382			return(n); /* all done */
383			}
384
385
386	schorsch	2.9	int
387			addrot( /* compute rotation (x,y,z) => (xp,yp,zp) */
388			register char *xf,
389			FVECT xp,
390			FVECT yp,
391			FVECT zp
392			)
393	greg	1.1	{
394	greg	1.2	int n;
395			double theta;
396	greg	1.1
397	greg	2.15	if (yp[2]yp[2] + zp[2]zp[2] < 2.FTINYFTINY) {
398			/* Special case for X' along Z-axis */
399			theta = -atan2(yp[0], yp[1]);
400			sprintf(xf, " -ry %f -rz %f",
401			xp[2] < 0.0 ? 90.0 : -90.0,
402			theta*(180./PI));
403			return(4);
404			}
405	greg	1.2	n = 0;
406			theta = atan2(yp[2], zp[2]);
407	greg	2.18	if (!FABSEQ(theta,0.0)) {
408	greg	1.2	sprintf(xf, " -rx %f", theta*(180./PI));
409	greg	2.5	while (*xf) ++xf;
410	greg	1.2	n += 2;
411			}
412	greg	2.16	theta = Asin(-xp[2]);
413	greg	2.18	if (!FABSEQ(theta,0.0)) {
414	greg	1.2	sprintf(xf, " -ry %f", theta*(180./PI));
415	greg	2.5	while (*xf) ++xf;
416	greg	1.2	n += 2;
417			}
418			theta = atan2(xp[1], xp[0]);
419	greg	2.18	if (!FABSEQ(theta,0.0)) {
420	greg	1.2	sprintf(xf, " -rz %f", theta*(180./PI));
421	greg	2.5	/* while (xf) ++xf; /
422	greg	1.2	n += 2;
423			}
424			return(n);
425	greg	1.1	}