src/gen/replmarks.c

#ifndef lint
static const char RCSid[] = "$Id: replmarks.c,v 2.22 2025/06/03 21:31:51 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 "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? */

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;

        fixargv0(argv[0]);              /* sets global progname */
        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,
        FILE    *fin
)
{
        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(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): warning - bad status from \"%s\"\n",
                                        progname, fname, buf);
        } else
                printf("\n%s\n", buf);
}


void
cvobject(               /* convert an object */
        char    *fname,
        FILE    *fin
)
{
        char    buf[128], typ[16], nam[128];
        int     i, n;
        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,
        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 */
        char    *xf,
        double  markscale,
        FILE    *fin
)
{
        static FVECT    vlist[MAXVERT];
        static EDGE     elist[MAXVERT];
        FVECT   xvec, yvec, zvec;
        double  xlen;
        int     n;
        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) */
        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:	2.23
Committed:	Sat Jun 7 05:09:45 2025 UTC (3 hours, 31 minutes ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	HEAD
Changes since 2.22:	+1 -2 lines
Log Message:	refactor: Put some declarations into "paths.h" and included in "platform.h"
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.23	static const char RCSid[] = "$Id: replmarks.c,v 2.22 2025/06/03 21:31:51 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	1.1	#include "fvect.h"
18
19			#ifdef M_PI
20	gregl	2.4	#define PI ((double)M_PI)
21	greg	1.1	#else
22			#define PI 3.14159265358979323846
23			#endif
24
25			#define MAXVERT 6 /* maximum number of vertices for markers */
26	greg	2.13	#define MAXMARK 128 /* maximum number of markers */
27	greg	1.1
28	greg	2.11	#define USE_XFORM 1 /* use !xform inline command */
29			#define USE_INSTANCE 2 /* use instance primitive */
30			#define USE_MESH 3 /* use mesh primitive */
31
32	greg	1.1	typedef struct {
33			short beg, end; /* beginning and ending vertex */
34			float len2; /* length squared */
35			} EDGE; /* a marker edge */
36
37	greg	2.2	struct mrkr {
38			char modout; / output modifier */
39			double mscale; /* scale by this to get unit */
40			char modin; / input modifier indicating marker */
41			char objname; / output object file or octree */
42	greg	2.11	int usetype; /* one of USE_* above */
43	greg	2.13	} marker[MAXMARK+1]; /* array of markers */
44	greg	2.2	int nmarkers = 0; /* number of markers */
45	greg	1.1
46	greg	2.2	int expand; /* expand commands? */
47	greg	1.1
48	schorsch	2.9	static void convert(char name, FILE fin);
49			static void cvcomm(char fname, FILE fin);
50			static void cvobject(char fname, FILE fin);
51			static void replace(char fname, struct mrkr m, char mark, FILE fin);
52			static int edgecmp(const void e1, const void e2);
53			static int buildxf(char xf, double markscale, FILE fin);
54			static int addrot(char *xf, FVECT xp, FVECT yp, FVECT zp);
55	greg	1.1
56	schorsch	2.9
57			int
58			main(
59			int argc,
60			char *argv[]
61			)
62	greg	1.1	{
63			FILE *fp;
64			int i, j;
65
66	greg	2.22	fixargv0(argv[0]); /* sets global progname */
67	greg	2.2	i = 1;
68			while (i < argc && argv[i][0] == '-') {
69			do {
70			switch (argv[i][1]) {
71			case 'i':
72	greg	2.11	marker[nmarkers].usetype = USE_INSTANCE;
73			marker[nmarkers].objname = argv[++i];
74			break;
75			case 'I':
76			marker[nmarkers].usetype = USE_MESH;
77	greg	2.2	marker[nmarkers].objname = argv[++i];
78			break;
79			case 'x':
80	greg	2.11	marker[nmarkers].usetype = USE_XFORM;
81	greg	2.2	marker[nmarkers].objname = argv[++i];
82			break;
83			case 'e':
84			expand = 1;
85			break;
86			case 'm':
87			marker[nmarkers].modout = argv[++i];
88			break;
89			case 's':
90			marker[nmarkers].mscale = atof(argv[++i]);
91			break;
92			default:
93			goto userr;
94			}
95			if (++i >= argc)
96			goto userr;
97			} while (argv[i][0] == '-');
98			if (marker[nmarkers].objname == NULL)
99			goto userr;
100	greg	2.13	if (nmarkers >= MAXMARK) {
101			fprintf(stderr, "%s: too many markers\n", progname);
102			return 1;
103			}
104	greg	2.2	marker[nmarkers++].modin = argv[i++];
105			marker[nmarkers].mscale = marker[nmarkers-1].mscale;
106			}
107			if (nmarkers == 0)
108	greg	1.1	goto userr;
109			/* simple header */
110			putchar('#');
111			for (j = 0; j < i; j++) {
112			putchar(' ');
113			fputs(argv[j], stdout);
114			}
115			putchar('\n');
116			if (i == argc)
117			convert("<stdin>", stdin);
118			else
119			for ( ; i < argc; i++) {
120			if ((fp = fopen(argv[i], "r")) == NULL) {
121			perror(argv[i]);
122			exit(1);
123			}
124			convert(argv[i], fp);
125			fclose(fp);
126			}
127	schorsch	2.9	return 0;
128	greg	1.1	userr:
129			fprintf(stderr,
130	greg	2.11	"Usage: %s [-e][-s size][-m modout] {-x objfile\|-i octree\|-I mesh} modname .. [file ..]\n",
131	greg	1.1	progname);
132	schorsch	2.9	return 1;
133	greg	1.1	}
134
135
136	schorsch	2.9	void
137			convert( /* replace marks in a stream */
138			char *name,
139	greg	2.21	FILE *fin
140	schorsch	2.9	)
141	greg	1.1	{
142	greg	2.21	int c;
143	greg	1.1
144			while ((c = getc(fin)) != EOF) {
145			if (isspace(c)) /* blank */
146			continue;
147			if (c == '#') { /* comment */
148			putchar(c);
149			do {
150			if ((c = getc(fin)) == EOF)
151			return;
152			putchar(c);
153			} while (c != '\n');
154			} else if (c == '!') { /* command */
155			ungetc(c, fin);
156			cvcomm(name, fin);
157			} else { /* object */
158			ungetc(c, fin);
159			cvobject(name, fin);
160			}
161			}
162			}
163
164
165	schorsch	2.9	void
166			cvcomm( /* convert a command */
167			char *fname,
168			FILE *fin
169			)
170	greg	1.1	{
171	schorsch	2.8	FILE *pin;
172	greg	2.21	char buf[512];
173	greg	1.1
174			fgetline(buf, sizeof(buf), fin);
175			if (expand) {
176			if ((pin = popen(buf+1, "r")) == NULL) {
177			fprintf(stderr,
178			"%s: (%s): cannot execute \"%s\"\n",
179			progname, fname, buf);
180			exit(1);
181			}
182			convert(buf, pin);
183	greg	2.20	if (pclose(pin) != 0)
184	greg	2.19	fprintf(stderr,
185	greg	2.20	"%s: (%s): warning - bad status from \"%s\"\n",
186	greg	2.19	progname, fname, buf);
187	greg	1.1	} else
188			printf("\n%s\n", buf);
189			}
190
191
192	schorsch	2.9	void
193			cvobject( /* convert an object */
194			char *fname,
195			FILE *fin
196			)
197	greg	1.1	{
198			char buf[128], typ[16], nam[128];
199	greg	2.2	int i, n;
200	greg	2.21	int j;
201	greg	1.1
202	greg	2.14	if (fgetword(buf, sizeof(buf), fin) == NULL \|\|
203			fgetword(typ, sizeof(typ), fin) == NULL \|\|
204			fgetword(nam, sizeof(nam), fin) == NULL)
205	greg	1.1	goto readerr;
206	greg	2.2	if (!strcmp(typ, "polygon"))
207			for (j = 0; j < nmarkers; j++)
208			if (!strcmp(buf, marker[j].modin)) {
209			replace(fname, &marker[j], nam, fin);
210			return;
211			}
212	greg	2.14	putchar('\n'); fputword(buf, stdout);
213			printf(" %s ", typ);
214			fputword(nam, stdout); putchar('\n');
215	greg	1.1	if (!strcmp(typ, "alias")) { /* alias special case */
216	greg	2.14	if (fgetword(buf, sizeof(buf), fin) == NULL)
217	greg	1.1	goto readerr;
218	greg	2.14	putchar('\t'); fputword(buf, stdout); putchar('\n');
219	greg	1.1	return;
220			}
221			for (i = 0; i < 3; i++) { /* pass along arguments */
222			if (fscanf(fin, "%d", &n) != 1)
223			goto readerr;
224			printf("%d", n);
225			for (j = 0; j < n; j++) {
226	greg	2.5	if (fgetword(buf, sizeof(buf), fin) == NULL)
227	greg	1.1	goto readerr;
228			if (j%3 == 0)
229			putchar('\n');
230	greg	2.5	putchar('\t');
231			fputword(buf, stdout);
232	greg	1.1	}
233			putchar('\n');
234			}
235			return;
236			readerr:
237			fprintf(stderr, "%s: (%s): read error for %s \"%s\"\n",
238			progname, fname, typ, nam);
239			}
240
241
242	schorsch	2.9	void
243			replace( /* replace marker */
244			char *fname,
245	greg	2.21	struct mrkr *m,
246	schorsch	2.9	char *mark,
247			FILE *fin
248			)
249	greg	1.1	{
250			int n;
251			char buf[256];
252
253	greg	2.5	buf[0] = '\0'; /* bug fix thanks to schorsch */
254	greg	2.11	if (m->usetype == USE_XFORM) {
255	greg	2.10	sprintf(buf, "xform -n %s", mark);
256	greg	2.2	if (m->modout != NULL)
257			sprintf(buf+strlen(buf), " -m %s", m->modout);
258			if (buildxf(buf+strlen(buf), m->mscale, fin) < 0)
259	greg	1.1	goto badxf;
260	greg	2.2	sprintf(buf+strlen(buf), " %s", m->objname);
261	greg	1.1	if (expand) {
262			fflush(stdout);
263			system(buf);
264			} else
265			printf("\n!%s\n", buf);
266			} else {
267	greg	2.2	if ((n = buildxf(buf, m->mscale, fin)) < 0)
268	greg	1.1	goto badxf;
269	greg	2.11	printf("\n%s %s %s\n",
270			m->modout==NULL?"void":m->modout,
271			m->usetype==USE_INSTANCE?"instance":"mesh",
272			mark);
273	greg	2.2	printf("%d %s%s\n0\n0\n", n+1, m->objname, buf);
274	greg	1.1	}
275			return;
276			badxf:
277			fprintf(stderr, "%s: (%s): bad arguments for marker \"%s\"\n",
278			progname, fname, mark);
279			exit(1);
280			}
281
282
283	schorsch	2.9	int
284			edgecmp( /* compare two edges, descending order */
285			const void *e1,
286			const void *e2
287			)
288	greg	1.1	{
289	schorsch	2.9	if (((EDGE)e1)->len2 > ((EDGE)e2)->len2)
290	greg	1.1	return(-1);
291	schorsch	2.9	if (((EDGE)e1)->len2 < ((EDGE)e2)->len2)
292	greg	1.1	return(1);
293			return(0);
294			}
295
296
297			int
298	schorsch	2.9	buildxf( /* build transform for marker */
299	greg	2.21	char *xf,
300	schorsch	2.9	double markscale,
301			FILE *fin
302			)
303	greg	1.1	{
304			static FVECT vlist[MAXVERT];
305			static EDGE elist[MAXVERT];
306			FVECT xvec, yvec, zvec;
307			double xlen;
308			int n;
309	greg	2.21	int i;
310	greg	1.1	/*
311			* Read and sort vectors: longest is hypotenuse,
312			* second longest is x' axis,
313			* third longest is y' axis (approximate),
314			* other vectors are ignored.
315			* It is an error if the x' and y' axes do
316			* not share a common vertex (their origin).
317			*/
318			if (fscanf(fin, "%d %d %d", &n) != 1)
319			return(-1);
320			if (n%3 != 0)
321			return(-1);
322			n /= 3;
323			if (n < 3 \|\| n > MAXVERT)
324			return(-1);
325			/* sort edges in descending order */
326			for (i = 0; i < n; i++) {
327			if (fscanf(fin, "%lf %lf %lf", &vlist[i][0],
328			&vlist[i][1], &vlist[i][2]) != 3)
329			return(-1);
330			if (i) {
331			elist[i].beg = i-1;
332			elist[i].end = i;
333			elist[i].len2 = dist2(vlist[i-1],vlist[i]);
334			}
335			}
336			elist[0].beg = n-1;
337			elist[0].end = 0;
338			elist[0].len2 = dist2(vlist[n-1],vlist[0]);
339			qsort(elist, n, sizeof(EDGE), edgecmp);
340			/* find x' and y' */
341			if (elist[1].end == elist[2].beg \|\| elist[1].end == elist[2].end) {
342			i = elist[1].beg;
343			elist[1].beg = elist[1].end;
344			elist[1].end = i;
345			}
346			if (elist[2].end == elist[1].beg) {
347			i = elist[2].beg;
348			elist[2].beg = elist[2].end;
349			elist[2].end = i;
350			}
351			if (elist[1].beg != elist[2].beg)
352			return(-1); /* x' and y' not connected! */
353			for (i = 0; i < 3; i++) {
354			xvec[i] = vlist[elist[1].end][i] - vlist[elist[1].beg][i];
355			yvec[i] = vlist[elist[2].end][i] - vlist[elist[2].beg][i];
356			}
357			if ((xlen = normalize(xvec)) == 0.0)
358			return(-1);
359			fcross(zvec, xvec, yvec);
360			if (normalize(zvec) == 0.0)
361			return(-1);
362			fcross(yvec, zvec, xvec);
363			n = 0; /* start transformation... */
364			if (markscale > 0.0) { /* add scale factor */
365			sprintf(xf, " -s %f", xlen*markscale);
366			n += 2;
367	greg	2.5	while (*xf) ++xf;
368	greg	1.1	}
369			/* add rotation */
370			n += addrot(xf, xvec, yvec, zvec);
371	greg	2.5	while (*xf) ++xf;
372	greg	1.1	/* add translation */
373			n += 4;
374			sprintf(xf, " -t %f %f %f", vlist[elist[1].beg][0],
375			vlist[elist[1].beg][1], vlist[elist[1].beg][2]);
376			return(n); /* all done */
377			}
378
379
380	schorsch	2.9	int
381			addrot( /* compute rotation (x,y,z) => (xp,yp,zp) */
382	greg	2.21	char *xf,
383	schorsch	2.9	FVECT xp,
384			FVECT yp,
385			FVECT zp
386			)
387	greg	1.1	{
388	greg	1.2	int n;
389			double theta;
390	greg	1.1
391	greg	2.15	if (yp[2]yp[2] + zp[2]zp[2] < 2.FTINYFTINY) {
392			/* Special case for X' along Z-axis */
393			theta = -atan2(yp[0], yp[1]);
394			sprintf(xf, " -ry %f -rz %f",
395			xp[2] < 0.0 ? 90.0 : -90.0,
396			theta*(180./PI));
397			return(4);
398			}
399	greg	1.2	n = 0;
400			theta = atan2(yp[2], zp[2]);
401	greg	2.18	if (!FABSEQ(theta,0.0)) {
402	greg	1.2	sprintf(xf, " -rx %f", theta*(180./PI));
403	greg	2.5	while (*xf) ++xf;
404	greg	1.2	n += 2;
405			}
406	greg	2.16	theta = Asin(-xp[2]);
407	greg	2.18	if (!FABSEQ(theta,0.0)) {
408	greg	1.2	sprintf(xf, " -ry %f", theta*(180./PI));
409	greg	2.5	while (*xf) ++xf;
410	greg	1.2	n += 2;
411			}
412			theta = atan2(xp[1], xp[0]);
413	greg	2.18	if (!FABSEQ(theta,0.0)) {
414	greg	1.2	sprintf(xf, " -rz %f", theta*(180./PI));
415	greg	2.5	/* while (xf) ++xf; /
416	greg	1.2	n += 2;
417			}
418			return(n);
419	greg	1.1	}