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root/radiance/ray/src/ot/wfconv.c
Revision: 2.12
Committed: Fri Jan 24 02:22:49 2014 UTC (10 years, 3 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.11: +8 -6 lines
Log Message:
Fixed bug in triangulation code

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: wfconv.c,v 2.11 2014/01/24 01:26:44 greg Exp $";
3 #endif
4 /*
5 * Load Wavefront .OBJ file and convert to triangles with mesh info.
6 * Code borrowed largely from obj2rad.c
7 */
8
9 #include "copyright.h"
10 #include "standard.h"
11 #include "cvmesh.h"
12 #include "triangulate.h"
13 #include <ctype.h>
14
15 typedef int VNDX[3]; /* vertex index (point,map,normal) */
16
17 #define CHUNKSIZ 1024 /* vertex allocation chunk size */
18
19 #define MAXARG 512 /* maximum # arguments in a statement */
20
21 static FVECT *vlist; /* our vertex list */
22 static int nvs; /* number of vertices in our list */
23 static FVECT *vnlist; /* vertex normal list */
24 static int nvns;
25 static RREAL (*vtlist)[2]; /* map vertex list */
26 static int nvts;
27
28 static char *inpfile; /* input file name */
29 static int havemats; /* materials available? */
30 static char material[256]; /* current material name */
31 static char group[256]; /* current group name */
32 static int lineno; /* current line number */
33 static int faceno; /* current face number */
34
35 static int getstmt(char *av[MAXARG], FILE *fp);
36 static int cvtndx(VNDX vi, char *vs);
37 static int putface(int ac, char **av);
38 static OBJECT getmod(void);
39 static int puttri(char *v1, char *v2, char *v3);
40 static void freeverts(void);
41 static int newv(double x, double y, double z);
42 static int newvn(double x, double y, double z);
43 static int newvt(double x, double y);
44 static void syntax(char *er);
45
46
47 void
48 wfreadobj( /* read in .OBJ file and convert */
49 char *objfn
50 )
51 {
52 FILE *fp;
53 char *argv[MAXARG];
54 int argc;
55 int nstats, nunknown;
56
57 if (objfn == NULL) {
58 inpfile = "<stdin>";
59 fp = stdin;
60 } else if ((fp = fopen(inpfile=objfn, "r")) == NULL) {
61 sprintf(errmsg, "cannot open \"%s\"", inpfile);
62 error(USER, errmsg);
63 }
64 havemats = (nobjects > 0);
65 nstats = nunknown = 0;
66 material[0] = '\0';
67 group[0] = '\0';
68 lineno = 0; faceno = 0;
69 /* scan until EOF */
70 while ( (argc = getstmt(argv, fp)) ) {
71 switch (argv[0][0]) {
72 case 'v': /* vertex */
73 switch (argv[0][1]) {
74 case '\0': /* point */
75 if (badarg(argc-1,argv+1,"fff"))
76 syntax("bad vertex");
77 newv(atof(argv[1]), atof(argv[2]),
78 atof(argv[3]));
79 break;
80 case 'n': /* normal */
81 if (argv[0][2])
82 goto unknown;
83 if (badarg(argc-1,argv+1,"fff"))
84 syntax("bad normal");
85 if (!newvn(atof(argv[1]), atof(argv[2]),
86 atof(argv[3])))
87 syntax("zero normal");
88 break;
89 case 't': /* coordinate */
90 if (argv[0][2])
91 goto unknown;
92 if (badarg(argc-1,argv+1,"ff"))
93 goto unknown;
94 newvt(atof(argv[1]), atof(argv[2]));
95 break;
96 default:
97 goto unknown;
98 }
99 break;
100 case 'f': /* face */
101 if (argv[0][1])
102 goto unknown;
103 faceno++;
104 switch (argc-1) {
105 case 0: case 1: case 2:
106 syntax("too few vertices");
107 break;
108 case 3:
109 if (!puttri(argv[1], argv[2], argv[3]))
110 syntax("bad triangle");
111 break;
112 default:
113 if (!putface(argc-1, argv+1))
114 syntax("bad face");
115 break;
116 }
117 break;
118 case 'u': /* usemtl/usemap */
119 if (!strcmp(argv[0], "usemap"))
120 break;
121 if (strcmp(argv[0], "usemtl"))
122 goto unknown;
123 if (argc > 1)
124 strcpy(material, argv[1]);
125 else
126 material[0] = '\0';
127 break;
128 case 'o': /* object name */
129 if (argv[0][1])
130 goto unknown;
131 break;
132 case 'g': /* group name */
133 if (argv[0][1])
134 goto unknown;
135 if (argc > 1)
136 strcpy(group, argv[1]);
137 else
138 group[0] = '\0';
139 break;
140 case '#': /* comment */
141 break;
142 default:; /* something we don't deal with */
143 unknown:
144 nunknown++;
145 break;
146 }
147 nstats++;
148 }
149 /* clean up */
150 freeverts();
151 fclose(fp);
152 if (nunknown > 0) {
153 sprintf(errmsg, "%d of %d statements unrecognized",
154 nunknown, nstats);
155 error(WARNING, errmsg);
156 }
157 }
158
159
160 static int
161 getstmt( /* read the next statement from fp */
162 char *av[MAXARG],
163 FILE *fp
164 )
165 {
166 static char sbuf[MAXARG*16];
167 char *cp;
168 int i;
169
170 do {
171 if (fgetline(cp=sbuf, sizeof(sbuf), fp) == NULL)
172 return(0);
173 i = 0;
174 for ( ; ; ) {
175 while (isspace(*cp) || *cp == '\\') {
176 if (*cp == '\n')
177 lineno++;
178 *cp++ = '\0';
179 }
180 if (!*cp)
181 break;
182 if (i >= MAXARG-1) {
183 sprintf(errmsg,
184 "%s: too many arguments near line %d (limit %d)\n",
185 inpfile, lineno+1, MAXARG-1);
186 break;
187 }
188 av[i++] = cp;
189 while (*++cp && !isspace(*cp))
190 ;
191 }
192 av[i] = NULL;
193 lineno++;
194 } while (!i);
195
196 return(i);
197 }
198
199
200 static int
201 cvtndx( /* convert vertex string to index */
202 VNDX vi,
203 char *vs
204 )
205 {
206 /* get point */
207 vi[0] = atoi(vs);
208 if (vi[0] > 0) {
209 if (vi[0]-- > nvs)
210 return(0);
211 } else if (vi[0] < 0) {
212 vi[0] += nvs;
213 if (vi[0] < 0)
214 return(0);
215 } else
216 return(0);
217 /* get map coord. */
218 while (*vs)
219 if (*vs++ == '/')
220 break;
221 vi[1] = atoi(vs);
222 if (vi[1] > 0) {
223 if (vi[1]-- > nvts)
224 return(0);
225 } else if (vi[1] < 0) {
226 vi[1] += nvts;
227 if (vi[1] < 0)
228 return(0);
229 } else
230 vi[1] = -1;
231 /* get normal */
232 while (*vs)
233 if (*vs++ == '/')
234 break;
235 vi[2] = atoi(vs);
236 if (vi[2] > 0) {
237 if (vi[2]-- > nvns)
238 return(0);
239 } else if (vi[2] < 0) {
240 vi[2] += nvns;
241 if (vi[2] < 0)
242 return(0);
243 } else
244 vi[2] = -1;
245 return(1);
246 }
247
248 /* determine dominant axis for triangle */
249 static int
250 dominant_axis(char *v1, char *v2, char *v3)
251 {
252 VNDX v1i, v2i, v3i;
253 FVECT e1, e2, vn;
254 int i, imax;
255
256 if (!cvtndx(v1i, v1) || !cvtndx(v2i, v2) || !cvtndx(v3i, v3))
257 return(-1);
258 VSUB(e1, vlist[v2i[0]], vlist[v1i[0]]);
259 VSUB(e2, vlist[v3i[0]], vlist[v2i[0]]);
260 VCROSS(vn, e1, e2);
261 for (i = imax = 2; i--; )
262 if (vn[i]*vn[i] > vn[imax]*vn[imax])
263 imax = i;
264 return(vn[imax]*vn[imax] > FTINY ? imax : -1);
265 }
266
267 /* callback for triangle output from polygon */
268 static int
269 tri_out(const Vert2_list *tp, int a, int b, int c)
270 {
271 return( puttri( ((char **)tp->p)[a],
272 ((char **)tp->p)[b],
273 ((char **)tp->p)[c] ) );
274 }
275
276 static int
277 putface( /* put out an N-sided polygon */
278 int ac,
279 char **av
280 )
281 {
282 Vert2_list *poly = polyAlloc(ac);
283 int i, ax, ay;
284
285 if (poly == NULL)
286 return(0);
287 poly->p = (void *)av;
288 for (i = ac-3; i >= 0; i--) /* identify dominant axis */
289 if ((ax = dominant_axis(av[i], av[i+1], av[i+2])) >= 0)
290 break;
291 if (ax < 0)
292 return(1); /* ignore degenerate face */
293 if (++ax >= 3) ax = 0;
294 ay = ax;
295 if (++ay >= 3) ay = 0;
296 for (i = 0; i < ac; i++) { /* convert to 2-D polygon */
297 VNDX vi;
298 if (!cvtndx(vi, av[i])) {
299 error(WARNING, "bad vertex reference");
300 polyFree(poly);
301 return(0);
302 }
303 poly->v[i].mX = vlist[vi[0]][ax];
304 poly->v[i].mY = vlist[vi[0]][ay];
305 }
306 /* break into triangles & output */
307 if (!polyTriangulate(poly, &tri_out))
308 error(WARNING, "self-intersecting face");
309 polyFree(poly);
310 return(1);
311 }
312
313
314 static OBJECT
315 getmod(void) /* get current modifier ID */
316 {
317 char *mnam;
318 OBJECT mod;
319
320 if (!havemats)
321 return(OVOID);
322 if (!strcmp(material, VOIDID))
323 return(OVOID);
324 if (material[0]) /* prefer usemtl statements */
325 mnam = material;
326 else if (group[0]) /* else use group name */
327 mnam = group;
328 else
329 return(OVOID);
330 mod = modifier(mnam);
331 if (mod == OVOID) {
332 sprintf(errmsg, "%s: undefined modifier \"%s\"",
333 inpfile, mnam);
334 error(USER, errmsg);
335 }
336 return(mod);
337 }
338
339
340 static int
341 puttri( /* convert a triangle */
342 char *v1,
343 char *v2,
344 char *v3
345 )
346 {
347 VNDX v1i, v2i, v3i;
348 RREAL *v1c, *v2c, *v3c;
349 RREAL *v1n, *v2n, *v3n;
350
351 if (!cvtndx(v1i, v1) || !cvtndx(v2i, v2) || !cvtndx(v3i, v3)) {
352 error(WARNING, "bad vertex reference");
353 return(0);
354 }
355 if (v1i[1]>=0 && v2i[1]>=0 && v3i[1]>=0) {
356 v1c = vtlist[v1i[1]];
357 v2c = vtlist[v2i[1]];
358 v3c = vtlist[v3i[1]];
359 } else
360 v1c = v2c = v3c = NULL;
361
362 if (v1i[2]>=0 && v2i[2]>=0 && v3i[2]>=0) {
363 v1n = vnlist[v1i[2]];
364 v2n = vnlist[v2i[2]];
365 v3n = vnlist[v3i[2]];
366 } else
367 v1n = v2n = v3n = NULL;
368
369 return(cvtri(getmod(), vlist[v1i[0]], vlist[v2i[0]], vlist[v3i[0]],
370 v1n, v2n, v3n, v1c, v2c, v3c) >= 0);
371 }
372
373
374 static void
375 freeverts(void) /* free all vertices */
376 {
377 if (nvs) {
378 free((void *)vlist);
379 nvs = 0;
380 }
381 if (nvts) {
382 free((void *)vtlist);
383 nvts = 0;
384 }
385 if (nvns) {
386 free((void *)vnlist);
387 nvns = 0;
388 }
389 }
390
391
392 static int
393 newv( /* create a new vertex */
394 double x,
395 double y,
396 double z
397 )
398 {
399 if (!(nvs%CHUNKSIZ)) { /* allocate next block */
400 if (nvs == 0)
401 vlist = (FVECT *)malloc(CHUNKSIZ*sizeof(FVECT));
402 else
403 vlist = (FVECT *)realloc((void *)vlist,
404 (nvs+CHUNKSIZ)*sizeof(FVECT));
405 if (vlist == NULL)
406 error(SYSTEM, "out of memory in newv");
407 }
408 /* assign new vertex */
409 vlist[nvs][0] = x;
410 vlist[nvs][1] = y;
411 vlist[nvs][2] = z;
412 return(++nvs);
413 }
414
415
416 static int
417 newvn( /* create a new vertex normal */
418 double x,
419 double y,
420 double z
421 )
422 {
423 if (!(nvns%CHUNKSIZ)) { /* allocate next block */
424 if (nvns == 0)
425 vnlist = (FVECT *)malloc(CHUNKSIZ*sizeof(FVECT));
426 else
427 vnlist = (FVECT *)realloc((void *)vnlist,
428 (nvns+CHUNKSIZ)*sizeof(FVECT));
429 if (vnlist == NULL)
430 error(SYSTEM, "out of memory in newvn");
431 }
432 /* assign new normal */
433 vnlist[nvns][0] = x;
434 vnlist[nvns][1] = y;
435 vnlist[nvns][2] = z;
436 if (normalize(vnlist[nvns]) == 0.0)
437 return(0);
438 return(++nvns);
439 }
440
441
442 static int
443 newvt( /* create a new texture map vertex */
444 double x,
445 double y
446 )
447 {
448 if (!(nvts%CHUNKSIZ)) { /* allocate next block */
449 if (nvts == 0)
450 vtlist = (RREAL (*)[2])malloc(CHUNKSIZ*2*sizeof(RREAL));
451 else
452 vtlist = (RREAL (*)[2])realloc((void *)vtlist,
453 (nvts+CHUNKSIZ)*2*sizeof(RREAL));
454 if (vtlist == NULL)
455 error(SYSTEM, "out of memory in newvt");
456 }
457 /* assign new vertex */
458 vtlist[nvts][0] = x;
459 vtlist[nvts][1] = y;
460 return(++nvts);
461 }
462
463
464 static void
465 syntax( /* report syntax error and exit */
466 char *er
467 )
468 {
469 sprintf(errmsg, "%s: Wavefront syntax error near line %d: %s\n",
470 inpfile, lineno, er);
471 error(USER, errmsg);
472 }