ViewVC Help
View File | Revision Log | Show Annotations | Download File | Root Listing
root/radiance/ray/src/rt/rpict.c
Revision: 2.55
Committed: Thu Jun 5 19:29:34 2003 UTC (20 years, 10 months ago) by schorsch
Content type: text/plain
Branch: MAIN
Changes since 2.54: +7 -14 lines
Log Message:
Macros for setting binary file mode. Replacing MSDOS by _WIN32.

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id";
3 #endif
4 /*
5 * rpict.c - routines and variables for picture generation.
6 */
7
8 #include "copyright.h"
9
10 #include "ray.h"
11
12 #include <sys/types.h>
13
14 #ifndef NIX
15 #ifdef BSD
16 #include <sys/time.h>
17 #include <sys/resource.h>
18 #else
19 #include <sys/times.h>
20 #include <unistd.h>
21 #endif
22 #endif
23
24 #include <time.h>
25 #include <signal.h>
26
27 #include "platform.h"
28 #include "view.h"
29 #include "random.h"
30 #include "paths.h"
31
32
33 #define RFTEMPLATE "rfXXXXXX"
34
35 #ifndef SIGCONT
36 #define SIGCONT SIGIO
37 #endif
38
39 CUBE thescene; /* our scene */
40 OBJECT nsceneobjs; /* number of objects in our scene */
41
42 int dimlist[MAXDIM]; /* sampling dimensions */
43 int ndims = 0; /* number of sampling dimensions */
44 int samplendx; /* sample index number */
45
46 extern void ambnotify();
47 void (*addobjnotify[])() = {ambnotify, NULL};
48
49 VIEW ourview = STDVIEW; /* view parameters */
50 int hresolu = 512; /* horizontal resolution */
51 int vresolu = 512; /* vertical resolution */
52 double pixaspect = 1.0; /* pixel aspect ratio */
53
54 int psample = 4; /* pixel sample size */
55 double maxdiff = .05; /* max. difference for interpolation */
56 double dstrpix = 0.67; /* square pixel distribution */
57
58 double mblur = 0.; /* motion blur parameter */
59
60 void (*trace)() = NULL; /* trace call */
61
62 int do_irrad = 0; /* compute irradiance? */
63
64 double dstrsrc = 0.0; /* square source distribution */
65 double shadthresh = .05; /* shadow threshold */
66 double shadcert = .5; /* shadow certainty */
67 int directrelay = 1; /* number of source relays */
68 int vspretest = 512; /* virtual source pretest density */
69 int directvis = 1; /* sources visible? */
70 double srcsizerat = .25; /* maximum ratio source size/dist. */
71
72 COLOR cextinction = BLKCOLOR; /* global extinction coefficient */
73 COLOR salbedo = BLKCOLOR; /* global scattering albedo */
74 double seccg = 0.; /* global scattering eccentricity */
75 double ssampdist = 0.; /* scatter sampling distance */
76
77 double specthresh = .15; /* specular sampling threshold */
78 double specjitter = 1.; /* specular sampling jitter */
79
80 int backvis = 1; /* back face visibility */
81
82 int maxdepth = 6; /* maximum recursion depth */
83 double minweight = 5e-3; /* minimum ray weight */
84
85 char *ambfile = NULL; /* ambient file name */
86 COLOR ambval = BLKCOLOR; /* ambient value */
87 int ambvwt = 0; /* initial weight for ambient value */
88 double ambacc = 0.2; /* ambient accuracy */
89 int ambres = 32; /* ambient resolution */
90 int ambdiv = 128; /* ambient divisions */
91 int ambssamp = 0; /* ambient super-samples */
92 int ambounce = 0; /* ambient bounces */
93 char *amblist[128]; /* ambient include/exclude list */
94 int ambincl = -1; /* include == 1, exclude == 0 */
95
96 int ralrm = 0; /* seconds between reports */
97
98 double pctdone = 0.0; /* percentage done */
99 time_t tlastrept = 0L; /* time at last report */
100 time_t tstart; /* starting time */
101
102 #define MAXDIV 16 /* maximum sample size */
103
104 #define pixjitter() (.5+dstrpix*(.5-frandom()))
105
106 int hres, vres; /* resolution for this frame */
107
108 static VIEW lastview; /* the previous view input */
109
110 extern char *mktemp(); /* XXX should be in stdlib.h or unistd.h */
111
112 void report();
113
114 double pixvalue();
115
116 #ifdef NIX
117 #define file_exists(f) (access(f,F_OK)==0)
118 #else
119 #include <sys/types.h>
120 #include <sys/stat.h>
121 int
122 file_exists(fname) /* ordinary file exists? */
123 char *fname;
124 {
125 struct stat sbuf;
126 if (stat(fname, &sbuf) < 0) return(0);
127 return((sbuf.st_mode & S_IFREG) != 0);
128 }
129 #endif
130
131
132 void
133 quit(code) /* quit program */
134 int code;
135 {
136 if (code) /* report status */
137 report();
138 #ifndef NIX
139 headclean(); /* delete header file */
140 pfclean(); /* clean up persist files */
141 #endif
142 exit(code);
143 }
144
145
146 #ifndef NIX
147 void
148 report() /* report progress */
149 {
150 extern char *myhostname();
151 double u, s;
152 #ifdef BSD
153 struct rusage rubuf;
154 #else
155 struct tms tbuf;
156 double period;
157 #endif
158
159 tlastrept = time((time_t *)NULL);
160 #ifdef BSD
161 getrusage(RUSAGE_SELF, &rubuf);
162 u = rubuf.ru_utime.tv_sec + rubuf.ru_utime.tv_usec/1e6;
163 s = rubuf.ru_stime.tv_sec + rubuf.ru_stime.tv_usec/1e6;
164 getrusage(RUSAGE_CHILDREN, &rubuf);
165 u += rubuf.ru_utime.tv_sec + rubuf.ru_utime.tv_usec/1e6;
166 s += rubuf.ru_stime.tv_sec + rubuf.ru_stime.tv_usec/1e6;
167 #else
168 times(&tbuf);
169 #ifdef _SC_CLK_TCK
170 period = 1.0 / sysconf(_SC_CLK_TCK);
171 #else
172 period = 1.0 / 60.0;
173 #endif
174 u = ( tbuf.tms_utime + tbuf.tms_cutime ) * period;
175 s = ( tbuf.tms_stime + tbuf.tms_cstime ) * period;
176 #endif
177
178 sprintf(errmsg,
179 "%lu rays, %4.2f%% after %.3fu %.3fs %.3fr hours on %s\n",
180 nrays, pctdone, u/3600., s/3600.,
181 (tlastrept-tstart)/3600., myhostname());
182 eputs(errmsg);
183 #ifndef BSD
184 signal(SIGCONT, report);
185 #endif
186 }
187 #else
188 void
189 report() /* report progress */
190 {
191 tlastrept = time((time_t *)NULL);
192 sprintf(errmsg, "%lu rays, %4.2f%% after %5.4f hours\n",
193 nrays, pctdone, (tlastrept-tstart)/3600.0);
194 eputs(errmsg);
195 }
196 #endif
197
198
199 void
200 rpict(seq, pout, zout, prvr) /* generate image(s) */
201 int seq;
202 char *pout, *zout, *prvr;
203 /*
204 * If seq is greater than zero, then we will render a sequence of
205 * images based on view parameter strings read from the standard input.
206 * If pout is NULL, then all images will be sent to the standard ouput.
207 * If seq is greater than zero and prvr is an integer, then it is the
208 * frame number at which rendering should begin. Preceeding view parameter
209 * strings will be skipped in the input.
210 * If pout and prvr are the same, prvr is renamed to avoid overwriting.
211 * Note that pout and zout should contain %d format specifications for
212 * sequenced file naming.
213 */
214 {
215 char fbuf[128], fbuf2[128];
216 int npicts;
217 register char *cp;
218 RESOLU rs;
219 double pa;
220 /* check sampling */
221 if (psample < 1)
222 psample = 1;
223 else if (psample > MAXDIV) {
224 sprintf(errmsg, "pixel sampling reduced from %d to %d",
225 psample, MAXDIV);
226 error(WARNING, errmsg);
227 psample = MAXDIV;
228 }
229 /* get starting frame */
230 if (seq <= 0)
231 seq = 0;
232 else if (prvr != NULL && isint(prvr)) {
233 register int rn; /* skip to specified view */
234 if ((rn = atoi(prvr)) < seq)
235 error(USER, "recover frame less than start frame");
236 if (pout == NULL)
237 error(USER, "missing output file specification");
238 for ( ; seq < rn; seq++)
239 if (nextview(stdin) == EOF)
240 error(USER, "unexpected EOF on view input");
241 setview(&ourview);
242 prvr = fbuf; /* mark for renaming */
243 }
244 if (pout != NULL & prvr != NULL) {
245 sprintf(fbuf, pout, seq);
246 if (!strcmp(prvr, fbuf)) { /* rename */
247 strcpy(fbuf2, fbuf);
248 for (cp = fbuf2; *cp; cp++)
249 ;
250 while (cp > fbuf2 && !ISDIRSEP(cp[-1]))
251 cp--;
252 strcpy(cp, RFTEMPLATE);
253 prvr = mktemp(fbuf2);
254 if (rename(fbuf, prvr) < 0)
255 if (errno == ENOENT) { /* ghost file */
256 sprintf(errmsg,
257 "new output file \"%s\"",
258 fbuf);
259 error(WARNING, errmsg);
260 prvr = NULL;
261 } else { /* serious error */
262 sprintf(errmsg,
263 "cannot rename \"%s\" to \"%s\"",
264 fbuf, prvr);
265 error(SYSTEM, errmsg);
266 }
267 }
268 }
269 npicts = 0; /* render sequence */
270 do {
271 if (seq && nextview(stdin) == EOF)
272 break;
273 pctdone = 0.0;
274 if (pout != NULL) {
275 sprintf(fbuf, pout, seq);
276 if (file_exists(fbuf)) {
277 if (prvr != NULL || !strcmp(fbuf, pout)) {
278 sprintf(errmsg,
279 "output file \"%s\" exists",
280 fbuf);
281 error(USER, errmsg);
282 }
283 setview(&ourview);
284 continue; /* don't clobber */
285 }
286 if (freopen(fbuf, "w", stdout) == NULL) {
287 sprintf(errmsg,
288 "cannot open output file \"%s\"", fbuf);
289 error(SYSTEM, errmsg);
290 }
291 SET_FILE_BINARY(stdout);
292 dupheader();
293 }
294 hres = hresolu; vres = vresolu; pa = pixaspect;
295 if (prvr != NULL)
296 if (viewfile(prvr, &ourview, &rs) <= 0
297 || rs.rt != PIXSTANDARD) {
298 sprintf(errmsg,
299 "cannot recover view parameters from \"%s\"", prvr);
300 error(WARNING, errmsg);
301 } else {
302 pa = 0.0;
303 hres = scanlen(&rs);
304 vres = numscans(&rs);
305 }
306 if ((cp = setview(&ourview)) != NULL)
307 error(USER, cp);
308 normaspect(viewaspect(&ourview), &pa, &hres, &vres);
309 if (seq) {
310 if (ralrm > 0) {
311 fprintf(stderr, "FRAME %d:", seq);
312 fprintview(&ourview, stderr);
313 putc('\n', stderr);
314 fflush(stderr);
315 }
316 printf("FRAME=%d\n", seq);
317 }
318 fputs(VIEWSTR, stdout);
319 fprintview(&ourview, stdout);
320 putchar('\n');
321 if (pa < .99 || pa > 1.01)
322 fputaspect(pa, stdout);
323 fputformat(COLRFMT, stdout);
324 putchar('\n');
325 if (zout != NULL)
326 sprintf(cp=fbuf, zout, seq);
327 else
328 cp = NULL;
329 render(cp, prvr);
330 prvr = NULL;
331 npicts++;
332 } while (seq++);
333 /* check that we did something */
334 if (npicts == 0)
335 error(WARNING, "no output produced");
336 }
337
338
339 nextview(fp) /* get next view from fp */
340 FILE *fp;
341 {
342 char linebuf[256];
343
344 copystruct(&lastview, &ourview);
345 while (fgets(linebuf, sizeof(linebuf), fp) != NULL)
346 if (isview(linebuf) && sscanview(&ourview, linebuf) > 0)
347 return(0);
348 return(EOF);
349 }
350
351
352 render(zfile, oldfile) /* render the scene */
353 char *zfile, *oldfile;
354 {
355 COLOR *scanbar[MAXDIV+1]; /* scanline arrays of pixel values */
356 float *zbar[MAXDIV+1]; /* z values */
357 char *sampdens; /* previous sample density */
358 int ypos; /* current scanline */
359 int ystep; /* current y step size */
360 int hstep; /* h step size */
361 int zfd;
362 COLOR *colptr;
363 float *zptr;
364 register int i;
365 /* check for empty image */
366 if (hres <= 0 || vres <= 0) {
367 error(WARNING, "empty output picture");
368 fprtresolu(0, 0, stdout);
369 return;
370 }
371 /* allocate scanlines */
372 for (i = 0; i <= psample; i++) {
373 scanbar[i] = (COLOR *)malloc(hres*sizeof(COLOR));
374 if (scanbar[i] == NULL)
375 goto memerr;
376 }
377 hstep = (psample*140+49)/99; /* quincunx sampling */
378 ystep = (psample*99+70)/140;
379 if (hstep > 2) {
380 i = hres/hstep + 2;
381 if ((sampdens = (char *)malloc(i)) == NULL)
382 goto memerr;
383 while (i--)
384 sampdens[i] = hstep;
385 } else
386 sampdens = NULL;
387 /* open z-file */
388 if (zfile != NULL) {
389 if ((zfd = open(zfile, O_WRONLY|O_CREAT, 0666)) == -1) {
390 sprintf(errmsg, "cannot open z-file \"%s\"", zfile);
391 error(SYSTEM, errmsg);
392 }
393 SET_FD_BINARY(zfd);
394 for (i = 0; i <= psample; i++) {
395 zbar[i] = (float *)malloc(hres*sizeof(float));
396 if (zbar[i] == NULL)
397 goto memerr;
398 }
399 } else {
400 zfd = -1;
401 for (i = 0; i <= psample; i++)
402 zbar[i] = NULL;
403 }
404 /* write out boundaries */
405 fprtresolu(hres, vres, stdout);
406 /* recover file and compute first */
407 i = salvage(oldfile);
408 if (i >= vres)
409 goto alldone;
410 if (zfd != -1 && i > 0 &&
411 lseek(zfd, (off_t)i*hres*sizeof(float), 0) < 0)
412 error(SYSTEM, "z-file seek error in render");
413 pctdone = 100.0*i/vres;
414 if (ralrm > 0) /* report init stats */
415 report();
416 #ifndef BSD
417 else
418 #endif
419 signal(SIGCONT, report);
420 ypos = vres-1 - i; /* initialize sampling */
421 if (directvis)
422 init_drawsources(psample);
423 fillscanline(scanbar[0], zbar[0], sampdens, hres, ypos, hstep);
424 /* compute scanlines */
425 for (ypos -= ystep; ypos > -ystep; ypos -= ystep) {
426 /* bottom adjust? */
427 if (ypos < 0) {
428 ystep += ypos;
429 ypos = 0;
430 }
431 colptr = scanbar[ystep]; /* move base to top */
432 scanbar[ystep] = scanbar[0];
433 scanbar[0] = colptr;
434 zptr = zbar[ystep];
435 zbar[ystep] = zbar[0];
436 zbar[0] = zptr;
437 /* fill base line */
438 fillscanline(scanbar[0], zbar[0], sampdens,
439 hres, ypos, hstep);
440 /* fill bar */
441 fillscanbar(scanbar, zbar, hres, ypos, ystep);
442 if (directvis) /* add bitty sources */
443 drawsources(scanbar, zbar, 0, hres, ypos, ystep);
444 /* write it out */
445 #ifndef BSD
446 signal(SIGCONT, SIG_IGN); /* don't interrupt writes */
447 #endif
448 for (i = ystep; i > 0; i--) {
449 if (zfd != -1 && write(zfd, (char *)zbar[i],
450 hres*sizeof(float))
451 < hres*sizeof(float))
452 goto writerr;
453 if (fwritescan(scanbar[i], hres, stdout) < 0)
454 goto writerr;
455 }
456 if (fflush(stdout) == EOF)
457 goto writerr;
458 /* record progress */
459 pctdone = 100.0*(vres-1-ypos)/vres;
460 if (ralrm > 0 && time((time_t *)NULL) >= tlastrept+ralrm)
461 report();
462 #ifndef BSD
463 else
464 signal(SIGCONT, report);
465 #endif
466 }
467 /* clean up */
468 signal(SIGCONT, SIG_IGN);
469 if (zfd != -1 && write(zfd, (char *)zbar[0], hres*sizeof(float))
470 < hres*sizeof(float))
471 goto writerr;
472 fwritescan(scanbar[0], hres, stdout);
473 if (fflush(stdout) == EOF)
474 goto writerr;
475 alldone:
476 if (zfd != -1) {
477 if (close(zfd) == -1)
478 goto writerr;
479 for (i = 0; i <= psample; i++)
480 free((void *)zbar[i]);
481 }
482 for (i = 0; i <= psample; i++)
483 free((void *)scanbar[i]);
484 if (sampdens != NULL)
485 free(sampdens);
486 pctdone = 100.0;
487 if (ralrm > 0)
488 report();
489 signal(SIGCONT, SIG_DFL);
490 return;
491 writerr:
492 error(SYSTEM, "write error in render");
493 memerr:
494 error(SYSTEM, "out of memory in render");
495 }
496
497
498 fillscanline(scanline, zline, sd, xres, y, xstep) /* fill scan at y */
499 register COLOR *scanline;
500 register float *zline;
501 register char *sd;
502 int xres, y, xstep;
503 {
504 static int nc = 0; /* number of calls */
505 int bl = xstep, b = xstep;
506 double z;
507 register int i;
508
509 z = pixvalue(scanline[0], 0, y);
510 if (zline) zline[0] = z;
511 /* zig-zag start for quincunx pattern */
512 for (i = ++nc & 1 ? xstep : xstep/2; i < xres-1+xstep; i += xstep) {
513 if (i >= xres) {
514 xstep += xres-1-i;
515 i = xres-1;
516 }
517 z = pixvalue(scanline[i], i, y);
518 if (zline) zline[i] = z;
519 if (sd) b = sd[0] > sd[1] ? sd[0] : sd[1];
520 if (i <= xstep)
521 b = fillsample(scanline, zline, 0, y, i, 0, b/2);
522 else
523 b = fillsample(scanline+i-xstep,
524 zline ? zline+i-xstep : (float *)NULL,
525 i-xstep, y, xstep, 0, b/2);
526 if (sd) *sd++ = nc & 1 ? bl : b;
527 bl = b;
528 }
529 if (sd && nc & 1) *sd = bl;
530 }
531
532
533 fillscanbar(scanbar, zbar, xres, y, ysize) /* fill interior */
534 register COLOR *scanbar[];
535 register float *zbar[];
536 int xres, y, ysize;
537 {
538 COLOR vline[MAXDIV+1];
539 float zline[MAXDIV+1];
540 int b = ysize;
541 register int i, j;
542
543 for (i = 0; i < xres; i++) {
544 copycolor(vline[0], scanbar[0][i]);
545 copycolor(vline[ysize], scanbar[ysize][i]);
546 if (zbar[0]) {
547 zline[0] = zbar[0][i];
548 zline[ysize] = zbar[ysize][i];
549 }
550 b = fillsample(vline, zbar[0] ? zline : (float *)NULL,
551 i, y, 0, ysize, b/2);
552
553 for (j = 1; j < ysize; j++)
554 copycolor(scanbar[j][i], vline[j]);
555 if (zbar[0])
556 for (j = 1; j < ysize; j++)
557 zbar[j][i] = zline[j];
558 }
559 }
560
561
562 int
563 fillsample(colline, zline, x, y, xlen, ylen, b) /* fill interior points */
564 register COLOR *colline;
565 register float *zline;
566 int x, y;
567 int xlen, ylen;
568 int b;
569 {
570 double ratio;
571 double z;
572 COLOR ctmp;
573 int ncut;
574 register int len;
575
576 if (xlen > 0) /* x or y length is zero */
577 len = xlen;
578 else
579 len = ylen;
580
581 if (len <= 1) /* limit recursion */
582 return(0);
583
584 if (b > 0 ||
585 (zline && 2.*fabs(zline[0]-zline[len]) > maxdiff*(zline[0]+zline[len]))
586 || bigdiff(colline[0], colline[len], maxdiff)) {
587
588 z = pixvalue(colline[len>>1], x + (xlen>>1), y + (ylen>>1));
589 if (zline) zline[len>>1] = z;
590 ncut = 1;
591 } else { /* interpolate */
592 copycolor(colline[len>>1], colline[len]);
593 ratio = (double)(len>>1) / len;
594 scalecolor(colline[len>>1], ratio);
595 if (zline) zline[len>>1] = zline[len] * ratio;
596 ratio = 1.0 - ratio;
597 copycolor(ctmp, colline[0]);
598 scalecolor(ctmp, ratio);
599 addcolor(colline[len>>1], ctmp);
600 if (zline) zline[len>>1] += zline[0] * ratio;
601 ncut = 0;
602 }
603 /* recurse */
604 ncut += fillsample(colline, zline, x, y, xlen>>1, ylen>>1, (b-1)/2);
605
606 ncut += fillsample(colline+(len>>1),
607 zline ? zline+(len>>1) : (float *)NULL,
608 x+(xlen>>1), y+(ylen>>1),
609 xlen-(xlen>>1), ylen-(ylen>>1), b/2);
610
611 return(ncut);
612 }
613
614
615 double
616 pixvalue(col, x, y) /* compute pixel value */
617 COLOR col; /* returned color */
618 int x, y; /* pixel position */
619 {
620 RAY thisray;
621 FVECT lorg, ldir;
622 double hpos, vpos, lmax, d;
623 /* compute view ray */
624 hpos = (x+pixjitter())/hres;
625 vpos = (y+pixjitter())/vres;
626 if ((thisray.rmax = viewray(thisray.rorg, thisray.rdir,
627 &ourview, hpos, vpos)) < -FTINY) {
628 setcolor(col, 0.0, 0.0, 0.0);
629 return(0.0);
630 }
631
632 samplendx = pixnumber(x,y,hres,vres); /* set pixel index */
633
634 /* optional motion blur */
635 if (lastview.type && mblur > FTINY && (lmax = viewray(lorg, ldir,
636 &lastview, hpos, vpos)) >= -FTINY) {
637 register int i;
638 register double d = mblur*(.5-urand(281+samplendx));
639
640 thisray.rmax = (1.-d)*thisray.rmax + d*lmax;
641 for (i = 3; i--; ) {
642 thisray.rorg[i] = (1.-d)*thisray.rorg[i] + d*lorg[i];
643 thisray.rdir[i] = (1.-d)*thisray.rdir[i] + d*ldir[i];
644 }
645 if (normalize(thisray.rdir) == 0.0)
646 return(0.0);
647 }
648
649 rayorigin(&thisray, NULL, PRIMARY, 1.0);
650
651 rayvalue(&thisray); /* trace ray */
652
653 copycolor(col, thisray.rcol); /* return color */
654
655 return(thisray.rt); /* return distance */
656 }
657
658
659 int
660 salvage(oldfile) /* salvage scanlines from killed program */
661 char *oldfile;
662 {
663 COLR *scanline;
664 FILE *fp;
665 int x, y;
666
667 if (oldfile == NULL)
668 goto gotzip;
669
670 if ((fp = fopen(oldfile, "r")) == NULL) {
671 sprintf(errmsg, "cannot open recover file \"%s\"", oldfile);
672 error(WARNING, errmsg);
673 goto gotzip;
674 }
675 SET_FILE_BINARY(fp);
676 /* discard header */
677 getheader(fp, NULL, NULL);
678 /* get picture size */
679 if (!fscnresolu(&x, &y, fp)) {
680 sprintf(errmsg, "bad recover file \"%s\" - not removed",
681 oldfile);
682 error(WARNING, errmsg);
683 fclose(fp);
684 goto gotzip;
685 }
686
687 if (x != hres || y != vres) {
688 sprintf(errmsg, "resolution mismatch in recover file \"%s\"",
689 oldfile);
690 error(USER, errmsg);
691 }
692
693 scanline = (COLR *)malloc(hres*sizeof(COLR));
694 if (scanline == NULL)
695 error(SYSTEM, "out of memory in salvage");
696 for (y = 0; y < vres; y++) {
697 if (freadcolrs(scanline, hres, fp) < 0)
698 break;
699 if (fwritecolrs(scanline, hres, stdout) < 0)
700 goto writerr;
701 }
702 if (fflush(stdout) == EOF)
703 goto writerr;
704 free((void *)scanline);
705 fclose(fp);
706 unlink(oldfile);
707 return(y);
708 gotzip:
709 if (fflush(stdout) == EOF)
710 error(SYSTEM, "error writing picture header");
711 return(0);
712 writerr:
713 sprintf(errmsg, "write error during recovery of \"%s\"", oldfile);
714 error(SYSTEM, errmsg);
715 }
716
717
718 int
719 pixnumber(x, y, xres, yres) /* compute pixel index (brushed) */
720 register int x, y;
721 int xres, yres;
722 {
723 x -= y;
724 while (x < 0)
725 x += xres;
726 return((((x>>2)*yres + y) << 2) + (x & 3));
727 }