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root/radiance/ray/src/rt/rpict.c
Revision: 2.54
Committed: Mon Mar 10 17:26:26 2003 UTC (21 years, 1 month ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: rad3R5
Changes since 2.53: +1 -2 lines
Log Message:
Compile fixes for Linux

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 extern time_t time();
25
26 #include <signal.h>
27
28 #include "view.h"
29
30 #include "random.h"
31
32 #include "paths.h"
33
34 #define RFTEMPLATE "rfXXXXXX"
35
36 #ifndef SIGCONT
37 #define SIGCONT SIGIO
38 #endif
39
40 CUBE thescene; /* our scene */
41 OBJECT nsceneobjs; /* number of objects in our scene */
42
43 int dimlist[MAXDIM]; /* sampling dimensions */
44 int ndims = 0; /* number of sampling dimensions */
45 int samplendx; /* sample index number */
46
47 extern void ambnotify();
48 void (*addobjnotify[])() = {ambnotify, NULL};
49
50 VIEW ourview = STDVIEW; /* view parameters */
51 int hresolu = 512; /* horizontal resolution */
52 int vresolu = 512; /* vertical resolution */
53 double pixaspect = 1.0; /* pixel aspect ratio */
54
55 int psample = 4; /* pixel sample size */
56 double maxdiff = .05; /* max. difference for interpolation */
57 double dstrpix = 0.67; /* square pixel distribution */
58
59 double mblur = 0.; /* motion blur parameter */
60
61 void (*trace)() = NULL; /* trace call */
62
63 int do_irrad = 0; /* compute irradiance? */
64
65 double dstrsrc = 0.0; /* square source distribution */
66 double shadthresh = .05; /* shadow threshold */
67 double shadcert = .5; /* shadow certainty */
68 int directrelay = 1; /* number of source relays */
69 int vspretest = 512; /* virtual source pretest density */
70 int directvis = 1; /* sources visible? */
71 double srcsizerat = .25; /* maximum ratio source size/dist. */
72
73 COLOR cextinction = BLKCOLOR; /* global extinction coefficient */
74 COLOR salbedo = BLKCOLOR; /* global scattering albedo */
75 double seccg = 0.; /* global scattering eccentricity */
76 double ssampdist = 0.; /* scatter sampling distance */
77
78 double specthresh = .15; /* specular sampling threshold */
79 double specjitter = 1.; /* specular sampling jitter */
80
81 int backvis = 1; /* back face visibility */
82
83 int maxdepth = 6; /* maximum recursion depth */
84 double minweight = 5e-3; /* minimum ray weight */
85
86 char *ambfile = NULL; /* ambient file name */
87 COLOR ambval = BLKCOLOR; /* ambient value */
88 int ambvwt = 0; /* initial weight for ambient value */
89 double ambacc = 0.2; /* ambient accuracy */
90 int ambres = 32; /* ambient resolution */
91 int ambdiv = 128; /* ambient divisions */
92 int ambssamp = 0; /* ambient super-samples */
93 int ambounce = 0; /* ambient bounces */
94 char *amblist[128]; /* ambient include/exclude list */
95 int ambincl = -1; /* include == 1, exclude == 0 */
96
97 int ralrm = 0; /* seconds between reports */
98
99 double pctdone = 0.0; /* percentage done */
100 time_t tlastrept = 0L; /* time at last report */
101 time_t tstart; /* starting time */
102
103 #define MAXDIV 16 /* maximum sample size */
104
105 #define pixjitter() (.5+dstrpix*(.5-frandom()))
106
107 int hres, vres; /* resolution for this frame */
108
109 static VIEW lastview; /* the previous view input */
110
111 extern char *mktemp();
112
113 void report();
114
115 double pixvalue();
116
117 #ifdef NIX
118 #define file_exists(f) (access(f,F_OK)==0)
119 #else
120 #include <sys/types.h>
121 #include <sys/stat.h>
122 int
123 file_exists(fname) /* ordinary file exists? */
124 char *fname;
125 {
126 struct stat sbuf;
127 if (stat(fname, &sbuf) < 0) return(0);
128 return((sbuf.st_mode & S_IFREG) != 0);
129 }
130 #endif
131
132
133 void
134 quit(code) /* quit program */
135 int code;
136 {
137 if (code) /* report status */
138 report();
139 #ifndef NIX
140 headclean(); /* delete header file */
141 pfclean(); /* clean up persist files */
142 #endif
143 exit(code);
144 }
145
146
147 #ifndef NIX
148 void
149 report() /* report progress */
150 {
151 extern char *myhostname();
152 double u, s;
153 #ifdef BSD
154 struct rusage rubuf;
155 #else
156 struct tms tbuf;
157 double period;
158 #endif
159
160 tlastrept = time((time_t *)NULL);
161 #ifdef BSD
162 getrusage(RUSAGE_SELF, &rubuf);
163 u = rubuf.ru_utime.tv_sec + rubuf.ru_utime.tv_usec/1e6;
164 s = rubuf.ru_stime.tv_sec + rubuf.ru_stime.tv_usec/1e6;
165 getrusage(RUSAGE_CHILDREN, &rubuf);
166 u += rubuf.ru_utime.tv_sec + rubuf.ru_utime.tv_usec/1e6;
167 s += rubuf.ru_stime.tv_sec + rubuf.ru_stime.tv_usec/1e6;
168 #else
169 times(&tbuf);
170 #ifdef _SC_CLK_TCK
171 period = 1.0 / sysconf(_SC_CLK_TCK);
172 #else
173 period = 1.0 / 60.0;
174 #endif
175 u = ( tbuf.tms_utime + tbuf.tms_cutime ) * period;
176 s = ( tbuf.tms_stime + tbuf.tms_cstime ) * period;
177 #endif
178
179 sprintf(errmsg,
180 "%lu rays, %4.2f%% after %.3fu %.3fs %.3fr hours on %s\n",
181 nrays, pctdone, u/3600., s/3600.,
182 (tlastrept-tstart)/3600., myhostname());
183 eputs(errmsg);
184 #ifndef BSD
185 signal(SIGCONT, report);
186 #endif
187 }
188 #else
189 void
190 report() /* report progress */
191 {
192 tlastrept = time((time_t *)NULL);
193 sprintf(errmsg, "%lu rays, %4.2f%% after %5.4f hours\n",
194 nrays, pctdone, (tlastrept-tstart)/3600.0);
195 eputs(errmsg);
196 }
197 #endif
198
199
200 void
201 rpict(seq, pout, zout, prvr) /* generate image(s) */
202 int seq;
203 char *pout, *zout, *prvr;
204 /*
205 * If seq is greater than zero, then we will render a sequence of
206 * images based on view parameter strings read from the standard input.
207 * If pout is NULL, then all images will be sent to the standard ouput.
208 * If seq is greater than zero and prvr is an integer, then it is the
209 * frame number at which rendering should begin. Preceeding view parameter
210 * strings will be skipped in the input.
211 * If pout and prvr are the same, prvr is renamed to avoid overwriting.
212 * Note that pout and zout should contain %d format specifications for
213 * sequenced file naming.
214 */
215 {
216 char fbuf[128], fbuf2[128];
217 int npicts;
218 register char *cp;
219 RESOLU rs;
220 double pa;
221 /* check sampling */
222 if (psample < 1)
223 psample = 1;
224 else if (psample > MAXDIV) {
225 sprintf(errmsg, "pixel sampling reduced from %d to %d",
226 psample, MAXDIV);
227 error(WARNING, errmsg);
228 psample = MAXDIV;
229 }
230 /* get starting frame */
231 if (seq <= 0)
232 seq = 0;
233 else if (prvr != NULL && isint(prvr)) {
234 register int rn; /* skip to specified view */
235 if ((rn = atoi(prvr)) < seq)
236 error(USER, "recover frame less than start frame");
237 if (pout == NULL)
238 error(USER, "missing output file specification");
239 for ( ; seq < rn; seq++)
240 if (nextview(stdin) == EOF)
241 error(USER, "unexpected EOF on view input");
242 setview(&ourview);
243 prvr = fbuf; /* mark for renaming */
244 }
245 if (pout != NULL & prvr != NULL) {
246 sprintf(fbuf, pout, seq);
247 if (!strcmp(prvr, fbuf)) { /* rename */
248 strcpy(fbuf2, fbuf);
249 for (cp = fbuf2; *cp; cp++)
250 ;
251 while (cp > fbuf2 && !ISDIRSEP(cp[-1]))
252 cp--;
253 strcpy(cp, RFTEMPLATE);
254 prvr = mktemp(fbuf2);
255 if (rename(fbuf, prvr) < 0)
256 if (errno == ENOENT) { /* ghost file */
257 sprintf(errmsg,
258 "new output file \"%s\"",
259 fbuf);
260 error(WARNING, errmsg);
261 prvr = NULL;
262 } else { /* serious error */
263 sprintf(errmsg,
264 "cannot rename \"%s\" to \"%s\"",
265 fbuf, prvr);
266 error(SYSTEM, errmsg);
267 }
268 }
269 }
270 npicts = 0; /* render sequence */
271 do {
272 if (seq && nextview(stdin) == EOF)
273 break;
274 pctdone = 0.0;
275 if (pout != NULL) {
276 sprintf(fbuf, pout, seq);
277 if (file_exists(fbuf)) {
278 if (prvr != NULL || !strcmp(fbuf, pout)) {
279 sprintf(errmsg,
280 "output file \"%s\" exists",
281 fbuf);
282 error(USER, errmsg);
283 }
284 setview(&ourview);
285 continue; /* don't clobber */
286 }
287 if (freopen(fbuf, "w", stdout) == NULL) {
288 sprintf(errmsg,
289 "cannot open output file \"%s\"", fbuf);
290 error(SYSTEM, errmsg);
291 }
292 #ifdef MSDOS
293 setmode(fileno(stdout), O_BINARY);
294 #endif
295 dupheader();
296 }
297 hres = hresolu; vres = vresolu; pa = pixaspect;
298 if (prvr != NULL)
299 if (viewfile(prvr, &ourview, &rs) <= 0
300 || rs.rt != PIXSTANDARD) {
301 sprintf(errmsg,
302 "cannot recover view parameters from \"%s\"", prvr);
303 error(WARNING, errmsg);
304 } else {
305 pa = 0.0;
306 hres = scanlen(&rs);
307 vres = numscans(&rs);
308 }
309 if ((cp = setview(&ourview)) != NULL)
310 error(USER, cp);
311 normaspect(viewaspect(&ourview), &pa, &hres, &vres);
312 if (seq) {
313 if (ralrm > 0) {
314 fprintf(stderr, "FRAME %d:", seq);
315 fprintview(&ourview, stderr);
316 putc('\n', stderr);
317 fflush(stderr);
318 }
319 printf("FRAME=%d\n", seq);
320 }
321 fputs(VIEWSTR, stdout);
322 fprintview(&ourview, stdout);
323 putchar('\n');
324 if (pa < .99 || pa > 1.01)
325 fputaspect(pa, stdout);
326 fputformat(COLRFMT, stdout);
327 putchar('\n');
328 if (zout != NULL)
329 sprintf(cp=fbuf, zout, seq);
330 else
331 cp = NULL;
332 render(cp, prvr);
333 prvr = NULL;
334 npicts++;
335 } while (seq++);
336 /* check that we did something */
337 if (npicts == 0)
338 error(WARNING, "no output produced");
339 }
340
341
342 nextview(fp) /* get next view from fp */
343 FILE *fp;
344 {
345 char linebuf[256];
346
347 copystruct(&lastview, &ourview);
348 while (fgets(linebuf, sizeof(linebuf), fp) != NULL)
349 if (isview(linebuf) && sscanview(&ourview, linebuf) > 0)
350 return(0);
351 return(EOF);
352 }
353
354
355 render(zfile, oldfile) /* render the scene */
356 char *zfile, *oldfile;
357 {
358 COLOR *scanbar[MAXDIV+1]; /* scanline arrays of pixel values */
359 float *zbar[MAXDIV+1]; /* z values */
360 char *sampdens; /* previous sample density */
361 int ypos; /* current scanline */
362 int ystep; /* current y step size */
363 int hstep; /* h step size */
364 int zfd;
365 COLOR *colptr;
366 float *zptr;
367 register int i;
368 /* check for empty image */
369 if (hres <= 0 || vres <= 0) {
370 error(WARNING, "empty output picture");
371 fprtresolu(0, 0, stdout);
372 return;
373 }
374 /* allocate scanlines */
375 for (i = 0; i <= psample; i++) {
376 scanbar[i] = (COLOR *)malloc(hres*sizeof(COLOR));
377 if (scanbar[i] == NULL)
378 goto memerr;
379 }
380 hstep = (psample*140+49)/99; /* quincunx sampling */
381 ystep = (psample*99+70)/140;
382 if (hstep > 2) {
383 i = hres/hstep + 2;
384 if ((sampdens = (char *)malloc(i)) == NULL)
385 goto memerr;
386 while (i--)
387 sampdens[i] = hstep;
388 } else
389 sampdens = NULL;
390 /* open z-file */
391 if (zfile != NULL) {
392 if ((zfd = open(zfile, O_WRONLY|O_CREAT, 0666)) == -1) {
393 sprintf(errmsg, "cannot open z-file \"%s\"", zfile);
394 error(SYSTEM, errmsg);
395 }
396 #ifdef MSDOS
397 setmode(zfd, O_BINARY);
398 #endif
399 for (i = 0; i <= psample; i++) {
400 zbar[i] = (float *)malloc(hres*sizeof(float));
401 if (zbar[i] == NULL)
402 goto memerr;
403 }
404 } else {
405 zfd = -1;
406 for (i = 0; i <= psample; i++)
407 zbar[i] = NULL;
408 }
409 /* write out boundaries */
410 fprtresolu(hres, vres, stdout);
411 /* recover file and compute first */
412 i = salvage(oldfile);
413 if (i >= vres)
414 goto alldone;
415 if (zfd != -1 && i > 0 &&
416 lseek(zfd, (off_t)i*hres*sizeof(float), 0) < 0)
417 error(SYSTEM, "z-file seek error in render");
418 pctdone = 100.0*i/vres;
419 if (ralrm > 0) /* report init stats */
420 report();
421 #ifndef BSD
422 else
423 #endif
424 signal(SIGCONT, report);
425 ypos = vres-1 - i; /* initialize sampling */
426 if (directvis)
427 init_drawsources(psample);
428 fillscanline(scanbar[0], zbar[0], sampdens, hres, ypos, hstep);
429 /* compute scanlines */
430 for (ypos -= ystep; ypos > -ystep; ypos -= ystep) {
431 /* bottom adjust? */
432 if (ypos < 0) {
433 ystep += ypos;
434 ypos = 0;
435 }
436 colptr = scanbar[ystep]; /* move base to top */
437 scanbar[ystep] = scanbar[0];
438 scanbar[0] = colptr;
439 zptr = zbar[ystep];
440 zbar[ystep] = zbar[0];
441 zbar[0] = zptr;
442 /* fill base line */
443 fillscanline(scanbar[0], zbar[0], sampdens,
444 hres, ypos, hstep);
445 /* fill bar */
446 fillscanbar(scanbar, zbar, hres, ypos, ystep);
447 if (directvis) /* add bitty sources */
448 drawsources(scanbar, zbar, 0, hres, ypos, ystep);
449 /* write it out */
450 #ifndef BSD
451 signal(SIGCONT, SIG_IGN); /* don't interrupt writes */
452 #endif
453 for (i = ystep; i > 0; i--) {
454 if (zfd != -1 && write(zfd, (char *)zbar[i],
455 hres*sizeof(float))
456 < hres*sizeof(float))
457 goto writerr;
458 if (fwritescan(scanbar[i], hres, stdout) < 0)
459 goto writerr;
460 }
461 if (fflush(stdout) == EOF)
462 goto writerr;
463 /* record progress */
464 pctdone = 100.0*(vres-1-ypos)/vres;
465 if (ralrm > 0 && time((time_t *)NULL) >= tlastrept+ralrm)
466 report();
467 #ifndef BSD
468 else
469 signal(SIGCONT, report);
470 #endif
471 }
472 /* clean up */
473 signal(SIGCONT, SIG_IGN);
474 if (zfd != -1 && write(zfd, (char *)zbar[0], hres*sizeof(float))
475 < hres*sizeof(float))
476 goto writerr;
477 fwritescan(scanbar[0], hres, stdout);
478 if (fflush(stdout) == EOF)
479 goto writerr;
480 alldone:
481 if (zfd != -1) {
482 if (close(zfd) == -1)
483 goto writerr;
484 for (i = 0; i <= psample; i++)
485 free((void *)zbar[i]);
486 }
487 for (i = 0; i <= psample; i++)
488 free((void *)scanbar[i]);
489 if (sampdens != NULL)
490 free(sampdens);
491 pctdone = 100.0;
492 if (ralrm > 0)
493 report();
494 signal(SIGCONT, SIG_DFL);
495 return;
496 writerr:
497 error(SYSTEM, "write error in render");
498 memerr:
499 error(SYSTEM, "out of memory in render");
500 }
501
502
503 fillscanline(scanline, zline, sd, xres, y, xstep) /* fill scan at y */
504 register COLOR *scanline;
505 register float *zline;
506 register char *sd;
507 int xres, y, xstep;
508 {
509 static int nc = 0; /* number of calls */
510 int bl = xstep, b = xstep;
511 double z;
512 register int i;
513
514 z = pixvalue(scanline[0], 0, y);
515 if (zline) zline[0] = z;
516 /* zig-zag start for quincunx pattern */
517 for (i = ++nc & 1 ? xstep : xstep/2; i < xres-1+xstep; i += xstep) {
518 if (i >= xres) {
519 xstep += xres-1-i;
520 i = xres-1;
521 }
522 z = pixvalue(scanline[i], i, y);
523 if (zline) zline[i] = z;
524 if (sd) b = sd[0] > sd[1] ? sd[0] : sd[1];
525 if (i <= xstep)
526 b = fillsample(scanline, zline, 0, y, i, 0, b/2);
527 else
528 b = fillsample(scanline+i-xstep,
529 zline ? zline+i-xstep : (float *)NULL,
530 i-xstep, y, xstep, 0, b/2);
531 if (sd) *sd++ = nc & 1 ? bl : b;
532 bl = b;
533 }
534 if (sd && nc & 1) *sd = bl;
535 }
536
537
538 fillscanbar(scanbar, zbar, xres, y, ysize) /* fill interior */
539 register COLOR *scanbar[];
540 register float *zbar[];
541 int xres, y, ysize;
542 {
543 COLOR vline[MAXDIV+1];
544 float zline[MAXDIV+1];
545 int b = ysize;
546 register int i, j;
547
548 for (i = 0; i < xres; i++) {
549 copycolor(vline[0], scanbar[0][i]);
550 copycolor(vline[ysize], scanbar[ysize][i]);
551 if (zbar[0]) {
552 zline[0] = zbar[0][i];
553 zline[ysize] = zbar[ysize][i];
554 }
555 b = fillsample(vline, zbar[0] ? zline : (float *)NULL,
556 i, y, 0, ysize, b/2);
557
558 for (j = 1; j < ysize; j++)
559 copycolor(scanbar[j][i], vline[j]);
560 if (zbar[0])
561 for (j = 1; j < ysize; j++)
562 zbar[j][i] = zline[j];
563 }
564 }
565
566
567 int
568 fillsample(colline, zline, x, y, xlen, ylen, b) /* fill interior points */
569 register COLOR *colline;
570 register float *zline;
571 int x, y;
572 int xlen, ylen;
573 int b;
574 {
575 double ratio;
576 double z;
577 COLOR ctmp;
578 int ncut;
579 register int len;
580
581 if (xlen > 0) /* x or y length is zero */
582 len = xlen;
583 else
584 len = ylen;
585
586 if (len <= 1) /* limit recursion */
587 return(0);
588
589 if (b > 0 ||
590 (zline && 2.*fabs(zline[0]-zline[len]) > maxdiff*(zline[0]+zline[len]))
591 || bigdiff(colline[0], colline[len], maxdiff)) {
592
593 z = pixvalue(colline[len>>1], x + (xlen>>1), y + (ylen>>1));
594 if (zline) zline[len>>1] = z;
595 ncut = 1;
596 } else { /* interpolate */
597 copycolor(colline[len>>1], colline[len]);
598 ratio = (double)(len>>1) / len;
599 scalecolor(colline[len>>1], ratio);
600 if (zline) zline[len>>1] = zline[len] * ratio;
601 ratio = 1.0 - ratio;
602 copycolor(ctmp, colline[0]);
603 scalecolor(ctmp, ratio);
604 addcolor(colline[len>>1], ctmp);
605 if (zline) zline[len>>1] += zline[0] * ratio;
606 ncut = 0;
607 }
608 /* recurse */
609 ncut += fillsample(colline, zline, x, y, xlen>>1, ylen>>1, (b-1)/2);
610
611 ncut += fillsample(colline+(len>>1),
612 zline ? zline+(len>>1) : (float *)NULL,
613 x+(xlen>>1), y+(ylen>>1),
614 xlen-(xlen>>1), ylen-(ylen>>1), b/2);
615
616 return(ncut);
617 }
618
619
620 double
621 pixvalue(col, x, y) /* compute pixel value */
622 COLOR col; /* returned color */
623 int x, y; /* pixel position */
624 {
625 RAY thisray;
626 FVECT lorg, ldir;
627 double hpos, vpos, lmax, d;
628 /* compute view ray */
629 hpos = (x+pixjitter())/hres;
630 vpos = (y+pixjitter())/vres;
631 if ((thisray.rmax = viewray(thisray.rorg, thisray.rdir,
632 &ourview, hpos, vpos)) < -FTINY) {
633 setcolor(col, 0.0, 0.0, 0.0);
634 return(0.0);
635 }
636
637 samplendx = pixnumber(x,y,hres,vres); /* set pixel index */
638
639 /* optional motion blur */
640 if (lastview.type && mblur > FTINY && (lmax = viewray(lorg, ldir,
641 &lastview, hpos, vpos)) >= -FTINY) {
642 register int i;
643 register double d = mblur*(.5-urand(281+samplendx));
644
645 thisray.rmax = (1.-d)*thisray.rmax + d*lmax;
646 for (i = 3; i--; ) {
647 thisray.rorg[i] = (1.-d)*thisray.rorg[i] + d*lorg[i];
648 thisray.rdir[i] = (1.-d)*thisray.rdir[i] + d*ldir[i];
649 }
650 if (normalize(thisray.rdir) == 0.0)
651 return(0.0);
652 }
653
654 rayorigin(&thisray, NULL, PRIMARY, 1.0);
655
656 rayvalue(&thisray); /* trace ray */
657
658 copycolor(col, thisray.rcol); /* return color */
659
660 return(thisray.rt); /* return distance */
661 }
662
663
664 int
665 salvage(oldfile) /* salvage scanlines from killed program */
666 char *oldfile;
667 {
668 COLR *scanline;
669 FILE *fp;
670 int x, y;
671
672 if (oldfile == NULL)
673 goto gotzip;
674
675 if ((fp = fopen(oldfile, "r")) == NULL) {
676 sprintf(errmsg, "cannot open recover file \"%s\"", oldfile);
677 error(WARNING, errmsg);
678 goto gotzip;
679 }
680 #ifdef MSDOS
681 setmode(fileno(fp), O_BINARY);
682 #endif
683 /* discard header */
684 getheader(fp, NULL, NULL);
685 /* get picture size */
686 if (!fscnresolu(&x, &y, fp)) {
687 sprintf(errmsg, "bad recover file \"%s\" - not removed",
688 oldfile);
689 error(WARNING, errmsg);
690 fclose(fp);
691 goto gotzip;
692 }
693
694 if (x != hres || y != vres) {
695 sprintf(errmsg, "resolution mismatch in recover file \"%s\"",
696 oldfile);
697 error(USER, errmsg);
698 }
699
700 scanline = (COLR *)malloc(hres*sizeof(COLR));
701 if (scanline == NULL)
702 error(SYSTEM, "out of memory in salvage");
703 for (y = 0; y < vres; y++) {
704 if (freadcolrs(scanline, hres, fp) < 0)
705 break;
706 if (fwritecolrs(scanline, hres, stdout) < 0)
707 goto writerr;
708 }
709 if (fflush(stdout) == EOF)
710 goto writerr;
711 free((void *)scanline);
712 fclose(fp);
713 unlink(oldfile);
714 return(y);
715 gotzip:
716 if (fflush(stdout) == EOF)
717 error(SYSTEM, "error writing picture header");
718 return(0);
719 writerr:
720 sprintf(errmsg, "write error during recovery of \"%s\"", oldfile);
721 error(SYSTEM, errmsg);
722 }
723
724
725 int
726 pixnumber(x, y, xres, yres) /* compute pixel index (brushed) */
727 register int x, y;
728 int xres, yres;
729 {
730 x -= y;
731 while (x < 0)
732 x += xres;
733 return((((x>>2)*yres + y) << 2) + (x & 3));
734 }