src/rt/rc3.c

#ifndef lint
static const char RCSid[] = "$Id: rc3.c,v 2.3 2012/06/10 05:25:42 greg Exp $";
#endif
/*
 * Accumulate ray contributions for a set of materials
 * Controlling process for multiple children
 */

#include "rcontrib.h"
#include "platform.h"
#include "rtprocess.h"
#include "selcall.h"

/* Modifier contribution queue (results waiting to be output) */
typedef struct s_binq {
        int             ndx;            /* index for this entry */
        int             nadded;         /* accumulated so far */
        struct s_binq   *next;          /* next in queue */
        MODCONT         *mca[1];        /* contrib. array (extends struct) */
} BINQ;

static BINQ     *out_bq = NULL;         /* output bin queue */
static BINQ     *free_bq = NULL;        /* free queue entries */

static SUBPROC  kida[MAXPROCESS];       /* child processes */
static FILE     *inq_fp[MAXPROCESS];    /* input streams */


/* Get new bin queue entry */
static BINQ *
new_binq()
{
        BINQ    *bp;
        int     i;

        if (free_bq != NULL) {          /* something already available? */
                bp = free_bq;
                free_bq = bp->next;
                bp->next = NULL;
                bp->nadded = 1;
                return(bp);
        }
                                        /* else allocate fresh */
        bp = (BINQ *)malloc(sizeof(BINQ) + sizeof(MODCONT *)*(nmods-1));
        if (bp == NULL)
                goto memerr;
        for (i = nmods; i--; ) {
                MODCONT *mp = (MODCONT *)lu_find(&modconttab,modname[i])->data;
                bp->mca[i] = (MODCONT *)malloc(sizeof(MODCONT) +
                                                sizeof(DCOLOR)*(mp->nbins-1));
                if (bp->mca[i] == NULL)
                        goto memerr;
                memcpy(bp->mca[i], mp, sizeof(MODCONT)-sizeof(DCOLOR));
                /* memset(bp->mca[i]->cbin, 0, sizeof(DCOLOR)*mp->nbins); */
        }
        bp->ndx = 0;
        bp->nadded = 1;
        bp->next = NULL;
        return(bp);
memerr:
        error(SYSTEM, "out of memory in new_binq()");
        return(NULL);
}


/* Free a bin queue entry */
static void
free_binq(BINQ *bp)
{
        int     i;

        if (bp == NULL) {               /* signal to release our free list */
                while ((bp = free_bq) != NULL) {
                        free_bq = bp->next;
                        for (i = nmods; i--; )
                                free(bp->mca[i]);
                                /* Note: we don't own bp->mca[i]->binv */
                        free(bp);
                }
                return;
        }
                                        /* clear sums for next use */
/*      for (i = nmods; i--; )
                memset(bp->mca[i]->cbin, 0, sizeof(DCOLOR)*bp->mca[i]->nbins);
*/
        bp->ndx = 0;
        bp->next = free_bq;             /* push onto free list */
        free_bq = bp;
}


/* Add modifier values to accumulation record in queue and clear */
void
queue_modifiers()
{
        MODCONT *mpin, *mpout;
        int     i, j;

        if ((accumulate > 0) | (out_bq == NULL))
                error(CONSISTENCY, "bad call to queue_modifiers()");

        for (i = nmods; i--; ) {
                mpin = (MODCONT *)lu_find(&modconttab,modname[i])->data;
                mpout = out_bq->mca[i];
                for (j = mpout->nbins; j--; )
                        addcolor(mpout->cbin[j], mpin->cbin[j]);
                memset(mpin->cbin, 0, sizeof(DCOLOR)*mpin->nbins);
        }
}


/* Sum one modifier record into another (updates nadded) */
static void
add_modbin(BINQ *dst, BINQ *src)
{
        int     i, j;
        
        for (i = nmods; i--; ) {
                MODCONT *mpin = src->mca[i];
                MODCONT *mpout = dst->mca[i];
                for (j = mpout->nbins; j--; )
                        addcolor(mpout->cbin[j], mpin->cbin[j]);
        }
        dst->nadded += src->nadded;
}


/* Queue values for later output */
static void
queue_output(BINQ *bp)
{
        BINQ    *b_last, *b_cur;

        if (accumulate <= 0) {          /* just accumulating? */
                if (out_bq == NULL) {
                        bp->next = NULL;
                        out_bq = bp;
                } else {
                        add_modbin(out_bq, bp);
                        free_binq(bp);
                }
                return;
        }
        b_last = NULL;                  /* else insert in output queue */
        for (b_cur = out_bq; b_cur != NULL && b_cur->ndx < bp->ndx;
                                b_cur = b_cur->next)
                b_last = b_cur;

        if (b_last != NULL) {
                bp->next = b_cur;
                b_last->next = bp;
        } else {
                bp->next = out_bq;
                out_bq = bp;
        }
        if (accumulate == 1)            /* no accumulation? */
                return;
        b_cur = out_bq;                 /* else merge accumulation entries */
        while (b_cur->next != NULL) {
                if (b_cur->nadded >= accumulate ||
                                (b_cur->ndx-1)/accumulate !=
                                (b_cur->next->ndx-1)/accumulate) {
                        b_cur = b_cur->next;
                        continue;
                }
                add_modbin(b_cur, b_cur->next);
                b_last = b_cur->next;
                b_cur->next = b_last->next;
                b_last->next = NULL;
                free_binq(b_last);
        }
}


/* Count number of records ready for output */
static int
queue_ready()
{
        int     nready = 0;
        BINQ    *bp;

        if (accumulate <= 0)            /* just accumulating? */
                return(0);

        for (bp = out_bq; bp != NULL && bp->nadded >= accumulate &&
                                bp->ndx == lastdone+nready*accumulate+1;
                                bp = bp->next)
                ++nready;

        return(nready);
}


/* Catch up with output queue by producing ready results */
static int
output_catchup(int nmax)
{
        int     nout = 0;
        BINQ    *bp;
        int     i;

        if (accumulate <= 0)            /* just accumulating? */
                return(0);
                                        /* else output ready results */
        while (out_bq != NULL && out_bq->nadded >= accumulate
                                && out_bq->ndx == lastdone+1) {
                if ((nmax > 0) & (nout >= nmax))
                        break;
                bp = out_bq;                    /* pop off first entry */
                out_bq = bp->next;
                bp->next = NULL;
                for (i = 0; i < nmods; i++)     /* output record */
                        mod_output(bp->mca[i]);
                end_record();
                free_binq(bp);                  /* free this entry */
                lastdone += accumulate;
                ++nout;
        }
        return(nout);
}


/* Put a zero record in results queue & output */
void
put_zero_record(int ndx)
{
        BINQ    *bp = new_binq();
        int     i;

        for (i = nmods; i--; )
                memset(bp->mca[i]->cbin, 0, sizeof(DCOLOR)*bp->mca[i]->nbins);
        bp->ndx = ndx;
        queue_output(bp);
        output_catchup(0);
}


/* callback to set output spec to NULL (stdout) */
static int
set_stdout(const LUENT *le, void *p)
{
        (*(MODCONT *)le->data).outspec = NULL;
        return(0);
}


/* Start child processes if we can */
int
in_rchild()
{
#ifdef _WIN32
        error(WARNING, "multiprocessing unsupported -- running solo");
        nproc = 1;
        return(1);
#else
                                        /* try to fork ourselves */
        while (nchild < nproc) {
                int     p0[2], p1[2];
                int     pid;
                                        /* prepare i/o pipes */
                errno = 0;
                if (pipe(p0) < 0 || pipe(p1) < 0)
                        error(SYSTEM, "pipe() call failed!");
                pid = fork();           /* fork parent process */
                if (pid == 0) {         /* if in child, set up & return true */
                        close(p0[1]); close(p1[0]);
                        lu_doall(&modconttab, set_stdout, NULL);
                        lu_done(&ofiletab);
                        while (nchild--) {
                                close(kida[nchild].w);
                                fclose(inq_fp[nchild]);
                        }
                        dup2(p0[0], 0); close(p0[0]);
                        dup2(p1[1], 1); close(p1[1]);
                        inpfmt = (sizeof(RREAL)==sizeof(double)) ? 'd' : 'f';
                        outfmt = 'd';
                        header = 0;
                        waitflush = xres = 1;
                        yres = 0;
                        raysleft = 0;
                        account = accumulate = 1;
                        return(1);      /* child return value */
                }
                if (pid < 0)
                        error(SYSTEM, "fork() call failed!");
                                        /* connect parent's pipes */
                close(p0[0]); close(p1[1]);
                kida[nchild].r = p1[0];
                kida[nchild].w = p0[1];
                kida[nchild].pid = pid;
                kida[nchild].running = -1;
                inq_fp[nchild] = fdopen(p1[0], "rb");
                if (inq_fp[nchild] == NULL)
                        error(SYSTEM, "out of memory in in_rchild()");
#ifdef getc_unlocked
                flockfile(inq_fp[nchild]);      /* avoid mutex overhead */
#endif
                ++nchild;
        }
        return(0);                      /* parent return value */
#endif
}


/* Close child processes */
void
end_children()
{
        int     status;
        
        while (nchild-- > 0) {
                kida[nchild].r = -1;    /* close(-1) error is ignored */
                if ((status = close_process(&kida[nchild])) > 0) {
                        sprintf(errmsg,
                                "rendering process returned bad status (%d)",
                                        status);
                        error(WARNING, errmsg);
                }
                fclose(inq_fp[nchild]); /* performs actual close() */
        }
}


/* Wait for the next available child, managing output queue as well */
static int
next_child_nq(int force_wait)
{
        static struct timeval   polling;
        struct timeval          *pmode;
        fd_set                  readset, errset;
        int                     i, j, n, nr, nqr;

        if (!force_wait)                /* see if there's one free */
                for (i = nchild; i--; )
                        if (kida[i].running < 0)
                                return(i);

        nqr = queue_ready();            /* wait mode or polling? */
        if (!nqr | force_wait | (accumulate <= 0))
                pmode = NULL;
        else
                pmode = &polling;
tryagain:
        n = 0;                          /* catch up with output? */
        if ((pmode == &polling) & (nqr > nchild))
                n = nqr - nchild;
        if ((pmode == NULL) & (nqr > 0) | (n > 0))
                nqr -= output_catchup(n);
                                        /* prepare select() call */
        FD_ZERO(&readset); FD_ZERO(&errset);
        n = nr = 0;
        for (i = nchild; i--; ) {
                if (kida[i].running > 0) {
                        FD_SET(kida[i].r, &readset);
                        ++nr;
                }
                FD_SET(kida[i].r, &errset);
                if (kida[i].r >= n)
                        n = kida[i].r + 1;
        }
        if (!nr)                        /* nothing to wait for? */
                return(-1);
        if ((nr > 1) | (pmode == &polling)) {
                errno = 0;
                i = select(n, &readset, NULL, &errset, pmode);
                if (!i) {
                        pmode = NULL;   /* try again, blocking this time */
                        goto tryagain;
                }
                if (i < 0)
                        error(SYSTEM, "select() error in next_child_nq()");
        } else
                FD_ZERO(&errset);
        n = -1;                         /* read results from child(ren) */
        for (i = nchild; i--; ) {
                BINQ    *bq;
                if (FD_ISSET(kida[i].r, &errset))
                        error(USER, "rendering process died");
                if (!FD_ISSET(kida[i].r, &readset))
                        continue;
                bq = new_binq();        /* get results holder */
                bq->ndx = kida[i].running;
                                        /* read from child */
                for (j = 0; j < nmods; j++) {
                        nr = bq->mca[j]->nbins;
                        if (fread(bq->mca[j]->cbin, sizeof(DCOLOR), nr,
                                                        inq_fp[i]) != nr)
                                error(SYSTEM, "read error from render process");
                }
                queue_output(bq);       /* add results to output queue */
                kida[i].running = -1;   /* mark child as available */
                n = i;
        }
        return(n);                      /* first available child */
}


/* Run parental oversight loop */
void
parental_loop()
{
        static int      ignore_warning_given = 0;
        FVECT           orgdir[2];
        double          d;
        int             i;
                                        /* load rays from stdin & process */
#ifdef getc_unlocked
        flockfile(stdin);               /* avoid lock/unlock overhead */
#endif
        while (getvec(orgdir[0]) == 0 && getvec(orgdir[1]) == 0) {
                d = normalize(orgdir[1]);
                                                        /* asking for flush? */
                if ((d == 0.0) & (accumulate != 1)) {
                        if (!ignore_warning_given++)
                                error(WARNING,
                                "dummy ray(s) ignored during accumulation\n");
                        continue;
                }
                if ((d == 0.0) | (lastray+1 < lastray)) {
                        while (next_child_nq(1) >= 0)
                                ;                       /* clear the queue */
                        lastdone = lastray = 0;
                }
                if (d == 0.0) {
                        if ((yres <= 0) | (xres <= 0))
                                waitflush = 1;          /* flush right after */
                        put_zero_record(++lastray);
                } else {                                /* else assign ray */
                        i = next_child_nq(0);
                        if (writebuf(kida[i].w, (char *)orgdir,
                                        sizeof(orgdir)) != sizeof(orgdir))
                                error(SYSTEM, "pipe write error");
                        kida[i].running = ++lastray;
                }
                if (raysleft && !--raysleft)
                        break;                          /* preemptive EOI */
        }
        while (next_child_nq(1) >= 0)           /* empty results queue */
                ;
                                                /* output accumulated record */
        if (accumulate <= 0 || account < accumulate) {
                if (account < accumulate) {
                        error(WARNING, "partial accumulation in final record");
                        accumulate -= account;
                }
                for (i = 0; i < nmods; i++)
                        mod_output(out_bq->mca[i]);
                end_record();
                free_binq(out_bq);
                out_bq = NULL;
        }
        if (raysleft)
                error(USER, "unexpected EOF on input");
        free_binq(NULL);                        /* clean up */
        lu_done(&ofiletab);
}
Revision:	2.4
Committed:	Mon Jun 11 05:07:55 2012 UTC (11 years, 10 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.3:	+59 -23 lines
Log Message:	Fixed a number of bugs -- still testing
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.4	static const char RCSid[] = "$Id: rc3.c,v 2.3 2012/06/10 05:25:42 greg Exp $";
3	greg	2.1	#endif
4			/*
5			* Accumulate ray contributions for a set of materials
6			* Controlling process for multiple children
7			*/
8
9			#include "rcontrib.h"
10			#include "platform.h"
11			#include "rtprocess.h"
12			#include "selcall.h"
13
14			/* Modifier contribution queue (results waiting to be output) */
15			typedef struct s_binq {
16			int ndx; /* index for this entry */
17	greg	2.4	int nadded; /* accumulated so far */
18	greg	2.1	struct s_binq next; / next in queue */
19			MODCONT mca[1]; / contrib. array (extends struct) */
20			} BINQ;
21
22			static BINQ out_bq = NULL; / output bin queue */
23			static BINQ free_bq = NULL; / free queue entries */
24
25			static SUBPROC kida[MAXPROCESS]; /* child processes */
26	greg	2.2	static FILE inq_fp[MAXPROCESS]; / input streams */
27	greg	2.1
28
29	greg	2.4	/* Get new bin queue entry */
30	greg	2.1	static BINQ *
31			new_binq()
32			{
33	greg	2.4	BINQ *bp;
34	greg	2.1	int i;
35
36	greg	2.4	if (free_bq != NULL) { /* something already available? */
37			bp = free_bq;
38	greg	2.1	free_bq = bp->next;
39			bp->next = NULL;
40	greg	2.4	bp->nadded = 1;
41	greg	2.1	return(bp);
42			}
43			/* else allocate fresh */
44	greg	2.4	bp = (BINQ )malloc(sizeof(BINQ) + sizeof(MODCONT )*(nmods-1));
45	greg	2.1	if (bp == NULL)
46			goto memerr;
47			for (i = nmods; i--; ) {
48			MODCONT mp = (MODCONT )lu_find(&modconttab,modname[i])->data;
49			bp->mca[i] = (MODCONT *)malloc(sizeof(MODCONT) +
50			sizeof(DCOLOR)*(mp->nbins-1));
51			if (bp->mca[i] == NULL)
52			goto memerr;
53			memcpy(bp->mca[i], mp, sizeof(MODCONT)-sizeof(DCOLOR));
54			/* memset(bp->mca[i]->cbin, 0, sizeof(DCOLOR)mp->nbins); /
55			}
56			bp->ndx = 0;
57	greg	2.4	bp->nadded = 1;
58	greg	2.1	bp->next = NULL;
59			return(bp);
60			memerr:
61			error(SYSTEM, "out of memory in new_binq()");
62			return(NULL);
63			}
64
65
66			/* Free a bin queue entry */
67			static void
68			free_binq(BINQ *bp)
69			{
70			int i;
71
72			if (bp == NULL) { /* signal to release our free list */
73			while ((bp = free_bq) != NULL) {
74			free_bq = bp->next;
75			for (i = nmods; i--; )
76			free(bp->mca[i]);
77			/* Note: we don't own bp->mca[i]->binv */
78			free(bp);
79			}
80			return;
81			}
82			/* clear sums for next use */
83			/* for (i = nmods; i--; )
84			memset(bp->mca[i]->cbin, 0, sizeof(DCOLOR)*bp->mca[i]->nbins);
85			*/
86			bp->ndx = 0;
87			bp->next = free_bq; /* push onto free list */
88			free_bq = bp;
89			}
90
91
92			/* Add modifier values to accumulation record in queue and clear */
93			void
94			queue_modifiers()
95			{
96			MODCONT mpin, mpout;
97			int i, j;
98
99			if ((accumulate > 0) \| (out_bq == NULL))
100			error(CONSISTENCY, "bad call to queue_modifiers()");
101
102			for (i = nmods; i--; ) {
103			mpin = (MODCONT *)lu_find(&modconttab,modname[i])->data;
104			mpout = out_bq->mca[i];
105			for (j = mpout->nbins; j--; )
106			addcolor(mpout->cbin[j], mpin->cbin[j]);
107			memset(mpin->cbin, 0, sizeof(DCOLOR)*mpin->nbins);
108			}
109			}
110
111
112	greg	2.4	/* Sum one modifier record into another (updates nadded) */
113	greg	2.1	static void
114			add_modbin(BINQ dst, BINQ src)
115			{
116			int i, j;
117
118			for (i = nmods; i--; ) {
119			MODCONT *mpin = src->mca[i];
120			MODCONT *mpout = dst->mca[i];
121			for (j = mpout->nbins; j--; )
122			addcolor(mpout->cbin[j], mpin->cbin[j]);
123			}
124	greg	2.4	dst->nadded += src->nadded;
125	greg	2.1	}
126
127
128	greg	2.2	/* Queue values for later output */
129			static void
130	greg	2.1	queue_output(BINQ *bp)
131			{
132			BINQ b_last, b_cur;
133
134			if (accumulate <= 0) { /* just accumulating? */
135			if (out_bq == NULL) {
136			bp->next = NULL;
137			out_bq = bp;
138			} else {
139			add_modbin(out_bq, bp);
140			free_binq(bp);
141			}
142	greg	2.2	return;
143	greg	2.1	}
144			b_last = NULL; /* else insert in output queue */
145			for (b_cur = out_bq; b_cur != NULL && b_cur->ndx < bp->ndx;
146			b_cur = b_cur->next)
147			b_last = b_cur;
148	greg	2.4
149	greg	2.1	if (b_last != NULL) {
150			bp->next = b_cur;
151			b_last->next = bp;
152			} else {
153			bp->next = out_bq;
154			out_bq = bp;
155			}
156	greg	2.3	if (accumulate == 1) /* no accumulation? */
157	greg	2.2	return;
158			b_cur = out_bq; /* else merge accumulation entries */
159			while (b_cur->next != NULL) {
160	greg	2.4	if (b_cur->nadded >= accumulate \|\|
161	greg	2.2	(b_cur->ndx-1)/accumulate !=
162			(b_cur->next->ndx-1)/accumulate) {
163			b_cur = b_cur->next;
164			continue;
165	greg	2.1	}
166	greg	2.2	add_modbin(b_cur, b_cur->next);
167			b_last = b_cur->next;
168			b_cur->next = b_last->next;
169			b_last->next = NULL;
170			free_binq(b_last);
171	greg	2.1	}
172	greg	2.2	}
173
174
175	greg	2.4	/* Count number of records ready for output */
176			static int
177			queue_ready()
178			{
179			int nready = 0;
180			BINQ *bp;
181
182			if (accumulate <= 0) /* just accumulating? */
183			return(0);
184
185			for (bp = out_bq; bp != NULL && bp->nadded >= accumulate &&
186			bp->ndx == lastdone+nready*accumulate+1;
187			bp = bp->next)
188			++nready;
189
190			return(nready);
191			}
192
193
194			/* Catch up with output queue by producing ready results */
195	greg	2.2	static int
196	greg	2.4	output_catchup(int nmax)
197	greg	2.2	{
198			int nout = 0;
199			BINQ *bp;
200			int i;
201
202			if (accumulate <= 0) /* just accumulating? */
203			return(0);
204			/* else output ready results */
205	greg	2.4	while (out_bq != NULL && out_bq->nadded >= accumulate
206			&& out_bq->ndx == lastdone+1) {
207			if ((nmax > 0) & (nout >= nmax))
208			break;
209	greg	2.2	bp = out_bq; /* pop off first entry */
210			out_bq = bp->next;
211			bp->next = NULL;
212	greg	2.1	for (i = 0; i < nmods; i++) /* output record */
213	greg	2.2	mod_output(bp->mca[i]);
214	greg	2.1	end_record();
215	greg	2.2	free_binq(bp); /* free this entry */
216	greg	2.1	lastdone += accumulate;
217			++nout;
218			}
219			return(nout);
220			}
221
222
223	greg	2.3	/* Put a zero record in results queue & output */
224	greg	2.1	void
225	greg	2.3	put_zero_record(int ndx)
226	greg	2.1	{
227			BINQ *bp = new_binq();
228			int i;
229
230			for (i = nmods; i--; )
231			memset(bp->mca[i]->cbin, 0, sizeof(DCOLOR)*bp->mca[i]->nbins);
232			bp->ndx = ndx;
233			queue_output(bp);
234	greg	2.4	output_catchup(0);
235	greg	2.1	}
236
237
238			/* callback to set output spec to NULL (stdout) */
239			static int
240			set_stdout(const LUENT le, void p)
241			{
242			((MODCONT )le->data).outspec = NULL;
243			return(0);
244			}
245
246
247			/* Start child processes if we can */
248			int
249			in_rchild()
250			{
251			#ifdef _WIN32
252			error(WARNING, "multiprocessing unsupported -- running solo");
253			nproc = 1;
254			return(1);
255			#else
256			/* try to fork ourselves */
257			while (nchild < nproc) {
258			int p0[2], p1[2];
259			int pid;
260			/* prepare i/o pipes */
261	greg	2.3	errno = 0;
262	greg	2.1	if (pipe(p0) < 0 \|\| pipe(p1) < 0)
263			error(SYSTEM, "pipe() call failed!");
264			pid = fork(); /* fork parent process */
265			if (pid == 0) { /* if in child, set up & return true */
266			close(p0[1]); close(p1[0]);
267	greg	2.4	lu_doall(&modconttab, set_stdout, NULL);
268			lu_done(&ofiletab);
269			while (nchild--) {
270			close(kida[nchild].w);
271			fclose(inq_fp[nchild]);
272			}
273	greg	2.1	dup2(p0[0], 0); close(p0[0]);
274			dup2(p1[1], 1); close(p1[1]);
275			inpfmt = (sizeof(RREAL)==sizeof(double)) ? 'd' : 'f';
276			outfmt = 'd';
277			header = 0;
278			waitflush = xres = 1;
279			yres = 0;
280			raysleft = 0;
281			account = accumulate = 1;
282			return(1); /* child return value */
283			}
284			if (pid < 0)
285			error(SYSTEM, "fork() call failed!");
286	greg	2.3	/* connect parent's pipes */
287	greg	2.1	close(p0[0]); close(p1[1]);
288			kida[nchild].r = p1[0];
289			kida[nchild].w = p0[1];
290			kida[nchild].pid = pid;
291			kida[nchild].running = -1;
292	greg	2.2	inq_fp[nchild] = fdopen(p1[0], "rb");
293			if (inq_fp[nchild] == NULL)
294			error(SYSTEM, "out of memory in in_rchild()");
295	greg	2.3	#ifdef getc_unlocked
296			flockfile(inq_fp[nchild]); /* avoid mutex overhead */
297			#endif
298	greg	2.1	++nchild;
299			}
300			return(0); /* parent return value */
301			#endif
302			}
303
304
305			/* Close child processes */
306			void
307			end_children()
308			{
309			int status;
310
311	greg	2.2	while (nchild-- > 0) {
312			kida[nchild].r = -1; /* close(-1) error is ignored */
313	greg	2.1	if ((status = close_process(&kida[nchild])) > 0) {
314			sprintf(errmsg,
315			"rendering process returned bad status (%d)",
316			status);
317			error(WARNING, errmsg);
318			}
319	greg	2.2	fclose(inq_fp[nchild]); /* performs actual close() */
320			}
321	greg	2.1	}
322
323
324	greg	2.2	/* Wait for the next available child, managing output queue as well */
325	greg	2.1	static int
326			next_child_nq(int force_wait)
327			{
328	greg	2.2	static struct timeval polling;
329	greg	2.4	struct timeval *pmode;
330	greg	2.2	fd_set readset, errset;
331	greg	2.4	int i, j, n, nr, nqr;
332	greg	2.1
333			if (!force_wait) /* see if there's one free */
334			for (i = nchild; i--; )
335			if (kida[i].running < 0)
336			return(i);
337	greg	2.4
338			nqr = queue_ready(); /* wait mode or polling? */
339			if (!nqr \| force_wait \| (accumulate <= 0))
340			pmode = NULL;
341			else
342			pmode = &polling;
343			tryagain:
344			n = 0; /* catch up with output? */
345			if ((pmode == &polling) & (nqr > nchild))
346			n = nqr - nchild;
347			if ((pmode == NULL) & (nqr > 0) \| (n > 0))
348			nqr -= output_catchup(n);
349	greg	2.1	/* prepare select() call */
350			FD_ZERO(&readset); FD_ZERO(&errset);
351			n = nr = 0;
352			for (i = nchild; i--; ) {
353			if (kida[i].running > 0) {
354			FD_SET(kida[i].r, &readset);
355			++nr;
356			}
357			FD_SET(kida[i].r, &errset);
358			if (kida[i].r >= n)
359			n = kida[i].r + 1;
360			}
361	greg	2.3	if (!nr) /* nothing to wait for? */
362			return(-1);
363	greg	2.2	if ((nr > 1) \| (pmode == &polling)) {
364	greg	2.1	errno = 0;
365	greg	2.3	i = select(n, &readset, NULL, &errset, pmode);
366			if (!i) {
367	greg	2.2	pmode = NULL; /* try again, blocking this time */
368			goto tryagain;
369			}
370	greg	2.3	if (i < 0)
371			error(SYSTEM, "select() error in next_child_nq()");
372	greg	2.1	} else
373			FD_ZERO(&errset);
374			n = -1; /* read results from child(ren) */
375			for (i = nchild; i--; ) {
376			BINQ *bq;
377			if (FD_ISSET(kida[i].r, &errset))
378			error(USER, "rendering process died");
379			if (!FD_ISSET(kida[i].r, &readset))
380			continue;
381			bq = new_binq(); /* get results holder */
382			bq->ndx = kida[i].running;
383			/* read from child */
384			for (j = 0; j < nmods; j++) {
385	greg	2.3	nr = bq->mca[j]->nbins;
386			if (fread(bq->mca[j]->cbin, sizeof(DCOLOR), nr,
387			inq_fp[i]) != nr)
388	greg	2.1	error(SYSTEM, "read error from render process");
389			}
390	greg	2.3	queue_output(bq); /* add results to output queue */
391	greg	2.1	kida[i].running = -1; /* mark child as available */
392			n = i;
393			}
394	greg	2.3	return(n); /* first available child */
395	greg	2.1	}
396
397
398			/* Run parental oversight loop */
399			void
400			parental_loop()
401			{
402			static int ignore_warning_given = 0;
403			FVECT orgdir[2];
404			double d;
405	greg	2.3	int i;
406	greg	2.1	/* load rays from stdin & process */
407			#ifdef getc_unlocked
408			flockfile(stdin); /* avoid lock/unlock overhead */
409			#endif
410			while (getvec(orgdir[0]) == 0 && getvec(orgdir[1]) == 0) {
411			d = normalize(orgdir[1]);
412			/* asking for flush? */
413			if ((d == 0.0) & (accumulate != 1)) {
414			if (!ignore_warning_given++)
415			error(WARNING,
416			"dummy ray(s) ignored during accumulation\n");
417			continue;
418			}
419			if ((d == 0.0) \| (lastray+1 < lastray)) {
420			while (next_child_nq(1) >= 0)
421	greg	2.3	; /* clear the queue */
422	greg	2.1	lastdone = lastray = 0;
423			}
424			if (d == 0.0) {
425			if ((yres <= 0) \| (xres <= 0))
426			waitflush = 1; /* flush right after */
427	greg	2.3	put_zero_record(++lastray);
428			} else { /* else assign ray */
429			i = next_child_nq(0);
430			if (writebuf(kida[i].w, (char *)orgdir,
431			sizeof(orgdir)) != sizeof(orgdir))
432	greg	2.1	error(SYSTEM, "pipe write error");
433	greg	2.3	kida[i].running = ++lastray;
434	greg	2.1	}
435			if (raysleft && !--raysleft)
436			break; /* preemptive EOI */
437			}
438			while (next_child_nq(1) >= 0) /* empty results queue */
439			;
440			/* output accumulated record */
441			if (accumulate <= 0 \|\| account < accumulate) {
442			if (account < accumulate) {
443			error(WARNING, "partial accumulation in final record");
444			accumulate -= account;
445			}
446			for (i = 0; i < nmods; i++)
447			mod_output(out_bq->mca[i]);
448			end_record();
449	greg	2.3	free_binq(out_bq);
450			out_bq = NULL;
451	greg	2.1	}
452			if (raysleft)
453			error(USER, "unexpected EOF on input");
454			free_binq(NULL); /* clean up */
455			lu_done(&ofiletab);
456			}