src/rt/raypcalls.c

#ifndef lint
static const char       RCSid[] = "$Id$";
#endif
/*
 *  raypcalls.c - interface for parallel rendering using Radiance
 *
 *  External symbols declared in ray.h
 */

/* ====================================================================
 * The Radiance Software License, Version 1.0
 *
 * Copyright (c) 1990 - 2002 The Regents of the University of California,
 * through Lawrence Berkeley National Laboratory.   All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *         notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *           if any, must include the following acknowledgment:
 *             "This product includes Radiance software
 *                 (http://radsite.lbl.gov/)
 *                 developed by the Lawrence Berkeley National Laboratory
 *               (http://www.lbl.gov/)."
 *       Alternately, this acknowledgment may appear in the software itself,
 *       if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
 *       and "The Regents of the University of California" must
 *       not be used to endorse or promote products derived from this
 *       software without prior written permission. For written
 *       permission, please contact [email protected].
 *
 * 5. Products derived from this software may not be called "Radiance",
 *       nor may "Radiance" appear in their name, without prior written
 *       permission of Lawrence Berkeley National Laboratory.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.   IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Lawrence Berkeley National Laboratory.   For more
 * information on Lawrence Berkeley National Laboratory, please see
 * <http://www.lbl.gov/>.
 */

/*
 *  These calls are designed similarly to the ones in raycalls.c,
 *  but allow for multiple rendering processes on the same host
 *  machine.  There is no sense in specifying more child processes
 *  than you have processors, but one child may help by allowing
 *  asynchronous ray computation in an interactive program, and
 *  will protect the caller from fatal rendering errors.
 *
 *  You should first read and undrstand the header in raycalls.c,
 *  as some things are explained there that are not repated here.
 *
 *  The first step is opening one or more rendering processes
 *  with a call to ray_pinit(oct, nproc).  Before calling fork(),
 *  ray_pinit() loads the octree and data structures into the
 *  caller's memory.  This permits all sorts of queries that
 *  wouldn't be possible otherwise, without causing any real
 *  memory overhead, since all the static data are shared
 *  between processes.  Rays are then traced using a simple
 *  queuing mechanism, explained below.
 *
 *  The ray queue holds as many rays as there are rendering
 *  processes.  Rays are queued and returned by a single
 *  ray_pqueue() call.  A ray_pqueue() return
 *  value of 0 indicates that no rays are ready
 *  and the queue is not yet full.  A return value of 1
 *  indicates that a ray was returned, though it is probably
 *  not the one you just requested.  Rays may be identified by
 *  the rno member of the RAY struct, which is incremented
 *  by the rayorigin() call, or may be set explicitly by
 *  the caller.  Below is an example call sequence:
 *
 *      myRay.rorg = ( ray origin point )
 *      myRay.rdir = ( normalized ray direction )
 *      myRay.rmax = ( maximum length, or zero for no limit )
 *      rayorigin(&myRay, NULL, PRIMARY, 1.0);
 *      myRay.rno = ( my personal ray identifier )
 *      if (ray_pqueue(&myRay) == 1)
 *              { do something with results }
 *
 *  Note the differences between this and the simpler ray_trace()
 *  call.  In particular, the call may or may not return a value
 *  in the passed ray structure.  Also, you need to call rayorigin()
 *  yourself, which is normally for you by ray_trace().  The
 *  great thing is that ray_pqueue() will trace rays faster in
 *  proportion to the number of CPUs you have available on your
 *  system.  If the ray queue is full before the call, ray_pqueue()
 *  will block until a result is ready so it can queue this one.
 *  The global int ray_idle indicates the number of currently idle
 *  children.  If you want to check for completed rays without blocking,
 *  or get the results from rays that have been queued without
 *  queuing any new ones, the ray_presult() call is for you:
 *
 *      if (ray_presult(&myRay, 1) == 1)
 *              { do something with results }
 *
 *  If the second argument is 1, the call won't block when
 *  results aren't ready, but will immediately return 0.
 *  If the second argument is 0, the call will block
 *  until a value is available, returning 0 only if the
 *  queue is completely empty.  A negative return value
 *  indicates that a rendering process died.  If this
 *  happens, ray_close(0) is automatically called to close
 *  all child processes, and ray_nprocs is set to zero.
 *
 *  If you just want to fill the ray queue without checking for
 *  results, check ray_idle and call ray_psend():
 *
 *      while (ray_idle) {
 *              ( set up ray )
 *              ray_psend(&myRay);
 *      }
 *
 *  The ray_presult() and/or ray_pqueue() functions may then be
 *  called to read back the results.
 *
 *  When you are done, you may call ray_pdone(1) to close
 *  all child processes and clean up memory used by Radiance.
 *  Any queued ray calculations will be awaited and discarded.
 *  As with ray_done(), ray_pdone(0) hangs onto data files
 *  and fonts that are likely to be used in subsequent renderings.
 *  Whether you want to bother cleaning up memory or not, you
 *  should at least call ray_pclose(0) to clean the child processes.
 *
 *  Warning:  You cannot affect any of the rendering processes
 *  by changing global parameter values onece ray_pinit() has
 *  been called.  Changing global parameters will have no effect
 *  until the next call to ray_pinit(), which restarts everything.
 *  If you just want to reap children so that you can alter the
 *  rendering parameters without reloading the scene, use the
 *  ray_pclose(0) and ray_popen(nproc) calls to close
 *  then restart the child processes.
 *
 *  Note:  These routines are written to coordinate with the
 *  definitions in raycalls.c, and in fact depend on them.
 *  If you want to trace a ray and get a result synchronously,
 *  use the ray_trace() call to compute it in the parent process.
 *
 *  Note:  One of the advantages of using separate processes
 *  is that it gives the calling program some immunity from
 *  fatal rendering errors.  As discussed in raycalls.c,
 *  Radiance tends to throw up its hands and exit at the
 *  first sign of trouble, calling quit() to return control
 *  to the system.  Although you can avoid exit() with
 *  your own longjmp() in quit(), the cleanup afterwards
 *  is always suspect.  Through the use of subprocesses,
 *  we avoid this pitfall by closing the processes and
 *  returning a negative value from ray_pqueue() or
 *  ray_presult().  If you get a negative value from either
 *  of these calls, you can assume that the processes have
 *  been cleaned up with a call to ray_close(), though you
 *  will have to call ray_pdone() yourself if you want to
 *  free memory.  Obviously, you cannot continue rendering,
 *  but otherwise your process should not be compromised.
 */

#include  "ray.h"

#include  "selcall.h"

#ifndef RAYQLEN
#define RAYQLEN         16              /* # rays to send at once */
#endif

#ifndef MAX_RPROCS
#if (FD_SETSIZE/2-4 < 64) 
#define MAX_NPROCS      (FD_SETSIZE/2-4)
#else
#define MAX_NPROCS      64              /* max. # rendering processes */
#endif
#endif

extern char     *shm_boundary;          /* boundary of shared memory */

int             ray_nprocs = 0;         /* number of child processes */
int             ray_idle = 0;           /* number of idle children */

static struct child_proc {
        int     pid;                            /* child process id */
        int     fd_send;                        /* write to child here */
        int     fd_recv;                        /* read from child here */
        int     npending;                       /* # rays in process */
        unsigned long  rno[RAYQLEN];            /* working on these rays */
} r_proc[MAX_NPROCS];                   /* our child processes */

static RAY      r_queue[2*RAYQLEN];     /* ray i/o buffer */
static int      r_send_next;            /* next send ray placement */
static int      r_recv_first;           /* position of first unreported ray */
static int      r_recv_next;            /* next receive ray placement */

#define sendq_full()    (r_send_next >= RAYQLEN)


void
ray_pinit(otnm, nproc)          /* initialize ray-tracing processes */
char    *otnm;
int     nproc;
{
        if (nobjects > 0)               /* close old calculation */
                ray_pdone(0);

        ray_init(otnm);                 /* load the shared scene */

        preload_objs();                 /* preload auxiliary data */

                                        /* set shared memory boundary */
        shm_boundary = (char *)malloc(16);
        strcpy(shm_boundary, "SHM_BOUNDARY");

        r_send_next = 0;                /* set up queue */
        r_recv_first = r_recv_next = RAYQLEN;

        ray_popen(nproc);               /* fork children */
}


static int
ray_pflush()                    /* send queued rays to idle children */
{
        int     nc, n, nw, i, sfirst;

        if ((ray_idle <= 0 | r_send_next <= 0))
                return(0);              /* nothing we can send */
        
        sfirst = 0;                     /* divvy up labor */
        nc = ray_idle;
        for (i = ray_nprocs; nc && i--; ) {
                if (r_proc[i].npending > 0)
                        continue;       /* child looks busy */
                n = (r_send_next - sfirst)/nc--;
                if (!n)
                        continue;
                                        /* smuggle set size in crtype */
                r_queue[sfirst].crtype = n;
                nw = writebuf(r_proc[i].fd_send, (char *)&r_queue[sfirst],
                                sizeof(RAY)*n);
                if (nw != sizeof(RAY)*n)
                        return(-1);     /* write error */
                r_proc[i].npending = n;
                while (n--)             /* record ray IDs */
                        r_proc[i].rno[n] = r_queue[sfirst+n].rno;
                sfirst += r_proc[i].npending;
                ray_idle--;             /* now she's busy */
        }
        if (sfirst != r_send_next)
                error(CONSISTENCY, "code screwup in ray_pflush");
        r_send_next = 0;
        return(sfirst);                 /* return total # sent */
}


void
ray_psend(r)                    /* add a ray to our send queue */
RAY     *r;
{
        if (r == NULL)
                return;
                                        /* flush output if necessary */
        if (sendq_full() && ray_pflush() <= 0)
                error(INTERNAL, "ray_pflush failed in ray_psend");

        copystruct(&r_queue[r_send_next], r);
        r_send_next++;
}


int
ray_pqueue(r)                   /* queue a ray for computation */
RAY     *r;
{
        if (r == NULL)
                return(0);
                                        /* check for full send queue */
        if (sendq_full()) {
                RAY     mySend;
                int     rval;
                copystruct(&mySend, r);
                                        /* wait for a result */
                rval = ray_presult(r, 0);
                                        /* put new ray in queue */
                copystruct(&r_queue[r_send_next], &mySend);
                r_send_next++;
                return(rval);           /* done */
        }
                                        /* add ray to send queue */
        copystruct(&r_queue[r_send_next], r);
        r_send_next++;
                                        /* check for returned ray... */
        if (r_recv_first >= r_recv_next)
                return(0);
                                        /* ...one is sitting in queue */
        copystruct(r, &r_queue[r_recv_first]);
        r_recv_first++;
        return(1);
}


int
ray_presult(r, poll)            /* check for a completed ray */
RAY     *r;
int     poll;
{
        static struct timeval   tpoll;  /* zero timeval struct */
        static fd_set   readset, errset;
        int     n, ok;
        register int    pn;

        if (r == NULL)
                return(0);
                                        /* check queued results first */
        if (r_recv_first < r_recv_next) {
                copystruct(r, &r_queue[r_recv_first]);
                r_recv_first++;
                return(1);
        }
        n = ray_nprocs - ray_idle;      /* pending before flush? */

        if (ray_pflush() < 0)           /* send new rays to process */
                return(-1);
                                        /* reset receive queue */
        r_recv_first = r_recv_next = RAYQLEN;

        if (!poll)                      /* count newly sent unless polling */
                n = ray_nprocs - ray_idle;
        if (n <= 0)                     /* return if nothing to await */
                return(0);
getready:                               /* any children waiting for us? */
        for (pn = ray_nprocs; pn--; )
                if (FD_ISSET(r_proc[pn].fd_recv, &readset) ||
                                FD_ISSET(r_proc[pn].fd_recv, &errset))
                        break;
                                        /* call select if we must */
        if (pn < 0) {
                FD_ZERO(&readset); FD_ZERO(&errset); n = 0;
                for (pn = ray_nprocs; pn--; ) {
                        if (r_proc[pn].npending > 0)
                                FD_SET(r_proc[pn].fd_recv, &readset);
                        FD_SET(r_proc[pn].fd_recv, &errset);
                        if (r_proc[pn].fd_recv >= n)
                                n = r_proc[pn].fd_recv + 1;
                }
                                        /* find out who is ready */
                while ((n = select(n, &readset, (fd_set *)NULL, &errset,
                                poll ? &tpoll : (struct timeval *)NULL)) < 0)
                        if (errno != EINTR) {
                                error(WARNING,
                                        "select call failed in ray_presult");
                                ray_pclose(0);
                                return(-1);
                        }
                if (n > 0)              /* go back and get it */
                        goto getready;
                return(0);              /* else poll came up empty */
        }
        if (r_recv_next + r_proc[pn].npending > sizeof(r_queue)/sizeof(RAY))
                error(CONSISTENCY, "buffer shortage in ray_presult()");

                                        /* read rendered ray data */
        n = readbuf(r_proc[pn].fd_recv, (char *)&r_queue[r_recv_next],
                        sizeof(RAY)*r_proc[pn].npending);
        if (n > 0) {
                r_recv_next += n/sizeof(RAY);
                ok = (n == sizeof(RAY)*r_proc[pn].npending);
        } else
                ok = 0;
                                        /* reset child's status */
        FD_CLR(r_proc[pn].fd_recv, &readset);
        if (n <= 0)
                FD_CLR(r_proc[pn].fd_recv, &errset);
        r_proc[pn].npending = 0;
        ray_idle++;
                                        /* check for rendering errors */
        if (!ok) {
                ray_pclose(0);          /* process died -- clean up */
                return(-1);
        }
                                        /* preen returned rays */
        for (n = r_recv_next - r_recv_first; n--; ) {
                register RAY    *rp = &r_queue[r_recv_first + n];
                rp->rno = r_proc[pn].rno[n];
                rp->parent = NULL;
                rp->newcset = rp->clipset = NULL;
                rp->rox = NULL;
                rp->slights = NULL;
        }
                                        /* return first ray received */
        copystruct(r, &r_queue[r_recv_first]);
        r_recv_first++;
        return(1);
}


void
ray_pdone(freall)               /* reap children and free data */
int     freall;
{
        ray_pclose(0);                  /* close child processes */

        if (shm_boundary != NULL) {     /* clear shared memory boundary */
                free((void *)shm_boundary);
                shm_boundary = NULL;
        }
        ray_done(freall);               /* free rendering data */
}


static void
ray_pchild(fd_in, fd_out)       /* process rays (never returns) */
int     fd_in;
int     fd_out;
{
        int     n;
        register int    i;
                                        /* read each ray request set */
        while ((n = read(fd_in, (char *)r_queue, sizeof(r_queue))) > 0) {
                int     n2;
                if (n % sizeof(RAY))
                        break;
                n /= sizeof(RAY);
                                        /* get smuggled set length */
                n2 = r_queue[0].crtype - n;
                if (n2 < 0)
                        error(INTERNAL, "buffer over-read in ray_pchild");
                if (n2 > 0) {           /* read the rest of the set */
                        i = readbuf(fd_in, (char *)(r_queue+n),
                                        sizeof(RAY)*n2);
                        if (i != sizeof(RAY)*n2)
                                break;
                        n += n2;
                }
                                        /* evaluate rays */
                for (i = 0; i < n; i++) {
                        r_queue[i].crtype = r_queue[i].rtype;
                        r_queue[i].parent = NULL;
                        r_queue[i].clipset = NULL;
                        r_queue[i].slights = NULL;
                        r_queue[i].revf = raytrace;
                        samplendx++;
                        rayclear(&r_queue[i]);
                        rayvalue(&r_queue[i]);
                }
                                        /* write back our results */
                i = writebuf(fd_out, (char *)r_queue, sizeof(RAY)*n);
                if (i != sizeof(RAY)*n)
                        error(SYSTEM, "write error in ray_pchild");
        }
        if (n)
                error(SYSTEM, "read error in ray_pchild");
        ambsync();
        quit(0);                        /* normal exit */
}


void
ray_popen(nadd)                 /* open the specified # processes */
int     nadd;
{
                                        /* check if our table has room */
        if (ray_nprocs + nadd > MAX_NPROCS)
                nadd = MAX_NPROCS - ray_nprocs;
        if (nadd <= 0)
                return;
        fflush(stderr);                 /* clear pending output */
        fflush(stdout);
        while (nadd--) {                /* fork each new process */
                int     p0[2], p1[2];
                if (pipe(p0) < 0 || pipe(p1) < 0)
                        error(SYSTEM, "cannot create pipe");
                if ((r_proc[ray_nprocs].pid = fork()) == 0) {
                        int     pn;     /* close others' descriptors */
                        for (pn = ray_nprocs; pn--; ) {
                                close(r_proc[pn].fd_send);
                                close(r_proc[pn].fd_recv);
                        }
                        close(p0[0]); close(p1[1]);
                                        /* following call never returns */
                        ray_pchild(p1[0], p0[1]);
                }
                if (r_proc[ray_nprocs].pid < 0)
                        error(SYSTEM, "cannot fork child process");
                close(p1[0]); close(p0[1]);
                r_proc[ray_nprocs].fd_send = p1[1];
                r_proc[ray_nprocs].fd_recv = p0[0];
                r_proc[ray_nprocs].npending = 0;
                ray_nprocs++;
                ray_idle++;
        }
}


void
ray_pclose(nsub)                /* close one or more child processes */
int     nsub;
{
        static int      inclose = 0;
        RAY     res;
                                        /* check recursion */
        if (inclose)
                return;
        inclose++;
                                        /* check argument */
        if ((nsub <= 0 | nsub > ray_nprocs))
                nsub = ray_nprocs;
                                        /* clear our ray queue */
        while (ray_presult(&res,0) > 0)
                ;
                                        /* clean up children */
        while (nsub--) {
                int     status;
                ray_nprocs--;
                close(r_proc[ray_nprocs].fd_recv);
                close(r_proc[ray_nprocs].fd_send);
                while (wait(&status) != r_proc[ray_nprocs].pid)
                        ;
                if (status) {
                        sprintf(errmsg,
                                "rendering process %d exited with code %d",
                                        r_proc[ray_nprocs].pid, status>>8);
                        error(WARNING, errmsg);
                }
                ray_idle--;
        }
        inclose--;
}


void
quit(ec)                        /* make sure exit is called */
int     ec;
{
        exit(ec);
}
Revision:	2.1
Committed:	Sat Feb 22 02:07:29 2003 UTC (21 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Log Message:	Changes and check-in for 3.5 release Includes new source files and modifications not recorded for many years See ray/doc/notes/ReleaseNotes for notes between 3.1 and 3.5 release
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2			static const char RCSid[] = "$Id$";
3			#endif
4			/*
5			* raypcalls.c - interface for parallel rendering using Radiance
6			*
7			* External symbols declared in ray.h
8			*/
9
10			/* ====================================================================
11			* The Radiance Software License, Version 1.0
12			*
13			* Copyright (c) 1990 - 2002 The Regents of the University of California,
14			* through Lawrence Berkeley National Laboratory. All rights reserved.
15			*
16			* Redistribution and use in source and binary forms, with or without
17			* modification, are permitted provided that the following conditions
18			* are met:
19			*
20			* 1. Redistributions of source code must retain the above copyright
21			* notice, this list of conditions and the following disclaimer.
22			*
23			* 2. Redistributions in binary form must reproduce the above copyright
24			* notice, this list of conditions and the following disclaimer in
25			* the documentation and/or other materials provided with the
26			* distribution.
27			*
28			* 3. The end-user documentation included with the redistribution,
29			* if any, must include the following acknowledgment:
30			* "This product includes Radiance software
31			* (http://radsite.lbl.gov/)
32			* developed by the Lawrence Berkeley National Laboratory
33			* (http://www.lbl.gov/)."
34			* Alternately, this acknowledgment may appear in the software itself,
35			* if and wherever such third-party acknowledgments normally appear.
36			*
37			* 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
38			* and "The Regents of the University of California" must
39			* not be used to endorse or promote products derived from this
40			* software without prior written permission. For written
41			* permission, please contact [email protected].
42			*
43			* 5. Products derived from this software may not be called "Radiance",
44			* nor may "Radiance" appear in their name, without prior written
45			* permission of Lawrence Berkeley National Laboratory.
46			*
47			* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
48			* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
49			* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
50			* DISCLAIMED. IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
51			* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
52			* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
53			* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
54			* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
55			* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
56			* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
57			* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58			* SUCH DAMAGE.
59			* ====================================================================
60			*
61			* This software consists of voluntary contributions made by many
62			* individuals on behalf of Lawrence Berkeley National Laboratory. For more
63			* information on Lawrence Berkeley National Laboratory, please see
64			* <http://www.lbl.gov/>.
65			*/
66
67			/*
68			* These calls are designed similarly to the ones in raycalls.c,
69			* but allow for multiple rendering processes on the same host
70			* machine. There is no sense in specifying more child processes
71			* than you have processors, but one child may help by allowing
72			* asynchronous ray computation in an interactive program, and
73			* will protect the caller from fatal rendering errors.
74			*
75			* You should first read and undrstand the header in raycalls.c,
76			* as some things are explained there that are not repated here.
77			*
78			* The first step is opening one or more rendering processes
79			* with a call to ray_pinit(oct, nproc). Before calling fork(),
80			* ray_pinit() loads the octree and data structures into the
81			* caller's memory. This permits all sorts of queries that
82			* wouldn't be possible otherwise, without causing any real
83			* memory overhead, since all the static data are shared
84			* between processes. Rays are then traced using a simple
85			* queuing mechanism, explained below.
86			*
87			* The ray queue holds as many rays as there are rendering
88			* processes. Rays are queued and returned by a single
89			* ray_pqueue() call. A ray_pqueue() return
90			* value of 0 indicates that no rays are ready
91			* and the queue is not yet full. A return value of 1
92			* indicates that a ray was returned, though it is probably
93			* not the one you just requested. Rays may be identified by
94			* the rno member of the RAY struct, which is incremented
95			* by the rayorigin() call, or may be set explicitly by
96			* the caller. Below is an example call sequence:
97			*
98			* myRay.rorg = ( ray origin point )
99			* myRay.rdir = ( normalized ray direction )
100			* myRay.rmax = ( maximum length, or zero for no limit )
101			* rayorigin(&myRay, NULL, PRIMARY, 1.0);
102			* myRay.rno = ( my personal ray identifier )
103			* if (ray_pqueue(&myRay) == 1)
104			* { do something with results }
105			*
106			* Note the differences between this and the simpler ray_trace()
107			* call. In particular, the call may or may not return a value
108			* in the passed ray structure. Also, you need to call rayorigin()
109			* yourself, which is normally for you by ray_trace(). The
110			* great thing is that ray_pqueue() will trace rays faster in
111			* proportion to the number of CPUs you have available on your
112			* system. If the ray queue is full before the call, ray_pqueue()
113			* will block until a result is ready so it can queue this one.
114			* The global int ray_idle indicates the number of currently idle
115			* children. If you want to check for completed rays without blocking,
116			* or get the results from rays that have been queued without
117			* queuing any new ones, the ray_presult() call is for you:
118			*
119			* if (ray_presult(&myRay, 1) == 1)
120			* { do something with results }
121			*
122			* If the second argument is 1, the call won't block when
123			* results aren't ready, but will immediately return 0.
124			* If the second argument is 0, the call will block
125			* until a value is available, returning 0 only if the
126			* queue is completely empty. A negative return value
127			* indicates that a rendering process died. If this
128			* happens, ray_close(0) is automatically called to close
129			* all child processes, and ray_nprocs is set to zero.
130			*
131			* If you just want to fill the ray queue without checking for
132			* results, check ray_idle and call ray_psend():
133			*
134			* while (ray_idle) {
135			* ( set up ray )
136			* ray_psend(&myRay);
137			* }
138			*
139			* The ray_presult() and/or ray_pqueue() functions may then be
140			* called to read back the results.
141			*
142			* When you are done, you may call ray_pdone(1) to close
143			* all child processes and clean up memory used by Radiance.
144			* Any queued ray calculations will be awaited and discarded.
145			* As with ray_done(), ray_pdone(0) hangs onto data files
146			* and fonts that are likely to be used in subsequent renderings.
147			* Whether you want to bother cleaning up memory or not, you
148			* should at least call ray_pclose(0) to clean the child processes.
149			*
150			* Warning: You cannot affect any of the rendering processes
151			* by changing global parameter values onece ray_pinit() has
152			* been called. Changing global parameters will have no effect
153			* until the next call to ray_pinit(), which restarts everything.
154			* If you just want to reap children so that you can alter the
155			* rendering parameters without reloading the scene, use the
156			* ray_pclose(0) and ray_popen(nproc) calls to close
157			* then restart the child processes.
158			*
159			* Note: These routines are written to coordinate with the
160			* definitions in raycalls.c, and in fact depend on them.
161			* If you want to trace a ray and get a result synchronously,
162			* use the ray_trace() call to compute it in the parent process.
163			*
164			* Note: One of the advantages of using separate processes
165			* is that it gives the calling program some immunity from
166			* fatal rendering errors. As discussed in raycalls.c,
167			* Radiance tends to throw up its hands and exit at the
168			* first sign of trouble, calling quit() to return control
169			* to the system. Although you can avoid exit() with
170			* your own longjmp() in quit(), the cleanup afterwards
171			* is always suspect. Through the use of subprocesses,
172			* we avoid this pitfall by closing the processes and
173			* returning a negative value from ray_pqueue() or
174			* ray_presult(). If you get a negative value from either
175			* of these calls, you can assume that the processes have
176			* been cleaned up with a call to ray_close(), though you
177			* will have to call ray_pdone() yourself if you want to
178			* free memory. Obviously, you cannot continue rendering,
179			* but otherwise your process should not be compromised.
180			*/
181
182			#include "ray.h"
183
184			#include "selcall.h"
185
186			#ifndef RAYQLEN
187			#define RAYQLEN 16 /* # rays to send at once */
188			#endif
189
190			#ifndef MAX_RPROCS
191			#if (FD_SETSIZE/2-4 < 64)
192			#define MAX_NPROCS (FD_SETSIZE/2-4)
193			#else
194			#define MAX_NPROCS 64 /* max. # rendering processes */
195			#endif
196			#endif
197
198			extern char shm_boundary; / boundary of shared memory */
199
200			int ray_nprocs = 0; /* number of child processes */
201			int ray_idle = 0; /* number of idle children */
202
203			static struct child_proc {
204			int pid; /* child process id */
205			int fd_send; /* write to child here */
206			int fd_recv; /* read from child here */
207			int npending; /* # rays in process */
208			unsigned long rno[RAYQLEN]; /* working on these rays */
209			} r_proc[MAX_NPROCS]; /* our child processes */
210
211			static RAY r_queue[2RAYQLEN]; / ray i/o buffer */
212			static int r_send_next; /* next send ray placement */
213			static int r_recv_first; /* position of first unreported ray */
214			static int r_recv_next; /* next receive ray placement */
215
216			#define sendq_full() (r_send_next >= RAYQLEN)
217
218
219			void
220			ray_pinit(otnm, nproc) /* initialize ray-tracing processes */
221			char *otnm;
222			int nproc;
223			{
224			if (nobjects > 0) /* close old calculation */
225			ray_pdone(0);
226
227			ray_init(otnm); /* load the shared scene */
228
229			preload_objs(); /* preload auxiliary data */
230
231			/* set shared memory boundary */
232			shm_boundary = (char *)malloc(16);
233			strcpy(shm_boundary, "SHM_BOUNDARY");
234
235			r_send_next = 0; /* set up queue */
236			r_recv_first = r_recv_next = RAYQLEN;
237
238			ray_popen(nproc); /* fork children */
239			}
240
241
242			static int
243			ray_pflush() /* send queued rays to idle children */
244			{
245			int nc, n, nw, i, sfirst;
246
247			if ((ray_idle <= 0 \| r_send_next <= 0))
248			return(0); /* nothing we can send */
249
250			sfirst = 0; /* divvy up labor */
251			nc = ray_idle;
252			for (i = ray_nprocs; nc && i--; ) {
253			if (r_proc[i].npending > 0)
254			continue; /* child looks busy */
255			n = (r_send_next - sfirst)/nc--;
256			if (!n)
257			continue;
258			/* smuggle set size in crtype */
259			r_queue[sfirst].crtype = n;
260			nw = writebuf(r_proc[i].fd_send, (char *)&r_queue[sfirst],
261			sizeof(RAY)*n);
262			if (nw != sizeof(RAY)*n)
263			return(-1); /* write error */
264			r_proc[i].npending = n;
265			while (n--) /* record ray IDs */
266			r_proc[i].rno[n] = r_queue[sfirst+n].rno;
267			sfirst += r_proc[i].npending;
268			ray_idle--; /* now she's busy */
269			}
270			if (sfirst != r_send_next)
271			error(CONSISTENCY, "code screwup in ray_pflush");
272			r_send_next = 0;
273			return(sfirst); /* return total # sent */
274			}
275
276
277			void
278			ray_psend(r) /* add a ray to our send queue */
279			RAY *r;
280			{
281			if (r == NULL)
282			return;
283			/* flush output if necessary */
284			if (sendq_full() && ray_pflush() <= 0)
285			error(INTERNAL, "ray_pflush failed in ray_psend");
286
287			copystruct(&r_queue[r_send_next], r);
288			r_send_next++;
289			}
290
291
292			int
293			ray_pqueue(r) /* queue a ray for computation */
294			RAY *r;
295			{
296			if (r == NULL)
297			return(0);
298			/* check for full send queue */
299			if (sendq_full()) {
300			RAY mySend;
301			int rval;
302			copystruct(&mySend, r);
303			/* wait for a result */
304			rval = ray_presult(r, 0);
305			/* put new ray in queue */
306			copystruct(&r_queue[r_send_next], &mySend);
307			r_send_next++;
308			return(rval); /* done */
309			}
310			/* add ray to send queue */
311			copystruct(&r_queue[r_send_next], r);
312			r_send_next++;
313			/* check for returned ray... */
314			if (r_recv_first >= r_recv_next)
315			return(0);
316			/* ...one is sitting in queue */
317			copystruct(r, &r_queue[r_recv_first]);
318			r_recv_first++;
319			return(1);
320			}
321
322
323			int
324			ray_presult(r, poll) /* check for a completed ray */
325			RAY *r;
326			int poll;
327			{
328			static struct timeval tpoll; /* zero timeval struct */
329			static fd_set readset, errset;
330			int n, ok;
331			register int pn;
332
333			if (r == NULL)
334			return(0);
335			/* check queued results first */
336			if (r_recv_first < r_recv_next) {
337			copystruct(r, &r_queue[r_recv_first]);
338			r_recv_first++;
339			return(1);
340			}
341			n = ray_nprocs - ray_idle; /* pending before flush? */
342
343			if (ray_pflush() < 0) /* send new rays to process */
344			return(-1);
345			/* reset receive queue */
346			r_recv_first = r_recv_next = RAYQLEN;
347
348			if (!poll) /* count newly sent unless polling */
349			n = ray_nprocs - ray_idle;
350			if (n <= 0) /* return if nothing to await */
351			return(0);
352			getready: /* any children waiting for us? */
353			for (pn = ray_nprocs; pn--; )
354			if (FD_ISSET(r_proc[pn].fd_recv, &readset) \|\|
355			FD_ISSET(r_proc[pn].fd_recv, &errset))
356			break;
357			/* call select if we must */
358			if (pn < 0) {
359			FD_ZERO(&readset); FD_ZERO(&errset); n = 0;
360			for (pn = ray_nprocs; pn--; ) {
361			if (r_proc[pn].npending > 0)
362			FD_SET(r_proc[pn].fd_recv, &readset);
363			FD_SET(r_proc[pn].fd_recv, &errset);
364			if (r_proc[pn].fd_recv >= n)
365			n = r_proc[pn].fd_recv + 1;
366			}
367			/* find out who is ready */
368			while ((n = select(n, &readset, (fd_set *)NULL, &errset,
369			poll ? &tpoll : (struct timeval *)NULL)) < 0)
370			if (errno != EINTR) {
371			error(WARNING,
372			"select call failed in ray_presult");
373			ray_pclose(0);
374			return(-1);
375			}
376			if (n > 0) /* go back and get it */
377			goto getready;
378			return(0); /* else poll came up empty */
379			}
380			if (r_recv_next + r_proc[pn].npending > sizeof(r_queue)/sizeof(RAY))
381			error(CONSISTENCY, "buffer shortage in ray_presult()");
382
383			/* read rendered ray data */
384			n = readbuf(r_proc[pn].fd_recv, (char *)&r_queue[r_recv_next],
385			sizeof(RAY)*r_proc[pn].npending);
386			if (n > 0) {
387			r_recv_next += n/sizeof(RAY);
388			ok = (n == sizeof(RAY)*r_proc[pn].npending);
389			} else
390			ok = 0;
391			/* reset child's status */
392			FD_CLR(r_proc[pn].fd_recv, &readset);
393			if (n <= 0)
394			FD_CLR(r_proc[pn].fd_recv, &errset);
395			r_proc[pn].npending = 0;
396			ray_idle++;
397			/* check for rendering errors */
398			if (!ok) {
399			ray_pclose(0); /* process died -- clean up */
400			return(-1);
401			}
402			/* preen returned rays */
403			for (n = r_recv_next - r_recv_first; n--; ) {
404			register RAY *rp = &r_queue[r_recv_first + n];
405			rp->rno = r_proc[pn].rno[n];
406			rp->parent = NULL;
407			rp->newcset = rp->clipset = NULL;
408			rp->rox = NULL;
409			rp->slights = NULL;
410			}
411			/* return first ray received */
412			copystruct(r, &r_queue[r_recv_first]);
413			r_recv_first++;
414			return(1);
415			}
416
417
418			void
419			ray_pdone(freall) /* reap children and free data */
420			int freall;
421			{
422			ray_pclose(0); /* close child processes */
423
424			if (shm_boundary != NULL) { /* clear shared memory boundary */
425			free((void *)shm_boundary);
426			shm_boundary = NULL;
427			}
428			ray_done(freall); /* free rendering data */
429			}
430
431
432			static void
433			ray_pchild(fd_in, fd_out) /* process rays (never returns) */
434			int fd_in;
435			int fd_out;
436			{
437			int n;
438			register int i;
439			/* read each ray request set */
440			while ((n = read(fd_in, (char *)r_queue, sizeof(r_queue))) > 0) {
441			int n2;
442			if (n % sizeof(RAY))
443			break;
444			n /= sizeof(RAY);
445			/* get smuggled set length */
446			n2 = r_queue[0].crtype - n;
447			if (n2 < 0)
448			error(INTERNAL, "buffer over-read in ray_pchild");
449			if (n2 > 0) { /* read the rest of the set */
450			i = readbuf(fd_in, (char *)(r_queue+n),
451			sizeof(RAY)*n2);
452			if (i != sizeof(RAY)*n2)
453			break;
454			n += n2;
455			}
456			/* evaluate rays */
457			for (i = 0; i < n; i++) {
458			r_queue[i].crtype = r_queue[i].rtype;
459			r_queue[i].parent = NULL;
460			r_queue[i].clipset = NULL;
461			r_queue[i].slights = NULL;
462			r_queue[i].revf = raytrace;
463			samplendx++;
464			rayclear(&r_queue[i]);
465			rayvalue(&r_queue[i]);
466			}
467			/* write back our results */
468			i = writebuf(fd_out, (char )r_queue, sizeof(RAY)n);
469			if (i != sizeof(RAY)*n)
470			error(SYSTEM, "write error in ray_pchild");
471			}
472			if (n)
473			error(SYSTEM, "read error in ray_pchild");
474			ambsync();
475			quit(0); /* normal exit */
476			}
477
478
479			void
480			ray_popen(nadd) /* open the specified # processes */
481			int nadd;
482			{
483			/* check if our table has room */
484			if (ray_nprocs + nadd > MAX_NPROCS)
485			nadd = MAX_NPROCS - ray_nprocs;
486			if (nadd <= 0)
487			return;
488			fflush(stderr); /* clear pending output */
489			fflush(stdout);
490			while (nadd--) { /* fork each new process */
491			int p0[2], p1[2];
492			if (pipe(p0) < 0 \|\| pipe(p1) < 0)
493			error(SYSTEM, "cannot create pipe");
494			if ((r_proc[ray_nprocs].pid = fork()) == 0) {
495			int pn; /* close others' descriptors */
496			for (pn = ray_nprocs; pn--; ) {
497			close(r_proc[pn].fd_send);
498			close(r_proc[pn].fd_recv);
499			}
500			close(p0[0]); close(p1[1]);
501			/* following call never returns */
502			ray_pchild(p1[0], p0[1]);
503			}
504			if (r_proc[ray_nprocs].pid < 0)
505			error(SYSTEM, "cannot fork child process");
506			close(p1[0]); close(p0[1]);
507			r_proc[ray_nprocs].fd_send = p1[1];
508			r_proc[ray_nprocs].fd_recv = p0[0];
509			r_proc[ray_nprocs].npending = 0;
510			ray_nprocs++;
511			ray_idle++;
512			}
513			}
514
515
516			void
517			ray_pclose(nsub) /* close one or more child processes */
518			int nsub;
519			{
520			static int inclose = 0;
521			RAY res;
522			/* check recursion */
523			if (inclose)
524			return;
525			inclose++;
526			/* check argument */
527			if ((nsub <= 0 \| nsub > ray_nprocs))
528			nsub = ray_nprocs;
529			/* clear our ray queue */
530			while (ray_presult(&res,0) > 0)
531			;
532			/* clean up children */
533			while (nsub--) {
534			int status;
535			ray_nprocs--;
536			close(r_proc[ray_nprocs].fd_recv);
537			close(r_proc[ray_nprocs].fd_send);
538			while (wait(&status) != r_proc[ray_nprocs].pid)
539			;
540			if (status) {
541			sprintf(errmsg,
542			"rendering process %d exited with code %d",
543			r_proc[ray_nprocs].pid, status>>8);
544			error(WARNING, errmsg);
545			}
546			ray_idle--;
547			}
548			inclose--;
549			}
550
551
552			void
553			quit(ec) /* make sure exit is called */
554			int ec;
555			{
556			exit(ec);
557			}