src/rt/raypcalls.c

#ifndef lint
static const char       RCSid[] = "$Id: raypcalls.c,v 2.5 2003/07/27 22:12:03 schorsch Exp $";
#endif
/*
 *  raypcalls.c - interface for parallel rendering using Radiance
 *
 *  External symbols declared in ray.h
 */

#include "copyright.h"

/*
 *  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_pnidle 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_pnprocs is set to zero.
 *
 *  If you just want to fill the ray queue without checking for
 *  results, check ray_pnidle and call ray_psend():
 *
 *      while (ray_pnidle) {
 *              ( 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 <stdio.h>
#include <sys/types.h>
#include <sys/wait.h> /* XXX platform */

#include  "rtprocess.h"
#include  "ray.h"
#include  "ambient.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_pnprocs = 0;        /* number of child processes */
int             ray_pnidle = 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)

static int ray_pflush(void);
static void ray_pchild(int      fd_in, int      fd_out);


extern void
ray_pinit(              /* 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(void)                        /* send queued rays to idle children */
{
        int     nc, n, nw, i, sfirst;

        if ((ray_pnidle <= 0) | (r_send_next <= 0))
                return(0);              /* nothing we can send */
        
        sfirst = 0;                     /* divvy up labor */
        nc = ray_pnidle;
        for (i = ray_pnprocs; 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_pnidle--;           /* 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 */
}


extern void
ray_psend(                      /* 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");

        r_queue[r_send_next] = *r;
        r_send_next++;
}


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


extern int
ray_presult(            /* 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) {
                *r = r_queue[r_recv_first];
                r_recv_first++;
                return(1);
        }
        n = ray_pnprocs - ray_pnidle;   /* 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_pnprocs - ray_pnidle;
        if (n <= 0)                     /* return if nothing to await */
                return(0);
getready:                               /* any children waiting for us? */
        for (pn = ray_pnprocs; 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_pnprocs; 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_pnidle++;
                                        /* 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 */
        *r = r_queue[r_recv_first];
        r_recv_first++;
        return(1);
}


extern void
ray_pdone(              /* 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(     /* 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 */
}


extern void
ray_popen(                      /* open the specified # processes */
        int     nadd
)
{
                                        /* check if our table has room */
        if (ray_pnprocs + nadd > MAX_NPROCS)
                nadd = MAX_NPROCS - ray_pnprocs;
        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_pnprocs].pid = fork()) == 0) {
                        int     pn;     /* close others' descriptors */
                        for (pn = ray_pnprocs; 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_pnprocs].pid < 0)
                        error(SYSTEM, "cannot fork child process");
                close(p1[0]); close(p0[1]);
                r_proc[ray_pnprocs].fd_send = p1[1];
                r_proc[ray_pnprocs].fd_recv = p0[0];
                r_proc[ray_pnprocs].npending = 0;
                ray_pnprocs++;
                ray_pnidle++;
        }
}


extern void
ray_pclose(             /* 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_pnprocs))
                nsub = ray_pnprocs;
                                        /* clear our ray queue */
        while (ray_presult(&res,0) > 0)
                ;
                                        /* clean up children */
        while (nsub--) {
                int     status;
                ray_pnprocs--;
                close(r_proc[ray_pnprocs].fd_recv);
                close(r_proc[ray_pnprocs].fd_send);
                while (wait(&status) != r_proc[ray_pnprocs].pid)
                        ;
                if (status) {
                        sprintf(errmsg,
                                "rendering process %d exited with code %d",
                                        r_proc[ray_pnprocs].pid, status>>8);
                        error(WARNING, errmsg);
                }
                ray_pnidle--;
        }
        inclose--;
}


void
quit(ec)                        /* make sure exit is called */
int     ec;
{
        exit(ec);
}
Revision:	2.6
Committed:	Tue Mar 30 16:13:01 2004 UTC (20 years, 1 month ago) by schorsch
Content type:	text/plain
Branch:	MAIN
Changes since 2.5:	+45 -29 lines
Log Message:	Continued ANSIfication. There are only bits and pieces left now.
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	schorsch	2.6	static const char RCSid[] = "$Id: raypcalls.c,v 2.5 2003/07/27 22:12:03 schorsch Exp $";
3	greg	2.1	#endif
4			/*
5			* raypcalls.c - interface for parallel rendering using Radiance
6			*
7			* External symbols declared in ray.h
8			*/
9
10	greg	2.2	#include "copyright.h"
11	greg	2.1
12			/*
13			* These calls are designed similarly to the ones in raycalls.c,
14			* but allow for multiple rendering processes on the same host
15			* machine. There is no sense in specifying more child processes
16			* than you have processors, but one child may help by allowing
17			* asynchronous ray computation in an interactive program, and
18			* will protect the caller from fatal rendering errors.
19			*
20			* You should first read and undrstand the header in raycalls.c,
21			* as some things are explained there that are not repated here.
22			*
23			* The first step is opening one or more rendering processes
24			* with a call to ray_pinit(oct, nproc). Before calling fork(),
25			* ray_pinit() loads the octree and data structures into the
26			* caller's memory. This permits all sorts of queries that
27			* wouldn't be possible otherwise, without causing any real
28			* memory overhead, since all the static data are shared
29			* between processes. Rays are then traced using a simple
30			* queuing mechanism, explained below.
31			*
32			* The ray queue holds as many rays as there are rendering
33			* processes. Rays are queued and returned by a single
34			* ray_pqueue() call. A ray_pqueue() return
35			* value of 0 indicates that no rays are ready
36			* and the queue is not yet full. A return value of 1
37			* indicates that a ray was returned, though it is probably
38			* not the one you just requested. Rays may be identified by
39			* the rno member of the RAY struct, which is incremented
40			* by the rayorigin() call, or may be set explicitly by
41			* the caller. Below is an example call sequence:
42			*
43			* myRay.rorg = ( ray origin point )
44			* myRay.rdir = ( normalized ray direction )
45			* myRay.rmax = ( maximum length, or zero for no limit )
46			* rayorigin(&myRay, NULL, PRIMARY, 1.0);
47			* myRay.rno = ( my personal ray identifier )
48			* if (ray_pqueue(&myRay) == 1)
49			* { do something with results }
50			*
51			* Note the differences between this and the simpler ray_trace()
52			* call. In particular, the call may or may not return a value
53			* in the passed ray structure. Also, you need to call rayorigin()
54			* yourself, which is normally for you by ray_trace(). The
55			* great thing is that ray_pqueue() will trace rays faster in
56			* proportion to the number of CPUs you have available on your
57			* system. If the ray queue is full before the call, ray_pqueue()
58			* will block until a result is ready so it can queue this one.
59	greg	2.3	* The global int ray_pnidle indicates the number of currently idle
60	greg	2.1	* children. If you want to check for completed rays without blocking,
61			* or get the results from rays that have been queued without
62			* queuing any new ones, the ray_presult() call is for you:
63			*
64			* if (ray_presult(&myRay, 1) == 1)
65			* { do something with results }
66			*
67			* If the second argument is 1, the call won't block when
68			* results aren't ready, but will immediately return 0.
69			* If the second argument is 0, the call will block
70			* until a value is available, returning 0 only if the
71			* queue is completely empty. A negative return value
72			* indicates that a rendering process died. If this
73			* happens, ray_close(0) is automatically called to close
74	greg	2.3	* all child processes, and ray_pnprocs is set to zero.
75	greg	2.1	*
76			* If you just want to fill the ray queue without checking for
77	greg	2.3	* results, check ray_pnidle and call ray_psend():
78	greg	2.1	*
79	greg	2.3	* while (ray_pnidle) {
80	greg	2.1	* ( set up ray )
81			* ray_psend(&myRay);
82			* }
83			*
84			* The ray_presult() and/or ray_pqueue() functions may then be
85			* called to read back the results.
86			*
87			* When you are done, you may call ray_pdone(1) to close
88			* all child processes and clean up memory used by Radiance.
89			* Any queued ray calculations will be awaited and discarded.
90			* As with ray_done(), ray_pdone(0) hangs onto data files
91			* and fonts that are likely to be used in subsequent renderings.
92			* Whether you want to bother cleaning up memory or not, you
93			* should at least call ray_pclose(0) to clean the child processes.
94			*
95			* Warning: You cannot affect any of the rendering processes
96			* by changing global parameter values onece ray_pinit() has
97			* been called. Changing global parameters will have no effect
98			* until the next call to ray_pinit(), which restarts everything.
99			* If you just want to reap children so that you can alter the
100			* rendering parameters without reloading the scene, use the
101			* ray_pclose(0) and ray_popen(nproc) calls to close
102			* then restart the child processes.
103			*
104			* Note: These routines are written to coordinate with the
105			* definitions in raycalls.c, and in fact depend on them.
106			* If you want to trace a ray and get a result synchronously,
107			* use the ray_trace() call to compute it in the parent process.
108			*
109			* Note: One of the advantages of using separate processes
110			* is that it gives the calling program some immunity from
111			* fatal rendering errors. As discussed in raycalls.c,
112			* Radiance tends to throw up its hands and exit at the
113			* first sign of trouble, calling quit() to return control
114			* to the system. Although you can avoid exit() with
115			* your own longjmp() in quit(), the cleanup afterwards
116			* is always suspect. Through the use of subprocesses,
117			* we avoid this pitfall by closing the processes and
118			* returning a negative value from ray_pqueue() or
119			* ray_presult(). If you get a negative value from either
120			* of these calls, you can assume that the processes have
121			* been cleaned up with a call to ray_close(), though you
122			* will have to call ray_pdone() yourself if you want to
123			* free memory. Obviously, you cannot continue rendering,
124			* but otherwise your process should not be compromised.
125			*/
126
127	schorsch	2.6	#include <stdio.h>
128			#include <sys/types.h>
129			#include <sys/wait.h> /* XXX platform */
130
131			#include "rtprocess.h"
132	greg	2.1	#include "ray.h"
133	schorsch	2.6	#include "ambient.h"
134	greg	2.1	#include "selcall.h"
135
136			#ifndef RAYQLEN
137			#define RAYQLEN 16 /* # rays to send at once */
138			#endif
139
140			#ifndef MAX_RPROCS
141			#if (FD_SETSIZE/2-4 < 64)
142			#define MAX_NPROCS (FD_SETSIZE/2-4)
143			#else
144			#define MAX_NPROCS 64 /* max. # rendering processes */
145			#endif
146			#endif
147
148			extern char shm_boundary; / boundary of shared memory */
149
150	greg	2.3	int ray_pnprocs = 0; /* number of child processes */
151			int ray_pnidle = 0; /* number of idle children */
152	greg	2.1
153			static struct child_proc {
154			int pid; /* child process id */
155			int fd_send; /* write to child here */
156			int fd_recv; /* read from child here */
157			int npending; /* # rays in process */
158			unsigned long rno[RAYQLEN]; /* working on these rays */
159			} r_proc[MAX_NPROCS]; /* our child processes */
160
161			static RAY r_queue[2RAYQLEN]; / ray i/o buffer */
162			static int r_send_next; /* next send ray placement */
163			static int r_recv_first; /* position of first unreported ray */
164			static int r_recv_next; /* next receive ray placement */
165
166			#define sendq_full() (r_send_next >= RAYQLEN)
167
168	schorsch	2.6	static int ray_pflush(void);
169			static void ray_pchild(int fd_in, int fd_out);
170	greg	2.1
171	schorsch	2.6
172			extern void
173			ray_pinit( /* initialize ray-tracing processes */
174			char *otnm,
175			int nproc
176			)
177	greg	2.1	{
178			if (nobjects > 0) /* close old calculation */
179			ray_pdone(0);
180
181			ray_init(otnm); /* load the shared scene */
182
183			preload_objs(); /* preload auxiliary data */
184
185			/* set shared memory boundary */
186			shm_boundary = (char *)malloc(16);
187			strcpy(shm_boundary, "SHM_BOUNDARY");
188
189			r_send_next = 0; /* set up queue */
190			r_recv_first = r_recv_next = RAYQLEN;
191
192			ray_popen(nproc); /* fork children */
193			}
194
195
196			static int
197	schorsch	2.6	ray_pflush(void) /* send queued rays to idle children */
198	greg	2.1	{
199			int nc, n, nw, i, sfirst;
200
201	schorsch	2.5	if ((ray_pnidle <= 0) \| (r_send_next <= 0))
202	greg	2.1	return(0); /* nothing we can send */
203
204			sfirst = 0; /* divvy up labor */
205	greg	2.3	nc = ray_pnidle;
206			for (i = ray_pnprocs; nc && i--; ) {
207	greg	2.1	if (r_proc[i].npending > 0)
208			continue; /* child looks busy */
209			n = (r_send_next - sfirst)/nc--;
210			if (!n)
211			continue;
212			/* smuggle set size in crtype */
213			r_queue[sfirst].crtype = n;
214			nw = writebuf(r_proc[i].fd_send, (char *)&r_queue[sfirst],
215			sizeof(RAY)*n);
216			if (nw != sizeof(RAY)*n)
217			return(-1); /* write error */
218			r_proc[i].npending = n;
219			while (n--) /* record ray IDs */
220			r_proc[i].rno[n] = r_queue[sfirst+n].rno;
221			sfirst += r_proc[i].npending;
222	greg	2.3	ray_pnidle--; /* now she's busy */
223	greg	2.1	}
224			if (sfirst != r_send_next)
225			error(CONSISTENCY, "code screwup in ray_pflush");
226			r_send_next = 0;
227			return(sfirst); /* return total # sent */
228			}
229
230
231	schorsch	2.6	extern void
232			ray_psend( /* add a ray to our send queue */
233			RAY *r
234			)
235	greg	2.1	{
236			if (r == NULL)
237			return;
238			/* flush output if necessary */
239			if (sendq_full() && ray_pflush() <= 0)
240			error(INTERNAL, "ray_pflush failed in ray_psend");
241
242	schorsch	2.4	r_queue[r_send_next] = *r;
243	greg	2.1	r_send_next++;
244			}
245
246
247	schorsch	2.6	extern int
248			ray_pqueue( /* queue a ray for computation */
249			RAY *r
250			)
251	greg	2.1	{
252			if (r == NULL)
253			return(0);
254			/* check for full send queue */
255			if (sendq_full()) {
256			RAY mySend;
257			int rval;
258	schorsch	2.4	mySend = *r;
259	greg	2.1	/* wait for a result */
260			rval = ray_presult(r, 0);
261			/* put new ray in queue */
262	schorsch	2.4	r_queue[r_send_next] = mySend;
263	greg	2.1	r_send_next++;
264			return(rval); /* done */
265			}
266			/* add ray to send queue */
267	schorsch	2.4	r_queue[r_send_next] = *r;
268	greg	2.1	r_send_next++;
269			/* check for returned ray... */
270			if (r_recv_first >= r_recv_next)
271			return(0);
272			/* ...one is sitting in queue */
273	schorsch	2.4	*r = r_queue[r_recv_first];
274	greg	2.1	r_recv_first++;
275			return(1);
276			}
277
278
279	schorsch	2.6	extern int
280			ray_presult( /* check for a completed ray */
281			RAY *r,
282			int poll
283			)
284	greg	2.1	{
285			static struct timeval tpoll; /* zero timeval struct */
286			static fd_set readset, errset;
287			int n, ok;
288			register int pn;
289
290			if (r == NULL)
291			return(0);
292			/* check queued results first */
293			if (r_recv_first < r_recv_next) {
294	schorsch	2.4	*r = r_queue[r_recv_first];
295	greg	2.1	r_recv_first++;
296			return(1);
297			}
298	greg	2.3	n = ray_pnprocs - ray_pnidle; /* pending before flush? */
299	greg	2.1
300			if (ray_pflush() < 0) /* send new rays to process */
301			return(-1);
302			/* reset receive queue */
303			r_recv_first = r_recv_next = RAYQLEN;
304
305			if (!poll) /* count newly sent unless polling */
306	greg	2.3	n = ray_pnprocs - ray_pnidle;
307	greg	2.1	if (n <= 0) /* return if nothing to await */
308			return(0);
309			getready: /* any children waiting for us? */
310	greg	2.3	for (pn = ray_pnprocs; pn--; )
311	greg	2.1	if (FD_ISSET(r_proc[pn].fd_recv, &readset) \|\|
312			FD_ISSET(r_proc[pn].fd_recv, &errset))
313			break;
314			/* call select if we must */
315			if (pn < 0) {
316			FD_ZERO(&readset); FD_ZERO(&errset); n = 0;
317	greg	2.3	for (pn = ray_pnprocs; pn--; ) {
318	greg	2.1	if (r_proc[pn].npending > 0)
319			FD_SET(r_proc[pn].fd_recv, &readset);
320			FD_SET(r_proc[pn].fd_recv, &errset);
321			if (r_proc[pn].fd_recv >= n)
322			n = r_proc[pn].fd_recv + 1;
323			}
324			/* find out who is ready */
325			while ((n = select(n, &readset, (fd_set *)NULL, &errset,
326			poll ? &tpoll : (struct timeval *)NULL)) < 0)
327			if (errno != EINTR) {
328			error(WARNING,
329			"select call failed in ray_presult");
330			ray_pclose(0);
331			return(-1);
332			}
333			if (n > 0) /* go back and get it */
334			goto getready;
335			return(0); /* else poll came up empty */
336			}
337			if (r_recv_next + r_proc[pn].npending > sizeof(r_queue)/sizeof(RAY))
338			error(CONSISTENCY, "buffer shortage in ray_presult()");
339
340			/* read rendered ray data */
341			n = readbuf(r_proc[pn].fd_recv, (char *)&r_queue[r_recv_next],
342			sizeof(RAY)*r_proc[pn].npending);
343			if (n > 0) {
344			r_recv_next += n/sizeof(RAY);
345			ok = (n == sizeof(RAY)*r_proc[pn].npending);
346			} else
347			ok = 0;
348			/* reset child's status */
349			FD_CLR(r_proc[pn].fd_recv, &readset);
350			if (n <= 0)
351			FD_CLR(r_proc[pn].fd_recv, &errset);
352			r_proc[pn].npending = 0;
353	greg	2.3	ray_pnidle++;
354	greg	2.1	/* check for rendering errors */
355			if (!ok) {
356			ray_pclose(0); /* process died -- clean up */
357			return(-1);
358			}
359			/* preen returned rays */
360			for (n = r_recv_next - r_recv_first; n--; ) {
361			register RAY *rp = &r_queue[r_recv_first + n];
362			rp->rno = r_proc[pn].rno[n];
363			rp->parent = NULL;
364			rp->newcset = rp->clipset = NULL;
365			rp->rox = NULL;
366			rp->slights = NULL;
367			}
368			/* return first ray received */
369	schorsch	2.4	*r = r_queue[r_recv_first];
370	greg	2.1	r_recv_first++;
371			return(1);
372			}
373
374
375	schorsch	2.6	extern void
376			ray_pdone( /* reap children and free data */
377			int freall
378			)
379	greg	2.1	{
380			ray_pclose(0); /* close child processes */
381
382			if (shm_boundary != NULL) { /* clear shared memory boundary */
383			free((void *)shm_boundary);
384			shm_boundary = NULL;
385			}
386			ray_done(freall); /* free rendering data */
387			}
388
389
390			static void
391	schorsch	2.6	ray_pchild( /* process rays (never returns) */
392			int fd_in,
393			int fd_out
394			)
395	greg	2.1	{
396			int n;
397			register int i;
398			/* read each ray request set */
399			while ((n = read(fd_in, (char *)r_queue, sizeof(r_queue))) > 0) {
400			int n2;
401			if (n % sizeof(RAY))
402			break;
403			n /= sizeof(RAY);
404			/* get smuggled set length */
405			n2 = r_queue[0].crtype - n;
406			if (n2 < 0)
407			error(INTERNAL, "buffer over-read in ray_pchild");
408			if (n2 > 0) { /* read the rest of the set */
409			i = readbuf(fd_in, (char *)(r_queue+n),
410			sizeof(RAY)*n2);
411			if (i != sizeof(RAY)*n2)
412			break;
413			n += n2;
414			}
415			/* evaluate rays */
416			for (i = 0; i < n; i++) {
417			r_queue[i].crtype = r_queue[i].rtype;
418			r_queue[i].parent = NULL;
419			r_queue[i].clipset = NULL;
420			r_queue[i].slights = NULL;
421			r_queue[i].revf = raytrace;
422			samplendx++;
423			rayclear(&r_queue[i]);
424			rayvalue(&r_queue[i]);
425			}
426			/* write back our results */
427			i = writebuf(fd_out, (char )r_queue, sizeof(RAY)n);
428			if (i != sizeof(RAY)*n)
429			error(SYSTEM, "write error in ray_pchild");
430			}
431			if (n)
432			error(SYSTEM, "read error in ray_pchild");
433			ambsync();
434			quit(0); /* normal exit */
435			}
436
437
438	schorsch	2.6	extern void
439			ray_popen( /* open the specified # processes */
440			int nadd
441			)
442	greg	2.1	{
443			/* check if our table has room */
444	greg	2.3	if (ray_pnprocs + nadd > MAX_NPROCS)
445			nadd = MAX_NPROCS - ray_pnprocs;
446	greg	2.1	if (nadd <= 0)
447			return;
448			fflush(stderr); /* clear pending output */
449			fflush(stdout);
450			while (nadd--) { /* fork each new process */
451			int p0[2], p1[2];
452			if (pipe(p0) < 0 \|\| pipe(p1) < 0)
453			error(SYSTEM, "cannot create pipe");
454	greg	2.3	if ((r_proc[ray_pnprocs].pid = fork()) == 0) {
455	greg	2.1	int pn; /* close others' descriptors */
456	greg	2.3	for (pn = ray_pnprocs; pn--; ) {
457	greg	2.1	close(r_proc[pn].fd_send);
458			close(r_proc[pn].fd_recv);
459			}
460			close(p0[0]); close(p1[1]);
461			/* following call never returns */
462			ray_pchild(p1[0], p0[1]);
463			}
464	greg	2.3	if (r_proc[ray_pnprocs].pid < 0)
465	greg	2.1	error(SYSTEM, "cannot fork child process");
466			close(p1[0]); close(p0[1]);
467	greg	2.3	r_proc[ray_pnprocs].fd_send = p1[1];
468			r_proc[ray_pnprocs].fd_recv = p0[0];
469			r_proc[ray_pnprocs].npending = 0;
470			ray_pnprocs++;
471			ray_pnidle++;
472	greg	2.1	}
473			}
474
475
476	schorsch	2.6	extern void
477			ray_pclose( /* close one or more child processes */
478			int nsub
479			)
480	greg	2.1	{
481			static int inclose = 0;
482			RAY res;
483			/* check recursion */
484			if (inclose)
485			return;
486			inclose++;
487			/* check argument */
488	schorsch	2.5	if ((nsub <= 0) \| (nsub > ray_pnprocs))
489	greg	2.3	nsub = ray_pnprocs;
490	greg	2.1	/* clear our ray queue */
491			while (ray_presult(&res,0) > 0)
492			;
493			/* clean up children */
494			while (nsub--) {
495			int status;
496	greg	2.3	ray_pnprocs--;
497			close(r_proc[ray_pnprocs].fd_recv);
498			close(r_proc[ray_pnprocs].fd_send);
499			while (wait(&status) != r_proc[ray_pnprocs].pid)
500	greg	2.1	;
501			if (status) {
502			sprintf(errmsg,
503			"rendering process %d exited with code %d",
504	greg	2.3	r_proc[ray_pnprocs].pid, status>>8);
505	greg	2.1	error(WARNING, errmsg);
506			}
507	greg	2.3	ray_pnidle--;
508	greg	2.1	}
509			inclose--;
510			}
511
512
513			void
514			quit(ec) /* make sure exit is called */
515			int ec;
516			{
517			exit(ec);
518			}