--- ray/src/rt/raypcalls.c	2005/12/20 20:36:44	2.13
+++ ray/src/rt/raypcalls.c	2008/02/08 18:27:31	2.18
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: raypcalls.c,v 2.13 2005/12/20 20:36:44 greg Exp $";
+static const char	RCSid[] = "$Id: raypcalls.c,v 2.18 2008/02/08 18:27:31 greg Exp $";
 #endif
 /*
  *  raypcalls.c - interface for parallel rendering using Radiance
@@ -30,8 +30,9 @@ static const char	RCSid[] = "$Id: raypcalls.c,v 2.13 2
  *  between processes.  Rays are then traced using a simple
  *  queuing mechanism, explained below.
  *
- *  The ray queue holds at least RAYQLEN rays, up to
- *  as many rays as there are rendering processes.
+ *  The ray queue buffers RAYQLEN rays before sending to
+ *  children, each of which may internally buffer RAYQLEN rays.
+ *
  *  Rays are queued and returned by a single
  *  ray_pqueue() call.  A ray_pqueue() return
  *  value of 0 indicates that no rays are ready
@@ -130,13 +131,11 @@ static const char	RCSid[] = "$Id: raypcalls.c,v 2.13 2
  *  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  <sys/types.h>
+#include  <sys/wait.h>
 #include  "selcall.h"
 
 #ifndef RAYQLEN
@@ -245,8 +244,7 @@ ray_psend(			/* add a ray to our send queue */
 	if (sendq_full() && ray_pflush() <= 0)
 		error(INTERNAL, "ray_pflush failed in ray_psend");
 
-	r_queue[r_send_next] = *r;
-	r_send_next++;
+	r_queue[r_send_next++] = *r;
 }
 
 
@@ -265,19 +263,16 @@ ray_pqueue(			/* queue a ray for computation */
 					/* wait for a result */
 		rval = ray_presult(r, 0);
 					/* put new ray in queue */
-		r_queue[r_send_next] = mySend;
-		r_send_next++;
+		r_queue[r_send_next++] = mySend;
 		return(rval);		/* done */
 	}
 					/* else add ray to send queue */
-	r_queue[r_send_next] = *r;
-	r_send_next++;
+	r_queue[r_send_next++] = *r;
 					/* 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++;
+	*r = r_queue[r_recv_first++];
 	return(1);
 }
 
@@ -297,8 +292,10 @@ ray_presult(		/* check for a completed ray */
 		return(0);
 					/* check queued results first */
 	if (r_recv_first < r_recv_next) {
-		*r = r_queue[r_recv_first];
-		r_recv_first++;
+		*r = r_queue[r_recv_first++];
+					/* make sure send queue has room */
+		if (sendq_full() && ray_pflush() <= 0)
+			return(-1);
 		return(1);
 	}
 	n = ray_pnprocs - ray_pnidle;	/* pending before flush? */
@@ -312,6 +309,9 @@ ray_presult(		/* check for a completed ray */
 		n = ray_pnprocs - ray_pnidle;
 	if (n <= 0)			/* return if nothing to await */
 		return(0);
+	if (!poll && ray_pnprocs == 1)	/* one process -> skip select() */
+		FD_SET(r_proc[0].fd_recv, &readset);
+
 getready:				/* any children waiting for us? */
 	for (pn = ray_pnprocs; pn--; )
 		if (FD_ISSET(r_proc[pn].fd_recv, &readset) ||
@@ -400,6 +400,8 @@ ray_pchild(	/* process rays (never returns) */
 {
 	int	n;
 	register int	i;
+					/* flag child process for quit() */
+	ray_pnprocs = -1;
 					/* read each ray request set */
 	while ((n = read(fd_in, (char *)r_queue, sizeof(r_queue))) > 0) {
 		int	n2;
@@ -523,5 +525,7 @@ void
 quit(ec)			/* make sure exit is called */
 int	ec;
 {
+	if (ray_pnprocs > 0)	/* close children if any */
+		ray_pclose(0);		
 	exit(ec);
 }