--- ray/src/hd/rholo4.c	1997/10/31 10:23:29	3.1
+++ ray/src/hd/rholo4.c	1997/11/10 18:07:15	3.5
@@ -10,23 +10,166 @@ static char SCCSid[] = "$SunId$ SGI";
 
 #include "rholo.h"
 #include "rhdisp.h"
+#include <sys/uio.h>
 
+#ifndef HDSUF
+#define HDSUF	".hdisp"
+#endif
 
-open_display(dname)		/* open a display process */
+static int	inp_flags;
+static int	dpd[3];
+static int	pipesiz;
+static FILE	*dpout;
+
+
+disp_open(dname)		/* open the named display driver */
 char	*dname;
 {
-	error(INTERNAL, "display process unimplemented");
+	char	dpath[128], *com[3];
+	int	i;
+
+#ifdef DEVPATH
+	sprintf(dpath, "%s/%s%s", DEVPATH, dname, HDSUF);
+#else
+	sprintf(dpath, "dev/%s%s", dname, HDSUF);
+#endif
+	com[0] = dpath; com[1] = froot; com[2] = NULL;
+	pipesiz = open_process(dpd, com);
+	if (pipesiz <= 0)
+		error(USER, "cannot start display process");
+	if ((dpout = fdopen(dup(dpd[1]), "w")) == NULL)
+		error(SYSTEM, "cannot associate FILE with display pipe");
+	inp_flags = 0;
+				/* write out hologram grids */
+	for (i = 0; hdlist[i] != NULL; i++)
+		disp_result(DS_ADDHOLO, sizeof(HDGRID), (char *)hdlist[i]);
+	disp_flush();
 }
 
 
+disp_packet(p)			/* display a packet */
+register PACKHEAD	*p;
+{
+	disp_result(DS_BUNDLE, packsiz(p->nr), (char *)p);
+}
+
+
 disp_check(block)		/* check display process */
 int	block;
 {
-	return(1);
+	MSGHEAD	msg;
+	int	n;
+	char	*buf = NULL;
+
+	if (pipesiz <= 0)
+		return(-1);
+					/* flush display output */
+	disp_flush();
+					/* check read blocking */
+	if (block != (inp_flags == 0)) {
+		inp_flags = block ? 0 : FNONBLK;
+		if (fcntl(dpd[0], F_SETFL, inp_flags) < 0)
+			goto fcntlerr;
+	}
+					/* read message header */
+	n = read(dpd[0], (char *)&msg, sizeof(MSGHEAD));
+	if (n != sizeof(MSGHEAD)) {
+		if (n >= 0)
+			error(USER, "display process died");
+		if (errno != EAGAIN & errno != EINTR)
+			goto readerr;
+		return(2);		/* acceptable failure */
+	}
+	if (msg.nbytes) {		/* get the message body */
+		buf = (char *)malloc(msg.nbytes);
+		if (buf == NULL)
+			error(SYSTEM, "out of memory in disp_check");
+		if (fcntl(dpd[0], F_SETFL, inp_flags=0) < 0)
+			goto fcntlerr;
+		if (readbuf(dpd[0], buf, msg.nbytes) != msg.nbytes)
+			goto readerr;
+	}
+	switch (msg.type) {		/* take appropriate action */
+	case DR_BUNDLE:
+		if (msg.nbytes != sizeof(PACKHEAD))
+			error(INTERNAL, "bad DR_BUNDLE from display process");
+		bundle_set(BS_ADD, (PACKHEAD *)buf, 1);
+		break;
+	case DR_NEWSET:
+		if (msg.nbytes % sizeof(PACKHEAD))
+			error(INTERNAL, "bad DR_NEWSET from display process");
+		disp_result(DS_STARTIMM, 0, NULL);
+		bundle_set(BS_NEW, (PACKHEAD *)buf, msg.nbytes/sizeof(PACKHEAD));
+		disp_result(DS_ENDIMM, 0, NULL);
+		disp_flush();
+		break;
+	case DR_ADDSET:
+		if (msg.nbytes % sizeof(PACKHEAD))
+			error(INTERNAL, "bad DR_ADDSET from display process");
+		disp_result(DS_STARTIMM, 0, NULL);
+		bundle_set(BS_ADD, (PACKHEAD *)buf, msg.nbytes/sizeof(PACKHEAD));
+		disp_result(DS_ENDIMM, 0, NULL);
+		disp_flush();
+		break;
+	case DR_DELSET:
+		if (msg.nbytes % sizeof(PACKHEAD))
+			error(INTERNAL, "bad DR_DELSET from display process");
+		bundle_set(BS_DEL, (PACKHEAD *)buf, msg.nbytes/sizeof(PACKHEAD));
+		break;
+	case DR_ATTEN:
+		if (msg.nbytes)
+			error(INTERNAL, "bad DR_ATTEN from display process");
+					/* send acknowledgement */
+		disp_result(DS_ACKNOW, 0, NULL);
+		return(disp_check(1));	/* block on following request */
+	case DR_SHUTDOWN:
+		if (msg.nbytes)
+			error(INTERNAL, "bad DR_SHUTDOWN from display process");
+		return(0);		/* zero return signals shutdown */
+	default:
+		error(INTERNAL, "unrecognized request from display process");
+	}
+	if (msg.nbytes)			/* clean up */
+		free(buf);
+	return(1);			/* normal return value */
+fcntlerr:
+	error(SYSTEM, "cannot change display blocking mode");
+readerr:
+	error(SYSTEM, "error reading from display process");
 }
 
 
-disp_packet(p)			/* display a packet */
-register PACKET	*p;
+int
+disp_close()			/* close our display process */
 {
+	int	rval;
+
+	if (pipesiz <= 0)
+		return(-1);
+	disp_result(DS_SHUTDOWN, 0, NULL);
+	fclose(dpout);
+	dpout = NULL;
+	pipesiz = 0;
+	return(close_process(dpd));
+}
+
+
+disp_result(type, nbytes, p)	/* queue result message to display process */
+int	type, nbytes;
+char	*p;
+{
+	MSGHEAD	msg;
+
+	msg.type = type;
+	msg.nbytes = nbytes;
+	fwrite((char *)&msg, sizeof(MSGHEAD), 1, dpout);
+	if (nbytes > 0)
+		fwrite(p, 1, nbytes, dpout);
+}
+
+
+disp_flush()			/* flush output to display */
+{
+	if (fflush(dpout) < 0)
+		error(SYSTEM, "error writing to the display process");
 }