--- ray/src/rt/virtuals.c	2004/03/01 18:11:20	2.12
+++ ray/src/rt/virtuals.c	2012/09/14 13:34:02	2.20
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: virtuals.c,v 2.12 2004/03/01 18:11:20 greg Exp $";
+static const char	RCSid[] = "$Id: virtuals.c,v 2.20 2012/09/14 13:34:02 greg Exp $";
 #endif
 /*
  * Routines for simulating virtual light sources
@@ -21,16 +21,31 @@ static const char	RCSid[] = "$Id: virtuals.c,v 2.12 20
 #define  MINSAMPLES	16		/* minimum number of pretest samples */
 #define  STESTMAX	32		/* maximum seeks per sample */
 
+#define FEQ(a,b)	((a)-(b)+FTINY >= 0 && (b)-(a)+FTINY >= 0)
 
+
 static OBJECT  *vobject;		/* virtual source objects */
 static int  nvobjects = 0;		/* number of virtual source objects */
 
 
+static int
+isident4(MAT4 m)
+{
+	int	i, j;
+
+	for (i = 4; i--; )
+		for (j = 4; j--; )
+			if (!FEQ(m[i][j], i==j))
+				return(0);
+	return(1);
+}
+
+
 void
-markvirtuals()			/* find and mark virtual sources */
+markvirtuals(void)			/* find and mark virtual sources */
 {
-	register OBJREC  *o;
-	register int  i;
+	OBJREC  *o;
+	int  i;
 					/* check number of direct relays */
 	if (directrelay <= 0)
 		return;
@@ -70,11 +85,12 @@ markvirtuals()			/* find and mark virtual sources */
 
 
 void
-addvirtuals(sn, nr)		/* add virtuals associated with source */
-int  sn;
-int  nr;
+addvirtuals(		/* add virtuals associated with source */
+	int  sn,
+	int  nr
+)
 {
-	register int  i;
+	int  i;
 				/* check relay limit first */
 	if (nr <= 0)
 		return;
@@ -88,13 +104,14 @@ int  nr;
 
 
 void
-vproject(o, sn, n)		/* create projected source(s) if they exist */
-OBJREC  *o;
-int  sn;
-int  n;
+vproject(		/* create projected source(s) if they exist */
+	OBJREC  *o,
+	int  sn,
+	int  n
+)
 {
-	register int  i;
-	register VSMATERIAL  *vsmat;
+	int  i;
+	VSMATERIAL  *vsmat;
 	MAT4  proj;
 	int  ns;
 
@@ -116,14 +133,17 @@ int  n;
 
 
 OBJREC *
-vsmaterial(o)			/* get virtual source material pointer */
-OBJREC  *o;
+vsmaterial(			/* get virtual source material pointer */
+	OBJREC  *o
+)
 {
-	register int  i;
-	register OBJREC  *m;
+	int  i;
+	OBJREC  *m;
 
 	i = o->omod;
 	m = findmaterial(objptr(i));
+	if (m == NULL)
+		return(objptr(i));
 	if (m->otype != MAT_ILLUM || m->oargs.nsargs < 1 ||
 			!strcmp(m->oargs.sarg[0], VOIDID) ||
 			(i = lastmod(objndx(m), m->oargs.sarg[0])) == OVOID)
@@ -133,17 +153,20 @@ OBJREC  *o;
 
 
 int
-makevsrc(op, sn, pm)		/* make virtual source if reasonable */
-OBJREC  *op;
-register int  sn;
-MAT4  pm;
+makevsrc(		/* make virtual source if reasonable */
+	OBJREC  *op,
+	int  sn,
+	MAT4  pm
+)
 {
 	FVECT  nsloc, nsnorm, ocent, v;
 	double  maxrad2, d;
 	int  nsflags;
 	SPOT  theirspot, ourspot;
-	register int  i;
-
+	int  i;
+					/* check for no-op */
+	if (isident4(pm))
+		return(0);
 	nsflags = source[sn].sflags | (SVIRTUAL|SSPOT|SFOLLOW);
 					/* get object center and max. radius */
 	maxrad2 = getdisk(ocent, op, sn);
@@ -253,14 +276,16 @@ MAT4  pm;
 	return(i);
 memerr:
 	error(SYSTEM, "out of memory in makevsrc");
+	return -1; /* pro forma return */
 }
 
 
 double
-getdisk(oc, op, sn)		/* get visible object disk */
-FVECT  oc;
-OBJREC  *op;
-register int  sn;
+getdisk(		/* get visible object disk */
+	FVECT  oc,
+	OBJREC  *op,
+	int  sn
+)
 {
 	double  rad2, roffs, offs, d, rd, rdoto;
 	FVECT  rnrm, nrm;
@@ -289,21 +314,22 @@ register int  sn;
 
 
 int
-vstestvis(f, o, oc, or2, sn)		/* pretest source visibility */
-int  f;			/* virtual source flags */
-OBJREC  *o;		/* relay object */
-FVECT  oc;		/* relay object center */
-double  or2;		/* relay object radius squared */
-register int  sn;	/* target source number */
+vstestvis(		/* pretest source visibility */
+	int  f,			/* virtual source flags */
+	OBJREC  *o,		/* relay object */
+	FVECT  oc,		/* relay object center */
+	double  or2,		/* relay object radius squared */
+	int  sn	/* target source number */
+)
 {
 	RAY  sr;
 	FVECT  onorm;
 	FVECT  offsdir;
 	SRCINDEX  si;
-	double  or, d;
+	double  or, d, d1;
 	int  stestlim, ssn;
 	int  nhit, nok;
-	register int  i, n;
+	int  i, n;
 				/* return if pretesting disabled */
 	if (vspretest <= 0)
 		return(f);
@@ -351,8 +377,7 @@ register int  sn;	/* target source number */
 				sr.rorg[i] = oc[i] + offsdir[i] + d*onorm[i];
 				sr.rdir[i] = -onorm[i];
 			}
-			sr.rmax = 0.0;
-			rayorigin(&sr, NULL, PRIMARY, 1.0);
+			rayorigin(&sr, PRIMARY, NULL, NULL);
 		} while (!(*ofun[o->otype].funp)(o, &sr));
 					/* check against source */
 		VCOPY(sr.rorg, sr.rop);	/* starting from intersection */
@@ -366,14 +391,21 @@ register int  sn;	/* target source number */
 		}
 		sr.revf = srcvalue;
 		rayvalue(&sr);			/* check sample validity */
-		if (bright(sr.rcol) <= FTINY)
+		if ((d = bright(sr.rcol)) <= FTINY)
 			continue;
 		nok++;			/* got sample; check obstructions */
 		rayclear(&sr);
 		sr.revf = raytrace;
 		rayvalue(&sr);
-		if (bright(sr.rcol) > FTINY)
+		if ((d1 = bright(sr.rcol)) > FTINY) {
+			if (d - d1 > FTINY) {
+#ifdef DEBUG
+				fprintf(stderr, "\tpartially shadowed\n");
+#endif
+				return(f);	/* intervening transmitter */
+			}
 			nhit++;
+		}
 		if (nhit > 0 && nhit < nok) {
 #ifdef DEBUG
 			fprintf(stderr, "\tpartially occluded\n");
@@ -396,12 +428,11 @@ register int  sn;	/* target source number */
 
 #ifdef DEBUG
 void
-virtverb(sn, fp)	/* print verbose description of virtual source */
-register int  sn;
-FILE  *fp;
+virtverb(	/* print verbose description of virtual source */
+	int  sn,
+	FILE  *fp
+)
 {
-	register int  i;
-
 	fprintf(fp, "%s virtual source %d in %s %s\n",
 			source[sn].sflags & SDISTANT ? "distant" : "local",
 			sn, ofun[source[sn].so->otype].funame,