--- ray/src/rt/source.c	1992/10/22 09:55:16	2.7
+++ ray/src/rt/source.c	1993/08/18 00:19:05	2.12
@@ -1,4 +1,4 @@
-/* Copyright (c) 1992 Regents of the University of California */
+/* Copyright (c) 1993 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -81,7 +81,7 @@ marksources()			/* find and mark source objects */
 		if (m->otype == MAT_GLOW) {
 			source[ns].sflags |= SPROX;
 			source[ns].sl.prox = m->oargs.farg[3];
-			if (o->otype == OBJ_SOURCE)
+			if (source[ns].sflags & SDISTANT)
 				source[ns].sflags |= SSKIP;
 		} else if (m->otype == MAT_SPOT) {
 			source[ns].sflags |= SSPOT;
@@ -355,34 +355,44 @@ char  *p;			/* data for f */
  * because they are very nasty and difficult to understand.
  */
 
-/* wrongillum *
+/* illumblock *
  *
  * We cannot allow an illum to pass to another illum, because that
  * would almost certainly constitute overcounting.
  * However, we do allow an illum to pass to another illum
  * that is actually going to relay to a virtual light source.
+ * We also prevent an illum from passing to a glow; this provides a
+ * convenient mechanism for defining detailed light source
+ * geometry behind (or inside) an effective radiator.
  */
 
-#define  wrongillum(m, r)	(!(source[r->rsrc].sflags&SVIRTUAL) && \
-			objptr(source[r->rsrc].so->omod)->otype==MAT_ILLUM)
+static int weaksrcmod(obj) int obj;	/* efficiency booster function */
+{register OBJREC *o = objptr(obj);
+return(o->otype==MAT_ILLUM|o->otype==MAT_GLOW);}
 
+#define  illumblock(m, r)	(!(source[r->rsrc].sflags&SVIRTUAL) && \
+				r->rod > 0.0 && \
+				weaksrcmod(source[r->rsrc].so->omod))
+
 /* wrongsource *
  *
  * This source is the wrong source (ie. overcounted) if we are
  * aimed to a different source than the one we hit and the one
- * we hit is not an illum which should be passed.
+ * we hit is not an illum that should be passed.
  */
 
 #define  wrongsource(m, r)	(r->rsrc>=0 && source[r->rsrc].so!=r->ro && \
-				(m->otype!=MAT_ILLUM || wrongillum(m,r)))
+				(m->otype!=MAT_ILLUM || illumblock(m,r)))
 
 /* distglow *
  *
  * A distant glow is an object that sometimes acts as a light source,
  * but is too far away from the test point to be one in this case.
+ * (Glows with negative radii should NEVER participate in illumination.)
  */
 
 #define  distglow(m, r)		(m->otype==MAT_GLOW && \
+				m->oargs.farg[3] >= -FTINY && \
 				r->rot > m->oargs.farg[3])
 
 /* badcomponent *
@@ -398,13 +408,6 @@ char  *p;			/* data for f */
 				!(r->crtype&SHADOW || r->rod < 0.0 || \
 					distglow(m, r)))
 
-/* overcount *
- *
- * All overcounting possibilities are contained here.
- */
-
-#define  overcount(m, r)	(badcomponent(m,r) || wrongsource(m,r))
-
 /* passillum *
  *
  * An illum passes to another material type when we didn't hit it
@@ -418,10 +421,10 @@ char  *p;			/* data for f */
 
 /* srcignore *
  *
- * The -di flag renders light sources invisible, and here is the test.
+ * The -dv flag is normally on for sources to be visible.
  */
 
-#define  srcignore(m, r)	(directinvis && !(r->crtype&SHADOW) && \
+#define  srcignore(m, r)	(!directvis && !(r->crtype&SHADOW) && \
 				!distglow(m, r))
 
 
@@ -430,8 +433,10 @@ register OBJREC  *m;
 register RAY  *r;
 {
 						/* check for over-counting */
-	if (overcount(m, r))
+	if (badcomponent(m, r))
 		return;
+	if (wrongsource(m,r))
+		return;
 						/* check for passed illum */
 	if (passillum(m, r)) {
 		if (m->oargs.nsargs < 1 || !strcmp(m->oargs.sarg[0], VOIDID))
@@ -448,7 +453,7 @@ register RAY  *r;
 	if (srcignore(m, r))
 		return;
 						/* check for outside spot */
-	if (m->otype==MAT_SPOT && spotout(r, (SPOT *)m->os, r->rot>=FHUGE))
+	if (m->otype==MAT_SPOT && spotout(r, makespot(m), r->rot>=FHUGE))
 		return;
 						/* get distribution pattern */
 	raytexture(r, m->omod);