--- ray/src/rt/source.c	1992/10/22 09:55:16	2.7
+++ ray/src/rt/source.c	1995/04/25 19:51:38	2.16
@@ -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";
@@ -68,6 +68,9 @@ marksources()			/* find and mark source objects */
 				o->otype != OBJ_SOURCE &&
 				m->oargs.farg[3] <= FTINY)
 			continue;			/* don't bother */
+		if (m->oargs.farg[0] <= FTINY && m->oargs.farg[1] <= FTINY &&
+				m->oargs.farg[2] <= FTINY)
+			continue;			/* don't bother */
 
 		if (sfun[o->otype].of == NULL ||
 				sfun[o->otype].of->setsrc == NULL)
@@ -81,7 +84,7 @@ 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;
@@ -152,7 +155,7 @@ SRCINDEX  *si;			/* source sample index */
 
 
 srcvalue(r)			/* punch ray to source and compute value */
-RAY  *r;
+register RAY  *r;
 {
 	register SRCREC  *sp;
 
@@ -161,7 +164,8 @@ RAY  *r;
 					/* check intersection */
 		if (!(*ofun[sp->so->otype].funp)(sp->so, r))
 			return;
-		raycont(r);		/* compute contribution */
+		if (!rayshade(r, r->ro->omod))	/* compute contribution */
+			goto nomat;
 		return;
 	}
 					/* compute intersection */
@@ -169,9 +173,11 @@ RAY  *r;
 			(*ofun[sp->so->otype].funp)(sp->so, r)) {
 		if (sp->sa.success >= 0)
 			sp->sa.success++;
-		raycont(r);		/* compute contribution */
+		if (!rayshade(r, r->ro->omod))	/* compute contribution */
+			goto nomat;
 		return;
 	}
+					/* we missed our mark! */
 	if (sp->sa.success < 0)
 		return;			/* bitched already */
 	sp->sa.success -= AIMREQT;
@@ -180,6 +186,9 @@ RAY  *r;
 	sprintf(errmsg, "aiming failure for light source \"%s\"",
 			sp->so->oname);
 	error(WARNING, errmsg);		/* issue warning */
+	return;
+nomat:
+	objerror(r->ro, USER, "material not found");
 }
 
 
@@ -299,8 +308,10 @@ char  *p;			/* data for f */
 						/* modify threshold */
 	ourthresh = shadthresh / r->rweight;
 						/* test for shadows */
-	nhits = 0;
-	for (sn = 0; sn < ncnts; sn++) {
+	for (nhits = 0, hwt = 0.0, sn = 0; sn < ncnts;
+			hwt += (double)source[scp->sno].nhits /
+				(double)source[scp->sno].ntests,
+			sn++) {
 						/* check threshold */
 		if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
 				cntord[sn].brt-cntord[sn+nshadcheck].brt)
@@ -316,7 +327,8 @@ char  *p;			/* data for f */
 				( sr.ro != source[scp->sno].so ||
 				source[scp->sno].sflags & SFOLLOW )) {
 						/* follow entire path */
-			raycont(&sr);
+			if (!raycont(&sr))
+				objerror(sr.ro, USER, "material not found");
 			if (trace != NULL)
 				(*trace)(&sr);	/* trace execution */
 			if (bright(sr.rcol) <= FTINY)
@@ -329,13 +341,13 @@ char  *p;			/* data for f */
 		nhits++;
 		source[scp->sno].nhits++;
 	}
-					/* surface hit rate */
-	if (sn > 0)
-		hwt = (double)nhits / (double)sn;
+					/* source hit rate */
+	if (hwt > FTINY)
+		hwt = (double)nhits / hwt;
 	else
 		hwt = 0.5;
 #ifdef DEBUG
-	sprintf(errmsg, "%d tested, %d untested, %f hit rate\n",
+	sprintf(errmsg, "%d tested, %d untested, %f conditional hit rate\n",
 			sn, ncnts-sn, hwt);
 	eputs(errmsg);
 #endif
@@ -344,6 +356,8 @@ char  *p;			/* data for f */
 		scp = srccnt + cntord[sn].sndx;
 		prob = hwt * (double)source[scp->sno].nhits /
 				(double)source[scp->sno].ntests;
+		if (prob > 1.0)
+			prob = 1.0;
 		scalecolor(scp->val, prob);
 		addcolor(r->rcol, scp->val);
 	}
@@ -355,34 +369,44 @@ 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 +422,6 @@ 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 +435,10 @@ 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))
 
 
@@ -430,26 +447,27 @@ register OBJREC  *m;
 register RAY  *r;
 {
 						/* check for over-counting */
-	if (overcount(m, r))
-		return;
+	if (badcomponent(m, r))
+		return(1);
+	if (wrongsource(m,r))
+		return(1);
 						/* check for passed illum */
 	if (passillum(m, r)) {
-		if (m->oargs.nsargs < 1 || !strcmp(m->oargs.sarg[0], VOIDID))
-			raytrans(r);
-		else
-			rayshade(r, modifier(m->oargs.sarg[0]));
-		return;
+		if (m->oargs.nsargs && strcmp(m->oargs.sarg[0], VOIDID))
+			return(rayshade(r, modifier(m->oargs.sarg[0])));
+		raytrans(r);
+		return(1);
 	}
 					/* otherwise treat as source */
 						/* check for behind */
 	if (r->rod < 0.0)
-		return;
+		return(1);
 						/* check for invisibility */
 	if (srcignore(m, r))
-		return;
+		return(1);
 						/* check for outside spot */
-	if (m->otype==MAT_SPOT && spotout(r, (SPOT *)m->os, r->rot>=FHUGE))
-		return;
+	if (m->otype==MAT_SPOT && spotout(r, makespot(m), r->rot>=FHUGE))
+		return(1);
 						/* get distribution pattern */
 	raytexture(r, m->omod);
 						/* get source color */
@@ -458,4 +476,5 @@ register RAY  *r;
 			  m->oargs.farg[2]);
 						/* modify value */
 	multcolor(r->rcol, r->pcol);
+	return(1);
 }