--- ray/src/rt/ambient.c	1990/06/26 09:00:07	1.10
+++ ray/src/rt/ambient.c	1991/06/06 10:48:50	1.13
@@ -34,14 +34,19 @@ extern int  ambounce;		/* number of ambient bounces */
 extern char  *amblist[];	/* ambient include/exclude list */
 extern int  ambincl;		/* include == 1, exclude == 0 */
 
-OBJECT  ambset[256]={0};	/* ambient include/exclude set */
+#define  MAXASET	511	/* maximum number of elements in ambient set */
+OBJECT  ambset[MAXASET+1]={0};	/* ambient include/exclude set */
 
 double  maxarad;		/* maximum ambient radius */
 double  minarad;		/* minimum ambient radius */
 
+/*
+ * Since we've defined our vectors as float below to save space,
+ * watch out for changes in the definitions of VCOPY() and DOT().
+ */
 typedef struct ambval {
-	FVECT  pos;		/* position in space */
-	FVECT  dir;		/* normal direction */
+	float  pos[3];		/* position in space */
+	float  dir[3];		/* normal direction */
 	int  lvl;		/* recursion level of parent ray */
 	float  weight;		/* weight of parent ray */
 	COLOR  val;		/* computed ambient value */
@@ -101,13 +106,19 @@ char  *afile;
 ambnotify(obj)			/* record new modifier */
 OBJECT  obj;
 {
+	static int  hitlimit = 0;
 	register OBJREC  *o = objptr(obj);
 	register char  **amblp;
 
-	if (!ismodifier(o->otype))
+	if (hitlimit || !ismodifier(o->otype))
 		return;
 	for (amblp = amblist; *amblp != NULL; amblp++)
 		if (!strcmp(o->oname, *amblp)) {
+			if (ambset[0] >= MAXASET) {
+				error(WARNING, "too many modifiers in ambient list");
+				hitlimit++;
+				return;		/* should this be fatal? */
+			}
 			insertelem(ambset, obj);
 			return;
 		}
@@ -202,7 +213,7 @@ double  s;
 		for (j = 0; j < 3; j++)
 			d += (r->rop[j] - av->pos[j]) *
 					(av->dir[j] + r->ron[j]);
-		if (d < -minarad)
+		if (d*0.5 < -minarad*ambacc)
 			continue;
 		/*
 		 *  Jittering final test reduces image artifacts.
@@ -271,6 +282,7 @@ register RAY  *r;
 {
 	extern int  ambcmp();
 	extern double  sin(), cos(), sqrt();
+	int  hlist[4];
 	double  phi, xd, yd, zd;
 	double  b, b2;
 	register AMBSAMP  *div;
@@ -295,7 +307,8 @@ register RAY  *r;
 		div = (AMBSAMP *)malloc(ndivs*sizeof(AMBSAMP));
 		if (div == NULL)
 			error(SYSTEM, "out of memory in doambient");
-	}
+	} else
+		div = NULL;
 					/* make axes */
 	uy[0] = uy[1] = uy[2] = 0.0;
 	for (k = 0; k < 3; k++)
@@ -305,23 +318,31 @@ register RAY  *r;
 	fcross(ux, r->ron, uy);
 	normalize(ux);
 	fcross(uy, ux, r->ron);
+					/* set up urand */
+	hlist[0] = r->rno;
 						/* sample divisions */
 	arad = 0.0;
 	ne = 0;
-	for (i = 0; i < nt; i++)
+	for (i = 0; i < nt; i++) {
+		hlist[1] = i;
 		for (j = 0; j < np; j++) {
 			rayorigin(&ar, r, AMBIENT, 0.5);	/* pretested */
-			zd = sqrt((i+frandom())/nt);
-			phi = 2.0*PI * (j+frandom())/np;
+			hlist[2] = j;
+			hlist[3] = 0;
+			zd = sqrt((i+urand(ilhash(hlist,4)))/nt);
+			hlist[3] = 1;
+			phi = 2.0*PI * (j+urand(ilhash(hlist,4)))/np;
 			xd = cos(phi) * zd;
 			yd = sin(phi) * zd;
 			zd = sqrt(1.0 - zd*zd);
 			for (k = 0; k < 3; k++)
 				ar.rdir[k] = xd*ux[k]+yd*uy[k]+zd*r->ron[k];
+			dimlist[ndims++] = i*np + j + 38813;
 			rayvalue(&ar);
+			ndims--;
 			if (ar.rot < FHUGE)
 				arad += 1.0 / ar.rot;
-			if (ns > 0) {			/* save division */
+			if (div != NULL) {		/* save division */
 				div[ne].k = 0.0;
 				copycolor(div[ne].v, ar.rcol);
 				div[ne].n = 0;
@@ -356,6 +377,7 @@ register RAY  *r;
 			} else
 				addcolor(acol, ar.rcol);
 		}
+	}
 	for (k = 0; k < ne; k++) {		/* compute errors */
 		if (div[k].n > 1)
 			div[k].k /= div[k].n;
@@ -371,14 +393,21 @@ register RAY  *r;
 						/* super-sample */
 	for (i = ns; i > 0; i--) {
 		rayorigin(&ar, r, AMBIENT, 0.5);	/* pretested */
-		zd = sqrt((div[0].t+frandom())/nt);
-		phi = 2.0*PI * (div[0].p+frandom())/np;
+		hlist[1] = div[0].t;
+		hlist[2] = div[0].p;
+		hlist[3] = 0;
+		zd = sqrt((div[0].t+urand(ilhash(hlist,4)+div[0].n))/nt);
+		hlist[3] = 1;
+		phi = 2.0*PI * (div[0].p+urand(ilhash(hlist,4)+div[0].n))/np;
 		xd = cos(phi) * zd;
 		yd = sin(phi) * zd;
 		zd = sqrt(1.0 - zd*zd);
 		for (k = 0; k < 3; k++)
 			ar.rdir[k] = xd*ux[k]+yd*uy[k]+zd*r->ron[k];
+		dimlist[ndims++] = div[0].t*np + div[0].p + 38813;
 		rayvalue(&ar);
+		ndims--;
+		rayvalue(&ar);
 		if (ar.rot < FHUGE)
 			arad += 1.0 / ar.rot;
 						/* recompute error */
@@ -396,8 +425,11 @@ register RAY  *r;
 
 		if (ne >= i) {		/* extract darkest division */
 			ne--;
-			if (div[ne].n > 1)
-				scalecolor(div[ne].v, 1.0/div[ne].n);
+			if (div[ne].n > 1) {
+				b = 1.0/div[ne].n;
+				scalecolor(div[ne].v, b);
+				div[ne].n = 1;
+			}
 			addcolor(acol, div[ne].v);
 		}
 	}
@@ -410,7 +442,7 @@ register RAY  *r;
 		arad = maxarad;
 	else if (arad < minarad)
 		arad = minarad;
-	if (ns > 0)
+	if (div != NULL)
 		free((char *)div);
 	return(arad);
 }