--- ray/src/common/jitteraperture.c	2021/12/15 01:38:50	2.2
+++ ray/src/common/jitteraperture.c	2022/01/14 22:57:40	2.3
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: jitteraperture.c,v 2.2 2021/12/15 01:38:50 greg Exp $";
+static const char	RCSid[] = "$Id: jitteraperture.c,v 2.3 2022/01/14 22:57:40 greg Exp $";
 #endif
 /*
  *  jitteraperture.c - routine to sample depth-of-field
@@ -24,7 +24,7 @@ double  dia
 )
 {
 	RREAL  df[2];
-	double  vc;
+	double  adj;
 	int  i;
 					/* are we even needed? */
 	if (dia <= FTINY)
@@ -33,32 +33,40 @@ double  dia
 	square2disk(df, frandom(), frandom());
 	df[0] *= .5*dia;
 	df[1] *= .5*dia;
+
 	if ((v->type == VT_PER) | (v->type == VT_PAR)) {
-		double	adj = 1.0;	/* basic view cases */
+		adj = 1.0;		/* basic view cases */
 		if (v->type == VT_PER)
 			adj /= DOT(direc, v->vdir);
 		df[0] /= sqrt(v->hn2);
 		df[1] /= sqrt(v->vn2);
 		for (i = 3; i--; ) {
-			vc = v->vp[i] + adj*v->vdist*direc[i];
-			orig[i] += df[0]*v->hvec[i] +
+			orig[i] = v->vp[i] + df[0]*v->hvec[i] +
 						df[1]*v->vvec[i] ;
-			direc[i] = vc - orig[i];
+			direc[i] = v->vp[i] + adj*v->vdist*direc[i]
+					- orig[i];
 		}
 	} else {			/* difficult view cases */
-		double	dfd = PI/4.*dia*(.5 - frandom());
+		adj = PI/4.*dia*(.5 - frandom());
 		if ((v->type != VT_ANG) & (v->type != VT_PLS)) {
 			if (v->type != VT_CYL)
 				df[0] /= sqrt(v->hn2);
 			df[1] /= sqrt(v->vn2);
 		}
 		for (i = 3; i--; ) {
-			vc = v->vp[i] + v->vdist*direc[i];
-			orig[i] += df[0]*v->hvec[i] +
+			orig[i] = v->vp[i] + df[0]*v->hvec[i] +
 						df[1]*v->vvec[i] +
-						dfd*v->vdir[i] ;
-			direc[i] = vc - orig[i];
+						adj*v->vdir[i] ;
+			direc[i] = v->vp[i] + v->vdist*direc[i]
+					- orig[i];
 		}
 	}
-	return(normalize(direc) != 0.0);
+	if (normalize(direc) == 0.0)
+		return(0);
+	if ((adj = v->vfore) <= FTINY)
+		return(1);
+	if (v->type == VT_PER)
+		adj /= DOT(direc, v->vdir);
+	VSUM(orig, orig, direc, adj);
+	return(1);
 }