--- ray/src/rt/ambcomp.c	1991/06/11 16:37:49	1.4
+++ ray/src/rt/ambcomp.c	1991/06/13 10:54:00	1.6
@@ -179,10 +179,27 @@ FVECT  pg, dg;
 			}
 			addcolor(acol, dp->v);
 		}
-		if (pg != NULL)
-			posgradient(pg, div, &hemi);
-		if (dg != NULL)
-			dirgradient(dg, div, &hemi);
+		b = bright(acol);
+		if (b > FTINY) {
+			b = ndivs/b;
+			if (pg != NULL) {
+				posgradient(pg, div, &hemi);
+				for (i = 0; i < 3; i++)
+					pg[i] *= b;
+			}
+			if (dg != NULL) {
+				dirgradient(dg, div, &hemi);
+				for (i = 0; i < 3; i++)
+					dg[i] *= b;
+			}
+		} else {
+			if (pg != NULL)
+				for (i = 0; i < 3; i++)
+					pg[i] = 0.0;
+			if (dg != NULL)
+				for (i = 0; i < 3; i++)
+					dg[i] = 0.0;
+		}
 		free((char *)div);
 	}
 	b = 1.0/ndivs;
@@ -238,6 +255,11 @@ register AMBHEMI  *hp;
 	dp = da;
 	for (i = 0; i < hp->nt; i++)
 		for (j = 0; j < hp->np; j++) {
+#ifdef  DEBUG
+			if (dp->t != i || dp->p != j)
+				error(CONSISTENCY,
+					"division order in comperrs");
+#endif
 			b = bright(dp[0].v);
 			if (i > 0) {		/* from above */
 				b2 = bright(dp[-hp->np].v) - b;
@@ -321,7 +343,7 @@ AMBHEMI  *hp;
 		yd += mag0*sinp + mag1*cosp;
 	}
 	for (i = 0; i < 3; i++)
-		gv[i] = xd*hp->ux[i] + yd*hp->uy[i];
+		gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])/PI;
 }
 
 
@@ -353,5 +375,5 @@ AMBHEMI  *hp;
 		yd += mag * sin(phi);
 	}
 	for (i = 0; i < 3; i++)
-		gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])/(hp->nt*hp->np);
+		gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])*PI/(hp->nt*hp->np);
 }