--- ray/src/common/bsdf_t.c	2015/04/05 06:02:43	3.38
+++ ray/src/common/bsdf_t.c	2015/04/24 21:02:14	3.41
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: bsdf_t.c,v 3.38 2015/04/05 06:02:43 greg Exp $";
+static const char RCSid[] = "$Id: bsdf_t.c,v 3.41 2015/04/24 21:02:14 greg Exp $";
 #endif
 /*
  *  bsdf_t.c
@@ -569,12 +569,12 @@ SDqueryTre(const SDTre *sdt, float *coef,
 		return 0;		/* should be internal error */
 					/* get BSDF value */
 	yval = SDlookupTre(sdt->stc[tt_Y], gridPos, hc);
-	if (sdt->stc[tt_u] == NULL || sdt->stc[tt_v] == NULL) {
-		if (coef != NULL) *coef = yval;
-		return 1;		/* no color */
-	}
 	if (coef == NULL)		/* just getting hypercube? */
 		return 1;
+	if ((sdt->stc[tt_u] == NULL) | (sdt->stc[tt_v] == NULL)) {
+		*coef = yval;
+		return 1;		/* no color */
+	}
 					/* else decode color */
 	SDyuv2rgb(yval, SDlookupTre(sdt->stc[tt_u], gridPos, NULL),
 			SDlookupTre(sdt->stc[tt_v], gridPos, NULL), coef);
@@ -1194,8 +1194,8 @@ subtract_min_Y(SDNode *st)
 	} else				/* anisotropic covers entire tree */
 		vmin = SDgetTreMin(st);
 
-	if (vmin <= FTINY)
-		return .0;
+	if (vmin <= .01/M_PI)
+		return .0;		/* not worth bothering about */
 
 	SDsubtractTreVal(st, vmin);
 
@@ -1314,24 +1314,20 @@ subtract_min_RGB(C_COLOR *cs, SDNode *stc[])
 	my_min.new_stu = my_min.new_stv = NULL;
 					/* get minimum RGB value */
 	SDtraverseTre(stc[tt_Y], NULL, 0, get_min_RGB, &my_min);
-	ymin = tt_RGB_coef[0]*my_min.rgb[0] +
-			tt_RGB_coef[1]*my_min.rgb[1] +
-					tt_RGB_coef[2]*my_min.rgb[2];
-	if (ymin <= 1e-5) {
-		*cs = c_dfcolor;
-		return .0;		/* not worth bothering about */
-	}
-					/* adjust u' & v' values */
+					/* convert to C_COLOR */
+	ymin = 	c_fromSharpRGB(my_min.rgb, cs);
+	if (ymin <= .01/M_PI)		/* not worth bothering about? */
+		return .0;
+					/* adjust u' & v' trees */
 	SDtraverseTre(stc[tt_u], NULL, 0, adjust_utree, &my_min);
 	SDtraverseTre(stc[tt_v], NULL, 0, adjust_vtree, &my_min);
 	SDfreeTre(stc[tt_u]); SDfreeTre(stc[tt_v]);
 	stc[tt_u] = SDsimplifyTre(my_min.new_stu);
 	stc[tt_v] = SDsimplifyTre(my_min.new_stv);
-					/* finally, subtract Y value */
+					/* subtract Y & return hemispherical */
 	SDsubtractTreVal(stc[tt_Y], ymin);
-					/* return color and Y */
-	c_fromSharpRGB(my_min.rgb, cs);
-	return M_PI*ymin;
+
+	return M_PI * ymin;
 }
 
 /* Extract and separate diffuse portion of BSDF */