--- ray/src/gen/mkillum2.c	1991/08/22 12:12:23	1.11
+++ ray/src/gen/mkillum2.c	1994/01/07 14:51:46	2.6
@@ -26,8 +26,7 @@ char  *nm;
 	sprintf(errmsg, "(%s): cannot make illum for %s \"%s\"",
 			nm, ofun[ob->otype].funame, ob->oname);
 	error(WARNING, errmsg);
-	if (!(il->flags & IL_LIGHT))
-		printobj(il->altmat, ob);
+	printobj(il->altmat, ob);
 }
 
 
@@ -67,7 +66,21 @@ char  *nm;
 	distarr = (float *)calloc(n, 3*sizeof(float));
 	if (distarr == NULL)
 		error(SYSTEM, "out of memory in o_face");
-	mkaxes(u, v, fa->norm);
+				/* take first edge longer than sqrt(area) */
+	for (j = fa->nv-1, i = 0; i < fa->nv; j = i++) {
+		u[0] = VERTEX(fa,i)[0] - VERTEX(fa,j)[0];
+		u[1] = VERTEX(fa,i)[1] - VERTEX(fa,j)[1];
+		u[2] = VERTEX(fa,i)[2] - VERTEX(fa,j)[2];
+		if ((r1 = DOT(u,u)) >= fa->area-FTINY)
+			break;
+	}
+	if (i < fa->nv) {	/* got one! -- let's align our axes */
+		r2 = 1.0/sqrt(r1);
+		u[0] *= r2; u[1] *= r2; u[2] *= r2;
+		fcross(v, fa->norm, u);
+	} else			/* oh well, we'll just have to wing it */
+		mkaxes(u, v, fa->norm);
+				/* now, find limits in (u,v) coordinates */
 	ur[0] = vr[0] = FHUGE;
 	ur[1] = vr[1] = -FHUGE;
 	for (i = 0; i < fa->nv; i++) {
@@ -88,7 +101,7 @@ char  *nm;
 		    h = ilhash(dim, 3) + i;
 		    multisamp(sp, 2, urand(h));
 		    r1 = (dim[1] + sp[0])/nalt;
-		    r2 = (dim[2] + sp[1])/nazi;
+		    r2 = (dim[2] + sp[1] - .5)/nazi;
 		    flatdir(dn, r1, r2);
 		    for (j = 0; j < 3; j++)
 			dir[j] = -dn[0]*u[j] - dn[1]*v[j] - dn[2]*fa->norm[j];
@@ -116,10 +129,12 @@ char  *nm;
 		}
 	rayflush(rt);
 				/* write out the face and its distribution */
-	average(il, distarr, nalt*nazi);
-	if (il->sampdens > 0)
-		flatout(il, distarr, nalt, nazi, u, v, fa->norm);
-	illumout(il, ob);
+	if (average(il, distarr, nalt*nazi)) {
+		if (il->sampdens > 0)
+			flatout(il, distarr, nalt, nazi, u, v, fa->norm);
+		illumout(il, ob);
+	} else
+		printobj(il->altmat, ob);
 				/* clean up */
 	freeface(ob);
 	free((char *)distarr);
@@ -164,7 +179,7 @@ char  *nm;
 		    multisamp(sp, 4, urand(ilhash(dim,3)+i));
 					/* random direction */
 		    r1 = (dim[1] + sp[0])/nalt;
-		    r2 = (dim[2] + sp[1])/nazi;
+		    r2 = (dim[2] + sp[1] - .5)/nazi;
 		    rounddir(dir, r1, r2);
 					/* random location */
 		    mkaxes(u, v, dir);		/* yuck! */
@@ -183,12 +198,14 @@ char  *nm;
 		}
 	rayflush(rt);
 				/* write out the sphere and its distribution */
-	average(il, distarr, nalt*nazi);
-	if (il->sampdens > 0)
-		roundout(il, distarr, nalt, nazi);
-	else
-		objerror(ob, WARNING, "diffuse distribution");
-	illumout(il, ob);
+	if (average(il, distarr, nalt*nazi)) {
+		if (il->sampdens > 0)
+			roundout(il, distarr, nalt, nazi);
+		else
+			objerror(ob, WARNING, "diffuse distribution");
+		illumout(il, ob);
+	} else
+		printobj(il->altmat, ob);
 				/* clean up */
 	free((char *)distarr);
 }
@@ -232,7 +249,7 @@ char  *nm;
 		    multisamp(sp, 4, urand(ilhash(dim,3)+i));
 					/* random direction */
 		    r1 = (dim[1] + sp[0])/nalt;
-		    r2 = (dim[2] + sp[1])/nalt;
+		    r2 = (dim[2] + sp[1] - .5)/nazi;
 		    flatdir(dn, r1, r2);
 		    for (j = 0; j < 3; j++)
 			dir[j] = -dn[0]*u[j] - dn[1]*v[j] - dn[2]*co->ad[j];
@@ -243,7 +260,7 @@ char  *nm;
 		    r1 = r3*cos(r2);
 		    r2 = r3*sin(r2);
 		    for (j = 0; j < 3; j++)
-			org[j] = CO_P0(co)[j] + r1*u[j] + r1*v[j] +
+			org[j] = CO_P0(co)[j] + r1*u[j] + r2*v[j] +
 					.001*co->ad[j];
 
 					/* send sample */
@@ -251,10 +268,12 @@ char  *nm;
 		}
 	rayflush(rt);
 				/* write out the ring and its distribution */
-	average(il, distarr, nalt*nazi);
-	if (il->sampdens > 0)
-		flatout(il, distarr, nalt, nazi, u, v, co->ad);
-	illumout(il, ob);
+	if (average(il, distarr, nalt*nazi)) {
+		if (il->sampdens > 0)
+			flatout(il, distarr, nalt, nazi, u, v, co->ad);
+		illumout(il, ob);
+	} else
+		printobj(il->altmat, ob);
 				/* clean up */
 	freecone(ob);
 	free((char *)distarr);
@@ -285,6 +304,7 @@ register struct rtproc  *rt;
 	if (rt->nrays <= 0)
 		return;
 	bzero(rt->buf+6*rt->nrays, 6*sizeof(float));
+	errno = 0;
 	if ( process(rt->pd, (char *)rt->buf, (char *)rt->buf,
 			3*sizeof(float)*rt->nrays,
 			6*sizeof(float)*(rt->nrays+1)) <