--- ray/src/rt/ambient.c	1993/08/05 16:25:05	2.21
+++ ray/src/rt/ambient.c	1994/06/02 11:45:27	2.25
@@ -59,16 +59,18 @@ int  ar;
 	ambres = ar < 0 ? 0 : ar;		/* may be done already */
 						/* set min & max radii */
 	if (ar <= 0) {
-		minarad = 0.0;
+		minarad = 0;
 		maxarad = thescene.cusize / 2.0;
 	} else {
 		minarad = thescene.cusize / ar;
-		maxarad = 16.0 * minarad;		/* heuristic */
+		maxarad = 16 * minarad;			/* heuristic */
 		if (maxarad > thescene.cusize / 2.0)
 			maxarad = thescene.cusize / 2.0;
 	}
-	if (maxarad <= FTINY)
-		maxarad = .001;
+	if (minarad <= FTINY)
+		minarad = 10*FTINY;
+	if (maxarad <= minarad)
+		maxarad = 64 * minarad;
 }
 
 
@@ -214,7 +216,9 @@ double	s;
 		/*
 		 *  Ambient level test.
 		 */
-		if (av->lvl > al || av->weight < r->rweight-FTINY)
+		if (av->lvl > al)	/* list sorted, so this works */
+			break;
+		if (av->weight < r->rweight-FTINY)
 			continue;
 		/*
 		 *  Ambient radius test.
@@ -349,6 +353,7 @@ int  creat;
 #endif
 	setbuf(ambfp, bmalloc(BUFSIZ+8));
 	if (creat) {			/* new file */
+		newheader("RADIANCE", ambfp);
 		fprintf(ambfp, "%s -av %g %g %g -ab %d -aa %g ",
 				progname, colval(ambval,RED),
 				colval(ambval,GRN), colval(ambval,BLU),
@@ -401,6 +406,8 @@ avinsert(av)				/* insert ambient value in our tree */
 register AMBVAL	 *av;
 {
 	register AMBTREE  *at;
+	register AMBVAL  *ap;
+	AMBVAL  avh;
 	FVECT  ck0;
 	double	s;
 	int  branch;
@@ -424,8 +431,13 @@ register AMBVAL	 *av;
 			}
 		at = at->kid + branch;
 	}
-	av->next = at->alist;
-	at->alist = av;
+	avh.next = at->alist;		/* order by increasing level */
+	for (ap = &avh; ap->next != NULL; ap = ap->next)
+		if (ap->next->lvl >= av->lvl)
+			break;
+	av->next = ap->next;
+	ap->next = av;
+	at->alist = avh.next;
 }
 
 
@@ -493,7 +505,8 @@ ambsync()			/* synchronize ambient file */
 			avinsert(avstore(&avs));
 			n -= AMBVALSIZ;
 		}
-		if (n)				/* alignment */
+		/*** seek always as safety measure
+		if (n) ***/			/* alignment */
 			if (lseek(fileno(ambfp), flen-n, 0) < 0)
 				goto seekerr;
 	}