--- ray/src/common/cone.c	1989/02/02 10:34:30	1.1
+++ ray/src/common/cone.c	1991/10/23 13:43:12	1.6
@@ -1,4 +1,4 @@
-/* Copyright (c) 1986 Regents of the University of California */
+/* Copyright (c) 1991 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -49,6 +49,7 @@ register OBJREC  *o;
 int  getxf;
 {
 	double  fabs(), sqrt();
+	int  sgn0, sgn1;
 	register CONE  *co;
 
 	if ((co = (CONE *)o->os) == NULL) {
@@ -62,18 +63,43 @@ int  getxf;
 		if (o->otype == OBJ_CYLINDER || o->otype == OBJ_TUBE) {
 			if (o->oargs.nfargs != 7)
 				goto argcerr;
-			if (co->ca[6] <= FTINY)
+			if (co->ca[6] < -FTINY) {
+				objerror(o, WARNING, "negative radius");
+				o->otype = o->otype == OBJ_CYLINDER ?
+						OBJ_TUBE : OBJ_CYLINDER;
+				co->ca[6] = -co->ca[6];
+			} else if (co->ca[6] <= FTINY)
 				goto raderr;
 			co->r0 = co->r1 = 6;
 		} else {
 			if (o->oargs.nfargs != 8)
 				goto argcerr;
-			if (co->ca[6] < 0.0 || co->ca[7] < 0.0)
+			if (co->ca[6] < -FTINY) sgn0 = -1;
+			else if (co->ca[6] > FTINY) sgn0 = 1;
+			else sgn0 = 0;
+			if (co->ca[7] < -FTINY) sgn1 = -1;
+			else if (co->ca[7] > FTINY) sgn1 = 1;
+			else sgn1 = 0;
+			if (sgn0+sgn1 == 0)
 				goto raderr;
-			if (fabs(co->ca[7] - co->ca[6]) <= FTINY)
-				goto raderr;
+			if (sgn0 < 0 || sgn1 < 0) {
+				objerror(o, o->otype==OBJ_RING?USER:WARNING,
+					"negative radii");
+				o->otype = o->otype == OBJ_CONE ?
+						OBJ_CUP : OBJ_CONE;
+			}
+			co->ca[6] = co->ca[6]*sgn0;
+			co->ca[7] = co->ca[7]*sgn1;
 			co->r0 = 6;
 			co->r1 = 7;
+			if (fabs(co->ca[7] - co->ca[6]) <= FTINY) {
+				if (o->otype == OBJ_RING)
+					goto raderr;
+				o->otype = o->otype == OBJ_CONE ?
+						OBJ_CYLINDER : OBJ_TUBE;
+				o->oargs.nfargs = 7;
+				co->r1 = 6;
+			}
 		}
 						/* get axis orientation */
 		co->p0 = 0;
@@ -104,7 +130,7 @@ int  getxf;
 			co->sl = co->al;
 		}
 		co->tm = NULL;
-		(CONE *)o->os = co;
+		o->os = (char *)co;
 	}
 	if (getxf && co->tm == NULL)
 		conexform(co);
@@ -122,6 +148,8 @@ OBJREC  *o;
 {
 	register CONE  *co = (CONE *)o->os;
 
+	if (o->os == NULL)
+		return;
 	if (co->tm != NULL)
 		free((char *)co->tm);
 	free(o->os);
@@ -133,11 +161,11 @@ conexform(co)			/* get cone transformation matrix */
 register CONE  *co;
 {
 	double  sqrt(), fabs();
-	double  m4[4][4];
+	MAT4  m4;
 	register double  d;
 	register int  i;
 
-	co->tm = (double (*)[4])malloc(sizeof(m4));
+	co->tm = (FLOAT (*)[4])malloc(sizeof(m4));
 	if (co->tm == NULL)
 		error(SYSTEM, "out of memory in conexform");