--- ray/src/common/xf.c	1989/03/24 17:10:43	1.3
+++ ray/src/common/xf.c	1989/10/13 19:34:51	1.6
@@ -12,22 +12,29 @@ static char SCCSid[] = "$SunId$ LBL";
 
 
 #define  PI		3.14159265358979323846
+#define  d2r(a)		((PI/180.)*(a))
 
-#define  checkarg(a,n)	if (strcmp(av[i],a) || i+n >= ac) return(i)
+#define  checkarg(a,n)	if (av[i][a] || i+n >= ac) goto done
 
 
 int
-xf(xfmat, xfsca, ac, av)		/* get transform specification */
-double  xfmat[4][4];
-double  *xfsca;
+xf(retmat, retsca, ac, av)		/* get transform specification */
+double  retmat[4][4];
+double  *retsca;
 int  ac;
 char  *av[];
 {
 	double  atof(), sin(), cos();
-	double  m4[4][4];
-	double  theta;
-	int  i;
+	double  xfmat[4][4], m4[4][4];
+	double  xfsca, theta;
+	int  i, icnt;
 
+	setident4(retmat);
+	*retsca = 1.0;
+
+	setident4(xfmat);
+	xfsca = 1.0;
+
 	for (i = 0; i < ac && av[i][0] == '-'; i++) {
 	
 		setident4(m4);
@@ -35,7 +42,7 @@ char  *av[];
 		switch (av[i][1]) {
 	
 		case 't':			/* translate */
-			checkarg("-t",3);
+			checkarg(2,3);
 			m4[3][0] = atof(av[++i]);
 			m4[3][1] = atof(av[++i]);
 			m4[3][2] = atof(av[++i]);
@@ -44,20 +51,20 @@ char  *av[];
 		case 'r':			/* rotate */
 			switch (av[i][2]) {
 			case 'x':
-				checkarg("-rx",1);
-				theta = PI/180.0 * atof(av[++i]);
+				checkarg(3,1);
+				theta = d2r(atof(av[++i]));
 				m4[1][1] = m4[2][2] = cos(theta);
 				m4[2][1] = -(m4[1][2] = sin(theta));
 				break;
 			case 'y':
-				checkarg("-ry",1);
-				theta = PI/180.0 * atof(av[++i]);
+				checkarg(3,1);
+				theta = d2r(atof(av[++i]));
 				m4[0][0] = m4[2][2] = cos(theta);
 				m4[0][2] = -(m4[2][0] = sin(theta));
 				break;
 			case 'z':
-				checkarg("-rz",1);
-				theta = PI/180.0 * atof(av[++i]);
+				checkarg(3,1);
+				theta = d2r(atof(av[++i]));
 				m4[0][0] = m4[1][1] = cos(theta);
 				m4[1][0] = -(m4[0][1] = sin(theta));
 				break;
@@ -67,8 +74,8 @@ char  *av[];
 			break;
 
 		case 's':			/* scale */
-			checkarg("-s",1);
-			*xfsca *=
+			checkarg(2,1);
+			xfsca *=
 			m4[0][0] = 
 			m4[1][1] = 
 			m4[2][2] = atof(av[++i]);
@@ -77,18 +84,18 @@ char  *av[];
 		case 'm':			/* mirror */
 			switch (av[i][2]) {
 			case 'x':
-				checkarg("-mx",0);
-				*xfsca *=
+				checkarg(3,0);
+				xfsca *=
 				m4[0][0] = -1.0;
 				break;
 			case 'y':
-				checkarg("-my",0);
-				*xfsca *=
+				checkarg(3,0);
+				xfsca *=
 				m4[1][1] = -1.0;
 				break;
 			case 'z':
-				checkarg("-mz",0);
-				*xfsca *=
+				checkarg(3,0);
+				xfsca *=
 				m4[2][2] = -1.0;
 				break;
 			default:
@@ -96,29 +103,49 @@ char  *av[];
 			}
 			break;
 
+		case 'i':			/* iterate */
+			checkarg(2,1);
+			icnt = atoi(av[++i]);
+			while (icnt-- > 0) {
+				multmat4(retmat, retmat, xfmat);
+				*retsca *= xfsca;
+			}
+			setident4(xfmat);
+			xfsca = 1.0;
+			break;
+
 		default:
 			return(i);
 
 		}
 		multmat4(xfmat, xfmat, m4);
 	}
+done:
+	multmat4(retmat, retmat, xfmat);
+	*retsca *= xfsca;
 	return(i);
 }
 
 
 #ifdef  INVXF
 int
-invxf(xfmat, xfsca, ac, av)		/* invert transform specification */
-double  xfmat[4][4];
-double  *xfsca;
+invxf(retmat, retsca, ac, av)		/* invert transform specification */
+double  retmat[4][4];
+double  *retsca;
 int  ac;
 char  *av[];
 {
 	double  atof(), sin(), cos();
-	double  m4[4][4];
-	double  theta;
-	int  i;
+	double  xfmat[4][4], m4[4][4];
+	double  xfsca, theta;
+	int  i, icnt;
 
+	setident4(retmat);
+	*retsca = 1.0;
+
+	setident4(xfmat);
+	xfsca = 1.0;
+
 	for (i = 0; i < ac && av[i][0] == '-'; i++) {
 	
 		setident4(m4);
@@ -126,7 +153,7 @@ char  *av[];
 		switch (av[i][1]) {
 	
 		case 't':			/* translate */
-			checkarg("-t",3);
+			checkarg(2,3);
 			m4[3][0] = -atof(av[++i]);
 			m4[3][1] = -atof(av[++i]);
 			m4[3][2] = -atof(av[++i]);
@@ -135,20 +162,20 @@ char  *av[];
 		case 'r':			/* rotate */
 			switch (av[i][2]) {
 			case 'x':
-				checkarg("-rx",1);
-				theta = -PI/180.0 * atof(av[++i]);
+				checkarg(3,1);
+				theta = -d2r(atof(av[++i]));
 				m4[1][1] = m4[2][2] = cos(theta);
 				m4[2][1] = -(m4[1][2] = sin(theta));
 				break;
 			case 'y':
-				checkarg("-ry",1);
-				theta = -PI/180.0 * atof(av[++i]);
+				checkarg(3,1);
+				theta = -d2r(atof(av[++i]));
 				m4[0][0] = m4[2][2] = cos(theta);
 				m4[0][2] = -(m4[2][0] = sin(theta));
 				break;
 			case 'z':
-				checkarg("-rz",1);
-				theta = -PI/180.0 * atof(av[++i]);
+				checkarg(3,1);
+				theta = -d2r(atof(av[++i]));
 				m4[0][0] = m4[1][1] = cos(theta);
 				m4[1][0] = -(m4[0][1] = sin(theta));
 				break;
@@ -158,8 +185,8 @@ char  *av[];
 			break;
 
 		case 's':			/* scale */
-			checkarg("-s",1);
-			*xfsca *=
+			checkarg(2,1);
+			xfsca *=
 			m4[0][0] = 
 			m4[1][1] = 
 			m4[2][2] = 1.0 / atof(av[++i]);
@@ -168,18 +195,18 @@ char  *av[];
 		case 'm':			/* mirror */
 			switch (av[i][2]) {
 			case 'x':
-				checkarg("-mx",0);
-				*xfsca *=
+				checkarg(3,0);
+				xfsca *=
 				m4[0][0] = -1.0;
 				break;
 			case 'y':
-				checkarg("-my",0);
-				*xfsca *=
+				checkarg(3,0);
+				xfsca *=
 				m4[1][1] = -1.0;
 				break;
 			case 'z':
-				checkarg("-mz",0);
-				*xfsca *=
+				checkarg(3,0);
+				xfsca *=
 				m4[2][2] = -1.0;
 				break;
 			default:
@@ -187,12 +214,26 @@ char  *av[];
 			}
 			break;
 
+		case 'i':			/* iterate */
+			checkarg(2,1);
+			icnt = atoi(av[++i]);
+			while (icnt-- > 0) {
+				multmat4(retmat, xfmat, retmat);
+				*retsca *= xfsca;
+			}
+			setident4(xfmat);
+			xfsca = 1.0;
+			break;
+
 		default:
 			return(i);
 
 		}
 		multmat4(xfmat, m4, xfmat);	/* left multiply */
 	}
+done:
+	multmat4(retmat, xfmat, retmat);
+	*retsca *= xfsca;
 	return(i);
 }
 #endif