--- ray/src/common/mat4.h	1990/12/15 14:18:18	1.1
+++ ray/src/common/mat4.h	1991/06/18 12:01:18	1.2
@@ -16,3 +16,10 @@ typedef double  MAT4[4][4];
 #define  copymat4(m4a,m4b)	(void)memcpy((char *)m4a,(char *)m4b,sizeof(MAT4))
 extern char  *memcpy();
 #endif
+
+#define  MAT4IDENT		{ 1.,0.,0.,0., 0.,1.,0.,0., \
+				0.,0.,1.,0., 0.,0.,0.,1. }
+
+extern MAT4  m4ident;
+
+#define  setident4(m4)		copymat4(m4, m4ident)