Index: cdt.h
===================================================================
--- cdt.h	(revision 18406)
+++ cdt.h	(revision 18407)
@@ -43,6 +43,7 @@
 
 #define ORIENT_CCW(a, b, c) (orientation(a, b, c) < 0)
 #define ORIENT_CW(a, b, c) (orientation(a, b, c) > 0)
+#define ORIENT(dir, a, b, c) ((dir) ? ORIENT_CW(a, b, c) : ORIENT_CCW(a, b, c))
 /* TODO: check epsilon for collinear case? */
 #define ORIENT_COLLINEAR(a, b, c) (orientation(a, b, c) == 0)
 #define ORIENT_CCW_CL(a, b, c) (orientation(a, b, c) <= 0)